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1 2 3 4 5 The Dalradian rocks of the Highland Border region 6 7 of Scotland 8 9 P.W.G. Tanner, C.W. Thomas, A.L. Harris, D. Gould, B. Harte, J.E. 10 11 Treagus and D. Stephenson 12 13 P.W. Geoff Tanner Department of Geographical and Earth Sciences, 14 University of Glasgow, Gregory Building, Lilybank Gardens, Glasgow 15 G12 8QQ. 16 Christopher W. Thomas British Geological Survey, Murchison House, 17 West Mains Road, Edinburgh EH9 3LA. 18 Anthony L. Harris Department of Earth, Planetary and Marine 19 Sciences, Cardiff University, Park Place, Cardiff CF10 3YE. 20 David Gould formerly British Geological Survey, Edinburgh. 21 Ben Harte School of GeoSciences, University of Edinburgh, West 22 Mains Road, Edinburgh EH9 3JW. 23 Jack E. Treagus 15 Raynham Avenue, Didsbury, Manchester M20 6BW; 24 formerly Department of Earth Sciences, University of Manchester. 25 * David Stephenson British Geological Survey, Murchison House, 26 27 West Mains Road, Edinburgh EH9 3LA. 28 [email protected] 29 0131 650 0323 30 31 * Corresponding author 32 33 Keywords: 34 Geological Conservation Review 35 Highland Border region 36 Dalradian Supergroup 37 Lithostratigraphy 38 Structural geology 39 Metamorphism 40 41 42 43 ABSTRACT 44 45 The Highland Border region is defined here by the outcrop of the 46 Southern Highland Group that lies north-west of the Highland 47 Boundary Fault and runs from Stonehaven south-west to the Isle of 48 Bute, and thence to the Campbeltown peninsula. The late- 49 Neoproterozoic to early-Ordovician rocks of the Dalradian 50 Supergroup in this region form a stratigraphical and structural 51 entity that encompasses the >300 km-long surface traces of both the 52 Tay Nappe (D1-D2) and the Highland Border Downbend (D4). The least 53 deformed and metamorphosed Southern Highland Group rocks occur 54 along the south-east margin of the region and are in continuity 55 with the younger, newly recognized Trossachs Group, which has 56 therefore been assigned to the Dalradian Supergroup. The earliest 57 (D1) structures in the Dalradian rocks are dominant close to the 58 Highland Boundary Fault but are successively overprinted northwards 59 by D2, D3 and D4 structures and fabrics, here represented by a 60 series of zones near-parallel to the Highland Boundary. Regional 61 62 63 64 65 1 2 3 4 metamorphism increases progressively away from the Highland 5 Boundary Fault and ranges from greenschist to upper amphibolite 6 facies (sillimanite zone). Three fundamental features of deformed 7 and regionally metamorphosed rocks worldwide were first recognized 8 in this area: the 'stretching lineation' by Clough in 1897; the 9 concept of regional metamorphic 'Barrovian zones' by Barrow in 10 1901; and the 'facing direction' of folds by Shackleton in 1958. 11 The Highland Border region has acquired international recognition 12 for research undertaken into the origin and mode of emplacement of 13 the Tay Nappe, one of the largest recumbent folds known worldwide. 14 This structure provides a framework for linking together most of 15 the GCR sites in this paper. 16 17 1 INTRODUCTION 18 19 P.W.G. Tanner and J.E. Treagus 20 21 The Highland Border region is defined here as the outcrop of the 22 Southern Highland Group that is bounded to the north-west by its 23 24 contact with the outcrop of the Argyll Group, and to the south-east 25 by an ill-defined and much disputed contact with the Cambrian to 26 Ordovician Highland Border Complex (Johnson and Harris, 1967; 27 Tanner, 1995, 1997, 1998b; Tanner and Pringle, 1997; Bluck and 28 Ingham, 1997; Harris et al., 1998; Bluck, 2000; Tanner and 29 Sutherland, 2007). Both the Southern Highland Group and the 30 Highland Border Complex outcrops are truncated to the south-east by 31 a major structural discontinuity, the Highland Boundary Fault. 32 The Dalradian rocks of this area form a single narrow outcrop, up 33 to 35 km wide and 280 km long, extending from Kintyre to Stonehaven 34 (Figure 1). They consist of a rather monotonous pile of 35 metagreywackes, over 5 km thick, with relatively thin units of 36 slaty pelite that were once quarried for roofing slate at a number 37 of localities such as Arran, Aberfoyle and Dunkeld. Volcaniclastic 38 beds, commonly known as ‗green beds‘, occur in the lower part of 39 the sequence. Despite the uncertainty about its upper boundary, 40 the Southern Highland Group in this outcrop forms a discrete unit 41 42 in terms of its depositional history, structure, and regional 43 metamorphism. It consists of a series of deep-sea fan turbidites 44 that pass upwards into a passive-margin sequence, the sedimentary 45 edifice being contained within a single major fold structure, the 46 Tay Nappe. 47 The Tay Nappe is a large, early fold that was flat-lying, or 48 recumbent, following the D2 deformation and was then folded by the 49 Highland Border Downbend (F4) along a line close to, and parallel 50 with, the south-eastern limit of the Highland Border region (Figure 51 1). The lower, inverted limb of this fold occupies most of the 52 Highland Border region and the main hinge-zone crops out between 53 Arran and Callander. Farther to the north-east, beyond Dunkeld, it 54 is either truncated by the Highland Boundary Fault or buried 55 beneath an unconformable cover of Siluro-Devonian sedimentary and 56 volcanic rocks of the Old Red Sandstone Supergroup and hence is not 57 exposed. 58 Most of the Dalradian rocks are affected by up to four 59 60 superimposed phases of deformation (D1–D4), the first three of 61 62 63 64 65 1 2 3 4 which are attributed to the mid-Ordovician Grampian Event of the 5 Caledonian Orogeny and the last possibly to the mid-Silurian 6 Scandian Event. The Grampian deformation was accompanied by 7 regional metamorphism that reached a peak in the upper amphibolite 8 facies (sillimanite zone). Migmatites, arising from partial 9 melting, occur in the highest grade rocks, and the regional 10 metamorphic minerals include chlorite, biotite, garnet, chloritoid, 11 12 staurolite, kyanite, and sillimanite (see the Glen Esk GCR report). 13 The regional metamorphism reached its peak some 470 Ma ago, at 14 around D2–D3, and it is thought that the growth of the mineral 15 assemblages in each zone occurred during a relatively brief period 16 of 10–15 Ma (Oliver et al., 2000; Baxter et al., 2002). 17 A further compelling reason for considering this outcrop of the 18 Southern Highland Group as a separate region is that it displays a 19 structural unity throughout its length. This is defined in plan 20 view by: the NE-trending axial traces of the Tay Nappe (D1 and D2) 21 and the Highland Border Downbend (D4) (Figure 1); the line marking 22 the onset in a north-westerly direction of intense D2 reworking of 23 bedding and the S1 fabric; and, less exactly, the traces of the 24 biotite and garnet isograds. 25 This intensively studied region is now achieving international 26 status as a model for short-lived orogenesis (less than 10 Ma) in 27 which the unusually rapid rise in temperature of the deforming rock 28 mass probably resulted from advective heat introduced via 29 30 circulating fluids from contemporaneous intrusions (Atherton and 31 Ghani, 2002; Dewey, 2005). This was aided by the loading and 32 blanketing effects of an ophiolite nappe, which was emplaced over 33 the Dalradian sedimentary rocks early in the Grampian Event 34 (Tanner, 2007; Chew, et al., 2010; Cutts, et al., 2011). Although 35 some of the first radiometric ages from these rocks, especially K- 36 Ar ages on slaty pelites and on white micas, gave ages of over 500 37 Ma, these are now considered to be unreliable, and there is no 38 tangible evidence that a late-Neoproterozoic orogeny affected the 39 Dalradian prior to the Grampian Event (cf. Hutton and Alsop, 2004, 40 2005; and see Tanner, 2005). 41 Examples of seminal studies carried out in the Highland Border 42 region that have gained international recognition as being unique 43 in their field include: 44 (i) first use of minor structures in structural interpretation, 45 and the recognition of polyphase deformation (Cowal peninsula; 46 Clough, in Gunn et al., 1897) (Figure 5). This approach is 47 48 exemplified by the three GCR sites in the south-west (Ardscalpsie 49 Point, Cove Bay to Kilcreggan and Portincaple), and especially by 50 the three GCR sites around Dunkeld (Little Glen Shee, Craig a’Barns 51 and Rotmell) that have been grouped together with this purpose in 52 mind. 53 (ii) formulation of the concept of zones of metamorphic grade, and 54 the recognition of the Barrovian and Buchan types of metamorphism 55 (Barrow, 1912). The geology of the area in which this work was 56 carried out is described in the Glen Esk GCR site report, which 57 includes illustrations of the key Barrovian mineral assemblages. 58 (iii) introduction of the concept of structural facing in 59 polyphase terrains to facilitate understanding of the structural 60 evolution of an area, and to demonstrate the existence of a major 61 62 63 64 65 1 2 3 4 fold, the Tay Nappe (Shackleton, 1958). This theme is central to 5 many of the GCR site reports in this paper and Shackleton‘s work 6 features particularly strongly in the Duke’s Pass GCR site report 7 and in the reports of the three GCR sites around Dunkeld. 8 The Trossachs area, which includes the Bealach nam Bo and Duke’s 9 Pass GCR sites, is now part of the first National Park to be 10 established in Scotland. In the 19th Century it attracted many 11 12 famous painters, including Constable, Millais and Turner, and the 13 poet Wordsworth. But it is John Ruskin, founder member of the Pre- 14 Raphaelite movement, who has left us the legacy of the beautiful 15 drawing reproduced in Figure 3. Ruskin was inspired by the form of 16 natural objects and strove to reproduce their every detail; his aim 17 was to encourage his contemporaries to replace pastoral scenes with 18 paintings that depicted ‗rocks drawn with such accuracy that the 19 geologist‘s diagram was no longer necessary‘ (Greive, 1996). 20 In this paper, the GCR site reports are arranged as far as is 21 possible in geographical sequence from south-west to north-east 22 and, with the exception of the Glen Esk GCR site report on regional 23 metamorphism, all of them deal specifically with the stratigraphy 24 and structure of the Southern Highland Group. There are no GCR 25 sites on the Campbeltown peninsula or on the Isle of Arran, a total 26 area of some 30 km2, reflecting a lack of detailed studies of the 27 Dalradian rocks in that area. 28 29 30 1.1 Stratigraphy 31 32 The Southern Highland Group in the Highland Border region consists 33 of a thick sequence of turbidite-facies rocks (now metagreywackes) 34 with interdigitations of slaty pelite, and uncommon chlorite- 35 epidote-rich beds known as ‘green beds’, whose detrital 36 volcaniclastic origin is discussed in detail in the Bealach nam Bo 37 GCR site report (see also Pickett et al., 2006). Major lateral 38 facies changes occur at all levels within a sequence that, apart 39 from the green beds, generally lacks lithostratigraphical marker 40 horizons. Fault-controlled compartments have given rise to local 41 successions that are now seen at different depths of erosion due to 42 kilometre-scale displacements on major faults such as the Loch Tay 43 Fault (Figure 2). 44 The base of the Southern Highland Group is taken at the top of the 45 Loch Tay Limestone Formation throughout most of the Highland Border 46 region, although to the north-east of the Glen Doll Fault it is 47 48 taken above locally abundant calcsilicate beds in the dominantly 49 psammitic Tarfside Psammite Formation (Gibbons and Harris, 1994; 50 Stephenson and Gould, 1995). 51 The top of the Southern Highland Group (Figure 2) has defied 52 definition since the late 19th century and is still the subject of 53 controversy (see the Keltie Water GCR site report; Bluck and 54 Ingham, 1997; Tanner, 1997 for discussion). This is because, 55 despite the sharp contrast between the ubiquitous slaty 56 metamudstones and metagreywackes of the Southern Highland Group and 57 the great variety of rock types, such as serpentinite, black 58 graphitic mudstones and fossiliferous limestones, found in the 59 Highland Border Complex, the boundary between the two units is 60 difficult to define. Clough (in Gunn et al., 1897) concluded that 61 62 63 64 65 1 2 3 4 at Callander (Keltie Water GCR site) there is a passage or 5 transition between the two sequences, and Cunningham Craig (1904) 6 reported that there is a metamorphic transition in the Loch Lomond 7 area between a ‗slate-grit series‘ and ‗schists‘ to the north. 8 The problem facing the early surveyors was two fold: which is the 9 younger set of rocks; and where do the ‗Highland Schists‘ end and 10 the Highland Border rocks begin? Amongst the early workers there 11 12 were two schools of thought: (1) those like Macnair (1908) who, 13 because the bedding or foliation in both sets of rocks throughout 14 most of the zone dips steeply to the north-west, considered that 15 the rocks in the south (now named the ‗Highland Border Complex‘) 16 are older than the ‗Highland Schists‘ (now Dalradian) to the north; 17 and (2) those like Peach (1930) who, persuaded by lithological 18 similarities between the Highland Border Complex rocks and the 19 Arenig-age mudstones in the Southern Uplands of Scotland, 20 considered that they are the younger unit. 21 This latter interpretation was confirmed by the discovery of 22 poorly preserved Ordovician fossils in the Highland Border Complex, 23 for example in the Aberfoyle Forest (Jehu and Campbell, 1917), 24 followed by the finding of definitive fossil assemblages of Early 25 Cambrian age at Leny Quarry (Pringle, 1940), and of mid-Arenig age 26 at Lime Craig Quarry (Curry et al., 1984) (see the British Cambrian 27 to Ordovician Stratigraphy GCR volume; Rushton et al., 1999). This 28 shifted the focus of the argument to deciding whether or not the 29 30 two units are in stratigraphical sequence, or whether they are 31 separated by a tectonic break. Resolution of the main problem, 32 that of defining the top of the Dalradian succession, was not 33 furthered by Gregory (1931) who proposed that the ‗Dalradian‘ rocks 34 should be divided into five separate units, with the most southerly 35 of these, the ‗Lennoxian‘, being unconformable on the 'Dalradian' 36 and containing clasts derived from it. No evidence has been 37 published by later workers to support that interpretation. 38 In the decade that followed the publication by Curry et al. 39 (1984), it became generally accepted that the Highland Border 40 Complex is an ‗exotic terrane‘ that docked with the Grampian 41 Terrane in Silurian to Devonian times. This hypothesis was 42 challenged by Tanner (1995), who confirmed the conclusions of 43 Johnson and Harris (1967) and considered that much of the Highland 44 Border Complex is in stratigraphical and structural continuity with 45 the accepted Dalradian sequence. Tanner and Sutherland (2007) then 46 proposed that all of the Highland Border Complex that crops out 47 48 north-west of the Highland Border Ophiolite should be included in 49 the Dalradian Supergroup and assigned to a new Trossachs Group, 50 which ranges in age up to topmost Tremadocian. Although the 51 tendency in recent years has been to include an increasing 52 proportion of the Highland Border Complex in the Dalradian 53 succession (e.g. BGS 1:50 000 Sheet 38E, Aberfoyle, 2004; Henderson 54 et al., 2010), this topic is still being debated (Bluck, 2010; 55 Tanner and Bluck, 2011). For the purpose of this special issue, 56 the top of the Dalradian succession is taken to be at the south- 57 eastern limit of the Keltie Water Grit Formation (see the Keltie 58 Water GCR site report). 59 The Dalradian outcrop is terminated locally at its south-eastern 60 margin by a faulted or unconformable contact with Silurian, Lower 61 62 63 64 65 1 2 3 4 Devonian, Upper Devonian, or Lower Carboniferous rocks in the 5 Highland Border region, as seen at the Ardscalpsie Point, Cove Bay 6 to Kilcreggan, and Duke’s Pass GCR sites. 7 Having defined the top and base of the Southern Highland Group, 8 the stratigraphical sequence is now described with reference to the 9 NW–SE-trending serial cross-sections shown in Figure 4. The Loch 10 Tay Limestone, which marks the top of the Argyll Group, occurs in 11 12 the hinge-zones of the early folds and, together with the Green 13 Beds, provides a marker horizon for correlating between the 14 sections. It clearly shows that, although there is stratigraphical 15 and structural continuity along the whole belt, a marked difference 16 in structural level occurs across the Loch Tay Fault. This fault 17 has a significant downthrow to the east, and rocks now exposed at 18 the surface west of the fault (Figure 4, sections AA‘ to CC‘) 19 represent a deeper structural level than those to the east. 20 21 1.1.1 West of the Loch Tay Fault 22 23 The oldest exposed rocks of the Southern Highland Group occur both 24 along the north-west margin of the Highland Border region, and 25 close to its south-east margin, within the closure of the downward- 26 facing F1 Aberfoyle Anticline, in the hinge-zone of the Tay Nappe. 27 These slaty pelitic rocks appear to pass laterally into 28 impersistent volcaniclastic metasedimentary rocks that occur in 29 30 various places near the base of the Southern Highland Group (Figure 31 4, sections AA’ and CC’) and have been correlated with the Loch Avich 32 lavas at the Loch Avich GCR site (Treagus et al., 2013). They are 33 generally referred to semiformally as the Green Beds (e.g. at the 34 Barmore Island and Cove Bay to Kilcreggan GCR sites) (Figure 2), 35 but at the Duke’s Pass GCR site, where they are particularly well 36 developed, they define the Loch Katrine Volcaniclastic Formation. 37 The latter is overlain by the Craig Innich Sandstone Formation, a 38 local, laterally discontinuous formation containing beds of 39 microconglomerate up to two metres thick. 40 The ‗slate‘ formations are represented in the south-east by the 41 Aberfoyle Slate Formation, which is seen in its type area at the 42 Duke’s Pass GCR site as black, dark grey, purple, and olive-green 43 slaty metamudstones that are commonly slightly calcareous. These 44 metamudstones appear to be laterally continuous within the Highland 45 Border region but south-west of Aberfoyle there are several such 46 outcrops and their exact correlation with the metamudstones at Luss 47 48 on the west side of Loch Lomond is not secure. However, the ‗Luss 49 Slates‘ may be traced along strike across several sea lochs to 50 equate with metamudstones in the Dunoon Phyllite Formation at the 51 Cove Bay to Kilcreggan GCR site and on Bute. As the hinge of the 52 Aberfoyle Anticline is contained within the metamudstone outcrop, 53 the rocks on either side of it should young away from the 54 metamudstones, and be stratigraphically equivalent, if not 55 lithologically identical. 56 The rocks to the north-west of the Aberfoyle Slate/Dunoon Phyllite 57 outcrop have much the same character for over 15 km across strike, 58 as characterized by the Beinn Bheula Schist Formation seen at the 59 Portincaple GCR site. South-east of the metamudstone unit, on the 60 upper limb of the Tay Nappe, (Figure 2b) the right-way-up St Ninian 61 62 63 64 65 1 2 3 4 Formation in the south-west (i.e. at the Ardscalpsie Point and Cove 5 Bay to Kilcreggan GCR sites) consists largely of pebbly 6 metagreywackes in beds up to 3 m thick that commonly show graded 7 bedding. The more-extensive lower part of the St Ninian Formation 8 is the Bullrock Greywacke Member but locally the upper part of the 9 succession contains units of black slaty metamudstone and thin beds 10 of metacarbonate rock and has been referred to by some as the 11 12 Innellan ‗group‘ (e.g. Roberts, 1966a). On the current BGS 1:50 13 000 Sheet 29E (Dunoon and Millport, 2008) most of the former 14 Innellan ‗Group‘ is termed the Toward Quay Grit Member of the St 15 Ninian Formation but on the Isle of Bute the highest beds are 16 termed the Ardscalpsie Formation and are assigned to the Trossachs 17 Group. 18 The predicted correlation of the Bullrock Greywacke with the Beinn 19 Bheula Schist Formation, around the closure of the Aberfoyle 20 Anticline, is problematical (as discussed in the Cove Bay to 21 Kilcreggan GCR site report), for the pebbly and gritty 22 metasandstones of the former contrast with the thinly bedded, 23 chlorite-rich Beinn Bheula metagreywackes. Apart from the facies 24 change, the problem is compounded by the fact that the rocks on the 25 north-west limb are schistose and strongly deformed and rarely 26 preserve way-up structures. In order to clarify this difference, 27 the stratigraphical columns in Figure 2 show the lateral 28 correlations separately for the north and south limbs of the 29 30 Aberfoyle Anticline. 31 32 1.1.2 East of the Loch Tay Fault 33 34 Along the north-western edge of the Southern Highland Group 35 outcrop, the Loch Tay Limestone is succeeded by the Pitlochry 36 Schist Formation, which includes green beds at several 37 stratigraphical levels (e.g. Treagus, 2000). 38 On the south-east limb of the Aberfoyle Anticline, the Bullrock 39 Greywacke Member of the St Ninian Formnation passes north-east 40 along strike into the Ben Ledi Grit Formation, as seen at the 41 Duke’s Pass GCR site (Figure 2). The Keltie Water GCR site is 42 particularly important as the section demonstrates both structural 43 and stratigraphical continuity between strata of the Ben Ledi Grit 44 Formation that are indisputably in the upper part of the Southern 45 Highland Group and strata of the Keltie Water Grit Formation that 46 include the fossiliferous Leny Limestone. Hence, not only did 47 48 Dalradian sedimentation extend into the Early Cambrian, but its 49 principal phases of deformation must all have occurred in post- 50 Early Cambrian time, two crucial age relationships that until 51 recently had been widely disputed. 52 Farther north-east, the exact stratigraphical affinity of the 53 Birnam Slate, the Birnam Grit and the younger Dunkeld Grit 54 Formation, described in the Little Glen Shee and Craig a’ Barns GCR 55 site reports, is uncertain. They were at one time correlated with 56 the Aberfoyle Slates and the Ben Ledi Grits, but more-recent 57 mapping has shown that they occur at a higher level in the Southern 58 Highland Group succession (Figure 4, section DD‘). The 59 stratigraphical status of the psammites and semipelites at the 60 61 62 63 64 65 1 2 3 4 Rotmell GCR site is also not clear, but they could be a lateral 5 equivalent of the Pitlochry Schist Formation. 6 North-east from the Dunkeld area, the general stratigraphical 7 relationship of a lower, more-pelitic metagreywacke sequence 8 passing south-eastwards into an upper, more-psammitic metagreywacke 9 sequence persists to the coast north of Stonehaven (Anderson, 10 1942). The more-pelitic facies forms an outcrop continuous with 11 12 the Pitlochry Schist and contains similar lithologies, dominated by 13 garnet-mica schists but passing into slates or sillimanite gneisses 14 depending upon metamorphic grade. In the Glen Clova area this 15 basal unit has been termed the Longshank Gneiss Formation. This 16 unit shows a marked facies change from dominantly pelitic in the 17 south-west to dominantly psammitic in the north-east and is 18 characterized by strongly magnetic beds throughout (Chinner, 1960). 19 The younger, graded metagreywackes and schistose psammites of the 20 Rottal Schist Formation are continuous with the Ben Ledi Grit to 21 the south-west. Green beds are abundant between Kirkmichael and 22 Glen Clova but are notably absent north-east from Glen Clova. 23 An extensive right-way-up sequence that crops out around the Glen 24 Esk GCR site was assigned by Harte (1979) to a separate Tarfside 25 Nappe (see below). The sequence consists of an intimate 26 metagreywacke association of pelites, semipelites and psammites 27 typical of the Southern Highland Group. A lower unit, the Glen 28 Effock Schist Formation, passes upwards into the Glen Lethnot Grit 29 30 Formation, characterized by beds of pebbly psammite, and hence a 31 broad correlation is suggested with the Pitlochry Schists and Ben 32 Ledi Grit of the Tay Nappe. The outcrop of the Glen Lethnot Grit 33 can be traced to the coast around the Garron Point to Muchalls GCR 34 site, where the sequence is once again upside down, as in the Tay 35 Nappe. 36 37 1.2 Structure 38 39 Aspects of particular structural interest in the Highland Border 40 region are the geometry and mode of formation of two of the largest 41 folds in the British Isles, the Tay Nappe and the Highland Border 42 Downbend, and the intriguing geometrical relationship between the 43 D1 and D2 structures as expressed in the splendid development of 44 superimposed, spaced cleavages in the metasandstones. The latter 45 are matched only in the UK by those at Trearddur Bay, Holy Island, 46 Isle of Anglesey. The huge monoclinal downbend divides the region 47 48 into the Flat Belt to the north-west and the Highland Border Steep 49 Belt to the south-east (Figures 1 and 4). It folds the originally 50 recumbent or flat-lying Tay Nappe and brings the fold closure down 51 to ground level just north of the Highland Boundary Fault, so 52 exposing at the surface part of the upper limb of the nappe (Figure 53 4). 54 Over almost the whole outcrop of the Flat Belt, the level of 55 erosion lies in the lower, inverted limb of the Tay Nappe. 56 However, in a wide area around the Glen Esk GCR site a broad late 57 antiform, known as the Tarfside Culmination, exposes a sequence of 58 non-inverted strata, which Harte (1979) assigned to a separate 59 Tarfside Nappe and interpreted as a major recumbent structure below 60 the Tay Nappe. According to Harte the axial zone of the fold 61 62 63 64 65 1 2 3 4 separating the two nappes has been replaced by a slide, the Glen 5 Mark Slide. However, the structural relationships are not clear 6 and the distribution of units could also be explained in other 7 ways, for example by invoking later large-scale tight folding of 8 the Tay Nappe on gently dipping axial planes. Farther to the 9 north-east (around the Garron Point to Muchalls GCR site), the 10 structural relationships revert to those seen in the Tay Nappe to 11 12 the south-west. The flat-lying sequence is inverted and, south- 13 east of a marked downbend, it passes into a steep zone with 14 downward-facing D1 structures (Booth, 1984; Harte et. al., 1987) 15 (Figure 33). The relationships of these major structures to the 16 Tarfside Nappe, or indeed to the main Tay Nappe, are not clear. 17 18 1.2.1 The Highland Border Downbend 19 20 The regional significance of the Highland Border Downbend was 21 recognized by Clough (in Gunn et al., 1897) who noted that it folds 22 an earlier foliation and stretching lineation, and is associated 23 with a crenulation (strain-slip) cleavage. On the Cowal peninsula, 24 it is an open structure with the south-eastern limb dipping south- 25 east at less than 30o. As it is traced north-east, this limb 26 becomes vertical between Loch Lomond and Aberfoyle (Figure 4, 27 sections BB’ and CC’), and NW-dipping farther towards the north-east 28 (sections EE’ to GG’). Thus, the beds on the south-eastern side of 29 30 the Tay Nappe axial plane are right-way-up in Cowal and become 31 inverted to the north-east. This relationship has a direct bearing 32 upon the earlier debate as to whether the ‘Highland Schists’ are 33 older or younger than the Highland Border Complex, and it is a 34 sobering thought that one of the earliest workers in the field made 35 the most prescient observation of all: Nicol (1863) stated that 36 the rocks in question on Bute dip south and are right-way-up, and 37 in the Aberfoyle area dip north, and are inverted. North-east of 38 Birnam, the Highland Border Downbend approaches close to the line 39 of the Highland Boundary Fault and/or the margin of the 40 unconformable Lower Devonian sequence, and its south-eastern limb 41 is reduced to a width of less than 2 km (Figure 1). 42 The Portincaple, Craig a’Barns, and Garron Point to Muchalls GCR 43 sites each show different features of this structure. At 44 Portincaple, minor F3 folds on all scales up to several metres in 45 wavelength are clearly folded around the hinge zone of the major 46 downbend structure, and are cut by a sporadically developed, 47 48 steeply dipping, S4 crenulation cleavage (Figure_12). It is 49 significant that evidence for the presence of all four deformation 50 phases can be seen on a single rock face at this locality, leaving 51 no doubt as to the nature of each and of the relationship between 52 them. At the Craig a’Barns and Garron Point to Muchalls GCR sites, 53 the D3 deformation is absent and step-like minor F4 folds related 54 to the downbend hinge deform the familiar spaced S2 microlithons. 55 At the Craig a’Barns GCR site, the Highland Border Downbend gives 56 rise to the Steep Belt of downward-facing F1 folds seen in the 57 Little Glen Shee GCR site. Elsewhere, uncommon minor F4 warps, up 58 to a few metres across, are seen as far south of the downbend as 59 the Cove Bay to Kilcreggan and Ardscalpsie Point GCR sites. 60 61 62 63 64 65 1 2 3 4 1.2.2 The Tay Nappe hinge-zone 5 6 The hinge-zone of the Tay Nappe consists of the Aberfoyle Anticline 7 and a variable number of satellite folds. The hinge was first 8 described as a normal, upward-facing anticline closing to the 9 south-east (Henderson, 1938; Anderson, 1947a). However, although 10 these authors had used sedimentary way-up structures to identify 11 12 the structure as an anticline, they had incorrectly interpreted it 13 as closing upwards, a mistake easily made where the major fold is 14 tight to isoclinal. Another approach was needed, and it was 15 Shackleton (1958) who, using the concept of facing direction (as 16 applied to fold structures and cleavages, see Stephenson et al., 17 2013a) that he had developed in the course of his work in the 18 Highland Border region, demonstrated that the Aberfoyle Anticline 19 is a downward-facing, or synformal, anticline. He correctly 20 deduced that a large part of the South-west Grampian Highlands 21 consists of rocks that are upside down because they belong to the 22 lower limb of an originally recumbent, south-facing nappe-like 23 structure, named the Tay Nappe. 24 The closure of the Tay Nappe has been traced, as a single fold 25 from the Isle of Bute to Luss on the west side of Loch Lomond 26 (Roberts, 1967) (Figures 1 and 4, sections AA‘ and BB‘). It passes 27 through the Cove Bay to Kilcreggan GCR site where it is located 28 within the outcrop of the Dunoon Phyllites but unfortunately it is 29 30 not exposed on the coast due to faulting. East of Loch Lomond, the 31 fold closure becomes more complex and can be resolved into three, 32 well-defined major folds, the Ben Vane Anticline, the Ben Ledi 33 Syncline and the Aberfoyle Anticline (Mendum and Fettes, 1985) 34 (Figures 4 and 13). The Keltie Water GCR site lies on the now- 35 inverted upper limb of this tripartite structure. Farther to the 36 north-east, the Duke’s Pass, Craig a’Barns, and Little Glen Shee 37 sites all lie to the north-west of the predicted position of the 38 Tay Nappe closure, which in these localities is either faulted-out 39 or buried beneath an unconformable cover of Lower Old Red Sandstone 40 sedimentary rocks (Figure 1). Although downward-facing structures 41 inferred to be on the north-western side of the Tay Nappe hinge 42 zone can be traced to the east coast at the Garron Point to 43 Muchalls GCR site, the main hinge is not seen north-east of Little 44 Glen Shee. 45 46 47 1.2.3 Sequential development of the structural 48 fabrics, and their interpretation 49 50 The structural development of this region is most clearly 51 understood by considering the sequential development of minor 52 structures such as cleavages along a traverse from the higher 53 structural levels of the Tay Nappe (now seen adjacent to the 54 Highland Boundary Fault) to the deeper levels (as seen at the 55 Highland Border Downbend). 56 In a zone up to 10 km wide adjoining, and parallel with, the 57 Highland Boundary Fault, the Dalradian rocks are least deformed, 58 preserve abundant sedimentary structures, and carry only a single 59 (S1) cleavage. Farther to the north-west they are affected 60 progressively by three further, superimposed, phases of deformation 61 62 63 64 65 1 2 3 4 (D2, D3 and D4), accompanied by regional metamorphism that reached 5 a peak in the upper amphibolite facies (sillimanite zone) around 6 D2–D3. 7 The upper, right-way-up limb of the Tay Nappe is excellently 8 exposed at the Ardscalpsie Point GCR site where a single, 9 centimetre-spaced, anastomosing S1 pressure-solution cleavage cuts 10 across the bedding at a low angle and is unaffected by later 11 12 deformation (Figure 7). The S1 cleavage is seen to form extreme 13 cleavage fans in gritty metasandstones at the Little Glen Shee GCR 14 site, where the full geometry of the D1 phase may be examined 15 (Figure 19). Sedimentary and tectonic structures that proxy for 16 those anticipated in the very hinge of the nappe may be readily 17 seen at Camsail Bay, a few kilometres from the Cove Bay to 18 Kilcreggan GCR site (see Tanner, 1992). 19 The S2 fabric and associated minor structures is first seen a few 20 kilometres north-west of the Highland Boundary Fault and within a 21 short distance becomes the dominant structure. It forms a set of 22 penetrative pressure-solution-controlled microlithons. The S1 23 spaced cleavage was reworked during D2 and is commonly preserved 24 within the new microlithons as sigmoidally curved traces with a 25 distinctive appearance, unique in the structural history of the 26 Dalradian rocks. An example is shown in the Cove Bay to Kilcreggan 27 GCR site report (Figure 10). Minor structures of this type can be 28 recognized far to the north within the Flat Belt and are used as 29 30 event markers (see the Portincaple GCR site report, Figure 12). 31 They were recognized in the Cowal peninsula by Clough (in Gunn et 32 al., 1897), who called them ‗strain bands‘ (Figure 5). This zone 33 of intense D2 deformation can be recognized across the full width 34 of the region (Figure 1) and the morphology of the structures has 35 been described in detail from Birnam by Harris et al. (1976) and 36 from Stonehaven in the Garron Point to Muchalls GCR site report, in 37 this paper. 38 A contentious issue is the interpretation of the shear sense given 39 by the deformed early (S1) cleavage stripes within the S2 40 microlithons. A majority of authors favour top-to-the-SE shear 41 displacement, with others equally convinced that top-to-the-NW 42 displacement has taken place. In this paper, the Rotmell GCR site 43 report describes the typical F2 fold style in this part of the Flat 44 Belt, and its evolution by SE-directed simple shear, whereas the 45 author of the Bealach nam Bo and Duke’s Pass GCR site reports 46 favours the alternative interpretation. 47 48 These views have led to fundamentally different interpretations of 49 the tectonic regime responsible for the emplacement of the Tay 50 Nappe and related structures. The emplacement is generally 51 considered to have been coeval with the formation of the first 52 folds, although some workers have questioned this. Mendum and 53 Fettes (1985) and Mendum and Thomas (1997) considered that F1 folds 54 must have been recumbent and hence that the Tay Nappe was emplaced 55 during D1, with subsequent NW-directed simple-shear during D2. 56 However, Harris et al. (1976) and Harris and Bradbury (1977) 57 considered that the F1 folds were initially upright and were 58 subsequently modified by SE-directed, mainly simple-shear within a 59 continuous phase of deformation involving both D1 and D2. Their 60 model was modified by Krabbendam et al. (1997) who proposed that 61 62 63 64 65 1 2 3 4 only the lower levels of upright F1 folds were affected by a 5 crustal-scale shear-zone during D2, to produce SE-facing folds with 6 dominant inverted limbs that constitute the Flat Belt; the upper 7 levels of the F1 folds, unaffected by D2 shearing, were 8 subsequently brought down by the Highland Border Downbend to 9 produce the downward-facing Steep Belt. 10 During D3, the rocks were affected locally, for example around 11 12 Loch Lomond and at the Portincaple GCR site (but not at the Craig 13 a’Barns GCR site farther to the north-east), by minor folding and 14 very restricted cleavage development, but no new major folds were 15 formed. 16 The final event, during D4, was the bending down of the closure of 17 the Tay Nappe close to, and parallel with, the Highland Boundary 18 Fault by the Highland Border Downbend. This brought the hinge-zone 19 and a small part of the upper limb of the Tay Nappe structure down 20 to the present erosion level. The formation of D4 structures is 21 considered by some to be related to and also to post-date a phase 22 of crustal extension during uplift. The initial monoformal form of 23 the Highland Border Downbend is considered to be due to the draping 24 of Dalradian strata over a basement step (Harte et al., 1984). 25 Subsequent compression resulted in tightening of the downbend, 26 which became a focus for smaller-scale F4 folds. 27 28 29 1.3 Regional Metamorphism 30 31 Work in Glen Esk led Barrow (1912) to develop the concept of zones 32 of metamorphic grade, and to recognize two main types of 33 metamorphism in the Grampian Highlands, Barrovian and Buchan (see 34 Stephenson et al., 2013a). Modern studies in the Highland Border 35 region have shown that there, the regional metamorphism reached a 36 peak during the interval D2–D3, resulting in a series of Barrovian 37 zones characterized by the index minerals chlorite, biotite, 38 garnet, staurolite, kyanite and sillimanite (see the Glen Esk GCR 39 site report). The isograds are widely spaced in the west and 40 become very closely spaced towards the north-east (Stephenson et 41 al., 2013a, fig. 12). The lowest grade rocks are at greenschist 42 facies and retain detrital white mica and biotite, whereas the 43 highest grade rocks develop sillimanite and are associated with the 44 formation of migmatite by partial melting. All of the GCR sites in 45 the south-west of the region are in greenschist-facies rocks. 46 Garnet, wrapped by the S2 fabric, is prominent in the schists of 47 48 the Flat Belt at the Rotmell GCR site and is visible as pinhead- 49 size crystals, with biotite, in the phyllites at the Craig a’ Barns 50 GCR site. The green beds of the Bealach nam Bo GCR site, within 51 the Steep Belt of the Highland Border Downbend, are rich in 52 chlorite and epidote that are associated with the S2 cleavage. 53 Elsewhere along the Steep Belt the pelites are characteristically 54 chlorite-white mica-bearing slates with an S1 cleavage, as seen in 55 the Keltie Water, Duke’s Pass and Little Glen Shee GCR sites. 56 The close spacing of the regional metamorphic isograds in the 57 north-east has been a cause for some speculation in the past but 58 recent work suggests that advective heating by fluids from 59 contemporaneous intrusions is the probable culprit, assisted by 60 ductile shearing during D2 (Phillips and Auton, 1997). It has been 61 62 63 64 65 1 2 3 4 demonstrated that peak metamorphic temperatures reached throughout 5 these zones were synchronous to within 2 million years (Baxter et 6 al., 2002), the implication being that the deformation process was 7 also rapid. 8 9 2 ARDSCALPSIE POINT 10 11 (NS 043 580–NS 045 576) 12 13 P.W.G. Tanner 14 15 16 2.1 Introduction 17 18 The Ardscalpsie Point GCR site is situated on the west coast of the 19 Isle of Bute, just to the north of Scalpsie Bay. It consists of a 20 narrow rock platform backed by a steep rock face that forms an 21 almost straight, 400 m-long, section north-west of Ardscalpsie 22 Point (Figure 6). The immediate hinterland, which consists of a 23 raised beach backed by an ancient sea cliff, also provides some 24 excellent exposures. 25 The metasedimentary rocks exposed in this section are some of the 26 youngest in the Southern Highland Group. They were formerly 27 assigned to the Bullrock Greywacke (sensu Clough, in Gunn et al., 28 1897) and have also been referred to as the ‗Lower Leny Grits‘ 29 30 (Anderson, 1947a) and the Innellan ‗Group‘. They are now assigned 31 to the Toward Quay Grit Member of the St Ninian Formation, which 32 overlies the Bullrock Greywacke Member stratigraphically (i.e. on 33 the BGS 1:50 000 Sheet 29E, Dunoon and Millport, 2008). Immediately 34 east of the GCR site, the Toward Quay Grit Member is overlain by 35 the Ardscalpsie Formation, which is assigned to the Trossachs 36 Group. The GCR site lies well south of the outcrop of the Dunoon 37 Phyllite Formation, which contains the closure of the Tay Nappe 38 (see the Cove Bay to Kilcreggan site report), and has a splay of 39 the Highland Boundary Fault as its southern limit. 40 This GCR site is of national importance as it provides a unique 41 opportunity to examine a virtually continuous, and clean, coastal 42 section across part of the top limb of the Tay Nappe. The closure 43 of the Tay Nappe can be traced across Scotland but the upper limb 44 of the structure is seldom well exposed. It is seen, for example, 45 to the north-east of this site between Toward and Dunan on the 46 Dunoon peninsula (where it is named the Aberfoyle Anticline: 47 48 Roberts, 1974) and at the Cove Bay–to Kilcreggan GCR site, but is 49 not as readily studied as at Ardscalpsie Point. Here, the inland 50 exposures, deeply etched by weathering due to their slightly 51 calcareous nature, complement those on the coast and reveal in 52 detail the relationship between the spaced S1 cleavage and the 53 bedding (Figure 7). The contact between the uppermost Dalradian 54 and the much younger, Devonian to Lower Carboniferous strata, 55 seldom seen in the 250 km between Arran and Stonehaven, is well 56 exposed at the south-east end of the rock platform. 57 Surprisingly, considering the pioneering work carried out in the 58 neighbouring Cowal peninsula, no details of the Dalradian rocks 59 were given in the Geological Survey memoir covering this part of 60 Bute (Gunn et al. 1903). It was left to McCallien (1938) to 61 62 63 64 65 1 2 3 4 provide the first general account of the Dalradian of Bute. 5 Anderson (1947a) published a more-detailed account and map of 6 Scalpsie Bay, and concluded, from the dip of the beds combined with 7 way-up evidence, that the Dunoon Phyllites farther north on Bute 8 lie in the core of a ‗normal‘ (i.e. upward-facing) anticline. 9 Conversely, Shackleton (1958) suggested that the Tay Nappe 10 structure is probably a downward-facing anticline, based on an 11 12 admittedly small number of observations of the geometrical 13 relationship of bedding to cleavage, combined with way-up evidence. 14 The only detailed, modern study of this section was by Simpson and 15 Wedden (1974) who confirmed Shackleton‘s interpretation, and 16 recorded the three-dimensional relationship of the L1 stretching 17 lineation to the local fold hinges in these rocks. 18 19 2.2 Description 20 21 The coastal section trends at about 60° to the general strike of the 22 beds, and is excellent for cross-section construction (Figure 8). 23 The only drawback is that, despite almost continuous rock exposure 24 above the high-tide mark, many of the rock surfaces in the 25 intertidal zone, which would normally yield the finer detail, are 26 completely covered with a dense mat of barnacle and algal growth. 27 The rocks consist of beds of grey-green metagreywacke, generally 28 1–2 m thick in the northern part of the section, but reaching 3 m 29 30 thick at the southern end. They are separated by thin layers of 31 metasiltstone and/or slaty metamudstone (generally less than 10 cm 32 thick), or form amalgamated units. The metagreywackes, formerly 33 referred to as ‗grits‘, are fine to coarse grained, and many of the 34 beds show normal grading. 35 Over thirty examples of graded bedding have been recorded from the 36 section shown in Figure 8 and, as previously reported by McCallien 37 (1938), they show younging to the south-east. Beds are generally 38 right-way-up throughout the section, only becoming overturned on 39 the middle limbs of mesoscopic F1 folds (Figure 8, localities a and 40 b). As a result of the bonding effect of penetrative deformation 41 and cleavage development, the bottoms of beds are very rarely 42 exposed. However, flame structures are seen on the bases of a few 43 beds, and cross-lamination (showing younging to the south-east) is 44 seen in the uppermost, finer grained parts of some beds; Simpson 45 and Wedden (1974, plate 1a) illustrate an example from 450 m north 46 of the GCR site. 47 48 Thin beds of metamudstone and/or metasiltstone occur commonly 49 between the metagreywacke beds in the northern half of the section, 50 whereas thick, amalgamated beds of metagreywacke with no 51 intervening mudrock predominate in the younger rocks to the south. 52 The metamudstone occurs in several guises: as grey-green slaty 53 metamudstone with 1–5 mm-thick bands of black metamudstone; as grey 54 slaty metamudstone with centimetre-scale green bands; and as 55 purplish grey, slaty metamudstone. The latter variety is more 56 common at the southern end of the section. 57 The matrix of the metagreywackes consists of detrital grains of 58 quartz, feldspar, and muscovite, accompanied by flakes of chlorite 59 and white mica, which grew during the regional metamorphism 60 (Simpson and Wedden, 1974). The granule- to medium-pebble-sized 61 62 63 64 65 1 2 3 4 clasts found at the bases of graded beds are mainly of quartz, with 5 pink feldspar being common in some beds. Rip-up slabs and angular 6 fragments of dark mudstone, a few centimetres long, occur in a 7 number of the beds. 8 The beds forming the long limbs of the F1 minor folds are right- 9 way-up, and represent the regional orientation of the upper limb of 10 the ‗Tay Nappe‘. They dip consistently to the south-east at about 11 o 12 60 , at a steeper angle than the first cleavage (S1; dip 42°SE) 13 throughout the section (Figures 6, 7 and 8). An L1 stretching o 14 lineation, plunging at 33 to the east-south-east, is present as a 15 silky striation on slaty-cleavage surfaces, mainly in the northern 16 part of the section (Simpson and Wedden, 1974). 17 The penetrative slaty cleavage (S1) developed in the metamudstones 18 is fanned in mesoscopic fold closures and is continuous, via 19 cleavage refraction, with the centimetre-scale micolithons making 20 up the spaced cleavage that affects most of the metasiltstones and 21 metagreywackes (Figure 7b). This spaced cleavage is even seen in 22 some of the 2–3 m-thick metagreywacke beds. Evidence of later 23 ductile deformation is given by a few late, open structures that 24 fold the main cleavage (Figure 8, localities c, d and e), and by an 25 unrelated, gently dipping, crenulation cleavage that occurs 26 locally. Faults with varying orientations occur at regular 27 intervals throughout the section, becoming more significant and 28 marked by massive quartz veins or fault-breccia up to a metre 29 30 thick, as the Highland Boundary Fault is approached. 31 The faulted relationship between the Dalradian rocks and red 32 sandstones of the Lower Carboniferous, Kinesswood Formation is 33 fully exposed at beach level in the intertidal zone at locality f 34 on Figure 8. It is marked by a zone of brecciated Dalradian rock 35 up to 14 m thick, south-east of which major rectilinear fractures 36 separate the Dalradian from the Carboniferous rocks. A 45 cm- 37 thick, deeply weathered, dyke runs parallel to the fault zone (Hill 38 and Buist, 1994). Reddening of the Dalradian rocks along joints 39 and fractures at this locality suggests that the Old Red Sandstone- 40 facies Carboniferous rocks once lay unconformably on the Dalradian 41 north of the branch of the Highland Boundary Fault, prior the final 42 displacement on the fault. 43 The Dalradian rocks are weakly metamorphosed, and occur within the 44 chlorite zone of regional metamorphism; detrital white mica is 45 still present in the mineral assemblage, but is accompanied by a 46 felt of smaller, aligned, white mica crystals making up the S1 47 48 fabric. 49 50 2.3 Interpretation 51 52 The St Ninian Formation, and in particular the Bullrock Greywacke 53 Member, have been correlated with similar pebbly metagreywackes 54 found south of the Dunoon Phyllite Formation on the Toward 55 peninsula, Rosneath peninsula (Tanner, 1992; Cove Bay to 56 Kilcreggan GCR site), and west of Loch Lomond, as well as north of 57 the putative Highland Border Complex at North Glen Sannox, Isle of 58 Arran. At all of these localities the Bullrock Greywacke is right- 59 way-up and dips to the south-east on the upper limb of the Tay 60 Nappe. 61 62 63 64 65 1 2 3 4 At the Ardscalpsie Point GCR site, right-way-up beds dip 5 consistently to the south-east at a steeper angle than the first 6 cleavage (S1) (mean difference=19°; Figures 6 and 8). This agrees 7 with the minor fold vergence and confirms that the D1 facing 8 direction is down-to-south, and that the ‗Tay Nappe‘ here is a 9 synformal or downward-facing anticline (Shackleton, 1958; Simpson 10 and Wedden, 1974). 11 12 Stretching lineations were first described from Dalradian rocks by 13 Clough (in Gunn et al., 1897), from the Cowal peninsula to the 14 north-east of the Isle of Bute. When plotted on an equal area 15 stereographic projection, the F1 fold hinges and intersection 16 lineations from this GCR site are seen to be dispersed along a 17 great circle that contains the mean orientation of the stretching 18 lineation. This result is consistent with the curvilinear nature 19 of some minor folds observed in the field and indicates that a 20 considerable rotation of fold hinges towards the stretching 21 direction (X) has taken place (see the Strone Point and Glen Orchy 22 GCR site reports in Tanner et al., 2013a and Treagus et al., 2013 23 respectively). 24 Late warps of the bedding and early cleavage have the step-like 25 geometry characteristic of minor structures congruous with the F4 26 Highland Border Downbend (see the Portincaple GCR site). 27 28 29 2.4 Conclusions 30 31 The Tay Nappe is one of the largest fold structures in Scotland. 32 It was excised south-east of the Highlands by movement on the 33 Highland Boundary Fault, leaving the upper limb of the Nappe 34 exposed only in a relatively narrow SW–NE-trending outcrop across 35 Scotland. The importance of the Ardscalpsie Point GCR site lies in 36 the fact that it is probably the best place for studying in detail 37 this limb of the structure, to check whether the field 38 relationships accord with the proposed structural model for the 39 nappe (for details of the evolution of the Tay Nappe, see the Cove 40 Bay to Kilcreggan GCR site report). 41 At this site, the Dalradian rocks belong to the St Ninian 42 Formation, a thick unit of pebbly metagreywackes and thin beds of 43 slaty metamudstone, which was deposited from turbidity flows in a 44 submarine fan environment. It is amongst the youngest of the 45 Dalradian formations, and occupies a position close to the top of 46 the Southern Highland Group. Sedimentary structures, especially 47 48 graded bedding, and bedding-cleavage relationships can be very 49 clearly seen in these rocks on the 400 m-long coastal section 50 adjacent to Ardscalpsie Point. The combination of undoubted, and 51 plentiful, way-up evidence, with structural data, provides a very 52 clear demonstration that the St Ninian Formation lies on the upper 53 limb of a major F1 fold, the ‗Tay Nappe‘, that closes downwards and 54 yet has the older rocks in its core. It is a downward-facing, or 55 synformal, anticline, as envisaged by Shackleton (1958), from 56 preliminary observations at Ardscalpsie. This fold, originally 57 flat-lying, was rotated into its present position by folding on the 58 Highland Border Downbend (see the Portincaple GCR site report). 59 In addition, this GCR site is also excellent for studying the 60 development of spaced cleavage in quartz-rich metasedimentary 61 62 63 64 65 1 2 3 4 rocks, and is one of the few places where a branch of the Highland 5 Boundary Fault, the major fault bounding the Dalradian outcrop on 6 its south-east side, is fully exposed. In this part of Bute, the 7 Highland Boundary Fault brings Dalradian rocks against Lower 8 Carboniferous rocks: a related fault-zone is fully exposed 600 m 9 north-west of Ardscalpsie Point and is marked by a zone of 10 brecciated Dalradian rock up to 14 m wide, and by major rectilinear 11 12 fractures, which bring the Dalradian and Carboniferous rocks into 13 direct, knife-sharp contact. Evidence from this locality that the 14 Carboniferous rocks once lay unconformably on the Dalradian rocks 15 immediately north of the Highland Boundary Fault suggests that the 16 post Early Carboniferous displacement on the fault branch at 17 Ardscalpsie might have been relatively small. 18 19 3 COVE BAY TO KILCREGGAN 20 (NS 215 836–NS 242 804) 21 22 P.W.G. Tanner 23 24 25 3.1 Introduction 26 27 The Cove Bay to Kilcreggan GCR site consists of a 5 km-long strip 28 of coastal exposure, interrupted only by a few pebble beaches, that 29 30 runs between Knockderry Castle and Kilcreggan Pier on the west side 31 of the Rosneath peninsula (Figure 9). The site is of national 32 importance as it provides the only well-exposed coast section 33 across the putative closure of the Tay Nappe, one of the largest 34 folds in the British Isles. Plentiful minor structures document 35 the development and present-day geometry of this major fold. There 36 is undisputed evidence for four deformational episodes (D1–D4) in 37 the Daladian rocks farther north (see the Portincaple GCR site 38 report), but only D1 and D2 are fully developed at this site. 39 However, a major feature here is the manner in which the D2 40 deformation, that responsible for the southward propagation of the 41 Tay Nappe (Harris et al., 1976), increases in intensity northwards 42 (downwards in the originally near-horizontal nappe), overprints, 43 and finally destroys most field evidence for the prior existence of 44 the D1 structures. 45 The sequence of Southern Highland Group rocks within this GCR site 46 formed the original upper limb of the Tay Nappe and occupies a 47 48 structural setting comparable to that of the Ardscalpsie Point GCR 49 site. It consists mainly of right-way-up turbidite beds of the 50 Bullrock Greywacke Member of the St Ninian Formation, which dip to 51 the south-east and lie both stratigraphically and structurally 52 above the Dunoon Phyllite Formation. This formation in turn 53 overlies inverted strata of the Beinn Bheula Schist Formation. The 54 simplest geological interpretation of these relationships is that 55 the Bullrock Greywacke is the lateral stratigraphical equivalent of 56 the Beinn Bheula Schists, and that these two units represent the 57 two limbs of a downward-facing anticline, the Tay Nappe, which has 58 the Dunoon Phyllites in its core (Shackleton, 1958; Roberts, 1974). 59 60 61 62 63 64 65 1 2 3 4 All of the rocks have been affected by greenschist-facies regional 5 metamorphism. White mica-chlorite-bearing assemblages are 6 ubiquitous and give many of the rocks a greenish tinge. 7 Although the first published map of the Rosneath peninsula was 8 produced by the Geological Survey in 1878, it was not accompanied 9 by a sheet explanation or memoir. The first account of the geology 10 was by Roberts (1966a), who concentrated mainly on analysing the 11 12 depositional environment of each stratigraphical unit. This work 13 was followed by the publication of two field guides that described 14 the salient features of several localities within this GCR site 15 (Roberts, 1977b; Tanner, 1992). The geology of the peninsula was 16 also described succinctly by Henderson (in Paterson et al., 1990) 17 in the memoir to accompany the BGS 1:50 000 Sheet 30W/29E 18 (Greenock, 1990). 19 20 3.2 Description 21 22 The Bullrock Greywacke consists of gritty and pebbly feldspathic 23 metagreywacke, interbedded with some finer-grained metagreywackes 24 and metasiltstones, and some layers of black slaty metamudstone. 25 The pebbles are mainly of quartz and feldspar. Normal graded 26 bedding, confirmed in some cases by an accompanying erosional base 27 to the bed, or the presence in the same bed of bottom structures, 28 trough cross-bedding or channel infills, is seen at a number of 29 30 places. Sets of finely spaced cross-laminae are present in the 31 silty tops of a few turbidite beds. However, many of the beds are 32 apparently homogeneous or show evidence of amalgamation. 33 Calcareous concretions of diagenetic origin are common locally. 34 They occur as bedding-parallel lenses and pods up to a few 35 decimetres thick and reaching several metres in length, and as pod- 36 shaped bodies oblique to bedding. In each case, bedding 37 laminations preserved in the calcareous body are continuous with 38 those in the host greywacke (Tanner, 1992). 39 Due to faulting, combined with a 200 m gap in exposure, the 40 contact between the Bullrock Greywacke and the Dunoon Phyllites is 41 not seen on the coast, but evidence from outwith the area in 42 Aldownick Glen (NS 270 850) shows that it is a normal transitional 43 contact (Paterson et al., 1990). 44 The Dunoon Phyllite Formation consists mainly of black, purple, 45 grey, and olive-green slaty and phyllitic metamudstones, with some 46 beds of gritty metagreywacke, and of finer-grained metagreywacke 47 48 and metasiltstone. Rare beds of pebbly metagreywacke up to 2 m 49 thick are also present. Thin lenses and pods of metacarbonate rock 50 occur in the black, phyllitic, graphitic metamudstones. They 51 weather to a dull brown colour and are probably dolomitic in 52 composition. The un-named bed of metagreywacke within the Dunoon 53 Phyllites, exposed on the coast at Barons Point (Figure 9), appears 54 to be in normal stratigraphical contact with the metamudstones to 55 either side of it. There is sparse evidence of way-up from 56 chanelling and cross-lamination in most of the coastal outcrop of 57 the Dunoon Phyllites, but the northern part appears to young 58 towards the Beinn Bhuela Schists. 59 The Beinn Bheula Schist Formation consists of generally well- 60 bedded grey-green metagreywacke, less feldspathic than the Bullrock 61 62 63 64 65 1 2 3 4 Greywacke, with bands of phyllitic metamudstone and metasiltstone, 5 and uncommon pods of brown-weathering metacarbonate rock. Based on 6 the evidence of sporadic graded bedding and cross-lamination, that 7 part of the sequence exposed south of Knockderry Castle is 8 inverted. The formation includes an 18 m-thick unit of 9 metabasaltic sheets and (?) tuffaceous rocks just to the south of 10 Knockderry Castle (Figure 9) which resemble the green beds of the 11 12 Loch Lomond area. The contact between the Beinn Bheula Schists and 13 the Dunoon Phyllites is well exposed at NS 220 828 and is 14 transitional over more than 20 m. Way-up structures show clearly 15 that the structurally overlying Dunoon Phyllite is the older 16 formation and that both formations young to the north close to 17 their mutual contact. 18 The structures seen at this GCR site are almost entirely due to 19 the first two deformations, D1 and D2. The S1 cleavage is seen as 20 a centimetre-spaced set of anastomosing microlithons in the gritty 21 rocks; a shape fabric (deformed grit particles) in the finer 22 grained metagreywackes; or a slaty cleavage in the metamudstones. 23 No structures or fabrics related to D3 have been detected. The D4 24 deformation is very localized and is expressed as NNW-verging, 25 step-like folds, associated with a steep to vertical, millimetre- 26 spaced crenulation cleavage that folds S1 and S2. 27 Three major folds of D1 age occur in the Bullrock Greywacke west 28 and north of Kilcreggan Pier, but their hinge-zones are poorly 29 30 exposed. However, one of the closures is well exposed along strike 31 at Creag na Goibhre, Camsail Bay, north-east of Kilcreggan (NS 262 32 822) (Figure 9), and provides an analogue for the closure of the 33 Tay Nappe itself (Tanner, 1992). Structural analysis of the 34 orientations of bedding, S1 cleavage (axial-planar to millimetre- 35 scale minor folds and warps), bedding/cleavage intersection 36 lineations, and minor fold hinges show that this fold is a synform 37 with a near-vertical axial plane and a fold axis plunging at less 38 than 10° to the south-west. Way-up evidence from graded bedding 39 and cross-lamination shows that it is a downward-facing anticline. 40 D1 structures in the south of the area are in their pristine 41 state, unaffected by later deformation, but north of a line drawn 42 approximately through the Cove Burgh Hall a few hundred yards 43 south-east of Barons Point, the early cleavage can be seen in the 44 field to have been affected by the development of a later spaced 45 cleavage (S2). From this point northwards, the D2 deformation 46 takes over and S2 rapidly becomes dominant. It is the main, and in 47 48 some places only, planar structure in the Ben Bheula Schists in the 49 northern half the area, where the sedimentary structures are 50 progressively destroyed; in places only the coarser grained, 51 granule to pebbly metagreywackes and calcareous concretions and 52 layers preserve evidence of bedding surfaces. 53 D2 microlithons developed in the coarser metagreywackes have 54 centimetre-scale spacing, and in homogeneous gritty metagreywackes, 55 the anastomosing microlithons very closely resemble those of 56 undoubted D1 age seen farther south. The difference is that 57 further inspection usually reveals relics of the earlier spaced 58 cleavage within the D2 microlithons, a striking example of which is 59 shown in Figure 10. The S2 fabric in metamudstones is subtle; in 60 the field, it appears to be a slaty cleavage (S1), but under the 61 62 63 64 65 1 2 3 4 microscope it is a very closely spaced crenulation cleavage that 5 has clearly deformed an earlier fabric (Tanner, 1992). 6 F2 minor folds are rare; they fold an earlier cleavage and have 7 hinges plunging at moderate angles to the south-west. The latter 8 are statistically parallel to local bedding/cleavage intersection 9 lineations on a micro-crenulation cleavage (S2) that poses as 10 ‗slaty cleavage‘. 11 12 Inland mapping shows that three major faults cross the coast 13 section and cause a significant displacement of the outcrop of the 14 Dunoon Phyllites (Figure 9). Evidence for only one of these faults 15 is seen on the coast section. The Highland Boundary Fault is 16 marked by an erosional hollow at the south-eastern limit of the GCR 17 site but is not exposed. 18 19 3.3 Interpretation 20 21 The lateral correlation of stratigraphical units recognized on the 22 Rosneath peninsula is well established. The Bullrock Greywacke, a 23 right-way-up unit of gritty and pebbly, feldspathic metagreywackes, 24 correlates with rocks having a similar character from the Isle of 25 Bute to Loch Lomond side; the Dunoon Phyllites equate with slaty 26 metamudstones on the Isle of Bute and the Luss slates at Loch 27 Lomond; and the inverted sequence of Beinn Bheula Schists seen 28 north of the Dunoon Phyllites occupies the same relative structural 29 30 position at all of these localities. The metabasaltic and 31 associated rocks at Knockderry Castle may be correlated with the 32 green beds seen east of Loch Lomond. 33 The Bullrock Greywacke and Beinn Bheula Schists in the area of 34 this GCR site, the ‘greywacke affiliation‘ of Roberts (1966a), 35 originated mainly as sequences of siliciclastic turbidites 36 deposited in a submarine fan environment. In contrast, the Dunoon 37 Phyllites were most likely deposited in a deeper water, oceanic 38 setting, and consisted of pelagic muds diluted by the periodic 39 influx of siliciclastic turbidites. 40 The structural situation is more enigmatic. On the Rosneath 41 peninsula and at this GCR site in particular, the limbs of the 42 major D1 structure, the Tay Nappe, are clearly defined by the thick 43 unit of consistently inverted Beinn Bheula Schists (in the north- 44 west) and the largely right-way-up Bullrock Greywacke (in the 45 south-east), but the hinge-zone of this structure is difficult to 46 locate. 47 48 This problem had been recognized earlier (Roberts, 1974; Paterson 49 et al., 1990) and it was suggested that there is a major slide 50 along the south-eastern margin of the Dunoon Phyllite outcrop, 51 which cuts out some of the southern limb of the major fold. 52 However, this does not agree with the evidence from outwith the 53 peninsula that this boundary is a normal sedimentary contact 54 (Paterson et al., 1990). There are two alternative possibilities; 55 either the actual hinge-zone is poorly defined and is represented 56 by a number of mesoscopic fold closures, or it is hidden by 57 faulting. There is no field evidence to indicate the presence of 58 mesoscopic folds in the Dunoon Phyllite. On the other hand, three 59 large N-S-trending faults, each having a component of sinistral 60 transcurrent displacement, cause a considerable displacement of the 61 62 63 64 65 1 2 3 4 Dunoon Phyllites (Figure 9). The combined effect of this faulting 5 is to remove about three kilometres of cross-strike exposure of the 6 Dunoon Phyllites from view on the coast section within this GCR 7 site. This ‗hidden section‘ probably contains the closure of the 8 Tay Nappe, with the folds seen to the south in the Bullrock 9 Greywacke being congruous with the major fold. 10 The coastal section at this GCR site represents a depth profile of 11 12 some 4 km through the Tay Nappe, at a time when it was a flat- 13 lying, or recumbent, anticline closing to the south-east (Tanner, 14 1992) (see the Introduction to Tanner et al., 2013b for a fuller 15 explanation). At that time, the rocks at Kilcreggan formed part of 16 the top limb of this structure, and were at a higher level in the 17 Earth‘s crust than those at Knockderry Castle, on the lower limb. 18 D1 minor structures dominate the southern part of the section, but 19 north of Barons Point, the pervasive spaced or slaty S2 fabric 20 overprints the earlier one and evidence of D1 vergence can no 21 longer be recognized. D2 shear results in very regular planar S2 22 surfaces but several stages in the development of the D2 23 microlithons that formed at a high angle to the spaced S1 cleavage 24 are preserved. These features provide a reliable fingerprint for 25 identifying the D2 fabric in rocks of the Flat Belt to the north 26 and enable complex fold interference patterns to be unravelled (see 27 the Portincaple GCR site report, Figure 12). In some cases they 28 show the relative shear sense during D2 deformation (Harris et al., 29 30 1976; Krabbendam et al., 1997). 31 Subsequently, the nappe was affected by two further deformations 32 (D3 and D4), the second of which was responsible for rotating the 33 rocks at this GCR site into their present steeply dipping attitude. 34 The effects of these phases are best seen in the Portincaple GCR 35 site, where the relationship of D2 to both D3 and D4, and the 36 geometry of the Highland Border Downbend, may be examined. 37 38 3.4 Conclusions 39 40 The rocks seen in the coast section between Cove Bay and Kilcreggan 41 belong to the upper part of the Southern Highland Group and are 42 divided into three stratigraphical units. Both the Bullrock 43 Greywacke and the Beinn Bheula Schists consist of coarse-grained, 44 sometimes pebbly, metagreywackes that show graded bedding and 45 cross-lamination. They were deposited in a submarine fan 46 environment, whereas the Dunoon Phyllites, which consist largely of 47 48 varicoloured slaty rocks, were deposited farther away from the 49 continental margin in an oceanic basin setting. The exposures of 50 the Dunoon Phyllites are of such quality as to constitute a 51 reference section for this formation. All of the rocks have been 52 deformed and metamorphosed subsequently during the Grampian Event 53 of the Caledonian Orogeny, and now dip to the south-east at a 54 moderate angle. 55 This GCR site provides a unique coastal section across the closure 56 of the Tay Nappe, a structure that can be traced north-east–south- 57 west across the Dalradian outcrop from the Isle of Bute to the east 58 coast of the Grampian Highlands. The Bullrock Greywacke and the 59 Beinn Bheula Schists, although rather different in lithology and 60 mineralogy, have been correlated with each other, and are thought 61 62 63 64 65 1 2 3 4 to represent the right-way-up limb and inverted limb, respectively, 5 of the Tay Nappe. The Dunoon Phyllites, sandwiched structurally 6 between them, occupy the core of the fold. 7 The great value of this GCR site is that it preserves structural 8 information, in particular, that may be used to analyse and model 9 early stages in the development of the Tay Nappe, and test the 10 various hypotheses that have been proposed to explain its mode of 11 12 emplacement. The evidence for the first two stages is charted by 13 the sets of minor structures and cleavages so splendidly preserved 14 in places in these rocks. In addition, there are few locations in 15 the British Isles where the mechanisms involved in transforming an 16 early, spaced, pressure-solution cleavage to a new cleavage of the 17 same type can be studied in such detail. 18 19 4 PORTINCAPLE 20 (NS 227 928–NS 232 937) 21 22 P.W.G. Tanner 23 24 25 4.1 Introduction 26 27 This GCR site is situated on the eastern shore of Loch Long at the 28 small hamlet of Portincaple (Figure 11a). It consists of a rock 29 30 platform fringing the coastline in the south, and low cliffs in the 31 north that together expose an excellent section through the 32 southern part of the hinge-zone of the Highland Border Downbend. 33 This structure was responsible for rotating the Tay Nappe from an 34 originally gently dipping orientation now represented by the Flat 35 Belt, to its steeply dipping orientation in the Highland Border 36 Steep Belt (as represented by the Cove Bay to Kilcreggan GCR site). 37 Here, the broad, open form of the F4 hinge-zone and the concordant 38 geometry of the related minor structures are clearly shown. The 39 geometry and vergence of D3 structures may also be readily 40 examined, and there is clear evidence of their refolding by the 41 major F4 downbend. The value of this site is also enhanced by the 42 fact that it is the first significant accessible coastal section on 43 the lower limb of the Tay Nappe north of Coulport, 5 km to the 44 south. All of the intervening ground has been acquired by the 45 Ministry of Defence and closed to public access. 46 The rocks consist of metagreywackes belonging to the Beinn Bheula 47 48 Schist Formation. Bedding was thoroughly reworked during the 49 formation of two pressure-solution cleavages (S1 and S2) and has 50 been largely destroyed or rendered obscure during the process. 51 However, a wealth of folded and overprinted cleavages, intersection 52 and stretching lineations, and minor folds belonging to the three 53 latest generations of structures, are very well preserved in clean 54 rock exposures above mean tide level. 55 The Portincaple GCR site lies on the eastern margin of BGS 1:50 56 000 Sheet 37E (Loch Goilhead, 1990), but neither the map nor the 57 original sheet memoir (Peach et al., 1905) provide any geological 58 information specific to this site. The Tay Nappe and the manner in 59 which it is bent down by the Highland Border Downbend were first 60 recognised by Shackleton (1958), from mapping in adjoining areas 61 62 63 64 65 1 2 3 4 and the hinge structure at Portincaple was first mapped by Stringer 5 (1957). The area then received no further attention until Roberts 6 (1977b) gave a brief description of the minor structures seen at 7 Portincaple. This was followed by a more-detailed field guide to 8 the locality by Tanner (1992). 9 10 11 4.2 Description 12 13 The Beinn Bheula Schist Formation belongs to the upper part of the 14 Southern Highland Group and consists of fine- to coarse-grained 15 metagreywacke and metasiltstone interbedded with lesser amounts of 16 grey-green phyllitic rock. Bedding in these rocks has been largely 17 destroyed, except in a few gritty, non-graded metagreywackes and 18 one prominent, non-graded, pebbly metaconglomerate, less than 1 m 19 thick, which appears to be little deformed. 20 The Beinn Bheula Schists are highly contorted due to the 21 cumulative effects of four separate deformation events. The main 22 planar element is the spaced S2 fabric, generally seen as 23 anastomosing microlithons a few millimetres to over 1 cm thick, 24 within which traces of the S1 spaced fabric can be seen in places. 25 This fabric is identical to that which dominates the northern part 26 of the Cove Bay to Kilcreggan GCR site but here it has been 27 deformed by two further deformations, D3 and D4. 28 A SSE-plunging stretching lineation is seen as silky striations 29 30 that make a high angle with the L2 on S2 cleavage surfaces. It is 31 also present as quartz-fibre lineations in many of the quartz- 32 carbonate veins. 33 The D3 deformation is represented by fairly common sideways- 34 closing folds which invariably have the same vergence and Z-shaped 35 down-plunge profile throughout the area. The axial-planar dip of 36 these folds varies in a progressive but non-systematic manner from 37 50° N at the southern end of the section, to around 20° N in mid- 38 section, to about 5° N at the northern end. The minor folds are on 39 a decimetre scale and are curvilinear, plunging at a low angle to 40 both east-north-east and west-south-west. In these rocks they fold 41 the S2 spaced cleavage, the L2 intersection lineation seen on the 42 S1 cleavage, and the stretching lineation (?L2). A weak S3 43 crenulation cleavage is largely restricted to the hinge-zones of 44 these folds, where it cuts across and dissects the folded S2 45 cleavage. 46 Step-like, metre-scale, F4 minor folds are found throughout the 47 48 coastal section (Figure 11b). These folds are open to close, 49 upright structures that have nearly horizontal, slightly 50 curvilinear fold hinges. Their steep limbs are parallel to the 51 mean orientation of the foliation in the Steep Belt, and the near- 52 horizontal middle limb is parallel to the general orientation of 53 the same foliation in the Flat Belt (Figure 11b). The associated 54 crenulation cleavage is near vertical and has a fairly constant 55 strike (070–080o) but can be seen in the field to vary in dip about 56 the vertical as a result of cleavage refraction through rock 57 packages of differing competence. It is characteristically widely 58 spaced (1–2 mm) (Figure 12c). Flat-lying kink bands that rework 59 the S4 cleavage are seen locally. An equal-area stereographic plot 60 61 62 63 64 65 1 2 3 4 of poles to S2 and S4 shows that the major fold plunges at 10° to 5 079° (Figure 11c). 6 A number of faults are seen in the southern part of the GCR site. 7 They are either vertical or dip steeply to the south and have a 8 mean spacing of about 4 m (Figure 11b). 9 10 11 4.3 Interpretation 12 13 This GCR site is situated at the northern extremity of the Highland 14 Border Steep Belt where it turns into the antiformal closure of the 15 Highland Border Downbend, which is in effect a monoform. The 16 northern limb of the downbend (the Flat Belt) is best seen 3 km 17 farther north near Glenmallan (NS 249 965), where the exposures are 18 on two natural rock platforms formerly accessed by fixed steel 19 ladders from road level. There, the composite S1/S2 fabric is 20 generally flat-lying but is affected by strongly developed upright 21 F4 folds associated with a steep to vertical crenulation cleavage. 22 In the southern part of the Portincaple GCR site, F4 minor folds 23 with wavelengths of over 2 m are clearly congruous to a major 24 antiformal structure to the north and adopt a neutral vergence in 25 northern part of the section as the major fold hinge-zone is 26 entered. The axial trace of the major antiform/monoform trends 27 parallel to the strike of the measured crenulation cleavage and 28 this fold correlates with that identified on Loch Lomondside by 29 30 Stringer (1957) and Shackleton (1958). 31 No major F3 folds have been recognized in this area and this phase 32 of folding appears to have only local significance, for D3 33 structures are absent to the north-east along strike from Aberfoyle 34 (Tanner and Leslie, 1994) (see the Craig a’ Barns GCR site report). 35 Ever since it was first discovered by Clough (in Gunn et al., 36 1897), there has been disagreement over the relative age of the 37 downbend, but from the data presented here it is clear that it is a 38 D4 structure. 39 40 4.4 Conclusions 41 42 The Portincaple GCR site provides the best accessible coastal 43 section through part of the hinge-zone or closure of the Highland 44 Border Downbend to be found in the south-western Grampian 45 Highlands. This major D4 structure is responsible for folding the 46 Tay Nappe into a downward-facing structure along the entire 47 48 Highland Border zone from Loch Lomond to Stonehaven. 49 At this GCR site, minor structures formed in all four of the main 50 deformation episodes to affect the Dalradian succession can be 51 identified, and it is an excellent section for demonstrating the 52 effects of three-dimensional polyphase deformation. Geometrical 53 integrity of individual phases can be demonstrated, despite the 54 seemingly chaotic assemblage of ductile structures and the 55 complexity of their interference patterns. The clean rock 56 exposures provide a wealth of information on the minor folds, 57 cleavages, lineations, veins and fracture geometry found in this 58 complex zone. 59 This site could be considered as the type section for studying the 60 D3 deformation and for separating it clearly from the effects of D2 61 62 63 64 65 1 2 3 4 and of D4. It therefore contrasts with and complements the section 5 farther north-east in the Birnam area at the Craig a’ Barns GCR 6 site, where D3 is not developed. 7 8 5 BEALACH NAM BO 9 (NN 479 065–NN 485 079) 10 11 12 C.W. Thomas 13 14 15 5.1 Introduction 16 17 Bealach nam Bo (Gaelic: ‗Pass of the cattle‘) is a narrow pass 18 formed by a glacial overflow channel on the northern flanks of Ben 19 Venue, immediately west of the southern end of Loch Katrine in the 20 Trossachs (Figure 14). It lies at the centre of this GCR site, 21 which comprises about 4 km2 of ground underlain by volcaniclastic 22 metasandstones, ubiquitously referred to as ‘green beds’, and quartz- 23 rich, gritty and commonly pebbly metasandstones, assigned to 24 lithostratigraphical units within the lower part of the Southern 25 Highland Group. The green beds are distinctive and have been 26 treated as lithostratigraphical markers. The numerous exposures 27 around Bealach nam Bo illustrate the wide range in styles, varying 28 according to lithology, of the commonly spectacular structures 29 30 associated with the second phase of deformation and the nature of 31 the interaction between the first and second phases. 32 The area around Bealach nam Bo was mapped in the latter part of 33 the nineteenth century by officers of the Geological Survey, but 34 the manuscript for the accompanying memoir was never published and 35 has only recently been made available (Cunningham Craig, 2000). 36 Subsequently, the ground immediately south of the pass was included 37 in R.M. Shackleton‘s work on the structure of the Dalradian rocks 38 adjacent to the Highland Border (Shackleton, 1958). He showed that 39 the metasedimentary rocks are inverted, young towards the south and 40 dip steeply northwards. He also noted a conspicuous ‗later 41 fracture-cleavage or slip-cleavage‘, now known to result from the 42 main phase deformation, described below. The area was resurveyed 43 by the British Geological Survey between 1996 and 1998 as part of 44 the general mapping programme and lies within the BGS 1:50 000 45 Sheet 38E (Aberfoyle, 2004). 46 47 48 5.2 Description 49 50 The metasedimentary rocks within the GCR site area include green 51 beds and associated metasandstones in the north, structurally 52 overlying commonly gritty or pebbly, quartz-rich metasandstones in 53 the south. Finer grained metamudstones and metasiltstones are 54 generally rare. Although bedding generally ranges up to 1 m in 55 thickness, some massive and coarse-grained beds are in excess of 2 56 m thick. Graded bedding is commonly developed and shows that the 57 steep northerly dipping succession is generally inverted. 58 Determination of way-up of the succession in this and adjacent 59 areas has been critical in understanding the structural history of 60 the rocks within the site, and in the region in general. 61 62 63 64 65 1 2 3 4 Following the BGS resurvey, the green beds and associated rocks 5 have been assigned to the Loch Katrine Volcaniclastic Formation 6 (Figure 14). The green beds are chlorite- and epidote-rich 7 metasandstones, locally with abundant magnetite. The background 8 sediment with which the abundant mafic minerals were mixed is fine 9 to coarse grained, quartz rich and commonly gritty. The chlorite 10 and epidote impart an olive to dark bottle-green colour to fresh 11 12 surfaces, but the green beds weather to a characteristic sandy 13 brown colour, often with a sandpaper-like surface texture where 14 finer grained. The weathered rind extends up to a centimetre or so 15 into the surface. Careous weathering is also a feature in places, 16 yielding a surface honeycombed by rounded pits up to about 15 cm 17 across and 3 cm deep. Although the green beds display little 18 visible lithological variation in individual exposures, small 19 lenses of quartz-rich, gritty metasandstone are quite commonly 20 developed, often serving to highlight bedding. 21 The metasandstones associated with the green beds are chiefly 22 coarse-grained, gritty quartz- and feldspar-rich metasandstones 23 with only small amounts of chlorite and epidote. Although there 24 is, in effect, a continuum in composition between these and the 25 green beds, individual green beds are commonly sharply enough 26 defined to be mapped out as separate units within the Loch Katrine 27 Volcaniclastic Formation. 28 Typical green-bed lithologies are very well exposed in cliffs at 29 30 Bealach nam Bo and on ground to the south-west and north-east. In 31 these outcrops, they are massive, thickly to very thickly bedded 32 units of coarse metasandstone, as detailed in the sedimentary log 33 in Figure 15. A notable feature of some beds is the presence of 34 ellipsoidal, nodular structures concentrated in bedding-parallel 35 trains. They are up to about 10 cm long in the longest dimension 36 and usually have weathered-out cores. 37 The metasandstones that lie lithostratigraphically above, but 38 structurally underneath, the Loch Katrine Volcaniclastic Formation 39 are assigned to the Creag Innich Sandstone Formation (see also the 40 Duke’s Pass GCR site report). These are predominantly clean, 41 quartz-rich, coarse metasandstones with minor intercalations of 42 metasiltstone and more-micaceous metasandstone. In places, 43 spectacular pebbly lithologies form microconglomeratic units that 44 can exceed 2 m in thickness; good examples of such rocks are to be 45 found on the higher ground c. 600 m south-west of Bealach nam Bo 46 (around NN 478 069). The pebbly rocks are notable for their well- 47 48 rounded pebbles, their compositional maturity (chiefly quartz-vein 49 material) and their high degree of sorting. 50 The structures developed in the metasandstones within and around 51 the GCR site are complex, but allow the relationships between the 52 regional first (D1) and second (D2) phases of deformation to be 53 discerned. Although the D2 phase affected the whole region, it is 54 the lithologies and the architecture of the structures formed 55 during D1 that control the ways in which D2 structures are manifest 56 at both local and outcrop scale. 57 The very thick and massive green-bed lithologies, such as those 58 exposed in the cliffs at Bealach nam Bo (NN 480 070), commonly 59 appear to be only weakly deformed and cleavages are poorly 60 developed. In the exposures of metasandstones to the west and 61 62 63 64 65 1 2 3 4 north of the pass, metre- to decimetre-scale, south-verging folds 5 are common. In general, the hinge-zones of these folds host only a 6 single, moderate, penetrative, axial planar cleavage, good examples 7 of which are seen in exposures around NN 478 075 (Figure 16). Even 8 though this cleavage might have been modified by subsequent D2 9 deformation, it is considered to result principally from D1 10 deformation. This style of cleavage is very different to the 11 12 coarsely spaced, anastomosing S1 cleavage characteristic of 13 metasandstones that crop out to the south of the GCR site, towards 14 the Highland Boundary Fault. 15 Bedding dips consistently and steeply to the north-north-west on 16 either side of the F1 axial traces, showing that these early folds 17 are tight to isoclinal. The F1 folds plunge consistently to the 18 north-east at moderate angles. Abundant younging evidence, 19 combined with bedding/cleavage relationships, shows that the F1 20 folds face steeply downwards to the north-north-west throughout the 21 area. 22 The second phase of deformation, D2, is characterized by a coarse 23 crenulation of the first cleavage; S2 is approximately parallel to 24 bedding on the long limbs of F1 folds. The D2 crenulation is 25 particularly well developed in the ground c. 400 m south-west of 26 Bealach nam Bo (around NN 477 071). In general, the first cleavage 27 is folded by D2 folds on a small scale (Figure 17), but bedding is 28 not affected. The small-scale F2 folds plunge to the north-east 29 30 and south-west and commonly have strongly curvilinear hinges. The 31 style of folding varies from a chevron type with planar limbs and 32 very sharp angular hinges, to a type that has the sinusoidal form 33 of a classical crenulation. Domains bounded by the S2 cleavage 34 planes (‗microlithons‘) can be planar but are more typically 35 lenticular in shape. Discrete S2 cleavages only form locally 36 within the hinges of chevron-style folds and are rarely intensely 37 developed. In lenticular, crenulated domains, the cleavage that 38 defines the lenticle margins is a composite S1-S2 fabric. This 39 cleavage is discontinuous along its length and is variably and 40 widely spaced. 41 42 5.3 Interpretation 43 44 The lithologies that occur within the Bealach nam Bo GCR site are 45 typical of Southern Highland Group metasedimentary rocks in 46 general. The green beds are interpreted as metasandstones with a 47 48 mafic volcaniclastic component, the latter derived either from 49 contemporaneous or near-contemporaneous volcanic rocks, such as 50 those in the Tayvallich peninsula of the South-west Grampian 51 Highlands, or from the reworking of older volcanic terrains. How 52 the nodular structures formed is unclear at present; Cunningham 53 Craig (2000) suggested that they might have originated as clay- 54 galls, although it is possible that they could have had a volcanic 55 origin. 56 The cleaner metasandstones associated with the green beds and 57 within the Creag Innich Sandstone Formation are evidence that the 58 background sedimentation was dominated by generally coarse sand 59 deposited by turbidity currents and mass debris flows. The pebbly 60 component is likely to have been derived from a mature, well-sorted 61 62 63 64 65 1 2 3 4 beach deposit within the source area and admixed during 5 redeposition with the finer grained sediment that forms the matrix. 6 Although the D2 phase of deformation affected the whole area, the 7 various styles and characteristics of the D2 folding indicate that 8 D2 strain was variable, generally not very high and locally 9 partitioned. The finely spaced cleavage observed in the F1 fold 10 hinges in green beds is considered to be primarily the result of D1 11 12 deformation, even though the cleavage might have been enhanced by 13 coplanar D2 deformation. In addition, the variations in style and 14 distribution of D2 structures indicate that S1 cleavages in the 15 cleaner metasandstones were already closely spaced to penetrative 16 on the grain scale before the D2 small-scale folding. This closer 17 spacing contrasts with the wide, anastomosing S1 cleavage observed 18 in coarse metasandstones to the south-east at the Duke’s Pass GCR 19 site. This suggests that D1 deformation was generally more intense 20 at this structural level within the Tay Nappe than at higher 21 structural levels to the south-east. Alternatively, the closer 22 spacing of the S1 cleavage could be due to early D2 deformation 23 modifying the spacing by flattening, prior to simple-shear folding 24 of the S1 cleavages (see the Craig a’Barns and Rotmell GCR site 25 reports). As discussed elsewhere in this special issue, there are 26 strongly contrasting views on the significance of D2 deformation in 27 the Highland Border region (Harris et al., 1976; Harris and 28 Bradbury, 1977; Roberts, 1977a; Mendum and Fettes, 1985; Krabbendam 29 30 and Leslie, 1996; Krabbendam et al., 1997; Mendum and Thomas, 31 1997). The arguments are not rehearsed again here, but it is 32 considered that the evidence within the Bealach nam Bo site is 33 consistent with north-westerly directed simple shear during at 34 least the latter part of the D2 phase. 35 The steep north-north-west dips of bedding and the downward-facing 36 character of the F1 folds result from overturning of the folded 37 succession by a much later phase of deformation. This deformation 38 is generally considered to have occurred prior to the main D4 39 compressive phase (see Stephenson et al., 2013a) and is responsible 40 for the steep dips developed in this and other areas along the 41 south-eastern margin of the Grampian Highlands (e.g. Harte et al., 42 1985). 43 44 5.4 Conclusions 45 46 The Bealach nam Bo GCR site provides numerous outstanding and 47 48 readily accessible exposures that reveal clearly the contrasting 49 nature of two formations in the Southern Highland Group, both in 50 terms of rock type and the response of these units to regional 51 deformation events. 52 Metasandstones in the Loch Katrine Volcaniclastic Formation 53 commonly contain volcaniclastic detritus, now manifest as chlorite, 54 epidote and locally abundant magnetite. This detritus is 55 sufficiently abundant in many beds within the formation to impart a 56 strong, dark-green colour from which the ‗green beds‘ derive their 57 name. This detritus might have been derived from contemporary 58 volcanic activity, although this is, as yet, unproven. The rocks 59 within the overlying Creag Innich Sandstone Formation are dominated 60 61 62 63 64 65 1 2 3 4 by clean, coarse metasandstones and locally spectacular, pebbly 5 metaconglomerates, rich in well-rounded vein-quartz clasts. 6 The green beds appear to have undergone relatively simple 7 deformation dominated by cleavage and folding resulting from the 8 first regional phase (D1), although there might have been some 9 modification during the second deformation phase (D2). Folds 10 resulting from the first phase of deformation are very well exposed 11 12 locally and there is ample sedimentological evidence of the way-up 13 of beds; this allows the steeply downward- and NW-facing character 14 of the folds to be readily demonstrated. The metasandstones of the 15 Creag Innich Sandstone Formation are notable for the range and 16 complexity of minor structures developed within them as a result of 17 interaction between the D1 and D2 deformations. These observations 18 provide important insights into the overall structural evolution of 19 the Highland Border region. 20 21 6 DUKE’S PASS 22 (NN 499 030–NN 523 043) 23 24 C.W. Thomas 25 26 27 6.1 Introduction 28 29 30 The Duke’s Pass is followed by the A821 road between Aberfoyle and 31 the west end of Loch Achray. Ground extending either side of this 32 corridor provides numerous, readily accessible exposures of 33 metasedimentary rocks belonging to the Southern Highland Group, 34 which comprise the GCR site (Figure 18). The GCR site is 35 particularly important in revealing the nature of the earliest 36 phase of deformation, free of the effects of the main second 37 deformation event, and the way in which the second deformation 38 modified the earlier structures. 39 The Aberfoyle district was important in early work on the 40 Dalradian, yielding the now well-known names of some of the key 41 lithostratigraphical units in the Southern Highland Group, 42 especially the Aberfoyle Slates and Ben Ledi Grits. A resurvey by 43 the British Geological Survey of 1:50 000 Sheet 38E (Aberfoyle, 44 2004) has delineated other lithostratigraphical units and has 45 determined that faults related to the Loch Tay Fault system are 46 responsible for the mismatch of structures and outcrop pattern 47 48 across the Duke‘s Pass. 49 The area is of major importance in determining the 3-D structure 50 of this segment of the Highland Border region. The high degree of 51 deformation was recognized during the original mapping by the 52 Geological Survey in the late 19th Century (original unpublished 53 manuscript released as Cunningham-Craig, 2000), although its 54 precise nature and significance for the tectonic evolution of the 55 Grampian Terrane was not recognized until the latter half of the 56 twentieth century. Henderson (1938) was the first to demonstrate 57 the way-up of the beds from sedimentary structures and showed that 58 the Aberfoyle Slates occupy the core of the ‗Aberfoyle Anticline‘. 59 Anderson (1947a) maintained that this structure extends along the 60 Highland Border from West Water in the Edzell district, Angus, to 61 62 63 64 65 1 2 3 4 the Isle of Arran in the south-east. Subsequently, Shackleton 5 (1958), in his seminal paper on the structure of the Dalradian 6 rocks of the Highland Border, demonstrated that the structures 7 observed on either side of the Aberfoyle Slates are downward- 8 facing. The slaty metamudstones thus occupy the core of a 9 downward-facing anticline, constituting the inverted nose of the 10 Tay Nappe. Mendum and Fettes (1985) showed that at least two other 11 12 major early folds, complementary to the Aberfoyle Anticline, occupy 13 ground to the north of the latter structure and lie structurally 14 beneath it. This renders the hinge-zone of the Tay Nappe much more 15 complex than envisaged by Shackleton. The Aberfoyle Anticline is 16 thus just one of a number of early structures in the hinge-zone of 17 the nappe. The northern half of the GCR site is affected by a 18 second deformation and local, minor development of later cleavages, 19 which become more intense northwards. 20 21 6.2 Description 22 23 The GCR site lies entirely within the Highland Border Steep Belt, 24 the domain of steeply, generally north-west- to north-dipping 25 strata that occupy the ground south of the Highland Border Downbend 26 (Stephenson et al., 2013a, fig. 7). It also lies to the north-west 27 of the Loch Tay Fault Zone, which in this area trends south-west 28 from the north-west side of Meall Ear (NN 530 027), passing 29 30 immediately south-east of Creag Gownan (NN 533 025) and the lower 31 slopes of Craigmore (NN 510 021) (Figure 18). 32 Within the GCR site, the Southern Highland Group is dominated by 33 metasandstones. Although most of these were originally wackes, 34 carrying abundant matrix, many were quartz-rich arenites. The very 35 local nature of lithological variation within the metasandstones 36 limits the potential for lithological subdivision. However, 37 mapping by the British Geological Survey has delineated three 38 discrete metasandstone units on the western side of the Duke‘s Pass 39 Fault (Figure 18). Graded bedding is very commonly developed and 40 other sedimentary structures, which help to constrain the way up, 41 include scours, load structures and, very rarely, ripple marks. 42 Rip-up clasts, now metamudstone, are abundant locally and can reach 43 several tens of centimetres in size. The way-up criteria are 44 critical to the understanding of the structure of the Duke‘s Pass 45 area (see below). 46 The bulk of the metasandstones are assigned to the Ben Ledi Grit 47 48 Formation. In this unit they vary from massive, very thick, gritty 49 to locally pebbly coarse metasandstones to thin-bedded, fine- 50 grained units with metasiltstone and locally metamudstone 51 interbeds. The coarser grained lithologies dominate. Excellent 52 examples of the coarse-grained lithologies are exposed on the low 53 hillside around NN 518 031, where they occupy a fold hinge (see 54 below). Here, basal scours contain gravel lag deposits and loading 55 structures are common where very coarse material has been deposited 56 on finer grained units. 57 To the west of the Duke‘s Pass and north of the Aberfoyle slate 58 quarries, metasandstones are assigned to the Creag Innich Sandstone 59 Formation. They are grey, coarse-grained, quartz-rich, medium- to 60 thick-bedded rocks that crop out extensively in the high ground, 61 62 63 64 65 1 2 3 4 particularly around Creag a Mhadaidh (NN 513 036). This formation 5 lies below the Ben Ledi Grit Formation, but appears to be laterally 6 discontinuous on a regional scale (Thomas et al., in press). The 7 metasandstones in this formation are generally cleaner, with less 8 fine-grained matrix, than those of the Ben Ledi Grit Formation. 9 To the north of the Creag Innich Sandstone, metasandstones are 10 assigned to the Ledard Burn Member, a generally finer grained unit 11 12 within the Ben Ledi Grit Formation. This unit comprises medium- 13 bedded, fine-grained metasandstones with metasiltstone interbeds; 14 thin gritty units are present at the bases of some upward-fining 15 packets of sandstone. 16 Metasiltstone and metamudstone are common as interbeds and laminae 17 in many of the metasandstones. They also occur in much thicker 18 units, the most notable of which forms the Aberfoyle Slate 19 Formation west of the Duke‘s Pass Fault, which is well exposed in 20 the abandoned Aberfoyle Slate Quarries (NN 505 032). This unit is 21 dominated by grey and greenish or purplish grey metasiltstones with 22 darker laminae of metamudstone. Bedding is commonly picked out by 23 discontinuous thin wisps of quartzose material. Way-up is rarely 24 determinable in these rocks, but very locally the thin quartzose 25 laminae contain discernible cross-lamination and have small-scale 26 scours at their bases, indicating the direction of younging. The 27 Aberfoyle Slate Formation contains the oldest Southern Highland 28 Group rocks within the GCR site, these rocks being correlated 29 30 traditionally with the Pitlochry Schist of Perthshire. They were 31 worked extensively for slate in the Aberfoyle quarries in the 19th 32 century before extraction become uneconomic in the face of 33 competition from lighter and higher quality Welsh slate. 34 The metasiltstones of the Aberfoyle Slate Formation pass 35 southwards into pale, quartzose metasandstones that are correlated, 36 on the basis of recent BGS mapping, with the Creag Innich Sandstone 37 Formation to the north. The metasandstones pass southwards, in 38 turn, into the more-impure metasandstones, metasiltstones and 39 subordinate metamudstones of the Ben Ledi Grit Formation, the 40 outcrop of which continues to the Highland Boundary Fault at the 41 southern margin of the GCR site. 42 East of the Duke‘s Pass, within the Achray Forest, a unit of 43 metamudstone within the Ben Ledi Grit Formation is bounded to the 44 east by the Loch Tay Fault and to the west by smaller faults 45 (Figure 18). The metamudstones are black, grey, green or maroon in 46 colour and are strongly cleaved. In the ground immediately west of 47 48 and within the Loch Tay Fault Zone (200–300 m west of Meall Ear, NN 49 530 027), metamudstones are black, rich in pyrite and contain 50 cherty laminae. These lithologies are similar to those seen in the 51 Leny Quarry (NN 619 101), north-west of Callander (see the Keltie 52 Water GCR site report), but differ significantly from those exposed 53 in the Aberfoyle slate quarries. Thinner units of metasiltstone 54 and metamudstone, such as that trending eastwards about 500 m north 55 of Aberfoyle, occur throughout the general mass of Ben Ledi Grit to 56 the east of the Duke‘s Pass Fault and are generally similar 57 lithologically to those described above. Hence, contrary to 58 previous interpretations (Shackleton, 1958; Mendum and Fettes, 59 1985), the fine-grained rocks to the east of the Duke‘s Pass Fault 60 are not lithostratigraphical correlatives of those seen in the 61 62 63 64 65 1 2 3 4 Aberfoyle Slate Quarries. The corollary is that there has been 5 considerable displacement across the Duke‘s Pass Fault, resulting 6 in the juxtaposition of different lithostratigraphical units and 7 different structural levels (see below). 8 Bedding in the metamudstones, very rarely observed, is picked out 9 by very thin silty laminae or by subtle variations in hardness that 10 indicate a more siliceous layer. Metre- to decimetre-scale folding 11 12 in these rocks is well observed in exposures on a forest track west 13 of Creag Gownan, at NN 520 024. Very fine-scale graded bedding in 14 silty laminae shows that the rocks are inverted and that the folds 15 and first cleavage face downwards. 16 The southern part of the GCR site, south of Hill Cottage (NN 515 17 031), contains exposures that reveal the nature and geometry of the 18 D1 deformation, free from the effects of subsequent deformation 19 events, most particularly D2. Outcrops of thick-bedded, very 20 coarse wacke metasandstone on the eastern flanks of Craigmore (NN 21 510 021) lie in large-scale F1 fold closures, as indicated by 22 locally variable and moderate easterly dips and by high-angle 23 intersections between bedding and cleavage. The dominant S1 24 cleavage is widely spaced (c. 0.5–1.0 cm) and anastomosing in the 25 coarse-grained lithologies, becoming more finely spaced where the 26 grain size is less. This cleavage is the S1p cleavage of the 27 Little Glen Shee, Craig a’Barns and Rotmell GCR sites. 28 The exposures on the low hills immediately east of Hill Cottage 29 30 lie within an antiform, the core of which contains very coarse 31 metasandstones with locally developed gravel lags filling scours in 32 bed tops. Graded bedding is well developed in these rocks, showing 33 unequivocally that the fold is a syncline facing downwards on the 34 first cleavage. The dominantly strongly oblique relationship 35 between bedding and first cleavage displayed in the coarse 36 metasandstones shows that most exposures lie within or close to 37 fold hinges throughout the area. The F1 folds are tight to 38 isoclinal and are generally on the decimetre scale or larger 39 (Figure 19). 40 Moving north-westwards from the Highland Boundary Fault in this 41 area, D2 structures are first seen in the coarse metasandstones of 42 the Creag Innich Sandstone Formation to the north of Hill Cottage 43 on the western side of the Duke‘s Pass and are clearly observed in 44 exposures above the A821 road in the area around NN 518 040. D2 45 structures occur only as cleavages within the Duke‘s Pass GCR site, 46 but these are widely enough spaced to appear as stacks of F2 minor 47 48 folds of the S1 spaced cleavage (cf. Booth, 1984; Harte et al., 49 1987). Large F2 folds of bedding are not observed. Where it is 50 more intense, the S2 cleavage is in general nearly parallel to the 51 steep north-dipping bedding. Towards its southern limit, it is 52 commonly more oblique to bedding, dipping generally at shallower 53 angles to the north. In the northern part of the GCR site, the S2 54 cleavage is more intensely developed and becomes the dominant 55 fabric, manifest as a strongly planar spaced cleavage, particularly 56 in the finer grained lithologies. D2 structures and their effects 57 on S1 are particularly well observed at the northern limit of the 58 GCR site at Craig Noran (NN 504 066), just north of the Achray 59 Hotel. Here, graded bedding in a thin, coarse-grained unit beneath 60 a massive, thick gritty metasandstone unit shows that the beds are 61 62 63 64 65 1 2 3 4 inverted. The S1 cleavage is nearly normal to the coarse-grained, 5 thick bed and is clearly deformed by D2, the latter resulting in a 6 locally developed, widely spaced crenulation cleavage. The near- 7 parallelism between S2 and bedding is readily apparent. 8 Effects of the D4 deformation related to the formation of the 9 Highland Border Downbend, as seen elsewhere along the Highland 10 Border (e.g. at the Craig a’Barns GCR site), are developed only 11 12 very locally within the northern part of this GCR site. For 13 example, a shallow and northerly dipping crenulation cleavage is 14 developed in metamudstones in a small exposure by the A821 road at 15 about NN 516 051. 16 17 6.3 Interpretation 18 19 The overall lithological character and the bedforms of the coarse- 20 to very coarse-grained metasedimentary rocks in the Duke’s Pass area 21 indicate that they were deposited by turbidity currents and debris 22 flows within major channels of a fan system on a continental 23 margin. They are, therefore, just part of the much more-extensive, 24 extremely dynamic, depositional system manifested by the Southern 25 Highland Group throughout the Dalradian outcrop of Scotland and 26 Ireland (Burt, 2002). In such an environment it is likely that the 27 finer grained rocks represent off-channel or overbank deposits. 28 However, the locally developed, black, cherty, sulphidic 29 30 metamudstones near Meall Ear (NN 530 027) suggest that more- 31 euxinic, pelagic or isolated basinal sedimentation occurred at 32 times. This might have reflected a major geographical shift in the 33 depositional system as much as a major deepening of the 34 depositional basin. 35 Faulting is an important feature of the Duke‘s Pass area, which 36 contains the southern end of the Loch Tay Fault system. The Loch 37 Tay Fault is known to have experienced several kilometres of 38 oblique, sinistral strike-slip movement (Treagus, 1991). This 39 precludes any close correlation of lithostratigraphical units 40 across it in the Aberfoyle area, despite apparent lithological 41 similarities. This problem applies equally to the related Duke‘s 42 Pass Fault and other parallel faults within the area. Notable 43 effects of the Duke‘s Pass Fault include the apparent displacement 44 of the incoming of D2 deformation, which is farther to the north- 45 east and in a different lithostratigraphical unit on the eastern 46 side, implying a significant change in structural level across the 47 48 fault (Figure 18). 49 The structures reveal that the Duke‘s Pass area is occupied by a 50 major F1 fold system. The original interpretation of a single 51 synformal closure centred on the Aberfoyle Slate Formation is 52 likely to be an over-simplification. Evidence for extensive long 53 fold limbs is lacking and fold hinges are commonly observed, either 54 directly or via the changes in bedding/cleavage relationships. 55 Mendum and Fettes (1985) have already shown that the Highland 56 Border Steep Belt in this area is occupied by regional-scale F1 57 nappe structures that lie structurally beneath the Aberfoyle 58 Anticline. The structural evidence in the Duke‘s Pass area, 59 outwith the effects of D2, indicates the presence of a complex F1 60 fold hinge-zone, which is most easily interpreted as the front of a 61 62 63 64 65 1 2 3 4 major nappe structure of which the Aberfoyle Anticline is part. 5 The style and degree of deformation in the metasedimentary rocks 6 suggest that the southern part of the Duke‘s Pass GCR site, south- 7 east of the Duke‘s Pass Fault, is occupied by the upper and outer 8 structural parts of this nappe front. 9 Based on the younging and structural evidence in the Duke‘s Pass 10 area, D2 structures only begin to appear at deeper structural 11 12 levels within the F1 nappe system. Hence, the absence of D2 13 effects in the southernmost part of the GCR site suggests that 14 these rocks were originally at higher structural levels and allows 15 the original geometry of the major F1 fold structures to be 16 discerned. The field evidence indicates that the F1 nappe and fold 17 structures were recumbent when formed; their current attitude in 18 the south of the GCR site resulted essentially from rotation around 19 the late Highland Border Downbend and subsequent compression during 20 D4. 21 Observations on the effects of D2 deformation on S1 cleavages in 22 particular, made in the Duke’s Pass and Bealach nam Bo GCR sites, 23 strongly suggest that D2 deformation was dominated by NW-directed 24 simple-shearing accompanied by flattening (Mendum and Fettes, 1985; 25 Mendum and Thomas, 1997). This interpretation differs 26 fundamentally from those of other workers who interpreted the Tay 27 Nappe and related structures as resulting from the combined effects 28 of D1 and SE-directed D2 deformation, the latter dominated by 29 30 simple-shearing (Harris and Bradbury, 1977; Krabbendam et al., 31 1997). Thus, the evidence from the Duke‘s Pass area, combined with 32 that from other GCR sites in this paper (Little Glen Shee, Craig 33 a’Barns, Rotmell, Garron Point to Muchalls), is critical to the 34 debate on the nature of the early orogenic events that affected the 35 south-eastern part of the Grampian Terrane as a whole (see 36 discussion by Stephenson et al., 2013a). 37 38 6.4 Conclusions 39 40 The Duke’s Pass between Aberfoyle and Loch Achray provides 41 outstanding and readily accessible exposures of Southern Highland 42 Group metasedimentary rocks. These exposures not only reveal the 43 nature of the processes that deposited the original sediments, but 44 also the effects of the subsequent, mainly Ordovician deformation. 45 The coarse metasandstones were deposited by sediment-laden currents 46 (turbidity currents) and debris flows within major channel systems 47 48 in a marine fan delta complex on a continental margin. 49 The rocks were deformed several times. The dominant early 50 structures were flat-lying, kilometre-scale folds, of which the 51 Aberfoyle Anticline is the best known. The true nature and 52 orientation of the early structures are revealed in the southern 53 part of this GCR site, because there they are unaffected by the 54 second deformation, which is observed in the northern part of the 55 site. There, the relationship between the first and second phases 56 of deformation can be readily discerned; the second structures are 57 largely parallel to the original bedding and their main effect was 58 to deform the first cleavage. 59 The structural evidence indicates that the rocks in the southern 60 part of the site occupied the upper and outer part of the uppermost 61 62 63 64 65 1 2 3 4 of the major nappes in the region, probably close to the nappe 5 front. The present steep orientation of the bedding and downward 6 facing of the folds arose from refolding of the rocks around the 7 Highland Border Downbend, a major late fold that re-orientated the 8 nose of the nappe structures. 9 10 11 7 KELTIE WATER, CALLANDER 12 (NN 644 120–NN 633 131) 13 14 P.W.G. Tanner 15 16 17 7.1 Introduction 18 19 The Keltie Water is a spate stream whose rocky bed and low cliffs 20 provide the most-complete and best-exposed section through the 21 uppermost Dalradian sequence to be found in the Highland Border 22 region. The rocks consist of an inverted succession of low 23 metamorphic grade slaty pelites and gritty metasandstones, with 24 subordinate metalimestones, which dip northwards at a low to 25 moderate angle (Figure 20). They lie stratigraphically well above 26 the Aberfoyle Slate Formation (see the Duke’s Pass GCR site report), 27 and the older part of the sequence is equated with the Ben Ledi 28 Grit Formation of the Southern Highland Group. Structurally, the 29 30 rocks lie on the south-east limb of the downward-facing F1 31 Aberfoyle Anticline, which is the local equivalent of the main 32 closure of the Tay Nappe. 33 The geology of the Keltie Water section has aroused much interest 34 and controversy since it was first examined in detail by Clough (in 35 Geikie, 1897, p. 28); the early history of research has been 36 reviewed by Tanner (1995). The most significant contributions were 37 made by Clough, who concluded that it is not possible to make a 38 clear distinction between undoubted Dalradian rocks in the north 39 and other rocks farther south; by Stone (1957), who recognized a 40 single southward-younging sequence, and disproved Anderson‘s 41 (1947a) interpretation that the rocks now referred to as the Keltie 42 Limestone and Shale Member (Figure 20) occupy a synclinal infold in 43 the metasandstones; and by Harris (1962, 1969), who concluded that 44 there is no evidence for a major stratigraphical or structural 45 break within the Keltie Water section. The subsequent debate has 46 focussed on whether or not there is stratigraphical and structural 47 48 continuity between undoubted Dalradian rocks belonging to the Ben 49 Ledi Grit Formation (which crop out in the northern part of the 50 river section) and a younger group of rocks found farther south, 51 named the Keltie Water Grit Formation (Tanner, 1995). A full 52 understanding of the relationship between these two groups of rocks 53 is vitally important, for the Keltie Water Grit Formation includes 54 the fossiliferous Leny Limestone, which is of late Early Cambrian 55 age (Pringle, 1940; Brasier et al., 1992). 56 If stratigraphical and structural continuity between undoubted 57 Dalradian rocks and the Keltie Water Grits can be demonstrated in 58 the Keltie Water section, it follows that the deformation that has 59 affected the southern part of the Dalradian block must be younger 60 than Early Cambrian in age, specifically post 519 Ma (Tanner and 61 62 63 64 65 1 2 3 4 Pringle, 1999); a conclusion that has profound implications for the 5 age of the Grampian Event in the Scottish Caledonides. The 6 alternative, strongly argued, viewpoint (Bluck and Ingham, 1997; 7 but see Tanner, 1997) is that there is a major structural break 8 between these two rock units, which is interpreted as a terrane 9 boundary separating the Dalradian succession sensu stricto from the 10 Keltie Water Grits (Brasier et al., 1992). In this scenario, the 11 12 Leny Limestone and Keltie Water Grits would be part of the Highland 13 Border Complex, which is interpreted by those authors as an exotic 14 terrane that docked with the Dalradian of the Grampian Terrane in 15 late-Silurian to Devonian times. In this case, separation of the 16 fossiliferous rocks from the Dalradian by a terrane boundary would 17 remove any restriction on the maximum age of the deformation of the 18 Dalradian rocks, and hence on the timing of the Grampian Event. 19 The rocks exposed in the Keltie Water provide some of the key 20 evidence for deciding between these two opposing hypotheses. 21 The other important feature of this site is the faulted contact of 22 the Keltie Water Grits against Lower Old Red Sandstone conglomerate 23 and volcanic rocks seen at the southern limit of the stream 24 section. This fault has been referred to as the ‗Highland Boundary 25 Fault‘. 26 27 7.2 Description 28 29 30 The emphasis in this account is upon the rocks exposed in the 31 Keltie Water and the lower part of its tributary, the Allt Breac- 32 nic (Figure 20). These rocks, referred to as the ‘Leny Grits’ by 33 previous authors, were divided by Tanner (1995) into two main 34 parts, from north to south: 35 (1) undisputed Dalradian rocks, mainly green gritty metasandstones, 36 which are petrographically similar to those of the Ben Ledi Grit 37 Formation in the classical Dalradian sequence farther north; and 38 (2) the Keltie Water Grit Formation, which comprises a thick 39 sequence of pale-coloured gritty metasandstones associated with 40 grey and black slaty horizons, and includes a Transition Member of 41 metasandstones and slaty pelites at the base. 42 All of the metasandstones in the c. 1.4 km-thick sequence exposed 43 in the Keltie Water section are of turbidite facies and have a very 44 similar field appearance. They preserve abundant way-up evidence 45 from graded bedding, and less common cross-lamination, in beds that 46 consistently preserve bottom structures, probably modified load- 47 48 casts. This sequence is affected by faults and is cut by many, 49 thick, irregularly shaped bodies of felsite (?late Caledonian) and 50 two dolerite dykes of Palaeogene age. 51 52 7.2.1 Stratigraphy 53 54 Exposures in the upper part of the Allt Breac-nic are in massive 55 gritty metasandstones with few minor structures or cleavages. The 56 southern boundary of the Ben Ledi Grit Formation has been drawn at 57 the southern limit of green and grey-green gritty metasandstones 58 with abundant chlorite, detrital pink feldspar, and quartz 59 (commonly pale blue). Workers familiar with the Southern Highland 60 Group would confidently label these rocks as ‘Dalradian’. They 61 62 63 64 65 1 2 3 4 almost certainly interdigitate with those of the Transition Member 5 to the south, and include rare pale-coloured metasandstones similar 6 to those commonly found in the main part of the Keltie Water Grit 7 Formation. 8 The Transition Member comprises green, grey-green, brown and pale- 9 coloured gritty metasandstones with green, grey and purple slaty 10 pelites. The limit of the green-coloured rocks southwards marks 11 12 the southern boundary of the transition and is accompanied by the 13 incoming of grey and white metasandstones characteristic of the 14 Keltie Water Grit Formation. The latter occur together with grey, 15 black and variegated slaty pelites. The pale-coloured 16 metasandstones are generally clast-supported, highly siliceous and 17 have much Fe-rich carbonate in their matrix, so explaining why they 18 are much more deeply weathered than the greenish coloured 19 metasandstones to the north. 20 The Keltie Limestone and Slate Member appears to be a local facies 21 development within a sequence of metasandstones that all young to 22 the south-east. The black slaty pelites forming the middle unit 23 contain numerous beds of orange-weathering, finely laminated 24 carbonate rock, which contains abundant ferroan dolomite. A metre- 25 sized lens of calcite metalimestone (the Keltie Limestone) is 26 exposed in a small disused working at NN 6468 1252; major and trace 27 element analyses show that it has the same overall composition as 28 the Leny Limestone (Tanner and Pringle, 1999). 29 30 The black slaty pelites, which are part of the Leny Limestone and 31 Slate Member, can be traced intermittently from Leny Quarry to the 32 Keltie Water, and are correlated with the southernmost exposures of 33 pelites found in the Keltie Water section. A full account of the 34 setting, age, and correlation of the metalimestone, which is only 35 exposed in Leny Quarry some 4 km south-west of the Keltie Water, is 36 given in a GCR site report for that locality (in Rushton et al., 37 1999) and in the paper by Tanner and Pringle (1999). The Leny 38 Limestone and Slate Member consists of contorted and brecciated 39 dull green to black slaty pelites with some chert bands, and grey 40 and purple slaty pelites, intruded by 55 cm- and 15 m-thick 41 dolerite dykes and by bodies of felsite; no metalimestone has been 42 positively identified from these rocks in the Keltie Water section. 43 A detailed petrographical study of the entire sequence from the 44 Ben Ledi Grit Formation to the southernmost exposure of the Keltie 45 Water Grit Formation (Tanner and Pringle, 1999) has shown that the 46 gritty metasandstones making up the bulk of this sequence have a 47 48 distinctive detrital mineralogy throughout of quartz, plagioclase 49 feldspar, white mica, biotite, tourmaline and zircon. K-feldspar 50 is absent, and the amounts of detrital plagioclase and biotite 51 decrease stratigrphically upwards. However, metasandstones of 52 comparable grain size throughout this sequence show no discernable 53 difference in petrographical features such as grain shape, strain 54 fabrics and state of preservation of detrital micas (Figure 21). 55 56 7.2.2 Structure 57 58 Bedding throughout the section is generally inverted and dips to 59 the north, except locally on the middle limbs of metre-scale minor 60 folds where the beds are right way up and in places dip southwards. 61 62 63 64 65 1 2 3 4 The main cleavage is a spaced cleavage in the metasandstones, with 5 microlithons up to 2 cm thick (Figure 22). It appears, in 6 exposures and under the hand-lens, to be a slaty cleavage in silty 7 and argillaceous rocks. The cleavage is axial planar to the minor 8 folds, or forms weak cleavage fans symmetrical to them; the folds 9 have a variable plunge, which is gentle in the north but more 10 variable and steep (up to 50° to either south-west or north-east) at 11 12 the south end of the section. The main cleavage is invariably 13 steeper than inverted bedding throughout the section. 14 In order to test for continuity in structural geometry across the 15 boundary between the Ben Ledi Grit and the Keltie Water Grit 16 formations, stereographic projections of the main cleavage were 17 prepared for the southern part of the Ben Ledi Grit outcrop (Figure 18 20, area A), the Transition Member (area B), and the northern part 19 of the Keltie Water Grit outcrop (area C). These plots show that 20 the mean orientation of the main cleavage in these three subareas 21 is very similar and that it is not possible to separate the areas 22 on the basis of structural geometry. 23 Harris (1969) recognized two main fabrics in these rocks, a 24 penetrative slaty cleavage and a crenulation cleavage, which he 25 correlated with similar structures in the adjoining Dalradian 26 sequences. The crenulation cleavage is superimposed upon, and 27 crenulates, the main cleavage described here and is most strongly 28 developed in the argillaceous horizons such as the black slaty 29 30 pelites above the waterfall at NN 6458 1247. The crenulation 31 cleavage formed during a weak deformational event, which resulted 32 in a gentle upright warping of beds in parts of the section. From 33 a microscope study of the structural fabrics, Harris and Fettes 34 (1972) subsequently identified an early cleavage in these rocks, 35 which lies at a very low angle to bedding, and formed before the 36 main cleavage. It is very difficult to see the early cleavage in 37 the field. 38 The contact between the Keltie Water Grit Formation and the Lower 39 Old Red Sandstone is seen as a fault at NN 6451 1221, first 40 described in detail by Harris (1969). The fault plane dips at 54° 41 to the north-west (strike 048°) and is overlain by 40 cm of fault 42 gouge and fragmented rock, followed by several metres of contorted 43 and polished black slaty pelites. The exposed Old Red Sandstone 44 succession commences with 5 m of conglomerate found in the stream 45 bed immediately south of the fault, which is overlain by volcanic 46 rocks dipping steeply to the south-east. 47 48 49 7.3 Interpretation 50 51 All previous workers, from Clough in 1897 to the present day, have 52 agreed that the Ben Ledi Grit Formation and the overlying pale 53 metasandstones and black slaty pelites of the Keltie Water Grit 54 Formation form an essentially unbroken stratigraphical succession 55 (i.e. Harris, 1962; Tanner, 1995). The transition beds, which 56 occur between them, appear to be a normal stratigraphical part of 57 the sequence and not to have arisen from tectonic interleaving. 58 The rocks have all been affected by the same sequence of structural 59 events, and are all at the same metamorphic grade (Tanner and 60 61 62 63 64 65 1 2 3 4 Pringle, 1999). No evidence has been presented that contradicts 5 any of these conclusions. 6 As has been demonstrated here, the main cleavage (S1) in the 7 Keltie Water section maintains a consistent orientation and facing 8 direction across the boundary between the Bed Ledi Grit and the 9 Keltie Water Grit formations. Recent confirmation that there is 10 evidence of a pre-D1 deformation phase in both the Bed Ledi Grit 11 12 and the Keltie Water Grit formations, strengthens the structural 13 correlation between these two units (Harris et al., 1998; Tanner, 14 1998b). It is extremely unlikely that two sets of structural 15 fabrics, which have formed at relatively low strains (Figure 20 16 insets) and at low metamorphic grade, could have originated 17 independently in two terranes of entirely different age and origin 18 and then, upon amalgamation of the two terranes, become 19 indistinguishable in their morphology, geometry, and facing 20 direction. No alternative interpretation has been proposed to 21 explain the structural data. 22 Recent work has also shown that that the metasandstones in the 23 sequence have many petrographical features in common, despite the 24 fact that burial diagenesis has almost certainly altered all of the 25 detrital plagioclase to nearly pure albite (An1-3), and caused 26 dissolution of any pre-existing K-feldspar (Figure 21). The 27 results of a whole-rock geochemical study of these metasandstones 28 are consistent with the conclusion reached from the petrography, 29 30 that the main vertical changes in composition reflect a progressive 31 upward decline in amounts of detrital plagioclase and biotite 32 (Tanner and Pringle, 1999). In addition, electron-microprobe 33 analysis of the detrital white micas from these rocks has shown 34 that they have a comparable range in Si, Fe, Mg, and Ti contents at 35 all levels of the sequence, with more-sodic micas occurring in the 36 Transition Member and younger rocks. The wide range in chemistry 37 suggests that they were derived from a complex source region. 38 40Ar/39Ar laser fusion ages on detrital white micas from 39 metasandstones at five different levels in the sequence gave age 40 spectra which show a gradation from all old mica ages in the Ben 41 Ledi Grit Formation (mainly 1600–1800 Ma, with a few at 2100 Ma) to 42 a mixed population of old and younger white micas (507–886 Ma) in 43 the Keltie Water Grit Formation. This work shows that none of the 44 mica ages has been reset by Caledonian regional metamorphism, 45 agreeing with the results of the petrographical work that the 46 regional metamorphism was of low greenschist facies throughout, 47 48 with no detectable metamorphic breaks, and maximum temperatures o 49 probably not exceeding 270 C. 50 The reported differences in whole-rock geochemistry, detrital mica 40 39 51 composition and Ar/ Ar age upward in the succession are, as far as 52 can be determined, progressive. Some of these changes may be 53 linked to the establishment of a stable shelf environment, with the 54 incoming upwards from the Ben Ledi Grits to the top of the Keltie 55 Water Grit Formation of black muds, dark limestones, and 56 dolostones, and an increase in the amount of possible detrital 57 carbonate minerals in the turbidites (Tanner and Pringle, 1999). 58 These data do not however preclude the possibility that an 59 intraformational break may be present somewhere in the sequence. 60 61 62 63 64 65 1 2 3 4 The most illuminating finding from these investigations is that 5 there is no suggestion from either the field observations or the 6 various analytical data, of a major stratigraphical/structural 7 break at a single, discrete level within the sequence that might be 8 taken as positive evidence for the presence of a terrane boundary. 9 Such a terrane boundary, if it existed, would have to be located 10 between the southernmost exposure of undoubted Dalradian rocks (Ben 11 12 Ledi Grit Formation), belonging to the Grampian Terrane, and the 13 rocks farther south which include the Leny Limestone and were once 14 considered to belong to an exotic terrane (the Highland Border 15 Complex), which collided with the Grampian Terrane in late-Silurian 16 to Devonian times (Brasier et al., 1992; Bluck and Ingham, 1997). 17 In view of the conclusion supported here that the rocks from the 18 undoubted Dalradian Supergroup to the top of the Keltie Water Grit 19 Formation are in their original stratigraphical sequence, this 20 latter formation should be included logically within the Dalradian 21 Supergroup. It is the lowest formation in the proposed Trossachs 22 Group of Tanner and Sutherland (2007), which would include all 23 units of the Highland Border Complex that crop out structurally 24 below (i.e. north-west of) the Highland Border Ophiolite. This new 25 Dalradian group would include strata containing fossils as young as 26 Arenig in age. 27 It follows from the above relationships that the upper part of the 28 Dalradian succession must have been deposited between 646 Ma (the 29 30 youngest reliable detrital white mica age in the Keltie Water 31 sequence and c. 517–509 Ma (the probable age range of upper Lower 32 Cambrian rocks such as the trilobite-bearing Leny Limestone; 33 Davidek et al., 1998). This conclusion is compatible with the U-Pb 34 age on zircon of 595 ± 4 Ma for the Tayvallich Volcanic Formation, 35 which lies near the top of the Argyll Group (Halliday et al. 36 1989), and with the 590 ± 2 Ma age for the Ben Vuirich Granite 37 (Rogers et al. 1989; Dempster et al., 2002), which hornfelsed 38 previously undeformed Dalradian rocks prior to the Grampian Event 39 (Tanner and Leslie, 1994; Tanner, 1996; Tanner et al., 2006). 40 In conclusion, as all of the rocks at this site can be shown to 41 have shared the same structural history, then the Grampian Event 42 where it affects the Southern Highland Group, is of post-Early 43 Cambrian age (i.e. post 509 Ma). The Tay Nappe deformations 44 (regional D1 and D2), and a possible earlier episode of deformation 45 (Harris et al., 1998; Tanner, 1998b) are also therefore of post- 46 Cambrian age. 47 48 49 7.4 Conclusions 50 51 The Keltie Water provides a unique section of national importance 52 through the uppermost Dalradian strata exposed in the Highland 53 Border region. Its importance lies in the fact that it is the only 54 place in the Grampian Terrane where there is an exposed section 55 linking undoubted Dalradian rocks with fossiliferous rocks of known 56 biostratigraphical age. Trilobites of Early Cambrian age have been 57 reported from the Leny Limestone, which occurs at the nearby Leny 58 Quarry GCR site (Rushton et al., 1999). As the Dalradian rocks 59 were once thought to be much older than this, the stratigraphical 60 and structural relationship between undoubted Dalradian rocks and 61 62 63 64 65 1 2 3 4 strata in the Keltie Water that are correlated with the Cambrian 5 rocks at Leny Quarry, has excited much scientific interest. 6 Accordingly, the geological relationships seen at this GCR site 7 have been the subject of much research and rigorous scientific 8 debate in the past few decades. 9 Most geologists who have studied this GCR site now conclude that 10 there is stratigraphical and structural continuity within the 11 12 Keltie Water section, and a corresponding lack of evidence for a 13 postulated terrane boundary between the undoubted Dalradian and the 14 Cambrian rocks. The important corollary to this is that the 15 Grampian Event, where it affects the upper part of the Dalradian 16 sequence, commenced after the Early Cambrian, and that there is no 17 evidence to support the hypothesis that a prior Precambrian 18 orogenic event had affected the Dalradian rocks. 19 20 8 21 22 23 LITTLE GLEN SHEE 24 (NN 979 346) 25 CRAIG A’BARNS 26 (NO 019 438–NO 014 442) 27 ROTMELL 28 29 (NO 014 469–NO 011 475) 30 31 A.L. Harris 32 33 34 8.1 Introduction 35 36 The Little Glen Shee, Craig a’Barns and Rotmell GCR sites, in the 37 Dunkeld area of the Highland Border, collectively display the 38 essential features of the structure, sedimentology and metamorphism 39 of the Perthshire outcrop of the Southern Highland Group. In order 40 to fully appreciate the overall geological situation, it is 41 necessary to combine observations and deductions from all three 42 sites (Figure 23). Consequently this site report consists of a 43 general introduction, detailed descriptions of the three individual 44 sites, an overall interpretation and combined conclusions. 45 The three sites, which are in fairly close geographical proximity, 46 were selected particularly to demonstrate the increasing structural 47 48 complexity and increasing metamorphic grade with tectonic depth in 49 the Tay Nappe, the major recumbent anticlinal nappe fold of the 50 South-eastern Grampian Highlands (Figure 24). All three occur in 51 the inverted lower limb of the nappe, which extends across strike 52 almost from the Highland Border to the NE-trending Tummel Steep 53 Belt, some 17 km to the north-west (Figures 23 and 24a). Over much 54 of its extent, the lower limb is not only inverted, but is 55 regionally subhorizontal, comprising the Flat Belt. However, to 56 the south-east of the Flat Belt, the flat-lying inverted rocks have 57 been bent down through as much as 120o, across the hinge of a late, 58 regional-scale, NE-trending asymmetrical antiform, the Highland 59 Border Downbend. On the south-east limb of this fold, the formerly 60 flat-lying rocks now dip steeply (c. 60o) to the north-west, and 61 62 63 64 65 1 2 3 4 thus are generally the right way-up (Figures 23 and 24). These 5 rocks constitute the Highland Border Steep Belt (Harris et al., 6 1976). Thus, the sites have been chosen to represent rocks low in 7 the Highland Border Steep Belt (Little Glen Shee), rocks high in 8 the Highland Border Steep Belt and lying in the hinge-zone of the 9 Highland Border Downbend (Craig a‘Barns) and in the Flat Belt 10 (Rotmell). 11 12 The detailed structural geology of the area containing these three 13 GCR sites has been described and discussed by Stringer (1957), 14 Shackleton (1958) and Harris et al. (1976); some of the tectonic 15 structures and fabrics discussed here were illustrated and 16 described by Bradbury and Harris (1982). Rose and Harris (2000), 17 working to the south-west of these GCR sites, distinguished two 18 zones within the Highland Border Steep Belt, which they termed A 19 and B. The exposures comprising the Little Glen Shee GCR site 20 relate to their Zone A, while many of the features of Zone B are 21 displayed in the south-eastern part of the Craig a‘Barns site. The 22 transition from Zone A to Zone B is not exposed in this area. 23 The rocks of all three GCR sites comprise interbedded 24 metasandstones and metasiltstones, stratigraphically assigned to 25 the Southern Highland Group (Harris et al., 1994). In the Dunkeld 26 area, three units were proposed by Harris (1972): the Birnam Grit 27 (oldest; base not seen), the Birnam Slate, and the Dunkeld Grit 28 (youngest; top not defined). Elsewhere, the lower two units have 29 30 been combined into a single Birnam Slate and Grit Formation, 31 reflecting a more-complex stratigraphical distribution of the two 32 sedimentary facies (Crane et al., 2002). The depositional 33 environment of the original clastic sediments, mainly comprising 34 poorly sorted turbiditic sands with minor silty beds, was discussed 35 by Harris et al. (1978) and Anderton (1985), who concluded that 36 the coarse-grained clastic deposits were laid down in channels on 37 the lower slopes and inner zones of deep-water submarine fans, with 38 the finer grained sediments being laid down as overbank deposits or 39 in outer-fan facies. Lateral continuity of any one facies is 40 therefore unlikely and, even where traceable over short distances, 41 probably has little chronostratigraphical significance. Hence 42 conclusions about the relative ages of the rocks at the three GCR 43 sites are tentative and are based on structural considerations (see 44 Interpretation). 45 The cross-sections in Figure 24 show the relative structural 46 positions of the three GCR sites; Little Glen Shee originally lay 47 48 at a higher level in the nappe than Craig a‘Barns and Rotmell, both 49 of which lie at a similar level. The Little Glen Shee site 50 illustrates the earliest deformation which, in addition to 51 producing folds of bedding, induced a cleavage in the rocks that 52 takes the form of a slaty cleavage in the metasiltstones and a 53 pressure-solution striping (S1p) in the metasandstones. Subsequent 54 deformation episodes modified the S1p; that associated with the 55 second deformation (D2) modified the original planar striping into 56 F2 folds having thick hinges but highly attenuated limbs. F2 57 folds, which predominate in the Flat Belt, are seen in their 58 original attitude at the Rotmell GCR site. They have been bent 59 down around the Highland Border Downbend at the Craig a‘Barns site 60 and there they are seen to be overprinted by the downbend-related 61 62 63 64 65 1 2 3 4 structures and fabrics. Although the rocks of the Little Glen Shee 5 site lay initially at a higher level in the Tay Nappe than those at 6 either Craig a‘Barns or Rotmell, they were bent down by the 7 Highland Border Downbend so that their original 8 stratigraphical/structural configuration has been changed and their 9 cleavage and folds now face downwards. The Little Glen Shee GCR 10 site therefore exemplifies the concept of ‗downward facing‘ on 11 12 first cleavage that was first developed by Shackleton (1958) in the 13 Highland Border region (see Stephenson et al., 2013a, p. 32). 14 The three GCR sites also illustrate the variation in the 15 metamorphic grade of the Southern Highland Group in the Highland 16 Border region of Perthshire. Metasiltstones at Little Glen Shee 17 are chloritic slates, whereas at Craig a‘Barns they are phyllites 18 typically containing chlorite and white mica with some biotite. 19 Metasiltstones at Rotmell carry conspicuous euhedral, almandine 20 garnets. While structural complexity and tectonic strain at Craig 21 a‘Barns are comparable with those at Rotmell, and are considerably 22 greater than at Little Glen Shee, the metamorphic grade at Rotmell 23 appears to be notably higher. 24 25 8.2 Description 26 27 28 29 8.2.1 Little Glen Shee GCR Site 30 31 Little Glen Shee intersects the Highland Border between the rivers 32 Almond and Tay, some 15 km north-west of Perth. The GCR site is 33 located some 450 m along the track leading north-west from Little 34 Glen Shee farm. It was chosen as an excellent example of the 35 sedimentary and tectonic features of the weakly deformed and 36 metamorphosed Southern Highland Group rocks occurring originally at 37 a high level of the Tay Nappe, but subsequently bent down to a 38 lower structural level by the Highland Border Downbend. 39 The rocks described here form a large crag to the north-east of 40 the track, about 100 m north of a large (4 m × 1.5 m) boulder 41 (Figure 25). 42 The metasedimentary rocks probably belong to the Birnam Slate and 43 Grit Formation and consist of well-defined beds of poorly sorted, 44 matrix-supported coarse- to medium-grained metasandstone wackes 45 that grade upwards, usually passing by rapid transition into fine- 46 grained metasandstones and mica-rich metasiltstones. Such graded 47 48 beds are up to 0.5 m thick and the grading is well picked out by 49 cleavage refraction (Figure 25, insets 1 and 2; Figure 26a). There 50 are abundant subangular clasts of quartz and feldspar up to 2 mm 51 across in the coarser fraction. Some of the metasandstone beds are 52 composite and are inferred to have been deposited by more than one 53 turbidity current. Bedding lamination (Figure 25, insets 1 and 2; 54 Figure 26b) and more-rarely small-scale cross-lamination are 55 commonly well displayed in the medium- to fine-grained 56 metasandstones. Where seen, the younging indicated by the cross- 57 lamination is consistent with that shown by the graded bedding. 58 The beds have been folded into a pair of modified buckles, having 59 o rounded hinges, straight limbs, interlimb angles of c. 70 and 60 wavelengths of c. 7 m (Figure 25). Parasitic on these, a smaller 61 62 63 64 65 1 2 3 4 pair of modified buckles have wavelengths of c. 1 m (Figure 26b), 5 and minor folds having wavelengths of 3–4 cm are developed in their 6 core. Sedimentary structures all young unequivocally towards the 7 cores of the antiforms and away from the cores of synforms, so that 8 successively younger beds are encountered as axial planes are 9 traced downwards. Hence, the folds face downwards. 10 In addition to the folding of the sedimentary layers, the D1 11 12 deformation imposed a cleavage which takes two distinct forms that 13 are lithologically dependent: (1) a pressure-solution cleavage in 14 the metasandstones (S1p of Harris et al., 1976); and (2) a slaty 15 cleavage in the metasiltstones (S1). 16 The S1p cleavage is confined to the metasandstone layers towards 17 the base of each graded bed and comprises well-defined planes, 18 normally orientated at a high angle to bedding. These planes, 19 which are spaced at intervals of c. 1 cm, coalesce and ramify in 20 detail, both laterally and normal to bedding such that the rock 21 between the planes is rendered into lenticles, commonly referred to 22 as ‗microlithons‘. Close examination of the planes of S1p shows 23 that they comprise, not planes, but narrow zones (less than 1 mm 24 wide) largely made up of micaceous material. The abundant mica in 25 these zones results in their differential weathering, leaving the 26 centimetre-scale siliceous lenticles standing conspicuously proud 27 of the weathered surface. Hence the orientation pattern of the S1p 28 laminae can be readily picked out and it is easy to see that it 29 o 30 fans through as much as 100 and that it is approximately 31 symmetrical about the fold axial planes. Fanning is a feature of 32 the S1p in Figure 26b. 33 During the process of deformation and the formation of S1p, 34 considerable re-orientation of primary bedding features within the 35 sandstone layers evidently took place. This becomes apparent where 36 the orientation of bedding lamination within the cleavage domains 37 (S0lam), is compared with the orientation of gross bedding (S0); S0lam o 38 is commonly 45 or more, oblique to S0, particularly on the inverted 39 SSE-younging limbs (Figure 25). Within-bed re-orientation of 40 cleavage is also displayed locally, although it probably occurred 41 entirely later than the formation of S1p. In some beds, S1p has 42 been buckled sufficiently to face upwards and downwards within the 43 same bed without the bed itself being apparently folded. 44 S1 refers to the penetrative axial-planar slaty cleavage that 45 occurs in the finer grained original tops of the graded beds. In 46 thin section this cleavage is seen to be defined by aligned white 47 48 mica and chlorite, and by quartz and feldspar having a preferred 49 dimensional orientation. S1 is oblique to S1p except in the fold 50 cores where it is approximately parallel. Elsewhere S1p refracts 51 into the plane of S1, the curving surface associated with the 52 change in orientation clearly indicating the narrow zone within 53 each bed where the decrease in original grain size from sand to 54 silt occurs. By contrast, the contact between the coarse-grained 55 base of each bed and the fine-grained top of the bed immediately 56 below it is emphasised by the sharp angular break between the S1 in 57 the older bed and the S1p in the younger bed. (Figure 26b). 58 D2 and Highland Border Downbend-related structures are not 59 developed at this site. 60 61 62 63 64 65 1 2 3 4 8.2.2 Craig a’Barns GCR Site 5 6 The Craig a’Barns GCR site lies within an area of steep crags, 7 several of which are popular rock-climbing venues, in an area of 8 woodland about 1 km north-west of Dunkeld. The site has been 9 chosen to represent rocks at a relatively high structural level in 10 the Highland Border Steep Belt and in the hinge-zone of the 11 12 Highland Border Downbend. The cross-sections in Figure 24 show 13 that the rocks at Craig a’Barns originally lay at a similar level in 14 the Tay Nappe to those at Rotmell, but the bedding and the F2 15 folds, which predominate in the Flat Belt, have been bent down 16 around the Highland Border Downbend and are seen to be overprinted 17 by the downbend-related structures and fabrics. While structural 18 complexity and tectonic strain at Craig a’Barns are comparable with 19 those at Rotmell and are considerably greater than at Little Glen 20 Shee, the metamorphic grade is not as high as at Rotmell. 21 The rocks at the site are probably among the youngest Dalradian 22 rocks exposed in the Dunkeld area, and are assigned to the Dunkeld 23 Grit Formation. They are described in a traverse through several 24 key localities across the Highland Border Downbend, from the steep 25 south-east limb through the hinge-zone to the gently inclined 26 north-west limb (Figures 23 and 24). The localities are shown on 27 Figure 27. The F1 folds exposed at the Little Glen Shee GCR site 28 have not been observed here, the dominant structures being F2 folds 29 30 of the S1 and S1p cleavages as well as D4 structures associated 31 with the Highland Border Downbend. The rocks are metamorphosed 32 sandstones and mudstones, but convincing way-up indicators have not 33 been found. The rocks are in the greenschist facies of Barrovian 34 metamorphism, so that the metasiltstones are phyllitic and 35 typically containing chlorite and white mica with some biotite. 36 Minute spessartine-rich almandine garnets occur in laminae between 37 pressure-solution cleavage planes (S1p) within the metasandstones 38 (M.P. Atherton, personal commmunication, 2000). 39 Locality A (NO 0194 4378) is a cliff face some 18 m high, above a 40 short, boulder-strewn slope. On this face, a fold-pair on the 41 scale of the crag is defined by a 2 m-thick metasandstone bed. The 42 long limbs of the fold-pair dip at 60o–70o to the north-west and the 43 short limb dips gently to the south-east. This fold-pair is 44 parasitic on the south-east limb of the Highland Border Downbend 45 and indicates that the main hinge lies to the north-west. Small- 46 scale open folds of 2–3 cm wavelength, associated with a weakly 47 48 developed crenulation cleavage dipping at moderate angles to the 49 north-west, are inferred to be downbend-related structures. 50 The early cleavages, S1p and S1, lie subparallel but at a 51 discernible angle to bedding; the millimetre-scale spacing of the 52 S1p planes shows that the intervening microlithons are considerably 53 attenuated in comparison with those seen at the Little Glen Shee 54 GCR site. Both cleavages are affected locally by D2 structures. 55 F2 fold wavelengths are on a centimetre to decimetre scale with 56 interlimb angles from 60o to isoclinal; hinges are curvilinear about 57 the horizontal and vergence is to the north-west. S2 cleavage is 58 axial planar to F2 folds, whose axial surface traces are also 59 subparallel to bedding. 60 61 62 63 64 65 1 2 3 4 Locality B (NO 0183 4389) consists of vertical to overhanging 5 crags. Although the crags display interference between F2 and 6 Highland Border Downbend-related folds and overprinting of S1, S1p 7 and S2 by downbend-related crenulations and minor folds, this 8 locality is most remarkable for its display, in microcosm, of the 9 essential relationships of the Highland Border Downbend. Up a 10 natural ―step‖, about 1 m high, in the base of the crag, a 1 m3 11 12 exposure of metasandstone displays a smooth planar surface defined 13 by bedding and S1p that has been bent down to the south-east around 14 a smooth open asymmetrical antiform from a subhorizontal into a 15 subvertical attitude. This NE-trending, small-scale antiform is 16 inferred to be parasitic on the south-east limb of the Highland 17 Border Downbend. A well-defined shape-fabric lineation, contained 18 within the folded planar surface, trends approximately N–S on the 19 flat top surface of the fold and is also bent down across the 20 antiform hinge to plunge steeply to the south-west in its steep 21 limb. Figure 28a shows a subvertical cross-section of the 22 antiform, illustrating the nature, attitude and sense of 23 overturning of F2 folds on both its subvertical and subhorizontal 24 limbs and the folding and downbending of S1p. The spacing of the 25 S1p cleavage has been severely attenuated by D2 (see 26 Interpretation). Adjacent metasiltstones show the NW-dipping 27 downbend-related crenulation cleavage to be approximately axial 28 planar to the antiform. 29 30 Locality C consists of crags that lie in the hinge-zone of the 31 Highland Border Downbend. In particular the first crag reached to 32 the north of the path (NO 0175 4387), probably lies very near to 33 the downbend hinge-zone. It displays, in micaceous lithologies, a 34 very strongly developed crenulation cleavage dipping generally to 35 the north-north-west at 45o–50o, but variable up to 60o–70o (Figure 36 28b); this is inferred to mark the attitude of the downbend axial 37 surface. The crenulation cleavage is axial planar to ENE-trending 38 open parasitic folds in the hinge-zone of the downbend (Figure 39 28c). At the top of the exposure illustrated in Figure 28c, 40 bedding is essentially parallel to both S1 and S2 but in the bottom 41 left, S1p is at a distinct angle to bedding. Tight F2 folds of S1p 42 (not seen in Figure 28c), having highly attenuated limbs, lie with 43 their axial surfaces at variable, but high, angles to the inferred 44 downbend axial surface. 45 The main path, running up a glacial meltwater channel, reaches a 46 deer fence at (NO 014 442) passing on the way numerous crags above 47 48 it on the right (north-east). All of these crags lie within the 49 Flat Belt but the two nearest to the fence (locality D, NO 0149 50 4411) are the most rewarding. Gross bedding, defined by 51 metasandstone - metasiltstone interlayering, and S1p are generally 52 flat lying or gently inclined but are bent locally into a steep 53 attitude to form the intermediate limb of a Z-shaped (looking 54 north-east) fold-pair. These folds, which are on a scale of metres 55 to decimetres, indicate an asymmetrical antiform to the south-east, 56 i.e. the Highland Border Downbend, although their hinge-zones are 57 transected by the NW-dipping crenulation cleavage also related to 58 the downbend (see Interpretation). 59 60 61 62 63 64 65 1 2 3 4 8.2.3 Rotmell GCR Site 5 6 Rotmell Farm is adjacent to the A9 trunk road and 4–5 km north- 7 north-west of Dunkeld. The Rotmell GCR site is a series of small 8 exposures within a rectangle of open heather-clad rocky hillside 9 above the farm, measuring some 700 m × 200 m and elongated almost 10 precisely north-west - south-east. The site has been chosen to 11 12 represent the lower, inverted limb of the Tay Nappe in the 13 regionally subhorizontal Flat Belt, to the north of and unaffected 14 by the Highland Border Downbend. 15 The rocks at the site could be assigned to either the Dunkeld Grit 16 Formation or to the stratigraphically lower Pitlochry Schist 17 Formation (see Interpretation). The cross-sections in Figure 24 18 show that they occur at a similar stratigraphical level to those of 19 the Craig a‘Barns site and that they originally lay at a similar 20 structural level in the Tay Nappe. At this level, the original 21 planar striping (S1p) generated during the first deformation 22 episode (D1), has been modified during the second deformation (D2). 23 F2 folds having thick hinges but highly attenuated limbs, which 24 predominate in the Flat Belt, are seen in their original flat-lying 25 attitude at Rotmell. While the structural complexity and tectonic 26 strain at Rotmell are comparable with those at Craig a‘Barns, the 27 metamorphic grade at Rotmell appears notably higher. 28 The solid geology comprises metasandstones interbedded with 29 30 subsidiary metasiltstones and metamudstones, now quartz-mica 31 schists and garnet-mica schists. Locally the metasandstones are 32 notably pebbly, containing granules of less than 5 mm diameter. 33 These rocks, which are more highly metamorphosed than those at 34 locality D at Craig a‘Barns, some 3–4 km to the south, are typical 35 of the Southern Highland Group at moderate metamorphic grade. The 36 rocks are inferred to be inverted, but convincing direct evidence 37 from sedimentary structures is lacking at this site. 38 Conspicuous in the metasandstones are centimetre- to metre-scale 39 zones, in which thin seams between the early pressure-solution 40 cleavage planes (S1p) are affected by F2 folding. The centimetre- 41 scale, NE-trending, F2 folds occur in pairs or even-numbered 42 multiples and the seams are notably thinner on the limbs than in 43 the hinges (Figure 29). The zones containing folds are commonly 44 separated from one another by zones lacking folds but in which the 45 S1p seams are strongly attenuated. The folds are almost invariably 46 overturned and are stacked in such a manner as to suggest that they 47 48 are parasitic on a recumbent fold, the axial surface of which lies 49 above the present erosion surface and closes to the south. F1 50 folds and angular relationships between bedding (S0) and S1 51 cleavages have not been observed. Marked lineations, similar to 52 those described from locality B at the Craig a‘Barns GCR site, 53 comprise grain-shape and quartz rodding, and are approximately 54 north-trending on flat-lying foliation surfaces formed by composite 55 S1 and S2 cleavages. Together the lineations and foliation define 56 an LS fabric, the lineation representing the finite extension 57 direction related to D2. This is well displayed at NO 1496 4703. 58 The metasiltstone layers in particular carry subhedral to 59 euhedral, spessartine-poor almandine garnets up to 0.5 cm in 60 diameter. Close examination of these with a hand lens shows that 61 62 63 64 65 1 2 3 4 individual garnets contain an internal planar fabric defined by 5 relict inclusions, a pre-garnet foliation (?S1), while the garnet 6 crystals themselves are wrapped by the conspicuous mica-defined 7 foliation in their matrix (composite S1/S2). S1/S2 itself is 8 crenulated by small-scale folds the axial surfaces of which dip 9 north-west at c. 30o with the development of an incipient 10 crenulation cleavage. This modification of the fabric may well be 11 12 related to the Highland Border Downbend episode of deformation 13 (D4). Excellent examples of these relationships may be seen at NO 14 0122 4734, about 70 m north-west of a solitary, conspicuous beech 15 tree. 16 17 8.3 Interpretation 18 19 The Little Glen Shee, Craig a’Barns and Rotmell GCR sites complement 20 one another and together are important to our understanding of: 1) 21 the mechanisms of deformation and regional metamorphism, including 22 pressure solution, that accompany the development of a major nappe, 23 in this case the Tay Nappe, from its earliest stages to its 24 transport and emplacement; and 2) the geological history of the 25 Scottish Highlands and the timing of events in the Scottish sector 26 of the Caledonide /Appalachian Orogen. 27 The turbiditic environment in which the sediments of these three 28 GCR sites were deposited makes the relative ages of the rocks and 29 30 the stratigraphical correlation between them difficult. Regional 31 structural and stratigraphical relationships strongly suggest that 32 the rocks at Little Glen Shee might lie some 2–3 km 33 stratigraphically below the Craig a‘Barns strata (Harris, 1972; 34 Harris and Fettes 1972). The rocks at Little Glen Shee lie in the 35 Birnam Slate and Grit Formation, which is older than the Dunkeld 36 Grit Formation of the Craig a‘Barns site, which probably includes 37 the youngest Dalradian rocks exposed in the area. However, there 38 is ambiguity in assigning the rocks at Rotmell to a 39 lithostratigraphical unit. The gentle overall dip to the north- 40 west of the rocks on the north side of the Craig a‘Barns site 41 suggests that the inverted strata there are likely to pass below 42 those at Rotmell, which are also inferred to be inverted. If so, 43 the rocks at Rotmell are slightly older than those at Craig 44 a‘Barns. The high metamorphic grade of the rocks at Rotmell, 45 indicated by the coarse grain size and the conspicuous garnet also 46 lends them obvious affinity to the Pitlochry Schist Formation of 47 48 the area to the north. Defining a boundary between the Pitlochry 49 Schist and the Dunkeld Grit formations, however, has never been 50 attempted. The differences between them are probably due as much 51 to secondary effects, such as metamorphic grade and intensity of 52 pressure solution, as to any primary contrasts in the protolith. 53 The Highland Border Downbend, an asymmetrical, overturned open 54 antiform, has as its steep south-east limb a zone of steeply NW- 55 dipping, right-way-up rocks that, pre-downbend, were flat-lying and 56 inverted on the lower limb of the nappe (Figure 24). These steeply 57 dipping strata now crop out between the axial surface trace of the 58 Highland Border Downbend and the Highland Boundary Fault. 59 Consequently, a horizontal traverse from south-east to north-west 60 across the zone is equivalent to a vertical section from high to 61 62 63 64 65 1 2 3 4 lower levels of the nappe. Excellent examples of the contrasting 5 phenomena typical of each level are displayed by the Little Glen 6 Shee and the Craig a‘Barns GCR sites respectively. Thus insights 7 into the significant changes in the conditions of temperature and 8 pressure (confining and directed) that took place with increasing 9 depth in the nappe can be obtained by comparing these two sites. 10 The Little Glen Shee site offers opportunities to view and 11 12 interpret the effects of the earlier stages in nappe development 13 (D1), unobscured by the overprinting of the D2 fabrics resulting 14 from the transport and emplacement of the nappe (as seen at the 15 Craig a‘Barns and Rotmell GCR sites). North-west of the axial 16 surface trace of the Highland Border Downbend the lower, inverted 17 limb of the nappe is essentially at the same structural level as 18 the Craig a‘Barns site over the c. 17 km of gently undulating rocks 19 that lie between the downbend and the Tummel Steep Belt (Figures 23 20 and 24). These are represented by the Rotmell GCR site, where the 21 rocks are in their post-D2, pre-downbend attitude. Rotmell thus 22 complements Craig a‘Barns because, although significantly higher in 23 metamorphic grade, the fabrics in the rocks here relate only to D1 24 and D2 and were not complicated by the post-D2 overprint of fabrics 25 related to the Highland Border Downbend. The post-D2 fabrics are 26 largely confined to the axial zone of the downbend and can be 27 correlated broadly with the regional D4 phase. 28 The F2 folds that are a feature of the Craig a‘Barns and Rotmell 29 30 sites have been related by Harris et al. (1976) and Rose and 31 Harris (2000) to SE-directed shear that contributed to the 32 emplacement of the Tay Nappe. These sites thus offer important 33 insights into the mechanisms of nappe emplacement in general and 34 the Tay Nappe in particular (but see also the Duke’s Pass GCR site 35 report for an alternative interpretation). The thinned ‗limbs‘ of 36 the F2 folds are interpreted here as top-to-the-SE shear-zones 37 (involving largely simple-shear) whereas the ‗hinges‘ are zones in 38 which D2 strain is low. The thin micaceous seams that comprise the 39 conspicuously folded laminae at Craig a‘Barns and Rotmell 40 originated by pressure solution as the S1p cleavage. In its 41 pristine state, this cleavage can be studied at Little Glen Shee, 42 where the S1p seams normally lie at a high angle to bedding (60o– 43 90o). At the Craig a‘Barns and Rotmell GCR sites, the angle between 44 bedding and S1p, albeit small as a result of D2 strain, is still 45 discernable, as is their original ramifying and coalescing primary 46 pattern of intersection. Consequently, it is concluded that, at an 47 48 early stage of deformation (D1), tectonically induced pressure 49 solution produced a lithological lamination in the rocks that was 50 not related to primary bedding and that this lamination was 51 subsequently deformed as the D2 emplacement of the nappe proceeded. 52 The emplacement and transport of the nappe by the D2 structures 53 might only have become possible as increased metamorphic grade, 54 rising through the nappe with time, permitted the formation of the 55 ductile shear-zones that comprise the F2 fold limbs. If so there 56 was likely to have been a strong element of diachroneity in the 57 imposition of both the D1 and D2 structures. 58 Tentative, but important and regionally significant conclusions 59 about the pattern and timing of regional metamorphism can be drawn 60 from the combined evidence at the three GCR sites. It seems likely 61 62 63 64 65 1 2 3 4 from the evidence at the Rotmell site that the peak of metamorphism 5 post-dated the fabrics included in the garnets and pre-dated the 6 crumpling of the composite S1/S2 schistosity during the deformation 7 that produced the Highland Border Downbend (D4). One could 8 conclude from these relationships that the isograds reflecting the 9 pressure and temperature patterns at the regional metamorphic peak 10 were essentially established before the imposition of the downbend 11 12 and that the isograd surfaces were bent down to the south-east into 13 the Highland Border Steep Belt with the earlier tectonic 14 structures. This would account for the rise in metamorphic grade 15 from Little Glen Shee to Craig a‘Barns. The contrast in grade 16 between these two sites could be explained by isograds dipping 17 generally south-eastwards slightly more steeply than the 18 subhorizontal to gently inclined bedding/foliation planes in the 19 inverted limb of the nappe. This interpretation would be 20 consistent with the metamorphic grade at Rotmell being intermediate 21 between that at Craig a‘Barns and that of the kyanite-bearing 22 migmatitic pelites of the Ben Lui and Pitlochry Schist formations 23 to the north. 24 A general conclusion that can be drawn from these three GCR sites, 25 taken collectively, is that the intensity of deformation and 26 metamorphism is independent of age in rocks as complex as those 27 described. The oldest rocks, i.e. those from Little Glen Shee, are 28 the least deformed and metamorphosed of the three sites. However, 29 30 without their comparative simplicity, explicit facing and younging 31 characteristics and well-developed pressure-solution cleavage, 32 interpretation of the other two sites would be more difficult and 33 uncertain than is the case. 34 The sets of folds and fabrics described and interpreted above are 35 widely recognized and correlated throughout the south-eastern 36 Grampian Highlands. The first and second sets have been 37 demonstrated by Rose and Harris (2000) to be the result of an 38 essentially continuous process of early deformation producing 39 upright folds and pressure-solution cleavage, passing into 40 recumbent folds as the former were deformed and transported to the 41 south-south-east on D2 shear-zones. This continuity is important 42 in interpreting the age of orogenesis in the Grampian Terrane. The 43 earliest cleavages overprint the Keltie Water Grit Formation of the 44 Callander district, which includes the Lower Cambrian Leny 45 Limestone (Tanner, 1995; Harris et al., 1998; see the Keltie Water 46 GCR site report) and hence must be younger than the radiometrically 47 48 dated Ben Vuirich Granite (590 ± 2 Ma; Rogers et al., 1989) that 49 had formerly been used to indicate the minimum age of the 50 orogenesis (see the Ben Vuirich GCR site report). The conclusion 51 that the earliest fabrics post-date Cambrian rocks means that the 52 orogenesis was Early Palaeozoic in age, probably mid Ordovician, 53 rather than Neoproterozoic, as was believed formerly. 54 55 8.4 Conclusions 56 57 The Little Glen Shee, Craig a’Barns and Rotmell GCR sites together 58 display the best set of exposures in the British Isles to exhibit 59 the sequence of structures developed during the initiation, 60 emplacement and modification of a major recumbent fold (nappe). 61 62 63 64 65 1 2 3 4 This fold, the Tay Nappe, is one of the largest and most 5 significant major structures in the whole of the Grampian Terrane, 6 and indeed in the whole of Great Britain. The sites also show 7 typical examples of the primary sedimentary and subsequent 8 metamorphic characteristics of the rocks that comprise the Southern 9 Highland Group. 10 Relative to the other two GCR sites in this area, the rocks of the 11 12 Little Glen Shee site originated at the highest level in the Tay 13 Nappe and are at the lowest metamorphic grade. They display 14 exceptionally well-preserved sedimentary structures, especially the 15 graded bedding that results from the rapid deposition of coarse 16 sands in a turbiditic deep-water environment. They also display 17 unusually clear examples of the first generation of folds, together 18 with their steeply dipping axial-planar cleavage, which in the 19 coarser grained rocks takes the form of a widely spaced pressure- 20 solution cleavage. The bedding/cleavage relationships, together 21 with the sedimentary structures, show quite dramatically at this 22 site that the folds are totally inverted; this was the classic area 23 where Shackleton (1958) first developed the concept of structural 24 ‗facing‘, now an internationally accepted term. These folds are 25 thus ‗downward-facing‘, the explanation for which requires 26 examination of the Craig a‘Barns GCR site. 27 The rocks of the Craig a’Barns GCR site once occupied deeper 28 levels of the Tay Nappe than those of the Little Glen Shee site. 29 30 Consequently, the original sedimentary bedding characteristics, and 31 the small-scale folds and cleavages that formed during the initial 32 stage of nappe formation, have all been considerably modified by a 33 second generation of small-scale structures, both folds and 34 cleavage, which relate to subsequent development of the nappe. The 35 site also contains possibly unique exposures of the hinge of a 36 later major fold, the Highland Border Downbend, which was 37 responsible for the rotation of the original flat-lying rocks, 38 exemplified in the Rotmell GCR site, into the steep-dipping 39 downward-facing attitude, seen in the Little Glen Shee GCR site. 40 At the Rotmell GCR site it can be clearly seen that the cleavage 41 related to the first generation structures, as seen at the Little 42 Glen Shee GCR site, has been strongly modified by a second 43 deformation. It has been suggested that the second generation of 44 small-scale structures, both folds and cleavage, are a result of 45 the transport and emplacement of the Tay Nappe. Originally upward- 46 facing first structures are believed to have been translated many 47 48 kilometres to the south-east, and modified by the second 49 deformation, so that much of the Southern Highland Group, such as 50 that in the Rotmell GCR site, lies in the inverted limb of the 51 resulting sideways-facing fold. Rocks in the Rotmell GCR site 52 contain crystals of garnet, which are evidence of relatively deep 53 burial, but rocks originally at a higher level in the nappe and 54 subsequently bent down, such as those now exposed at the Little 55 Glen Shee GCR site, exhibit a much lower grade of metamorphism. 56 57 58 59 60 61 62 63 64 65 1 2 3 4 9 GLEN ESK 5 (NO 586 733–NO 583 736, 579 744, 583 756, 574 766, 560 6 785) 7 8 D. Gould and B. Harte 9 10 11 12 9.1 Introduction 13 14 The valley of the River North Esk in the Angus Glens is in the 15 heart of the area where George Barrow first demonstrated the 16 development of successive mineral assemblages during the 17 progressive regional metamorphism of pelitic rocks (Barrow, 1893, 18 1912). Here, the transition from low to high metamorphic grade can 19 be studied over a distance of a few kilometres and the GCR site 20 comprises six localities, one for each metamorphic zone, selected 21 largely on grounds of ease of access (Figure 30). These 22 localities, together with alternatives for some of the zones, were 23 described by Harte (1987). 24 While working for the Geological Survey in this area, Barrow was 25 the first person to define a scheme of indicator minerals for 26 different degrees of regional metamorphism in pelitic rocks. He 27 initially defined seven zones: the lowest grades were ‗clastic 28 mica‘ and then ‗digested clastic mica‘, and up grade of these were 29 30 zones defined by the progressive incoming of biotite, garnet, 31 staurolite, kyanite and sillimanite. Tilley (1925) combined the 32 two lowest grades into a single chlorite zone, since the 33 distinction between clastic and non-clastic white micas was 34 doubtful. Hence we now recognize six zones ranging from chlorite 35 to sillimanite (Figure 31). This scheme, known as the Barrovian 36 scheme, was found to apply to large areas of the Dalradian outcrop, 37 and has been recognized in many other regional metamorphic terranes 38 worldwide. In terms of overall metamorphic facies, it corresponds 39 to a relatively high-pressure part of the greenschist and 40 amphibolite facies. 41 However, in the area north of the River Dee and east of the 42 Portsoy Shear-zone, a different sequence of metamorphic zones is 43 developed. This, the Buchan scheme of Read (1955), corresponds to 44 lower pressures over the same range of temperatures (see Stephenson 45 et al., 2013b). A transitional zonal sequence between the two 46 regimes is exposed on the coast north of Stonehaven (Harte and 47 48 Hudson, 1979) (see the Garron Point to Muchalls GCR site report). 49 Barrow‘s original zonal scheme has stood the test of time, 50 although Chinner (1966) regarded the development of fibrolitic 51 sillimanite as a later thermal ‗overprint‘ upon both the Barrovian 52 and the Buchan zones. However, Harte and Johnson (1969) used thin 53 sections to date the development of the metamorphic fabric of the 54 rocks with respect to the various fold episodes in the district. 55 They showed that prograde metamorphism continued longer in the 56 higher grade rocks than in the lower grade rocks, and that the 57 post-D3 crystallization of sillimanite, although overstepping the 58 lower grade zones in places, was the culmination of a single long 59 period of prograde metamorphism. Retrogression was associated with 60 D4 and later movements. 61 62 63 64 65 1 2 3 4 Also in this area, Atherton and Brotherton (1972) showed that the 5 first appearance of kyanite in regionally metamorphosed pelites and 6 semipelites is controlled by the effective Mg/Fe2+ ratio of the 7 rock. Harte and Hudson (1979) used petrological and geochemical 8 methods to attempt to quantify pressures and temperatures at 9 various stages in the metamorphic history of the eastern Grampian 10 Highlands. 11 12 Field excursions that visit this GCR site have been described by 13 Harte (1987) and MacGregor (1996). 14 15 9.2 Description 16 17 The first three localities are along the banks of the River North 18 Esk; the others are on crags away from the river (Figure 30). 19 20 9.2.1 Locality 1, Chlorite Zone: North Esk Gorge (NO 586 733) 21 The North Esk Fault at this locality separates Dalradian rocks to 22 the north-west from Highland Border Complex rocks to the south- 23 east. The Dalradian rocks consist of compositionally layered, 24 grey-green schistose chlorite-muscovite pelites, semipelites and 25 psammites. Porphyroblasts of magnetite and rare pyrite up to 2 mm 26 across are widely visible. A spaced cleavage developed during D1 27 is overprinted by an S4 crenulation cleavage, which is only visible 28 in the more-micaceous lithologies. 29 30 31 9.2.2 Locality 2, Biotite Zone: North Esk Gorge (NO 583 736) 32 This locality is only c. 200 m upstream of locality 1. The 33 lithologies are similar to those at locality 1, but also include 34 beds of gritty psammite up to 1 m thick. The rocks look very 35 similar to the chlorite-zone rocks, but a few flakes of brown 36 biotite are visible in some layers. In thin section, the rocks are 37 well-foliated semipelites and pelites with a good fabric formed by 38 the alignment of muscovite and chlorite parallel to an S1 39 foliation. This fabric has been crenulated during D4. Post-dating 40 the S1 fabric but pre-dating the S4 crenulations, are scattered, 41 randomly orientated biotite porphyroblasts up to 1 mm long by 0.5 42 mm wide, which are visible on freshly broken surfaces of the more- 43 pelitic rocks. 44

45 9.2.3 Locality 3, Garnet Zone: Auchmull (NO 579 744) 46 One of the few accessible exposures of garnet-zone rocks is c. 800 47 48 m upstream of locality 2, on the west bank of the River North Esk, 49 near the end of the largely continuous exposures through the 50 chlorite and biotite zones. Here, the rocks are grey-green 51 schistose semipelites and pelites, similar to those at localities 1 52 and 2, but slightly coarser in grain size. The S1 foliation can be 53 seen to be disrupted locally by a widely-spaced S2 cleavage, which 54 gradually becomes more persistent northwards. The F4 folds are 55 less numerous than at locations 1 and 2, and the S4 crenulation 56 cleavage is only weakly developed. The locally abundant garnet 57 porphyroblasts, up to 5 mm in diameter, are best seen on the south- 58 east side of low exposures that protrude into the river. 59 Elsewhere, where the rocks are more psammitic, garnet is hard to 60 find. The garnets are seen in thin section to be poikilitic, with 61 62 63 64 65 1 2 3 4 inclusions generally smaller than the grain size of the matrix. 5 The folds in the inclusion trails show that the garnets grew post 6 D2 and pre D4. Biotite porphyroblasts up to 3 mm across also occur. 7 8 9.2.4 Locality 4, Staurolite Zone: Craig of Weston (NO 583 756) 9 This is the upper of the two localities described by Harte (1987), 10 in an area where there is much loose rock but little material 11 12 definitely in situ. Staurolite is developed in the more-pelitic 13 layers lying within a dominantly psammitic to semipelitic 14 succession. Here, the dominant fabric in the pelitic rocks is a 15 penetrative schistosity, which is related to the well-developed S2 16 spaced cleavage in the semipelites and psammites. Relics of S1 are 17 preserved in the microlithons between the S2 cleavages. The S2 18 cleavage is in places folded by tight minor folds ascribed to D3, 19 but the broad open F4 folds, characteristic of lower Glen Esk, are 20 absent. 21 The pelites are considerably coarser grained than those at 22 localities 1 to 3. A fabric defined by 2–3 mm-long muscovite and 23 biotite crystals dominates the rock. Randomly orientated 24 porphyroblasts of garnet and staurolite reach 5 mm in size. Some 25 of the rocks contain anhedral porphyroblasts of poorly twinned 26 plagioclase. Much of the coarsening of the fabric of the rocks and 27 the prophyroblast growth probably occurred during D3. 28 29 30 9.2.5 Locality 5, Kyanite Zone: Craigoshina (NO 574 766) 31 At this locality, the rocks have the same coarse mica fabric as at 32 locality 4, and the dominant fabric is S2, which is folded by minor 33 F3 folds. In the Glen Esk–Glen Lethnot area in general, kyanite is 34 best developed in silvery muscovite-rich pelites, many of which 35 also contain abundant haematite porphyroblasts. These pelites form 36 units up to 100 m thick, extending for up to 2 km along strike, and 37 represent a distinctive lithology with a higher Fe3+/Fe2+ ratio than 38 the surrounding rocks. Because of the oxidized nature of the 39 rocks, kyanite is abundant at this locality despite the rocks being 40 below the regional kyanite isograd for less-oxidized rocks 41 (Chinner, 1960; Harte, 1966; Atherton and Brotherton, 1972). The 42 fabric of the rocks is dominated by abundant well-aligned muscovite 43 flakes with relatively little biotite. Porphyroblasts of garnet 44 and staurolite reach 5 mm in size, and kyanite crystals are 45 typically up to 3 cm in length. The kyanite porphyroblasts contain 46 abundant inclusions of fine-grained haematite, and many of them 47 48 have retrogressed to fine-grained aggregates of white mica. Better 49 crystallized, and more typically blue kyanite is present in some of 50 the numerous quartz veins. Garnet occurs in the haematite-kyanite 51 schists but is fine grained and hence difficult to see (Chinner, 52 1960). 53 54 9.2.6 Locality 6, Sillimanite Zone: Hillock (NO 560 785) 55 At this locality schistose semipelites and pelites form rough 56 craggy knolls. The rough surface of the more-pelitic rocks 57 displays welts and knots up to several centimetres long, consisting 58 of tiny fibres of sillimanite, usually intimately associated with 59 quartz. Larger upstanding ‗blobs‘ of fibrous sillimanite, 1–2 cm 60 across, on weathered surfaces, can be found surrounding garnets. 61 62 63 64 65 1 2 3 4 In this area, the main foliation of the rocks is still the 5 composite S0-S1-S2, but in the cores of the tightest of the 6 abundant flat-lying F3 folds, the axial planar S3 cleavage merges 7 with the earlier composite foliation. Minor folds showing 8 crenulation of the mica fabric are attributed to D4. Between the 9 kyanite-zone exposure and this exposure, the more-feldspathic 10 semipelites and impure psammites show incipient segregations of 11 12 quartzofeldspathic laminae, typically with biotitic selvedges, 13 indicating the commencement of migmatization in susceptible 14 lithologies. 15 16 9.3 Interpretation 17 18 The sequence of six typical exposures illustrates the effects of 19 progressive regional metamorphism of pelitic rocks at medium to 20 high pressures. The first five of these exposures occur within the 21 Glen Lethnot Grit Formation, a 1500 m-thick succession of gritty, 22 turbiditic psammites, with interbeds of semipelite and pelite, 23 typically forming graded units 0.5–2.5 m thick (Harte, 1979; Gould, 24 2001). The sillimanite-zone exposure lies within the older, Glen 25 Effock Schist Formation, which contains more semipelite and less 26 psammite than the Glen Lethnot Formation. 27 The Barrovian index minerals are typically confined to the pelitic 28 lithologies, although chlorite and biotite also occur in 29 30 semipelites and impure psammites. Kyanite is best developed in an 31 atypical, highly oxidized type of pelite characterized by silvery 32 mica felts and numerous small haematite porphyroblasts. One of 33 these pelites has been chosen for inclusion in the GCR site. 34 The local peak of metamorphism occurred progressively later in the 35 higher metamorphic grades (Harte and Johnson, 1969; Robertson, 36 1994); it was syn to post D2 in the chlorite and biotite zones, post 37 D2 but pre D3 in the garnet zone, and syn D3 in the staurolite, 38 kyanite and sillimanite zones. The migmatization in the highest- 39 grade rocks overlapped D3 in nearby Glen Clova (Robertson, 1991). 40 Retrogressive effects, with alteration of biotite to chlorite and 41 of staurolite and kyanite to sericitic felts, are associated with 42 areas of intense D4 crenulation, and with the post-D4 folds 43 associated with emplacement of the Mount Battock Pluton. Dempster 44 (1985a) has used Rb-Sr and K-Ar dating to plot pressure-temperature 45 paths and to work out the cooling and uplift history of the area. 46 He concluded that the main metamorphism occurred at 520–490 Ma, 47 48 with peak temperatures occurring progressively later at greater 49 burial depths. After local uplift at 520–490 Ma, two major periods 50 of uplift occurred at 460–440 Ma, associated with D4, and 410–390 51 Ma, associated with intrusion of the Mount Battock Pluton. 52 Dempster (1985b) also estimated that peak metamorphism in the 53 kyanite and sillimanite zones in nearby Glen Lethnot occurred at a 54 temperature of 630–660 oC and a pressure of 5.7–6.2 kbar. 55 The temperature and pressure gradients estimated from the 56 compositions of pairs of co-existing minerals is steeper than would 57 be calculated from the exposed outcrop width of the zones in Glen 58 Esk. This probably implies a considerable degree of tectonic 59 thinning within the Glen Lethnot Grit Formation. A clue to the 60 timing of the thinning occurs in areas a short distance to the 61 62 63 64 65 1 2 3 4 east, where Phillips and Auton (1997) described blastomylonites 5 within Glen Lethnot Formation rocks south of the Mount Battock 6 Pluton. From their mineral textures, they deduced that most of the 7 mylonitization and accompanying attentuation of the metamorphic 8 zones occurred during D2. 9 10 11 9.4 Conclusions 12 13 The Glen Esk GCR site is within the internationally recognized type 14 area for the Barrovian type of regional metamorphism. It was here 15 in 1893 that George Barrow first erected a scheme of metamorphic 16 zones based upon the first appearance of various index minerals 17 with increasing metamorphic grade in pelitic rocks. These zones 18 are typical of regional metamorphism at moderate to high pressures 19 within the greenschist and amphibolite facies and have subsequently 20 been recognized throughout the world. The GCR site provides, 21 within a short distance, examples of Dalradian pelitic rocks from 22 all of the Barrovian metamorphic zones, which are characterized, 23 with increasing grade, by chlorite, biotite, garnet, staurolite, 24 kyanite and sillimanite. 25 The exposures are all readily accessible and are invaluable for 26 teaching purposes. Only the garnet-zone exposure is of less than 27 excellent quality, and even it is acceptable. The index minerals 28 can mostly be seen with the naked eye, and all are conspicuous 29 30 under a hand lens. The exposures can also be used to demonstrate 31 the development of folds and cleavages during successive 32 deformation and progressive coarsening of texture within rocks of 33 increasing metamorphic grade. 34 Thin sections from these rocks have enabled the timing of growth 35 of the various minerals to be worked out with respect to the four 36 regional deformations that affected Dalradian rocks of the eastern 37 Grampian Highlands. Further work could involve electron-microprobe 38 analysis of co-existing mineral phases to work out the temperature 39 and pressure during deformation in different parts of the site. 40 However, such studies would be partly hampered by the effects of 41 retrogression that are particularly associated with the D4 42 deformation. 43 44 10 GARRON POINT TO MUCHALLS 45 (NO 894 877–NO 907 921) 46 47 48 C.W. Thomas 49 50 51 10.1 Introduction 52 53 The east coast of the Grampian Highlands, north of Stonehaven, 54 provides a continuously exposed and largely accessible section 55 through Southern Highland Group metasedimentary rocks (Figure 32). 56 The outcrops reveal in outstanding detail, the characteristics of 57 the original sedimentary rocks and their response to metamorphism 58 and deformation. In particular, there is a continuous section 59 across the Tay Nappe, from the Flat Belt, across the Highland 60 Border Downbend, into the Highland Border Steep Belt and the 61 62 63 64 65 1 2 3 4 downward-facing complex hinge-zone of the nappe, which is truncated 5 here by the Highland Boundary Fault (Figure 33). In addition, 6 distinctive metamorphic mineral assemblages are developed within 7 the pelitic rocks, which differ from those of the ‘Buchan’ 8 metamorphism to the north, and the ‗Barrovian‘ metamorphism to the 9 west. 10 The importance of this coast section has long been recognized. 11 12 Although the study of the metamorphic mineral assemblages has been 13 an important feature (e.g. Williamson, 1953; Harte and Hudson, 14 1979), it is the study of the structure that has been particularly 15 important and highly relevant to the regional Dalradian structure. 16 Anderson (1942, 1947a) was the first to describe and interpret the 17 geological structure of the coast, relating this to the structure 18 he observed in the River North Esk. And Stringer (1957) identified 19 the four main phases of deformation, which he traced from the coast 20 along the Highland Border to the south-west. However, it was 21 Shackleton (1958) who recognized the monoformal Highland Border 22 Downbend, and was able to show, by combining way-up evidence in the 23 metasedimentary rocks with the geometrical relationships between 24 first cleavage and bedding, that the first fold structures in the 25 Highland Border Steep Belt are downward-facing. In other words, he 26 showed that the sequence was already inverted prior to folding 27 around the Highland Border Downbend. This inversion was attributed 28 to the emplacement of an early nappe, equivalent to the Tay Nappe 29 30 of Perthshire. However, the recognition of a right-way-up 31 succession in the Tarfside district to the west led Harte (1979) to 32 propose that the coast section may not lie on the inverted limb of 33 the Tay Nappe, but on the right-way-up limb of an underlying 34 ‗Tarfside Nappe‘. This interpretation was supported by Booth 35 (1984), who also concluded that the coast section lies on a right- 36 way-up fold limb. But more-recent work by the British Geological 37 Survey during the remapping of 1:50 000 Sheet 67 (Stonehaven, 1999) 38 indicated that this interpretation is difficult to substantiate. 39 Younging evidence in outcrops to the north of the Highland Border 40 Downbend shows that the rocks are generally inverted, which is more 41 consistent with the traditional interpretation that the coast 42 section lies in the lower, inverted limb of the Tay Nappe. 43 44 10.2 Description 45 46 The GCR site extends for some 5 km from the southern end of Skatie 47 48 Shore at Garron Point (NO 894 877), to Ritchie Shore (NO 907 921), 49 some 300 m south-east of Muchalls. The coast is dominated by steep 50 cliffs, locally up to 30 m or more in height, above a rock platform 51 that is exposed at mid to low tides. 52 The metasedimentary rocks are very well bedded. Bedding is 53 generally planar, although beds do wedge out locally. Graded 54 bedding is abundant and is seen particularly well in the south of 55 the site, where the metamorphic grade is lower. The succession is 56 dominated by metasandstone (psammite), with metasiltstone 57 (semipelite) and metamudstone (pelite) common in many places. The 58 metasandstones vary from fine-grained, thinly bedded units to 59 massive, very coarse-grained and sometimes pebbly or 60 microconglomeratic units in excess of 2 m in thickness. To the 61 62 63 64 65 1 2 3 4 north of the Highland Border Downbend, calcsilicate-bearing layers 5 commonly occur in the centre of metasandstone beds. These are 6 thought likely to be of diagenetic origin, but now contain garnet, 7 amphibole and plagioclase. Units containing volcanic debris, 8 informally known as ‗green beds‘ and a notable feature of the 9 Southern Highland Group elsewhere, are conspicuously absent from 10 the coast section, exacerbating correlation problems. 11 12 The structure of the coast section is complex. Four major phases 13 of deformation are developed between Garron Point and Findon Ness 14 (NO 944 974), to the north of the GCR site, and three of these are 15 readily observed within the site. The site is divided into two 16 structural domains by the Highland Border Downbend (Figures 32 and 17 33). This major structure cuts the coast at Castle Rock of 18 Muchalls (NO 899 907), where it is very sharply defined, much more 19 so than in many other areas of the Highland Border region. The 20 coast to the north of the downbend is occupied generally by 21 relatively shallow-dipping strata of the Flat Belt. To the south 22 of the downbend, strata dip steeply, generally to the north-north- 23 west, in the Highland Border Steep Belt. 24 D1 structures dominate the southern part of the GCR site along 25 Skatie Shore and Perthumie Bay, and this early phase of deformation 26 appears to be generally more intense than in some other areas where 27 lithostratigraphically equivalent rocks are exposed (e.g. in the 28 Aberfoyle district; see the Duke’s Pass GCR site report). It is 29 30 manifested most obviously as coarsely spaced, anastomising 31 cleavages (S1) in gritty metasandstone beds. Tight to isoclinal F1 32 folds can be shown to be present on the basis of changes in 33 younging direction, but hinges are very rarely seen. The best 34 example is exposed below mid tide on the rock platform in the 35 southern part of Perthumie Bay. In this example, the S1 cleavage 36 is seen to fan around the hinge. On the basis of the facing of the 37 S1 cleavages observed in the southern part of the site, it is clear 38 that the F1 fold system is not cylindrical, and F1 fold plunges are 39 markedly variable. 40 D2 structures probably occur throughout the GCR site, but are only 41 readily observable north of Perthumie Bay. In addition, it appears 42 that the D2 deformation is not pervasive. D2 is manifested by 43 complex minor structures that deform the first cleavage in the 44 metasandstones in a very characteristic manner, giving rise to what 45 is most easily described as a very coarse crenulation cleavage. 46 The minor F2 folds formed within this cleavage have axial planes 47 48 that are approximately parallel to the bedding and have markedly 49 curvilinear hinges. F2 folds to the south of the Highland Border 50 Downbend plunge generally to the south-west. To the north of the 51 downbend they plunge to the north. Larger F2 folds of bedding are 52 developed more commonly in the northern part of the coast section, 53 where they are tight to isoclinal in form. The D2 deformation is 54 probably heavily partitioned into the pelitic rocks, but the fine- 55 grained and recrystallized nature of these lithologies obscures the 56 D1-D2 relationships that are so readily observed in the coarse- 57 grained metasandstones. D2 deformation is generally considered to 58 just pre-date or be synchronous with the peak of metamorphism. 59 The D3 deformation is not well developed within the GCR site; 60 unequivocal D3 structures are best observed in the Portlethen area 61 62 63 64 65 1 2 3 4 about 6 km to the north of Muchalls. Folds just north of Red Man 5 (NO 892 888), ascribed by Booth to D3 (Booth, 1984; see also Harte 6 et al., 1987, locality 6), are thought more likely to have resulted 7 from D1 deformation. Locally developed cleavages of obscure origin 8 might be due to D3 effects, but their relationships to other 9 cleavages are commonly ambiguous and they could well have arisen 10 from local strain partitioning. 11 12 The D4 deformation is complex and probably occurred over a 13 protracted period, involving early extension, followed by 14 compression. The observable effects of this phase of deformation 15 are focussed on the Highland Border Downbend. F4 folds are 16 overturned towards the downbend from both the south and the north. 17 They are open to close, parallel fold structures that become more 18 intense towards the downbend. In the Steep Belt, F4 folds are 19 centimetre- to ten metre-scale structures. In the Flat Belt, F4 20 folds range in scale from small, centimetre-sized structures to 21 large folds on the scale of tens of metres. These larger 22 structures produce local steep zones that form the short limbs of 23 the folds. Crenulation cleavages are best developed in pelitic 24 beds and in laminae within the hinge regions of the folds. F4 25 folds plunge at shallow angles mainly to the south-west and, less 26 frequently, to the north-east. F4 axial planes dip at shallow 27 angles to the north-west. 28 Faults and dislocations are a common feature of the coast section. 29 30 In general, they appear to become more common towards the Highland 31 Border Downbend from the south and are common in the Flat Belt 32 towards Muchalls, where they result in a complex, incised 33 coastline. In broad terms, they can be divided into low-angle and 34 high-angle sets. 35 The low-angle faults were probably related to D4 compression after 36 the formation of the Highland Border Downbend, probably originating 37 as thrust structures during or after the development of F4 folds. 38 Good examples of low-angle faults are observed in Hall Bay (NO 898 39 899). One at the northern end of Hall Bay is clearly a thrust, 40 having a thin gouge along the fault plane. Low-angle 41 discontinuities are displaced by a steep fault in the section east 42 of Craigview (NO 9050 9127), about 1 km south of Muchalls. This 43 suggests that the steep faults post-date the low-angle faults. 44 Two sets of steep faults are identified. A dominant set trending 45 north-west is responsible for the deeply incised coastline north of 46 the Highland Border Downbend, particularly around Doonie Point (NO 47 48 903 910) and on the promontory at Grim Haven, south of Muchalls. 49 These faults generally dip steeply to the north-east or south-west 50 and the available field evidence indicates that they are normal 51 faults. The other conjugate set trends north-east and dips steeply 52 to the south-east or north-west, but these faults are relatively 53 uncommon compared to the NW-trending set. They are roughly 54 parallel to the regional strike and the Highland Boundary Fault and 55 might be related to the formation of the Highland Border Downbend. 56 The metamorphism within the coast section is characterized by a 57 rapid increase in grade northwards from the Highland Boundary 58 Fault. This is manifested by the development of distinctive 59 mineral assemblages in the pelitic rocks, most notably chloritoid + 60 biotite and andalusite, the latter in place of the kyanite that is 61 62 63 64 65 1 2 3 4 characteristic of the classic Barrovian assemblages of the Angus 5 glens to the south-west. The presence of chloritoid and andalusite 6 led Harte (1975) to define the ‗Stonehavian‘ metamorphic assemblage 7 sequence, which is intermediate between the relatively high- 8 pressure Barrovian and high-temperature Buchan sequences (Harte and 9 Hudson, 1979). Biotite + chlorite-bearing pelitic rocks at Skatie 10 Shore become garnet-bearing in the northern part of Perthumie Bay. 11 12 Chloritoid appears first in the northern part of Red Man in highly 13 aluminous pelites (Harte and Hudson, 1979). The main appearance of 14 chloritoid results from the discontinuous reaction between garnet 15 and chlorite to yield chloritoid + biotite, this being the 16 chloritoid isograd in the Stonehavian sequence. Staurolite first 17 appears just to the north of Red Man (NO 892 888), initially 18 resulting from reaction between chloritoid and chlorite to produce 19 staurolite + biotite and then from the terminal breakdown of 20 chloritoid to give staurolite + garnet + biotite. Andalusite is 21 the stable aluminosilicate polymorph throughout the site. The 22 staurolite + biotite assemblages coupled with the presence of 23 andalusite indicate peak metamorphic pressures of no more than 24 about 3 kbar at temperatures in excess of 500°C (Spear, 1993). 25 26 10.3 Interpretation 27 28 There are no precise constraints on the age of the metasedimentary 29 30 rocks within this GCR site. All are assigned to the Glen Lethnot 31 Grit Formation, in the upper part of the Southern Highland Group. 32 This formation is now generally considered to be broadly equivalent 33 in its lithological character and lithostratigraphical level to the 34 Ben Ledi Grit Formation of the Aberfoyle–Callander area, a 35 correlation first suggested by Anderson (1942). However, the lack 36 of significant marker horizons at this site precludes precise 37 correlation. Although metasiltstones and metamudstones are common 38 locally, metasandstones dominate. Their general sedimentological 39 characteristics indicate deposition within a submarine fan system 40 on a continental margin, generally by turbidity currents; mass-flow 41 mechanisms are thought to have been responsible for the deposition 42 of massive, very thick single units of coarse, gritty rocks. 43 The metasedimentary rocks were strongly deformed during the 44 Grampian Event of the Caledonian Orogeny and three of the four main 45 phases of deformation generally recognizable in the Dalradian are 46 developed within the GCR site. The pre-D2 way-up of the section is 47 48 critical to the interpretation of the overall structural setting. 49 Although Harte (1979) proposed, by analogy with the Tarfside 50 succession inland, that the coast section might lie in the right- 51 way-up limb of a nappe lying below the Tay Nappe, all the available 52 younging evidence in the Flat Belt indicates that the rocks are 53 generally inverted. This, coupled with the downward-facing nature 54 of the F1 folds in the Steep Belt, indicates that the rocks are 55 more-readily interpreted as lying within the inverted limb of an 56 early nappe structure most simply correlated with the Tay Nappe. 57 58 59 60 61 62 63 64 65 1 2 3 4 10.4 Conclusions 5 6 The coast between Garron Point and Muchalls contains outstanding 7 exposures of Southern Highland Group metasedimentary strata in an 8 area of the Highland Border region that is otherwise poorly 9 exposed. The site is of national and international importance for 10 the continuous section that it exhibits across the downbent complex 11 12 hinge-zone of the Tay Nappe, the most intensively studied and, 13 arguably, the most important structure in the Grampian Highlands. 14 The effects of three deformation events (D1, D2 and D4) can be 15 readily discerned and the site contains some of the first 16 localities in the world at which downward-facing geological 17 structures (e.g. synformal anticlines) were deduced from their 18 smaller scale component structures by Robert Shackleton in 1958. 19 The recognition of the facing of the early structures led to a 20 radical re-interpretation of the structure of the south-eastern 21 part of the Dalradian as a whole. 22 Metamorphism accompanying the deformation resulted in the 23 generation of mineral assemblages in the pelitic rocks that are a 24 distinctive feature of the area around the GCR site and indicate 25 rapidly increasing metamorphic grade northwards from the Highland 26 Boundary Fault. Metamorphic conditions were intermediate between 27 those of the high-temperature Buchan Zones to the north and those 28 of the high-pressure Barrovian Zones to the south-west. 29 30 The ready accessibility of the outcrops, the excellent exposure 31 and the nature of the lithologies make this an excellent site 32 within which to demonstrate and teach structural geology and the 33 temporal links between deformation and metamorphism within a 34 classic orogenic belt. 35 36 37 ACKNOWLEDGEMENTS 38 39 This regional paper is the combined work of 7 authors, many of 40 whom, in addition to their own site descriptions, have made 41 valuable comments on other aspects of the work. 42 The paper has been compiled by P.W.G. Tanner and has been edited 43 by D. Stephenson. The GCR editor was P.H. Banham and the referee 44 was M.R.W. Johnson, who also provided valuable editorial 45 suggestions. The project was cofunded by the Joint Nature 46 Conservation Committee (JNCC) and the British Geological Survey 47 48 (BGS) and has been managed by N.V. Ellis for JNCC and D.J. Fettes 49 and M. Smith for BGS. 50 The initial site selection and site documentation for the 51 Dalradian block of the Geological Conservation Review was by S.J. 52 Moorhouse. Since then, much new mapping and refined interpretation 53 has taken place, and the site list has been revised, firstly by 54 J.E. Treagus and subsequently through a panel consisting of R. 55 Anderton, A.L. Harris, J.R. Mendum, J.L. Roberts, P.W.G. Tanner, R. 56 Threadgould and J.E. Treagus. The necessary amendments to the GCR 57 documentation were greatly facilitated by R. Wignall (for Scottish 58 Natural Heritage). 59 K.M. Goodenough and S.W. Horsburgh assisted with preliminary 60 drafts of key maps and all diagrams were drafted for publication by 61 62 63 64 65 1 2 3 4 S.C. White (JS Publications, Newmarket) and K.J. Henderson (BGS, 5 Edinburgh). Photographs were scanned and prepared by B.M. McIntyre 6 (BGS, Edinburgh). Photographs from the BGS collection are 7 reproduced by kind permission of the Director, BGS © Natural 8 Environment Research Council; all rights reserved (PR/23–27). 9 The first complete draft of the Dalradian GCR was submitted to the 10 JNCC in June 2009. In 2010, the JNCC terminated its involvement in 11 12 Earth Science conservation and abandoned its contractual agreements 13 to publish the remaining GCR volumes. So, the authors are greatly 14 indebted to Diarmad Campbell, Chief Geologist Scotland for the BGS, 15 for funding the drafting of remaining figures and to the 16 Geologists‘ Association and Elsevier, for ensuring that this volume 17 is published as a Special Issue of their Proceedings. We are 18 particularly grateful to Neil Ellis of the JNCC for his efforts to 19 secure a new publisher and to Professor James Rose, Editor in Chief 20 of the PGA, for making it all happen. 21 Finally, on behalf of all of the site authors, we would like to 22 record our thanks to the owners and managers of land and quarries 23 who have allowed access to the sites, either during previous work 24 or specifically for the GCR exercise. 25 26 REFERENCES 27

28 Agrell, S. O. (1942) 1. A petrological investigation of the 29 adinoles at Dinas Head, Cornwall. 2. A petrofabric study of the 30 Ben Vuroch granite and the adjacent schists in Perthshire. 31 Unpublished PhD thesis, University of Cambridge. 32 Ahmed-Said Y. and Tanner P. W. G. (2000) P-T conditions during 33 emplacement, and D2 regional metamorphism, of the Ben Vuirich 34 Granite, Perthshire, Scotland. Mineralogical Magazine, 64, 737–53. 35 Ague, J.J. & Baxter, E.F., 2007. Brief thermal pulses during 36 mountain building recorded by Sr diffusion in apatite and 37 multicomponent diffusion in garnet. Earth and Planetary Science 38 Letters, 261, 500-516. 39 Allen, J. R. L. 1963. The classification of cross stratified units 40 with notes on their origin. Sedimentology, 2, pp. 93-114. 41 Allison, A. (1933) The Dalradian succession in Islay and Jura. 42 Quarterly Journal of the Geological Society, London, 89, 125–44. 43 Allison, A. 1941. Loch Awe succession and tectonics-Kilmartin- 44 Tayvallich-Danna. Quarterly Journal of the Geological Society, 45 London, 96, 423–49. 46 Allison, I., May, F and Strachan, R.A. (1988) An Excursion guide to 47 the Moine Geology of the Scottish Highlands. Scottish Academic 48 Press for Edinburgh Geological Society and Geological Society of 49 Glasgow. 50 Alsop, G.I. and Hutton, D.H.W. (1990) A review and revision of 51 Dalradian stratigraphy in central and southern Donegal, Ireland. 52 Irish Journal of Earth Sciences, 10, 181–98. 53 Alsop, G.I., Prave, A.R., Condon, D.J. and Phillips, C.A. (2000) 54 Cleaved clasts in Dalradian conglomerates: possible evidence for 55 Neoproterozoic compressional tectonism in Scotland and Ireland? 56 Geological Journal, 35, 87–98. 57 Amos, B.J. (1960). The geology of the Bowmore district, Islay. 58 Unpublished PhD thesis, University of London, Imperial College. 59 60 61 62 63 64 65 1 2 3 4 Anderson, E M. (1923). The geology of the schists of the 5 Schiehallion district. Quarterly Journal of the Geological Society 6 of London, 79, 423–45. 7 Anderson, E M. (1951) The Dynamics of Faulting. (Second edition). 8 (Edinburgh: Oliver and Boyd.) 9 Anderson, J. G. C., (1942) The stratigraphical order of the 10 Dalradian schists near the Highland Border in Angus and 11 Kincardineshire. Transactions of the Geological Society of 12 Glasgow, 20, 223–37. 13 Anderson, J.G.C. (1947a) The geology of the Highland Border, 14 Stonehaven to Arran. Transactions of the Royal Society of 15 Edinburgh, 61, 479–515. 16 Anderson, J.G.C. (1947b) The Kinlochlaggan Syncline, southern 17 Inverness-shire. Transactions of the Geological Society of 18 Glasgow, 21, 97–115. 19 Anderson, J.G.C. (1948) Stratigraphic nomenclature of Scottish 20 metamorphic rocks. Geological Magazine, 85, 89–96. 21 Anderson, J.G.C (1956). The Moinian and Dalradian rocks between 22 Glen Roy and the Monadhliath Mountains, Inverness-shire. 23 Transactions of the Royal Society of Edinburgh, 63, 15–36. 24 Anderton, R. (1974) Middle Dalradian sedimentation in Argyll, with 25 particular reference to the Jura quartzite, Scarba conglomerate 26 and Craignish phyllites. Unpublished PhD thesis, University of 27 Reading. 28 Anderton, R. (1975) Tidal flat and shallow marine sediments from 29 the Craignish Phyllites, Middle Dalradian, Argyll, Scotland. 30 Geological Magazine, 112, 337–40. 31 Anderton, R. (1976) Tidal-shelf sedimentation: an example from the 32 Scottish Dalradian. Sedimentology, 23, 429–58. 33 Anderton, R. (1977) The Dalradian rocks of Jura. Scottish Journal 34 of Geology, 13, 135–42. 35 Anderton, R. (1979) Slopes, submarine fans and syn-depositional 36 sedimentology of parts of the Middle and Upper Dalradian in the 37 S.W. Highlands of Scotland. In The British Caledonides - Reviewed 38 (eds. Harris, A. L., Holland, C. H. and Leake, B. E.), Geological 39 Society, London, Special Publications, 8. 40 Anderton, R. (1980). Distinctive pebbles as indicators of Dalradian 41 provenance. Scottish Journal of Geology, 16, 143–52. 42 Anderton, R. (1982) Dalradian deposition and the late Precambrian - 43 Cambrian history of the N Atlantic region: a review of the early 44 evolution of the Iapetus Ocean. Journal of the Geological Society 45 of London, 139, 421–31. 46 Anderton, R. (1985) Sedimentation and tectonics in the Scottish 47 Dalradian. Scottish Journal of Geology, 21, 407–36. 48 Anderton, R. (1988) Dalradian slides and basin development: a 49 radical interpretation of stratigraphy and structure in the SW and 50 Central Highlands of Scotland. Journal of the Geological Society 51 of London, 145, 669–78. 52 Arndt, N.T. and Nisbet, E.G. (editors) (1982) Komatiites. George 53 Allen and Unwin, London. 54 Ashcroft W.A., Kneller B.C., Leslie, A.G. and Munro M. (1984) Major 55 shear zones and autochthonous Dalradian in the northeast Scottish 56 Caledonides. Nature, London 310, 760–2. 57 Ashworth, J.R. (1972) Migmatites of the Huntly-Portsoy area, north- 58 east Scotland. Unpublished PhD thesis, University of Cambridge. 59 60 61 62 63 64 65 1 2 3 4 Ashworth, J.R. (1975) The sillimanite zones of the Huntly–Portsoy 5 area in the north-east Dalradian, Scotland. Geological Magazine, 6 112, 113–224. 7 Ashworth, J.R. (1976) Petrogenesis of migmatites in the Huntly– 8 Portsoy area, north-east Scotland. Mineralogical Magazine, 40, 9 661–82. 10 Ashworth, J.R. (1979) Comparative petrography of deformed and 11 undeformed migmatites from the Grampian Highlands of 12 Scotland. Geological Magazine, 116, 445–56. 13 Astin, T.R. and Rogers, D.A. (1991) ‗Subaqueous shrinkage cracks‘ 14 in the Devonian of Scotland re-interpreted. Journal of Sedimentary 15 Petrology, 61, 850–9. 16 Atherton, M.P. (1977) The metamorphism of the Dalradian rocks of 17 Scotland. Scottish Journal of Geology, 13, 331–70. 18 Atherton, M.P., and Brotherton, M.S. (1972) The composition of some 19 kyanite-bearing regionally-metamorphosed rocks from the Dalradian. 20 Scottish Journal of Geology, 8, 203–13. 21 Atherton, M.P. and Ghani, A.A. (2002) Slab breakoff: a model for 22 Caledonian, Late Granite syn-collisional magmatism in the ortho- 23 tectonic (metamorphic) zone of Scotland and Donegal. Lithos, 62, 24 65–85. 25 26 Bailey, E.B. (1910) Recumbent folds in the schists of the Scottish 27 Highlands. Quarterly Journal of the Geological Society of London, 28 66, 586–620. 29 Bailey, E. B. 1913. The Loch Awe Syncline (Argyllshire). Quarterly 30 Journal of the Geological Society of London, 69, 280–307. 31 Bailey, E.B. (1917) The Islay anticline (Inner Hebrides). Quarterly 32 Journal of the Geological Society of London, 72, 132–64. 33 Bailey, E.B. (1922) The structure of the South West Highlands of 34 Scotland. Quarterly Journal of the Geological Society of London, 35 78, 82–131. 36 Bailey, E.B. (1925) Perthshire tectonics: Loch Tummel, Blair 37 Atholl and Glen Shee. Transactions of the Royal Society of 38 Edinburgh, 53, 671–98. 39 Bailey, E.B. (1930) New Light on Sedimentation and Tectonics. 40 Geological Magazine, 67, 77. 41 Bailey, E.B. (1934) West Highland tectonics: Loch Leven to Glen 42 Roy. Quarterly Journal of the Geological Society of London, 90, 43 462–523. 44 Bailey, E.B. (1938) Eddies in mountain structure. Quarterly Journal 45 of the Geological Society of London, 94, 607–25. 46 Bailey, E B. (1953). Facies changes versus sliding: Loch Leven, 47 Argyll. Geological Magazine, 90, 111–13. 48 Bailey, E.B. (1960) The geology of Ben Nevis and Glencoe and the 49 surrounding country. (2nd edition). Memoir of the Geological 50 Survey of Great Britain, Sheet 53 (Scotland). 51 Bailey, E.B., and McCallien, W. (1937). Perthshire tectonics: 52 Schiehallion to Glen Lyon. Transactions of the Royal Society of 53 Edinburgh, 59, 79–118. 54 Bailey, E B, and MacGregor, M. 1912. The Glen Orchy Anticline, 55 Argyllshire. Quarterly Journal of the Geological Society of 56 London, Vol. 68, 164–179. 57 Bailey, E.B., and Maufe, H.B. (1916) The geology of Ben Nevis and 58 Glen Coe and the surrounding country. (1st edition). Memoir of the 59 Geological Survey of Great Britain, Sheet 53 (Scotland). 60 61 62 63 64 65 1 2 3 4 Bain, J.A., Briggs, D.A. and May, F. (1971) Geology and 5 mineralogical appraisal of an extensive talc-magnesite deposit in 6 the Shetlands. Transactions of the Institute of Mining and 7 Metallurgy, 80, B77–B84. 8 Baker, A.J. (1985) Pressures and temperatures of metamorphism in 9 the eastern Dalradian. Journal of the Geological Society of 10 London, 142, 137–48. 11 Baker, A.J. (1987) Models for the tectonothermal evolution of the 12 eastern Dalradian of Scotland. Journal of Metamorphic Geology, 5, 13 101–18. 14 Baker, A.J., and Droop, G.T.R. (1983) Grampian metamorphic 15 conditions deduced from mafic granulites and sillimanite–K- 16 feldspar gneisses in the Dalradian of Glen Muick, Scotland. 17 Journal of the Geological Society of London, 140, 489–97. 18 Baldwin, C.T. and Johnson, H.D. (1977) The Dalradian rocks of 19 Lunga, Luing and Shuna. Scottish Journal of Geology, 13, 143–54. 20 Banks, C. J. (2005). Neoproterozoic Basin Analysis: a combined 21 sedimentological and provenance study in the Grampian Group, 22 Central Highlands, Scotland. Unpublished PhD Thesis, University of 23 Keele. 24 Banks, C.J. (2007) Exceptional preservation of sedimentary 25 structures in metamorphic rocks: an example from the upper 26 Grampian Group, Creag Stalcair, Perthshire. Scottish Journal of 27 Geology, 43, 9–14. 28 Banks, C.J. and J.A. Winchester (2004). Sedimentology and 29 stratigraphic affinities of Neoproterozoic coarse clastic 30 successions, Glenshirra Group, Inverness-shire Scotland. Scottish 31 Journal of Geology 40, 159–174. 32 Banks, C.J., Smith, M., Winchester, J.A., Horstwood, M.S.A., Noble, 33 S.R. and Ottley, C.J. (2007) Provenance of intra-Rodinian basin- 34 fills: the lower Dalradian Supergroup, Scotland. Precambrian 35 Research, 153, 46-64. 36 Barreiro, B.A. (1998) U-Pb systematics on zircon from the Keith and 37 Portsoy granites, Grampian Highlands, Scotland. NERC Isotope 38 Geosciences Laboratory Report Series No. 132. 39 Barrow, G. (1893) On an intrusion of muscovite-biotite gneiss in 40 the south-east Highlands of Scotland, and its accompanying 41 metamorphism. Quarterly Journal of the Geological Society of 42 London, 49, 330–58. 43 Barrow, G. (1904) Moine gneisses of the east central Highlands and 44 their position in the Highland sequence. Quarterly Journal of the 45 Geological Society of London, 60, 400–44. 46 Barrow, G. (1912) On the geology of Lower Deeside and the southern 47 Highland border. Proceedings of the Geologists’ Association, 23, 48 274–90. 49 Barrow G. and Cunningham Craig E.H. (1912) The geology of the 50 districts of Braemar, Ballater and Glen Clova. Memoir of the 51 Geological Survey of Great Britain, Sheet 65 (Scotland). 52 Barrow, G, Grant Wilson, J S, and Cunningham Craig, E H. (1905). 53 The geology of the country around Blair Atholl, Pitlochry and 54 Aberfeldy. Memoir of the Geological Survey of Great Britain, Sheet 55 55 (Scotland). 56 Basahel, A.N. (1971) The Dalradian stratigraphy and structure of 57 southern Islay, Argyll. Unpublished PhD thesis. University of 58 Liverpool. 59 Batchelor, R.A. (2011) Geochemistry of Torridonian tuffs and 60 contemporary phosphorites; potential for correlation of 61 62 63 64 65 1 2 3 4 Torridonian sequences in NW Scotland. Scottish Journal of Geology, 5 47, 133-142. 6 Baxter, E.F., Ague, J.J. and Depaolo, D.J. (2002) Prograde 7 temperature-time evolution in the Barrovian type-locality 8 constrained by Sm/Nd garnet ages from Glen Clova, Scotland. 9 Journal of the Geological Society, London, 159, 71–82. 10 Beddoe-Stephens B. (1990) Pressures and temperatures of Dalradian 11 metamorphism and the andalusite-kyanite transformation in the 12 northeast Grampians. Scottish Journal of Geology 26, 3–14. 13 Bell, A. M. (1981) Vergence: an evaluation. Journal of Structural 14 Geology, Volume 3, 197–202. 15 Bendall, C.A. (1995). A geochronological, structural and 16 metamorphic study of rocks from the central and SW Dalradian of 17 Scotland. Unpublished PhD thesis, University of Manchester 18 Bentley, M.R. (1986) The tectonics of Colonsay, Scotland. 19 Unpublished PhD thesis, University of Wales, Aberystwyth. 20 Bentley, M.R. (1988). The Colonsay Group. In Winchester, J.A (ed.) 21 Later Proterozoic stratigraphy of the Northern Altlantic Regions. 22 Blackie and Son Ltd., London, 119–30. 23 Bentley, M.R., Maltman, A.J., and Fitches, W.R. (1988) Colonsay 24 and Islay: a suspect terrane within the Scottish 25 Caledonides. Geology, 16, 26–8. 26 Bingen B., Demaiffe D. and van Breemen O. (1998) The 616 Ma old 27 Egersund basaltic dyke swarm, SW Norway, and late Neoproterozoic 28 opening of the Iapetus Ocean. Journal of Geology, 106, 565–74. 29 Bingen, B., Griffin, W.L. Torsvik, T.H. and Saeed, A. (2005) Timing 30 of late Neoproterozoic glaciation on Baltica constrained by 31 detrital zircon geochronology in the Hedmark Group, south-east 32 Norway. Terra Nova, 17, 250–58. 33 Bliss, G.M. (1977) The micropalaeontology of the Dalradian. 34 Unpublished PhD thesis, University of London, Imperial College. 35 Bluck, B.J. (1983) Role of the Midland Valley of Scotland in the 36 Caledonian Orogeny. Transactions of the Royal Society of 37 Edinburgh: Earth Sciences, 74, 119 –136. 38 Bluck, B.J. (1984) Pre-Carboniferous history of the Midland Valley 39 of Scotland. Transactions of the Royal Society of Edinburgh: Earth 40 Sciences, 75, 275–95. 41 Bluck, B.J. (2000) ‗Where ignorance is bliss ‗tis a folly to be 42 wise‘ (Thomas Gray 1716–1761) – controversy in the basement blocks 43 of Scotland. Scottish Journal of Geology, 36, 97–101. 44 Bluck, B.J. (2001) Caledonian and related events in Scotland. 45 Transactions of the Royal Society of Edinburgh: Earth Sciences, 46 91, 375–404. 47 Bluck, B.J. (2002) The Midland Valley Terrane. In: Trewin, N.H. 48 (ed.) The Geology of Scotland. The Geological Society, London, 49 149–66. 50 Bluck, B.J. (2010) The Highland Boundary Fault and the Highland 51 Boundary Complex. Scottish Journal of Geology, 46, 113-124. 52 Bluck B.J. and Dempster T.J. (1991) Exotic metamorphic terranes in 53 the Caledonides: tectonic history of the Dalradian block, 54 Scotland. Geology, 19, 1133–6. 55 Bluck B.J., Dempster T.J., and Rogers G. (1997) Allochthonous 56 metamorphic blocks on the Hebridean passive margin, Scotland. 57 Journal of the Geological Society of London 154, 921–4. 58 Bluck, B.J., Gibbons, W. and Ingham, J.K. (1992). Terranes. 1–4 in 59 Atlas of palaeogeography and lithofacies. Cope, J.C.W., Ingham, 60 61 62 63 64 65 1 2 3 4 J.K., and Rawson, P.F. (editors). Geological Society of London 5 Memoir, No. 13. 6 Bluck B.J., Halliday A. N., Aftalion M., and Macintyre R.M. (1980) 7 Age and origin of the Ballantrae ophiolite and its significance to 8 the Caledonian orogeny and Ordovician time scale. Geology 8, 492– 9 95. 10 Bluck, B.J. and Ingham, J.K. (1997) The Highland Border 11 controversy: a discussion of ―New evidence that the Lower Cambrian 12 Leny Limestone at Callander, Perthshire belongs to the Dalradian 13 Supergroup, and a reassessment of the ‗exotic‘ status of the 14 Highland Border Complex‖. Geological Magazine, 134, 563–70. 15 Bluck B.J., Ingham J.K., Curry G.B., and Williams A. (1984) The 16 significance of a reliable age from some Highland Border rocks in 17 Central Scotland. Journal of the Geological Society of London 139, 18 451–4. 19 Boersma, J.R. (1969) Internal structures of some tidal megaripples 20 on a shoal in the Westerschelde estuary, the Netherlands. Geologie 21 on Mijnbouw, 48, 409–14. 22 Booth, J.E. (1984) Structural, stratigraphic and metamorphic 23 studies in the SE Dalradian Highlands. Unpublished PhD thesis. 24 University of Edinburgh. 25 Borradaile, G.J. (1970) The west limb of the Loch Awe syncline and 26 the associated cleavage fan. Geological Magazine, 107, 459–467. 27 Borradaile, G.J. (1972a) The structural and stratigraphic history 28 of the Dalradian rocks of the Northern Loch Awe syncline, 29 Argyllshire. Unpublished PhD thesis, University of Liverpool. 30 Borradaile, G.J. (1972b) Variably oriented co-planar primary folds. 31 Geological Magazine, 190, 89–98. 32 Borradaile, G. J. (1973) Dalradian structure and stratigraphy of 33 the northern Loch Awe district, Argyllshire. Transactions of the 34 Royal Society of Edinburgh, 69, 1–21. 35 Borradaile, G.J. (1974). Bulk finite strain estimates from the 36 deformation of Neptunian dykes. Tectonophysics, 22, 127–39. 37 Borradaile, G.J. (1977) The Dalradian rocks of the northern Loch 38 Awe district. Scottish Journal of Geology, 13, 155–64. 39 Borradaile, G.J. (1979). Pre-tectonic reconstruction of the Islay 40 anticline: implications for the depositional history of Dalradian 41 rocks in the SW Highlands. In The Caledonides of the British 42 Isles–reviewed. Harris, A L, Holland, C H, and Leake, B E 43 (editors). Special Publication of the Geological Society of 44 London, No. 8, pp. 229–38. 45 Borradaile, G.J. and Johnson, H.D. (1973) Finite strain estimates 46 from the Dalradian Dolomitic Formation, Islay, Argyll, Scotland. 47 Tectonophysics, 18, 249–59. 48 Boué, A. (1820) Essai Géologique sur l’Écosse. Ve Courcier, Paris. 49 Bouma, A. H. (1962). Sedimentology of some Flysch Deposits, a 50 Graphic Approach to Facies Interpretation. Elsevier Co. Amsterdam, 51 168 pp. 52 Bowden, A.J. (2007) Book review: MacCulloch‘s 1840 Geological Map 53 of Scotland. Scottish Journal of Geology, 43, 181–4. 54 Bowes, D.R. and Convery, H.J.E. (1966) The composition of some Ben 55 Ledi grits and its bearing on the origin of albite schists in the 56 south-west Highlands. Scottish Journal of Geology, 2, 67–75. 57 Bowes, D.R. and Wright, A.E. (1967) The explosion breccia pipes 58 near Kentallen, Scotland and their geological setting. 59 Transactions of the Royal Society of Edinburgh, 67, 109–43. 60 61 62 63 64 65 1 2 3 4 Bowes, D.R. and Wright, A.E. (1973) Early phases of Caledonian 5 deformation in the Dalradian of the Ballachulish district, 6 Argyll. Geological Journal, 8, 333–44. 7 Bowring, S., Myrow, P., Landing, E., Ramezani, J. and Grotzinger, 8 J. (2003) Geochronological constraints on Terminal Neoproterozoic 9 events and the rise of metazoans. Geophysical Research Abstracts 10 5, p13219. 11 Bradbury, H.J. (1978) Stratigraphic, structural, igneous and 12 metamorphic history of the Dalradian rocks of the Ben Vrackie-Ben 13 Vuirich district, Tayside, Scotland. Unpublished PhD thesis, 14 University of Liverpool. 15 Bradbury, H.J. (1979) Migmatization, deformation and porphyroblast 16 growth in the Dalradian of Tayside, Scotland. In The Caledonides 17 of the British Isles — Reviewed Harris, A.L., Holland, C.H. and 18 Leake, B.E. (eds). Geological Society, London, Special 19 Publications, 8, 351–6. 20 Bradbury, H.J. (1985) The Caledonian metamorphic core: an Alpine 21 model. Journal of the Geological Society of London, 142, 129–36. 22 Bradbury, H.J., and Harris, A.L. (1982) Low grade Dalradian 23 sediments carrying spaced cleavage; Polyphase deformation of 24 spaced cleavage. In Atlas of deformational and metamorphic rock 25 fabrics. Borradaile, G J, Bayly, M B, and Powell, C McA (editors). 26 Springer Verlag, Berlin, pp. 100–9. 27 Bradbury, H.J., Harris, A.L. and Smith, R.A. (1979). Geometry and 28 emplacement of nappes in the Central Scottish Highlands. In The 29 Caledonides of the British Isles - reviewed. (eds. Harris, A.L., 30 Holland, C.H. and Leake, B.E.), Special Publication of the 31 Geological Society of London, 8, 213–20. 32 Bradbury H.J., Smith R.A. and Harris A.L. (1976) ‗Older‘ granites 33 as time-markers in Dalradian evolution. Journal of the Geological 34 Society, London, 132, 677–84. 35 Brasier, M.D., Ingham, J.K. and Rushton, A.W.A. (1992) Cambrian. 36 13–18 in Atlas of Palaeogeography and Lithofacies. Cope, J.C.W., 37 Ingham, J.K. and Rawson, P. F. (editors). Memoirs of the 38 Geological Society, London, 13. 39 Brasier, M.D. and Mcilroy, D. (1998) Neonereites uniserialis from 40 c. 600 Ma year old rocks in western Scotland and the emergence of 41 animals. Journal of the Geological Society, London, 155, 5–12. 42 Brasier, M.D. and Shields, G. (2000) Neoproterozoic 43 chemostratigraphy and correlation of the Port Askaig glaciation, 44 Dalradian Supergroup of Scotland. Journal of the Geological 45 Society, London, 157, 909–14. 46 Brasier, M.D., McCarron, G., Tucker, R., Leather, J., Allen, P. and 47 Shields, G. (2000) New U-Pb zircon dates for the Neoproterozoic 48 Ghubrah glacaiation and for the top of the Huqf Supergroup, Oman. 49 Geology, 28, 175–8. 50 Briden, J.C., Turnell, H.B. and Watts, D.R. (1984) British 51 palaeomagnetism, Iapetus Ocean and the Great Glen Fault. Geology 52 12, 136–9. 53 Burgess J.G, Graham, C.M. and Harte, B. (1981). Kyanite and 54 chloritoid phyllites from the chlorite zone of the Scottish 55 Highlands. Journal of the Geological Society of London, 138, p. 56 634 (abstract). 57 Burt, C.E. (2002) Sedimentary environments and basin evolution of 58 the upper Dalradian: Tayvallich Subgroup and Southern Highland 59 Group. Unpublished PhD thesis, Kingston University. 60 61 62 63 64 65 1 2 3 4 Burton, C.J., Hocken, C., MacCallum, D. and Young, M.E. 1983. 5 Chitinozoa and the age of the Margie Limestone of the North Esk. 6 Proceedings of the Geological Society of Glasgow Vol. 124–125, 27– 7 32. 8 9 Cannat M. (1989) Late Caledonian northeastward ophiolite thrusting 10 in the Shetland Islands, U.K. Tectonophysics 169, 257–70. 11 Canning J.C., Henney P.J., Morrison M.A. and Gaskarth J.W. (1996) 12 Geochemistry of late Caledonian minettes from northern Britain: 13 implications for the Caledonian sub-continental lithospheric 14 mantle. Mineralogical Magazine 60, 221–36. 15 Canning, J.C., Henney, P.J., Morrison, M.A., Van Calsteren, P.W.C., 16 Gaskarth, J.W. and Swarbrick, A. (1998) The Great Glen Fault: a 17 major vertical lithospheric boundary. Journal of the Geological 18 Society, London, 155, 425–8. 19 Carty, J.P. (2001) Deformation, metamorphism, magmatism and fluid- 20 flow in the Portsoy Shear Zone, N.E. Scotland. Unpublished PhD 21 thesis, University of Derby. 22 Cawood, P.A., McCausland, P.J.A. and Dunning, G.R. (2001) Opening 23 Iapetus: constraints from the Laurentian margin in Newfoundland. 24 Geological Society of America Bulletin, 113, 443–53. 25 Cawood, P.A., Nemchin, A.A., Smith, M. and Loewy, S. (2003). Source 26 of the Dalradian Supergroup constrained by U-Pb dating of detrital 27 zircon and implications for the East Laurentian margin. Journal of 28 the Geological Society of London 160, 231–46. 29 Cawood, P.A., Nemchin, A.A., Strachan, R.A., Prave, A.R. and 30 Krabbendam, M. (2007) Sedimentary basin and detrital zircon record 31 along East Laurentia and Baltica during assembly and breakup of 32 Rodinia. Journal of the Geological Society, London, 164, 257–75. 33 Chew, D.M. (2001) Basement protrusion origin of serpentinite in the 34 Dalradian. Irish Journal of Earth Science, 19, 23-35. 35 Chew, D.M., Daly, J.S., Magna, T., Page, L.M., Kirkland, C.L., 36 Whitehouse, M.J. and Lam, R. (2010) Timing of ophiolite obduction 37 in the Grampian orogen. Geological Society of America Bulletin, 38 122, 1787-1799. 39 Chew, D.M., Fallon, N., Kennelly, C., Crowley, Q. and Pointon, 40 (2009) Basic volcanism contemporaneous with the Sturtian glacial 41 episode in NE Scotland. Earth and Environmental Science 42 Transactions of the Royal Society of Edinburgh, 100, 399-415 43 Chew, D.M., Graham, J.R. and Whitehouse, M.J. (2007) U-Pb zircon 44 geochronology of plagiogranites from the Lough Nafooey (= Midland 45 Valley) arc in western Ireland: constraints on the onset of the 46 Grampian orogeny. Journal of the Geological Society, London Vol. 47 164, 747–50. 48 Chinner, G.A. (1957) The metamorphic history of the Glen Clova 49 district, Angus. Unpublished PhD Thesis, University of Cambridge. 50 Chinner, G.A. (1960) Pelitic gneisses with varying ferrous/ferric 51 ratios from Glen Clova, Angus, Scotland. Journal of Petrology, 1, 52 178–217. 53 Chinner, G.A. (1961) The origin of sillimanite in Glen Clova, 54 Angus. Journal of Petrology Vol. 2, 312–23. 55 Chinner, G.A. (1966) The distribution of pressure and temperature 56 during Dalradian metamorphism. Quarterly Journal of the Geological 57 Society of London, 122, 159–86. 58 Chinner, G.A. (1978) Metamorphic zones and fault displacement in 59 the Scottish Highlands. Geological Magazine, Vol. 115, 37–45. 60 61 62 63 64 65 1 2 3 4 Chinner, G.A. and Heseltine, F.J. (1979) The Grampian 5 andalusite/kyanite isograd. Scottish Journal of Geology, Vol. 15, 6 117–127. 7 Coats, J.S., Pease, S.F. and Gallagher, M.J. (1984) Exploration of 8 the Scottish Dalradian. 21–34 in Prospecting in areas of glaciated 9 terrain. (London: Institution of Mining and Metallurgy.) 10 Coats, J.S., Smith, C.G., Gallagher, M.J., May, F., Fortey, N.J. 11 and Parker, M.E. (1978) Stratabound barium-zinc mineralisation in 12 Dalradian schist near Aberfeldy, Scotland: preliminary report. 13 Institute of Geological Sciences, Mineral Reconnaisance Programme 14 Report No. 26. 15 Coats, J.S., Smith, C.G., Fortey, N.J., Gallagher, M.J., May, F. 16 and McCourt, W.J. (1980) Stratabound barium-zinc mineralization in 17 Dalradian schist near Aberfeldy. Transactions of the Institution 18 of Mining and Metallurgy (Section B: Applied Earth Science), 89, 19 110–22. 20 Coats, J.S., Smith, C.G., Gallagher, M.J., May, F., McCourt, W.J., 21 Parker, M.E. and Fortey, N.J. (1981) Stratabound barium-zinc 22 mineralisation in Dalradian schist near Aberfeldy, Scotland: final 23 report. Institute of Geological Sciences, Mineral Reconnaissance 24 Programme Report No. 40. 25 Collerson, K.D., Jesseau, C.W. and Bridgewater, D. (1976). 26 Contrasting types of bladed olivine in ultramafic rocks from the 27 Archaean of Labrador. Canadian Journal of Earth Sciences, 13, 442– 28 50. 29 Collinson, J. (1994). Sedimentary deformational structures. pp. 95– 30 125 In Maltman, A. (ed.). The geological deformation of 31 sediments. Chapman and Hall. 32 Collinson, J.D. and Thompson, D.B. 1988. Sedimentary Structures. 33 George Allen and Unwin, London. 207 pp. 34 Condon, D.J. and Prave, A.R. (2000). Two from Donegal: 35 Neoproterozoic glacial episodes on the northeast margin of 36 Laurentia. Geology, 28, 951–4. 37 Cooper, M.R. and Johnston, T.P. (2004) Central Highlands (Grampian) 38 Terrane. 9–24, in: Mitchell, W.I. (editor), The Geology of 39 Northern Ireland–Our Natural Foundation (2nd edition). Geological 40 Survey of Northern Ireland, Belfast. 41 Coward, M.P. (1983) The thrust and shear zones of the Moine Thrust 42 Zone of NW Scotland. Journal of the Geological Society of London 43 140, 795–811. 44 Coward, M.P. (1990) The Precambrian, Caledonian and Variscan 45 framework to NW Europe. In Tectonic Events Responsible for 46 Britain’s Oil and Gas Reserves. Hardman, R.F.P. and Brooks, J. 47 (eds) Geological Society, London, Special Publications, 55, 1–34. 48 Craig G. Y., McIntyre D. B., and Waterston C. D. (1978) James 49 Hutton’s Theory of the Earth: the lost drawings. Scottish 50 Academic Press, Edinburgh. 51 Crane A., Goodman S., Krabbendam M., Leslie A. G., Paterson I. B., 52 Robertson S. And Rollin K. E. (2002) Geology of the Glen Shee 53 District. Memoir of the British Geological Survey. Sheet 56W with 54 parts of sheets 55E, 65W and 64E (Scotland). 55 Cummins, W.A. and Shackleton, R.M. (1955) The Ben Lui recumbent 56 syncline. Geological Magazine, 92, 353–62. 57 Cunningham Craig, E.H. (1904) Metamorphism in the Loch-Lomond 58 District. Quarterly Journal of the Geological Society, London, 60, 59 10–31. 60 61 62 63 64 65 1 2 3 4 Cunningham Craig, E.H. (2000) (written 1901). Explanation of Sheet 5 38 (Loch Lomond). Selected documents from the BGS Archives No 3. 6 British Geological Survey Technical Report No. WO/00/05. 7 Cunningham Craig, E.H., Wright, W.B. and Bailey, E.B. (1911) The 8 Geology of Colonsay and Oronsay with parts of Ross of Mull. Memoir 9 of the Geological Survey of Scotland, Sheet 35 (Scotland). 10 Curry, G.B., Bluck, B.J., Burton, C.J., Ingham, J.K., Siveter, D.J. 11 And Williams, A. (1984) Age, evolution and tectonic history of the 12 Highland Border Complex, Scotland. Transactions of the Royal 13 Society of Edinburgh: Earth Sciences, 75, 113–33. 14 Cutts, K.A., Hand, M., Kelsey, D.E. and Strachan, R.A. (2011) P–T 15 constraints and timing of Barrovian metamorphism in the Shetland 16 Islands, Scottish Caledonides: implications for the structural 17 setting of the Unst ophiolite. Journal of the Geological Society, 18 168, 1265-1284. 19 20 Dallmeyer, R.D., Strachan, R.A., Rogers, G., Watt, G.R. and Friend, 21 C.R.L. (2001) Dating deformation and cooling in the Caledonian 22 thrust nappes of north Sutherland, Scotland: insights from 23 40Ar/39Ar and Rb-Sr chronology. Journal of the Geological Society 24 of London 158, 501–12. 25 Daly, J.S., Muir, R.J. and Cliff, R.A. (1991) A precise U-Pb zircon 26 age for the Inishtrahull syenitic gneiss, County Donegal, Ireland. 27 Journal of the Geological Society, London, 148, 639–42. 28 Dalziel, I.W.D. (1994) Precambrian Scotland as a Laurentia–Gondwana 29 link: Origin and significance of cratonic promontories. Geology, 30 22, 589–92. 31 Dalziel, I.W.D. (1997) Neoproterozoic–Paleozoic geography and 32 tectonics; review, hypothesis, environmental speculation. 33 Geological Society of America Bulletin 109(1), 16–42. 34 Davidek, K., Landing, E., Bowring, S.A., Westrop, S.R., Rushton, 35 S.A., Fortey, R.A. And Adrain, J. (1998) New Uppermost Cambrian U- 36 Pb date from Avalonian Wales and age of the Cambrian-Ordovician 37 boundary. Geological Magazine, 135, 303–09. 38 Deer, W.A., Howie, R.A. and Zussman, J. (1992). An Introduction to 39 the Rock Forming Minerals, 2nd ed. Longman Scientific and 40 Technical, London. 41 Dempster, T.J. (1983) Studies of orogenic evolution in the Scottish 42 Dalradian. Unpublished PhD thesis, University of Edinburgh. 43 Dempster, T.J. (1985a) Uplift patterns and orogenic evolution in 44 the Scottish Dalradian. Journal of the Geological Society of 45 London, 142, 111–128. 46 Dempster, T.J. (1985b) Garnet zoning and metamorphism of the 47 Barrovian type. Contributions to Mineralogy and Petrology, 89, 30– 48 8. 49 Dempster T.J. and Bluck B.J. (1991) The age and tectonic 50 significance of the Bute amphibolite, Highland Border Complex, 51 Scotland. Geological Magazine 128, 77–80. 52 Dempster, T.J. and Harte, B. (1986) Polymetamorphism in the 53 Dalradian of the Central Scottish Highlands. Geological Magazine, 54 Vol. 123, 95–104. 55 Dempster, T.J., Hudson, N.F. and Rogers, G. (1995). Metamorphism 56 and cooling of the NE Dalradian. Journal of the Geological 57 Society, London, 152, 383–90. 58 Dempster, T.J., Rogers, G., Tanner, P.W.G., Bluck, B.J., Muir, 59 R.J., Redwood, S.D., Ireland, T.R. and Paterson, B.A. (2002) 60 Timing of deposition, orogenesis and glaciation within the 61 62 63 64 65 1 2 3 4 Dalradian rocks of Scotland: constraints from U-Pb zircon ages. 5 Journal of the Geological Society, London, 159, 83–94. 6 Dewey, H. and Flett, J.S. (1911) On some British pillow lavas and 7 the rocks associated with them. Geological Magazine, 8, 202–9, 8 240–8. 9 Dewey J. F. (1969) Evolution of the Appalchian/Caledonian orogen. 10 Nature, London 222, 124–9. 11 Dewey, J.F. (2005) Orogeny can be very short. Proceedings of the 12 National Academy of Sciences, USA Vol. 102, 15286–93. 13 Dewey, J.F. and Mange, M. (1999) Petrography of Ordovician and 14 Silurian sediments in the western Irish Caledonides: tracers of a 15 short-lived Ordovician continent–arc collision orogeny and the 16 evolution of the Laurentian Appalachian–Caledonian margin. In: 17 Continental Tectonics (edited by MacNiocaill, C. and Ryan, P. D.). 18 Geological Society, London, Special Publication, 164, 55–107. 19 Dewey, J.F. and Pankhurst, R.J. (1970) The evolution of the 20 Scottish Caledonides in relation to their radiometric age pattern. 21 Transactions of the Royal Society of Edinburgh, 68, 361–89. 22 Dewey, J.F. and Ryan, P.D. (1990) The Ordovician evolution of the 23 South Mayo Trough, Western Ireland. Tectonics, 9, 887–903. 24 Dewey J.F. and Shackleton R.M. (1984) A model for the evolution of 25 the Grampian tract in the early Caledonides and Appalachians. 26 Nature, London 312, 115–21. 27 Dewey, J.F. and Strachan, R.A. (2003) Changing Silurian–Devonian 28 relative plate motion in the Caledonides; sinistral transpression 29 to sinistral transtension. Journal of the Geological Society, 30 London, 160, 219–229. 31 Dickin, A.P. (1992). Evidence for an Early Proterozoic crustal 32 province in the North Atlantic region. Journal of the Geological 33 Society, London, 149, 483–6. 34 Dickin, A.P., and Bowes, D.R. (1991) Isotopic evidence for the 35 extent of the early Proterozoic basement of Scotland and northwest 36 Ireland. Geological Magazine, 128, 385–8. 37 Droop, G.T.R. (1987). A general equation for estimating Fe3+ 38 concentrations in ferromagnesian silicates or oxides from 39 microprobe analysis using stoichiometric criteria. Mineralogical 40 Magazine, 51, 431–55. 41 Droop G.T.R. and Charnley N. (1985) Comparative geobarometry of 42 pelitic hornfelses associated with the Newer Gabbros: a 43 preliminary study. Journal of the Geological Society of London 44 142, 53–62. 45 Droop, G.T.R., Clemens, J.D. and Dalrymple, D.J. (2003) Processes 46 and conditions during contact anatexis, melt escape and restite 47 formation: the Huntley Gabbro complex, NE Scotland. Journal of 48 Petrology Vol. 44, 995–1029. 49 Donovan, R.N. and Foster, R.J. (1972). Subaqueous shrinkage cracks 50 from the Caithness Flagstone Series (Middle Devonian) of north- 51 east Scotland. Journal of Sedimentary Petrology, 42, 309–17. 52 Downie, C. (1975) The Precambrian of the British Isles: 53 Palaeontology. In A Correlation of Precambrian Rocks in the 54 British Isles (eds. Harris, A.L., Shackleton, R.M., Watson, J.V., 55 Downie, C., Harland, W.B. and Moorbath, S.). Special Report of the 56 Geological Society of London, No. 6. Pp. 113–15 57 Downie, C. (1984) Acritarchs in British stratigraphy. Special 58 Report of the Geological Society of London, No. 17. 59 Downie, C., Lister, T.R., Harris, A.L. and Fettes, D.J. (1971) A 60 palynological investigation of the Dalradian rocks of 61 62 63 64 65 1 2 3 4 Scotland. Report of the Institute of Geological Sciences, No. 5 71/9. 6 Dymoke, P.L. (1989) Geochronological and petrological studies of 7 the thermal evolution of the Dalradian, South-west Scottish 8 Highlands. Unpublished PhD thesis, University of Edinburgh. 9 10 Eby G. N. (1992) Chemical subdivision of the A-type granitoids: 11 petrogenetic and tectonic implications. Geology, 20, 641–4. 12 Edwards, M.B. (1986) Glacial Environments. 416–436 in: Sedimentary 13 Environments and facies (Editor: H.G. Reading). Blackwell 14 Scientific 15 Publications. 16 Elles, G.L. (1926) The geological structure of Ben Lawers and Meall 17 Corranaich (Perthshire). Quarterly Journal of the Geological 18 Society of London, 82, 304–31. 19 Elles, G.L. (1931) Notes on the Portsoy coastal 20 district. Geological Magazine, 68, 24–34. 21 Elles, G.L. (1935) The Loch na Cille Boulder Bed and its place in 22 the Highland succession. Quarterly Journal of the Geological 23 Society of London, 91, 111–49. 24 Elles, G.L. and Tilley, C.E. (1930) Metamorphism in relation to 25 structure in the Scottish Highlands. Transactions of the Royal 26 Society of Edinburgh, 56, 621–46. 27 Ellis, D.J. and Green, D.H. (1979) An experimental study of the 28 effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equilibria. 29 Contributions to Mineralogy and Petrology, 71, 13–22. 30 Ellis, N.V., Bowen, D.Q., Campbell, S., Knill, J.L., McKirdy, A.P., 31 Prosser, C.D., Vincent, M.A. and Wilson, R.C.L. (1996) An 32 Introduction to the Geological Conservation Review. Joint Nature 33 Conservation Committee, Peterborough. 34 Emery, M. (2005) Polyorogenic history of the Moine rocks of Glen 35 Urquhart, Inverness-shire. Unpublished PhD thesis, University of 36 Portsmouth. 37 Evans, J.A., Fitches, W.R. and Muir, R.J. (1998) Laurentian Clasts 38 in a Neoproterozic Tillite in Scotland. Journal of Geology, 106, 39 361–9. 40 Evans, J.A, and Soper, N.J. (1997) Discussion on metamorphism and 41 cooling of the NE Dalradian and U-Pb and Rb-Sr geochronology of 42 magmatism and metamorphism in the Dalradian of Connemara, western 43 Ireland. Journal of the Geological Society, London, 154, 357–60. 44 Evans, R.H.S. and Tanner, P.W.G. (1996). A late Vendian age for the 45 Kinlochlaggan Boulder Bed (Dalradian)? Journal of the Geological 46 Society, London, 153, 823–6. 47 Evans, R.H.S. and Tanner, P.W.G. (1997). Discussion on a late 48 Vendian age for the Kinlochlaggan Boulder Bed (Dalradian): reply. 49 Journal of the Geological Society, London, 154, 917–19. 50 Eyles, C.H. (1988) Glacially - and tidally - influenced shallow 51 marine sedimentation of the Late Precambrian Port Askaig 52 Formation, Scotland. Palaeogeography, Palaeoclimatology, 53 Palaeoecology, 68, 1–25. 54 Eyles, C.H. and Eyles, N. (1983) Glaciomarine model for upper 55 Precambrian diamictiles of the Port Askaig Formation, Scotland. 56 Geology, 11, 692–6. 57 Eyles, N. and Clark, M. (1985) Gravity-induced soft-sediment 58 deformation in glaciomarine sequences of the upper Proterozoic 59 Port Askaig Formation, Scotland. Sedimentology, 32, 789–814. 60 61 62 63 64 65 1 2 3 4 Fairchild, I.J. (1977) Phengite spherules from the Dalradian 5 Bonnahaven Formation, Islay, Scotland: Glauconitized microfossils. 6 Geological Magazine, 114, 355–64. 7 Fairchild, I.F. (1980a) Sedimentation and origin of a Late 8 Precambrian ―dolomite‖ from Scotland. Journal of Sedimentary 9 Petrology, 50, 423–46. 10 Fairchild, I.J. (1980b) Stages in a Precambrian dolomitization, 11 Scotland: Cementing versus replacement textures. Sedimentology, 12 27, 631–50. 13 Fairchild, I.J. (1980c) The structure of NE Islay. Scottish Journal 14 of Geology, 16, 189–97. 15 Fairchild, I.J. (1985) Comment on ‗Glaciomarine model for Upper 16 Precambrian diamictiles of the Port Askaig Formation, Scotland‘. 17 Geology, 13, 89–90. 18 Fairchild, I.J. (1985) Petrography and carbonate chemistry of some 19 Dalradian dolomitic metasediments: preservation of diagenetic 20 textures. Journal of the Geological Society, London, 142, 167–85. 21 Fairchild, I.J. (1989) Dolomitic stromatolite-bearing units with 22 storm deposits from the Vendian of East Greenland and Scotland: a 23 case of facies equivalence. In Caledonian and related Geology of 24 Scandinavia (ed. Gayer, R. A.), pp. Graham and Trotman, London, 25 pp. 275–283. 26 Fairchild, I.J. (1991) Itinerary II: Topmost Islay Limestone (Appin 27 Group), Port Askaig and Bonahaven Formations (Argyll Group) Port 28 Askaig area, Islay. In The Late Precambrian geology of the 29 Scottish Highlands and Islands (ed. Lister, C.J.) Geologists‘ 30 Association Guide No. 44, pp. 33–41. 31 Fairchild, I.J. (1993) Balmy shores and icy wastes: the paradox of 32 carbonates associated with glacial deposits in Neoproterozoic 33 times. Sedimentology Review, 1, 1–16. 34 Ferry, J.M. and Spear, F.S. (1978) Experimental calibration of the 35 partitioning of Fe and Mg between biotite and garnet. 36 Contributions to Mineralogy and Petrology, 66, 113–17. 37 Fettes, D.J., (1968). Metamorphic structures of Dalradian rocks in 38 North East Scotland. Unpublished PhD thesis, University of 39 Edinburgh. 40 Fettes, D.J. (1970) The structural and metamorphic state of the 41 Dalradian rocks and their bearing on the age of emplacement of the 42 basic sheet. Scottish Journal of Geology, Vol. 6, 108–118. 43 Fettes, D.J. (1971) Relation of cleavage and metamorphism in the 44 Macduff Slates. Scottish Journal of Geology, 7, 248–53. 45 Fettes, D.J. (1979) A metamorphic map of the British and Irish 46 Caledonides. In: Harris, A.L., Holland, C.H. and Leake, B.E. (eds) 47 The Caledonides of the British Isles–Reviewed. Geological Society, 48 London, Special Publications, 8, 307–21. 49 Fettes, D.J. and Desmons, J. (editors) (2007) Metamorphic Rocks: a 50 Classification and Glossary of Terms. Recommendations of the 51 International Union of Geological Sciences Subcommission on the 52 Systematics of Metamorphic Rocks. Cambridge University Press, 53 Cambridge 54 Fettes, D.J., Graham, C.M., Harte, B., and Plant, 55 J.A. (1986a) Lineaments and basement domains; an alternative view 56 of Dalradian evolution. Journal of the Geological Society of 57 London, 143, 453–64. 58 Fettes, D.J., Graham, C.M., Sassi, F.P., and Scolari, A. (1976) The 59 lateral spacing of potassic white micas and facies series 60 61 62 63 64 65 1 2 3 4 variations across the Caledonides. Scottish Journal of Geology, 5 12, 227–36. 6 Fettes, D.J., Harris, A.L. and Hall, L.M. (1986b) The Caledonian 7 geology of the Scottish Highlands. In Synthesis of the 8 Caledonian rocks of Britain. Proceedings of the NATO Advanced 9 Study Institute. Fettes, D J, and Harris, A L (editors). Reidel 10 Dordrecht, pp. 303–34. 11 Fettes, D.J., Leslie A.G., Stephenson D., and Kimbell S.F. (1991) 12 Disruption of Dalradian stratigraphy along the Portsoy Lineament 13 from new geological and magnetic surveys. Scottish Journal of 14 Geology 27, 57–73. 15 Fettes, D.J., Long, C.B., Bevins, R.E., Max, M.D., Oliver, G.J.H., 16 Primmer, T.J., Thomas, L.J. and Yardley, B.W.D., 1985. Grade and 17 time of metamorphism in the Caledonide Orogen of Britain and 18 Ireland. . 5 In, Harris, A.L.(ed), The Nature and Timing of 19 Orogenic Activity in the Caledonian Rocks of the British Isles. 20 Memoir of the Geological Society, London, 9. 21 Fettes, D.J., Macdonald, R., Fitton, J.G., Stephenson, D. and 22 Cooper, M.R. (2011) Geochemical evolution of Dalradian 23 metavolcanic rocks: implications for the break-up of the Rodinia 24 supercontinent. Journal of the Geological Society, 168, 1133-1146. 25 Fisk, S. (1986) An oxygen isotope study of siliceous rocks 26 associated with stratabound mineralisation in Scotland and 27 Ireland. Unpublished PhD thesis, University of Strathclyde. 28 Fitches, W. R. And Maltman, A. J. (1984) Tectonic development and 29 stratigraphy of the western margin of the Caledonides: Islay and 30 Colonsay, Scotland. Transactions of the Royal Society of 31 Edinburgh, 75, 365–82. 32 Fitches, W.R., Muir, R.J., Maltman, A.J. and Bentley, M.R. (1990) 33 Is the Colonsay–west Islay block of SW Scotland an allochthonous 34 terrane? Evidence from Dalradian tillite clasts. Journal of the 35 Geological Society, London, 147, 417–20. 36 Fitches, W.R., Pearce, J.A., Evans, J.A. and Muir, R.J. (1996) 37 Provenance of the late Proterozoic Dalradian tillite clasts, Inner 38 Hebrides, Scotland. In Precambrian Crustal Evolution in the North 39 Atlantic Region (ed. Brewer, T. S.), pp. 367–77. 40 Flinn, D., (1953) Regional metamorphism and migmatisation in 41 Delting, Shetland. Unpublished PhD thesis, University of London, 42 Imperial College. 43 Flinn, D. (1954) On the time relations between regional 44 metamorphism amd permeation in Delting, Shetland. Quarterly 45 Journal of the Geological Society of London, 110, 177–99. 46 Flinn, D. (1961) Continuation of the Great Glen Fault beyond the 47 Moray Firth. Nature, London, 191, 589–91. 48 Flinn, D. (1967) The metamorphic rocks of the southern part of the 49 Mainland of Shetland. Geological Journal, 5, 251–90. 50 Flinn, D. (1985) The Caledonides of Shetland. In Gee, D. G. and 51 Sturt, B. A. (editors) The Caledonide Orogen–Scandinavia and 52 Related Areas. John Wiley and Sons, Chichester. 1161–72. 53 Flinn, D. (1995) Formation of gneisses of migmatite and diatexite 54 appearance in Yell, Shetland by solid-state grain growth 55 recrystallisation. Geological Journal, 30, 415–22. 56 Flinn, D. (1999) The Shetland Ophiolite. 31–33, 36–58 In Stephenson 57 et al. (editors) Caledonian Igneous Rocks of Great Britain. 58 Geological Conservation Review Series, No. 17. Joint Nature 59 Conservation Committee, Peterborough, UK. 60 61 62 63 64 65 1 2 3 4 Flinn, D. (2001) The basic rocks of the Shetland Ophiolite Complex 5 and their bearing on its genesis. Scottish Journal of Geology, 37, 6 79–96. 7 Flinn, D. (2007) The Dalradian rocks of Shetland and their 8 implications for the plate tectonics of the northern Iapetus. 9 Scottish Journal of Geology, Vol. 43, 125–42. 10 Flinn, D. in press. Geology of Unst and Fetlar in Shetland. Memoir 11 of the British Geological Survey, Sheet 131 (Scotland). 12 Flinn, D. and Moffat, D. T. 1985. A peridotitic komatiite from the 13 Dalradian of Shetland. Geological Journal, 20, 287–292. 14 Flinn, D. and Moffat, D.T. (1986) A reply to R. W. Nesbitt and L. 15 A. Hartmann. Geological Journal, 21, 207–9. 16 Flinn, D. and Pringle, I.R. (1976). Age of migmatisation in the 17 Dalradian of Shetland. Nature, London, 259, 299–300. 18 Flinn, D., Frank, P.L., Brook, M. and Pringle, I.R. (1979) 19 Basement–cover relations in Shetland. In The Caledonides of the 20 British Isles–reviewed. Harris, A.L., Holland, C.H. and Leake, 21 B.E. (eds), Geological Society of London Special Publication No. 22 8, 109–15. 23 Flinn, D., May, F., Roberts, J.L. and Treagus, J.E. (1972). A 24 revision of the stratigraphic succession of the East Mainland of 25 Shetland. Scottish Journal of Geology, 8, 335–343. 26 Flinn, D., Miller, J.A. and Roddam, D. (1991) The age of the 27 Norwick hornblendic schists of Unst and Fetlar and the obduction 28 of the Shetland ophiolite. Scottish Journal of Geology 27, 11–19. 29 Flinn, D. and Oglethorpe, R.J.D. (2005). A history of the Shetland 30 Ophiolite Complex. Scottish Journal of Geology, 41, 141–8. 31 Fortey, N.J., Coats, J.S., Gallagher, M.J., Greenwood, P.G. and 32 Smith, C.G. (1993) Dalradian stratabound baryte and base metals 33 near Braemar, NE Scotland. Transactions of the Institution of 34 Mining and Metallurgy (Section B: Applied Earth Science), Vol. 35 102, B55–64. 36 Fortey, N.J. and Smith, C.G. (1986). Stratabound mineralisation in 37 Dalradian rocks near Tyndrum, Perthshire. Scottish Journal of 38 Geology, 22, 377–93. 39 France, D.S. (1971) Structure and metamorphism of Moine and 40 Dalradian rocks in the Grampians of Scotland near Beinn Dorain 41 between Tyndrum and Moor of Rannoch. Unpublished PhD thesis, 42 University of Liverpool. 43 Francis, E.H. (1982). Magma and sediment–1: Emplacement mechanisms 44 of late Carboniferous tholeiitic sills in Northern Britain. 45 Journal of the Geological Society, London, 139, 1–20. 46 Friedrich, A.M, Hodges, K.V., Bowring, S.A. and Martin, M.W. (1999) 47 Geochronological constraints on the magmatic, metamorphic and 48 thermal evolution of the Connemara Caledonides, western Ireland. 49 Journal of the Geological Society, London, 156, 1217–30. 50 Friend, C.R.L., Kinny, P.D., Rogers, G., Strachan, R.A. and 51 Patterson, B.A. (1997) U-Pb zircon geochronological evidence for 52 Neoproterozoic events in the Glenfinnan Group (Moine Supergroup): 53 the formation of the Ardgour granite gneiss, north-west Scotland. 54 Contributions to Mineralogy and Petrology 128, 101–13. 55 Friend, C.R.L., Strachan, R.A., Kinny, P.D. and Watt, G.R. (2003) 56 Provenance of the Moine Supergroup of NW Scotland; evidence from 57 geochronology of detrital and inherited zircons from 58 (meta)sedimentary rocks, granites and migmatites. Journal of the 59 Geological Society, London 160, 247–57. 60 61 62 63 64 65 1 2 3 4 Gallagher, M.J., Smith, C.G., Coats, J.S., Greenwood, P.G., 5 Chacksfield, B.C., Fortey, N.J. and Nancarrow, P.H.A. (1989) 6 Stratabound barium and base-metal mineralisation in Middle 7 Dalradian metasediments near Braemar, Scotland. British Geological 8 Survey, Mineral Reconnaisance Programme Report, No. 104. 9 Ganguly, J. (1979) Garnet and clinopyroxene solid solutions, and 10 geothermometry based on Fe-Mg distribution coefficient. Geochemica 11 and Cosmochemica Acta 43, 1021–9. 12 Garson, M.S, and Plant, J. (1973) Alpine Type Ultramafic Rocks and 13 Episodic Mountain Building in the Scottish Highlands. Nature 14 Physical Science, 242, 34–8. 15 Geikie, A. (1865) The scenery of Scotland viewed in connection with 16 its physical geology (with a geological map by Sir Roderick I. 17 Murchison and Archibald Geikie). Macmillan, London and Cambridge. 18 Geikie, A. (1897) Annual report of the Geological Survey of the 19 United Kingdom and of the Museum of Practical Geology for the year 20 ending December 31, 1896. In Appendix E from the 44th Report of 21 the Department of Science and Art. (London: Her Majesty‘s 22 Stationery Office.) 23 Gibbons, W. And Harris, A.L. (1994) A Revised Correlation of 24 Precambrian rocks in the British Isles. Special Reports, 25 Geological Society, London, 22. 26 Gillen, C. (1987) Huntly, Elgin and Lossiemouth. 149–160 in 27 Excursion Guide to the Geology of the Aberdeen area. (editors 28 N.H.Trewin, B.C. Kneller, and C. Gillen,). (Edinburgh: Scottish 29 Academic press for Geological Society of Aberdeen). 30 Gillespie, M.R. and Styles, M.T. (1999). BGS rock classification 31 scheme, Volume 1: Classification of igneous rocks, 2nd edition. 32 British Geological Survey Research Report, RR/99/6 33 Glover, B.W. (1989). The sedimentology and basin evolution of the 34 Grampian Group. Unpublished PhD Thesis. University of Keele. 35 Glover, B.W. (1993). The sedimentology of the Neoproterozoic 36 Grampian Group and the significance of the Fort William Slide 37 between Spean Bridge and Rubha Cuilcheanna, Inverness-shire. 38 Scottish Journal of Geology, 29, 29–43. 39 Glover, B.W. (1998). Sedimentology and lateral extent of the 40 Glenshirra succession, Monadhliath Mountains, Scotland. British 41 Geological Survey Technical Report, WA/98/23. 42 Glover B.W., Key, R.M., May, F., Clark, G.C., Phillips, E.R. and 43 Chacksfield, B.C. (1995). A Neoproterozoic multi-phase rift 44 sequence: the Grampian and Appin groups of the southwestern 45 Monadhliath Mountains of Scotland. Journal of the Geological 46 Society of London, 152, 391–406. 47 Glover B.W. and McKie, T. (1996). A sequence stratigraphical 48 approach to the understanding of basin history in orogenic 49 Neoproterozoic successions: an example from the central Highlands 50 of Scotland. In: Sequence stratigraphy in British Geology (eds. 51 Hesselbo, S.P. and Parkinson, D.N. ). Geological Society of 52 London, Special Publication, 103, 257–69. 53 Glover, B.W. and Winchester, J.A. (1989) The Grampian Group: a 54 major Late Proterozoic clastic sequence in the central Highlands 55 of Scotland. Journal of the Geological Society, London, 146, 85– 56 97. 57 Goodman, S (1991) The Pannanich Hill Complex and the origin of the 58 Crinan Subgroup migmatites in the North-eastern and Central 59 Highlands. Scottish Journal of Geology, 27, 147–56. 60 61 62 63 64 65 1 2 3 4 Goodman, S. (1994) The Portsoy-Duchray Hill Lineament; a review of 5 the evidence. Geological Magazine 131, 407–15. 6 Goodman, S., Crane, A., Krabbendam, M. and Leslie, A.G. (1997) 7 Correlation of lithostratigraphic sequences in a structurally 8 complex area: Gleann Fearnach to Glen Shee, Scotland. Transactions 9 of the Royal Society of Edinburgh, 87, 503–13. 10 Goodman, S, and Lappin, M.A. (1996) The thermal aureole of the 11 Lochnagar Complex: mineral reactions and implications from thermal 12 modelling. Scottish Journal of Geology, 27, 159–72. 13 Goodman, S., Leslie, A.G., Ashcroft, W.A. and Crane, A. (1990) The 14 geology of the central part of Sheet 65E (Ballater); contribution 15 to the memoir. British Geological Survey Technical Report No. 16 WA/90/59. 17 Goodman, S. and Winchester, J.A. (1993) Geochemical variations 18 within metavolcanic rocks of the Dalradian Farragon Beds and 19 adjacent formations. Scottish Journal of Geology, 29, 131–41. 20 Gorokhov, M., Siedlecka, A., Roberts, D., Melnikov, N.N. and 21 Turchenko, T.L. (2001) Rb–Sr dating of diagenetic illite in 22 Neoproterozoic shales, Varanger Peninsula, northern Norway. 23 Geological Magazine, 138, 541–62. 24 Gould, D. (1997) The geology of the country around Inverurie and 25 Alford. Memoir of the British Geological Survey, Sheets 76E and 26 76W (Scotland). 27 Gould, D. (2001) Geology of the Aboyne district. Memoir of the 28 British Geological Survey, Sheet 66W (Scotland). 29 Gower, P.J. (1973) The Middle–Upper Dalradian Boundary with special 30 reference to the Loch Tay Limestone. Unpublished PhD thesis, 31 University of Liverpool. 32 Gower, P.J. (1977) The Dalradian rocks of the west coast of the 33 Tayvallich peninsula. Scottish Journal of Geology, 13, 125–33. 34 Gradstein, F.M., Ogg, J.G., and Smith, A.G., Agterberg, F.P., 35 Bleeker, W., Cooper, R.A., Davydov, V., Gibbard, P., Hinnov, L.A., 36 House, M.R., Lourens, L., Luterbacher, H.P., McArthur, J., 37 Melchin, M.J., Robb, L.J., Shergold, J., Villeneuve, M., Wardlaw, 38 B.R., Ali, J., Brinkhuis, H., Hilgen, F.J., Hooker, J., Howarth, 39 R.J., Knoll, A.H., Laskar, J., Monechi, S., Plumb, K.A., Powell, 40 J., Raffi, I., Röhl, U., Sadler, P., Sanfilippo, A., Schmitz, B., 41 Shackleton, N.J., Shields, G.A., Strauss, H., Van Dam, J., van 42 Kolfschoten, T., Veizer, J., and Wilson, D. (2004) A Geologic Time 43 Scale 2004. Cambridge University Press, 589 pp. 44 Graham, C.M. (1976) Petrochemistry and tectonic significance of 45 Dalradian metabasaltic rocks of the SW Scottish Highlands. Journal 46 of the Geological Society, London, 132, 61–84. 47 Graham, C.M. (1983). High-pressure greenschist to epidote- 48 amphibolite facies metamorphism of the Dalradian rocks of the SW 49 Scottish Highlands. Geological Society Newsletter, 12, No. 4, 19. 50 Graham, C.M. (1986) The role of the Cruachan Lineament during 51 Dalradian evolution. Scottish Journal of Geology, 22, 257–70. 52 Graham, C.M. and Borradaile, G.J. (1984). The petrology and 53 structure of Dalradian metabasic dykes of Jura: implications for 54 Dalradian evolution. Scottish Journal of Geology, 20, 257–70. Same 55 page range as previous ref? 56 Graham, C.M. and Bradbury, H.J. (1981) Cambrian and late 57 Precambrian basaltic igneous activity in the Scottish Dalradian: a 58 review. Geological Magazine, 118, 27–37. 59 Graham, C.M., Greig, K.M., Sheppard, S.M.F. and Turi, B. (1983) 60 Genesis and mobility of the H2O-CO2 fluid phase during regional 61 62 63 64 65 1 2 3 4 greenschist and epidote amphibolite facies metamorphism: a 5 petrological and stable isotope study in the Scottish Dalradian. 6 Journal of the Geological Society, London, 140, 577–599. 7 Graham, C.M. and Harte, B. (1985) Conditions of Dalradian 8 metamorphism. Journal of the Geological Society, London, 142, 1–3. 9 Grant Wilson, J.S. (1882) Explanation of Sheet 97. Northern 10 Aberdeenshire, Eastern Banffshire. Memoir of the Geological 11 Survey, Scotland. 12 Grant Wilson, J.S. (1886) Explanation of Sheet 87, North-east 13 Aberdeenshire and detached portions of Banffshire. Memoir of the 14 Geological Survey, Scotland. 15 Grant Wilson, J.S., and Hinxman, L.W. (1890) Geology of central 16 Aberdeenshire. Memoir of the Geological Survey of Scotland, Sheet 17 76 (Scotland). 18 Green, J.F.N. (1924) The structure of the Bowmore–Portaskaig 19 District of Islay. Quarterly Journal of the Geological Society, 20 London, 80, 72 –105. 21 Green, J.F.N. (1931) The South-west Highland Sequence. Quarterly 22 Journal of the Geological Society of London 87, 513–550. 23 Gregory, J.W. (1910) Work for Glasgow geologists–the problems of 24 the South-western Highlands. Transactions of the Geological 25 Society of Glasgow 14, 1–29. 26 Gregory, J.W. (1916) Pre-Cambrian of Scotland. Handbuch der 27 Regionaler Geologie, III, Part I, 34–42. 28 Gregory, J.W. (1928) The geology of Loch Lomond. Transactions of 29 the Geological Society of Glasgow 18, 301–23. 30 Gregory, J.W. (1929) The Pre-Cambrian or Pre-Palaeozoic of 31 Scotland. 28–42 in Evans, J. W. and Stubblefield, C. J. (editors) 32 Handbook of the geology of Great Britain. Murby. 33 Gregory, J.W. (1930) The sequence in Islay and Jura. Transactions 34 of the Geological Society of Glasgow Vol. 18, 420–441. 35 Gregory, J.W. (1931) Dalradian Geology: The Dalradian Rocks of 36 Scotland and their Equivalents in other Countries. Methuen, 37 London. 38 Greig, K.M., (1987) Metamorphosed carbonates and fluid behaviour in 39 the Dalradian of S.W. Argyll, Scotland. Unpublished PhD thesis, 40 University of Edinburgh 41 Grieve, A. (1996) Ruskin and Millais at Glenfinlas. The Burlington 42 Magazine, 138, 228–234. 43 Gunn, A.G., Styles, M.T., Stephenson, D., Shaw, M.H. and Rollin, 44 K. (1990) Platinum-group elements in ultramafic rocks of the 45 Upper Deveron Valley, near Huntly, Aberdeenshire. Mineral 46 Reconnaissance Programme Report, British Geological Survey, No. 47 115. 48 Gunn, W., Clough, C.T. and Hill, J.B. (1897) The Geology of Cowal, 49 including the part of Argyllshire between the Clyde and Loch Fyne. 50 Memoirs of the Geological Survey of Scotland, Sheets 29, 37 and 51 38. 52 53 Hackman, B.D. and Knill, J.L. (1962) Calcareous algae from the 54 Dalradian of Islay. Palaeontology, 5, 268–71. 55 Hall, A.J. (1993) Stratiform mineralisation in the Dalradian of 56 Scotland. In Mineralisation in the British Isles. Pattrick, 57 R.A.D., and Polya, D.A. (editors). Chapman and Hall, London, pp. 58 38–101. 59 Hall, J., Brewer, J.A., Matthews, D.H. and Warner, M. (1984) 60 Crustal structure across the Caledonides from the WINCH seismic 61 62 63 64 65 1 2 3 4 reflection profile: Influences on the evolution of the Midland 5 Valley of Scotland. Transactions of the Royal Society of 6 Edinburgh: Earth Sciences, 75, 97–109. 7 Halliday, A.N., Graham, C.M., Aftalion, M. and Dymoke, P. (1989) 8 The depositional age of the Dalradian Supergroup: U-Pb and Sm-Nd 9 isotopic studies of the Tayvallich Volcanics, Scotland. Journal of 10 the Geological Society, London, 146, 3–6. 11 Hambrey, M.J. (1983) Correlation of the Late Proterozoic tillites 12 in the North Atlantic region and Europe. Geological Magazine, 120, 13 209–32. 14 Hambrey, M.J. and Harland, W.B. (editors). (1981) Earth’s pre- 15 Pleistocene glacial record. Cambridge University Press, Cambridge. 16 Hambrey, M.J. and Harland, W.B. (1985) The Late Proterozoic glacial 17 era. Palaeogeography, Palaeoclimatology and Palaeoecology, 51, 18 255–72. 19 Hambrey, M.J. and Waddams, P. (1981) Glaciogenic boulder-bearing 20 deposits in the Upper Dalradian Macduff Slates, northeastern 21 Scotland. In Earth’s pre-Pleistocene glacial record. Hambrey, 22 M.J. and Harland, W.B. (editors). Cambridge University Press, 23 Cambridge, pp. 571–5. 24 Harkness, R. (1861) On the rocks of the portions of the Highlands 25 of Scotland south of the Caledonian Canal; and on their 26 equivalents in the north of Ireland. Quarterly Journal of the 27 Geological Society of London 17, 256–71. 28 Harris, A.L. (1960) Dalradian geology of an area between Pitlochry 29 and Blair Atholl. Unpublished PhD thesis, University of Wales, 30 Aberystwyth. 31 Harris, A.L. (1962) Dalradian geology of the Highland Border, near 32 Callander. Bulletin of the Geological Survey of Great Britain, 19, 33 1–15. 34 Harris, A.L. (1963). Structural investigations in the Dalradian 35 rocks between Pitlochry and Blair Atholl. Transactions of the 36 Edinburgh Geological Society, 19, 256–278. 37 Harris, A.L. (1969) The relationships of the Leny Limestone to the 38 Dalradian. Scottish Journal of Geology, 5, 187–90. 39 Harris, A.L. (1972) The Dalradian rocks at Dunkeld, Perthshire. 40 Bulletin of the Geological Survey of Great Britain, 38, 1–10. 41 Harris, A.L. (1995) Nature and timing of orogenesis in the Scottish 42 Highlands and the role of the Great Glen Fault. In Current 43 perspectives in the Appalachian–Caledonian Orogen, Hibbard, J., 44 van Stall, C.R. and Cawood, P.A. (editors) Geological Association 45 of Canada, Special Paper 41, 65–79. 46 Harris, A.L., Baldwin, C.T., Bradbury, H.J., Johnson, H.D. and 47 Smith, R.A. (1978) Ensialic basin sedimentation: the Dalradian 48 Supergroup. In Crustal evolution in northwestern Britain, Bowes, D 49 R, and Leake, B E (editors)Special Issue of the Geological Journal 50 No. 10 . Seel House Press, Liverpool, pp. 115–38 51 Harris, A.L., and Bradbury, H.J. (1977) Discussion of ‗The 52 evolution and transport of the Tay Nappe‗. Scottish Journal of 53 Geology, 13, 81–3. 54 Harris, A.L., Bradbury, H.J. and McGonigal, N.H. (1976) The 55 evolution and transport of the Tay Nappe. Scottish Journal of 56 Geology, 12, 103–13. 57 Harris, A.L. And Fettes, D.J. (1972) Stratigraphy and structure of 58 Upper Dalradian rocks at the Highland Border. Scottish Journal of 59 Geology, 8, 253–64. 60 61 62 63 64 65 1 2 3 4 Harris, A.L., Fettes, D.J. And Soper, N.J. (1998a) Age of the 5 Grampian event: a Discussion of ―New evidence that the Lower 6 Cambrian Leny Limestone at Callander, Perthshire, belongs to the 7 Dalradian Supergroup, and a re-assessment of the ―exotic‖ status 8 of the Highland Border Complex―. Geological Magazine, 135, 575. 9 Harris, A.L., Haselock, P.J., Kennedy, M.J., Mendum, J.R., Long, 10 J.A., Winchester, J.A. and Tanner, P.W.G. (1994). The Dalradian 11 Supergroup in Scotland, Shetland, and Ireland, In A Revised 12 Correlation of the Precambrian Rocks of the British Isles (eds. W. 13 Gibbons and A.L. Harris), Geological Society, London, Special 14 Report No. 22, 33–53. 15 Harris, A.L., Parson, L.M., Highton, A.J. and Smith, D.I. 1981. 16 New/Old Moine relationships between Fort Augustus and Inverness 17 (Abstract). Journal of Structural Geology, 3, 187–88. 18 Harris, A.L. and Pitcher, W.S. (1975) The Dalradian Supergroup. In 19 A Correlation of Precambrian Rocks in the British Isles. (eds. 20 Harris, A. L., Shackleton, R. M., Watson, J.V., Downie, C., 21 Harland, W. B. and Moorbath, S.), Special Reports of the 22 Geological Society, London, 6, pp. 52–75. 23 Harte, B. (1966) Stratigraphy, structure and metamorphism in the 24 south-eastern Grampian Highlands of Scotland. Unpublished PhD 25 thesis, University of Cambridge. 26 Harte, B., (1975) Determination of a pelite petrogenetic grid for 27 the eastern Scottish Dalradian. Yearbook of the Carnegie 28 Institute, Washington, 74, 438–446. 29 Harte, B. (1979) The Tarfside succession and the structure and 30 stratigraphy of the eastern Scottish Dalradian rocks. In Special 31 Publications, Geological Society, London, 8 (eds. Harris, A. L., 32 Holland, C. H. and Leake, B. E.), pp. 221–28. 33 Harte, B. (1987) Glen Esk Dalradian, Barrovian metamorphic zones. 34 In Excursion Guide to the Geology of the Aberdeen area. (editors 35 N.H.Trewin, B.C. Kneller, and C. Gillen,). Scottish Academic press 36 for Geological Society of Aberdeen, Edinburgh, p 193–210. 37 Harte, B. (1988) Lower Palaeozoic metamorphism in the Moine– 38 Dalradian belt of the British Isles. In The Caledonian— 39 Appalachian Orogen. Harris, A L, and Fettes, D J (editors). 40 Special Publication of the Geological Society of London, No. 38, 41 pp. 123–34. 42 Harte, B., Booth, J.E., Dempster, T.J., Fettes, D.J., Mendum, J.R. 43 and Watts, D. (1984) Aspects of the post-depositional evolution of 44 Dalradian and Highland Border Complex rocks in the Southern 45 Highlands of Scotland. Transactions of the Royal Society of 46 Edinburgh, 75, 151–63. 47 Harte, B., Booth, J.E. and Fettes, D.J., (1987) Stonehaven to 48 Findon: Dalradian Structure and Metamorphism. In Excursion Guide 49 to the Geology of the Aberdeen Area (eds Trewin, N. H., Kneller, 50 B. C. and Gillen, C.). Scottish Academic Press for Geological 51 Society of Aberdeen, Edinburgh, pp. 211–26 52 Harte, B. and Dempster, T.J. (1987) Regional metamorphic zones: 53 tectonic controls. Philosophical Transactions of the Royal Society 54 of London Vol. 321, 105–27. 55 Harte, B, and Hudson, N.F.C. (1979) Pelite facies series and the 56 temperatures and pressures of Dalradian metamorphism in E 57 Scotland. in The Caledonides of the British Isles–Reviewed. (eds. 58 A.L. Harris, C.H. Holland, and B.E. Leake,) Geological Society of 59 London Special Publication, 8, pp 323–37. 60 61 62 63 64 65 1 2 3 4 Harte, B, and Johnson, M.R.W. (1969) Metamorphic history of 5 Dalradian rocks in Glens Clova, Esk and Lethnot, Angus, Scotland. 6 Scottish Journal of Geology, 5, 54–80. 7 Haselock, P.J. (1982) The geology of the Corrieyairack Pass area, 8 Inverness-shire. Unpublished PhD thesis, University of Keele. 9 Haselock, P.J. (1984) The systematic geochemical variation between 10 two tectonically separate successions in the southern 11 Monadhliaths, Inverness-shire. Scottish Journal of Geology. 20, 12 191–205. 13 Haselock, P.J. and Gibbons, W. (1990). The Central Highland 14 controversy: a traverse through the Precambrian metasediments of 15 the Central Highlands of Scotland. Episodes 13, 113–15. 16 Haselock, P.J. and Leslie, A.G. (1992). Polyphase deformation in 17 Grampian Group rocks of the Monadhliath defined by a group 18 magnetic survey. Scottish Journal of Geology 28, 81–7. 19 Haselock, P.J., Winchester, J.A. and Whittles, K.H. (1982). The 20 stratigraphy and structure of the southern Monadhliath Mountains 21 between Loch Killin and upper Glen Roy. Scottish Journal of 22 Geology, 18, 275–90. 23 Heddle, M.F. (1878) Chapters on the mineralogy of Scotland. Chapter 24 fourth - augite, hornblende and serpentinous change. Transactions 25 of the Royal Society of Edinburgh 28, 453–555. 26 Heddle M. F. (1901) The mineralogy of Scotland. D. Douglas, 27 Edinburgh. 28 Henderson, S.M.K. (1938) The Dalradian Succession of the Southern 29 Highlands. Report of the meeting of the British Association for 30 the Advancement of Science, Cambridge, 1938, 424. 31 Henderson, W.G. and Robertson, A.H.F. (1982). The Highland Border 32 rocks and their relation to marginal basin development in the 33 Scottish Caledonides. Journal of the Geological Society of London, 34 139, 433–50. 35 Henderson, W.G., Tanner, P.W.G. and Strachan, R.A. (2009) The 36 Highland Border Ophiolite of Scotland: observations from the 37 Highland Workshop field excursion of April 2008. Scottish Journal 38 of Geology, 45, 13–18. 39 Hibbert, S. (1822) A Description of the Shetland Islands: 40 comprising an account of their geology, scenary, antiquities and 41 superstitions. Constable and Co., Edinburgh. 42 Hickman, A.H. (1975) The stratigraphy of late Precambrian 43 metasediments between Glen Roy and Lismore. Scottish Journal of 44 Geology, 11, 117–42. 45 Hickman, A H. (1978) Recumbent folds between Glen Roy and Lismore. 46 Scottish Journal of Geology, 14, 191–212. 47 Hickman, A.H. and Roberts, J.L. (1977). Discussion of the North 48 Ballachulish Dalradian. Journal of the Geological Society of 49 London, 133, Part 3, 277–79. 50 Hickman, A.H. and Wright, A.E. (1983) Geochemistry and 51 chemostratigraphical correlation of slates, marbles and quartzites 52 of the Appin Group, Argyll, Scotland. Transactions of the Royal 53 Society of Edinburgh: Earth Sciences, 73, 251–78. 54 Highton, A.J. (1986). Caledonian and pre-Caledonian events in the 55 Moine south of the Great Glen Fault, Unpublished PhD thesis, 56 University of Liverpool. 57 Highton, A.J. (1992). The tectonostratigraphical significance of 58 pre-750 Ma metagabbros within the northern Central Highlands, 59 Inverness-shire. Scottish Journal of Geology 28, 71–6. 60 61 62 63 64 65 1 2 3 4 Highton, A.J. (1999). Solid Geology of the Aviemore District. 5 Memoir of the British Geological Survey, Sheet 74E (Scotland). 6 Highton, A.J., Hyslop, E.K. and Noble, S.R. (1999).U-Pb zircon 7 geochronology of migmatization in the northern Central Highlands: 8 evidence for pre-Caledonian (Neoproterozoic) tectonmetamorphism in 9 the Grampian Block, Scotland. Journal of the Geological Society, 10 London, 156, 1195–204. 11 Hill, J.B. (1899) On the progressive metamorphism of some Dalradian 12 sediments in the region of Loch Awe. Quarterly Journal of the 13 Geological Society, London, 40, 470–93. 14 Hill, J.B. (1905) The geology of mid-Argyll. Memoirs of the 15 Geological Survey, Scotland. Explanation of Sheet 37. 16 Hill, J. and Buist, D. (1994) A Geological Field Guide to the 17 Island of Bute, Scotland. (editor Greensmith, J. T.) Geologists’ 18 Association Guide, No. 51, 95 pp. Warwick Press. 19 Hinxman, L.W. (1896). Explanation of Sheet 75. West Aberdeenshire, 20 Banffshire, parts of Elgin and Inverness. Memoir of the Geological 21 Survey, Scotland. 22 Hinxman, L. W. and Anderson, E. M. (1915). The geology of Mid- 23 Strathspey and Strathdearn, including the country between 24 Kingussie and Grantown, Scotland. Memoir of the Geological Survey, 25 Scotland, Sheet 74 (Scotland). 26 Hinxman, L. W., Carruthers, R. G. and Macgregor, M. (1923). The 27 geology of Corrour and the Moor of Rannoch. Memoir of the 28 Geological Survey, Scotland, Sheet 54 (Scotland). 29 Hinxman, L.W. and Grant Wilson, J.S. (1902) The geology of Lower 30 Strathspey. Memoir of the Geological Survey, Scotland, Sheet 85 31 (Scotland). 32 Hoffmann, P.F., Condon, D.J., Bowring, S.A. and Crowley, J.L. 33 (2004) U-Pb zircon date from the Neoproterozoic Ghaub Formation, 34 Namibia: Constraints on Marinoan glaciation. Geology, 32, 817–20. 35 Holdsworth, R.E., Woodcock, N. and Strachan, R. (2000) Geological 36 Framework of Britain and Ireland. In Geological History of Britain 37 and Ireland (edited by Woodcock, N. and Strachan, R.) Blackwell 38 Science, Oxford. 39 Holland, C.H. and Sanders, I.S. (editors) 2009. The Geology of 40 Ireland (2nd edition). Dunedin Academic Press, Edinburgh. 576 pp. 41 Howarth, R.J. and Leake, B.E. (2002) The Life of Frank Coles 42 Phillips (1902–1982) and the Structural Geology of the Moine 43 Petrofabric Controversy. Memoir of the Geological Society, London, 44 23, 95pp. 45 Hudson, N.F.C. (1976) Mineral facies in pelitic rocks, with 46 particular reference to the Buchan type metamorphism of north- 47 eastern Scotland. Unpublished PhD thesis, University of Edinburgh. 48 Hudson, N.F.C. (1980) Regional metamorphism of some Dalradian 49 pelites in the Buchan area, NE Scotland. Contributions to 50 Mineralogy and Petrology, 73, 39–51. 51 Hudson, N.F.C. (1985) Conditions of Dalradian metamorphism in the 52 Buchan area. Journal of the Geological Society of London, 142, 53 63–76. 54 Hutchison, A.R. and Oliver, G.J.H. (1998) Garnet provenance 55 studies, juxtaposition of Laurentian marginal terranes and timing 56 of the Grampian Orogeny in Scotland. Journal of the Geological 57 Society, London, 155, 541–50. 58 Hutton D.H.W. (1987) Strike slip terranes and a model for the 59 evolution of the British and Irish Caledonides. Geological 60 Magazine 124, 405–425. 61 62 63 64 65 1 2 3 4 Hutton, D.H.W. and Alsop, G.I. (2004) Evidence for a major 5 Neoproterozoic orogenic unconformity within the Dalradian 6 Supergroup of NW Ireland. Journal of the Geological Society, 7 London, 161, 629–40. 8 Hutton, D.H.W. and Alsop, G.I. (2005) Discussion on evidence for a 9 major Neoproterozoic orogenic unconformity within the Dalradian 10 Supergroup of NW Ireland. Journal of the Geological Society, 11 London, 162, 221–4. 12 Hutton J. (1788) Theory of the Earth; or an Investigation of the 13 Laws observable in the Composition, Dissolution, and Restoration 14 of the Land upon the Globe. Transactions of the Royal Society of 15 Edinburgh 1, 209–304. 16 Hyslop, E. K. (1992). Strain-induced metamorphism and pegmatite 17 development in the Moine rocks of Scotland. Unpublished PhD 18 thesis, University of Hull. 19 Hyslop, E.K. and Piasecki, M.A.J. (1999). Mineralogy, geochemistry 20 and the development of ductile shear zones in the Grampian Slide 21 Zone of the Scottish Central Highlands. Journal of the Geological 22 Society, London, 156, 577–90. 23 Hyslop, E.K. and Pickett, E.A. (1999) Stratigraphy and magmatism in 24 the uppermost Dalradian of the SW Scottish Highlands: A field 25 excursion to Tayvallich, Loch Avich and Tarbert (Loch Fyne). BGS 26 Technical Report WA/99/73. 27 28 Indares, A. and Dunning, G.R. (1997) Coronitic metagabbro and 29 eclogite from the Grenville Province of western Quebec; 30 interpretation of U-Pb geochronology and metamorphism. Canadian 31 Journal of Earth Sciences 34, 891–901. 32 33 Jacques J.M. and Reavy R.J. (1994) Caledonian plutonism and major 34 lineaments in the SW Scottish Highlands. Journal of the Geological 35 Society, London, 151, 955–69. 36 Jamieson, T.F. (1861) On the structure of the south-west Highlands 37 of Scotland. Quarterly Journal of the Geological Society of 38 London, 17, 133–45. 39 Jehu, T.J. and Campbell, R. (1917) The Highland Border rocks of the 40 Aberfoyle District. Transactions of the Royal Society of 41 Edinburgh, 52, 175–212. 42 Johnson, M.R.W. (1962) Relations of movement and metamorphism in 43 the Dalradians of Banffshire. Transactions of the Edinburgh 44 Geological Society, 19, 29–64. 45 Johnson, M.R.W. (1963) Some time relations of movement and 46 metamorphism in the Scottish Highlands. Geologie en Mijnbouw, 42, 47 121–42. 48 Johnson, M.R.W. (1965) Dalradian. In The Geology of Scotland (1st 49 edition). Craig, G. Y. (ed.) Oliver and Boyd, Edinburgh. 117–60. 50 Johnson, M.R.W. (1983) Dalradian. In Geology of Scotland (2nd 51 edition), Craig, G. Y. (ed.), Scottish Academic Press, Edinburgh, 52 pp. 77–104. 53 Johnson, M.R.W. (1991) Dalradian. In Geology of Scotland (3rd 54 edition). Craig, G. Y. (ed.) The Geological Society, London, pp. 55 125–60. 56 Johnson, M.R.W. and Harris, A.L. (1967) Dalradian–?Arenig relations 57 in part of the Highland Border, Scotland, and their significance 58 in the chronology of the Caledonian orogeny. Scottish Journal of 59 Geology, 3, 1–16. 60 61 62 63 64 65 1 2 3 4 Johnson, M.R.W. and Stewart, F.H. (1960) On Dalradian structures 5 in north-east Scotland. Transactions of the Edinburgh Geological 6 Society, 18, 94–103. 7 Johnson T.E. (1999) Partial melting in Dalradian pelitic migmatites 8 from the Fraserburgh–Inzie Head area of Buchan, northeast 9 Scotland. Unpublished PhD thesis, University of Derby. 10 Johnson T.E., Hudson N.F.C. and Droop G.T.R. (2001a) Partial 11 melting in the Inzie Head gneisses: the role of water and a 12 petrogenetic grid in KFMASH applicable to anatectic pelitic 13 migmatites. Journal of Metamorphic Geology, 19, 99–118. 14 Johnson T.E., Hudson N.F.C. and Droop, G.T.R (2001b) Melt 15 segregation structures within the Inzie Head gneisses of the 16 northeastern Dalradian. Scottish Journal of Geology, 37, 59–72. 17 Johnson T.E., Hudson N.F.C. and Droop G.T.R. (2003) Evidence for a 18 genetic granite–migmatite link in the Dalradian of NE Scotland. 19 Journal of the Geological Society, London, 160, 447– 57. 20 Johnstone, G.S. (1966) British regional geology: the Grampian 21 Highlands (3rd edition). HMSO, Edinburgh for Geological Survey and 22 Museum. 23 Johnstone, G.S. (1975) The Moine Succession. In A Correlation of 24 Precambrian Rocks in the British Isles (eds. Harris, A. L., 25 Shackleton, R. M., Watson, J.V., Downie, C., Harland, W. B. and 26 Moorbath, S.) Geological Society, London, Special Report, 6, 30– 27 42. 28 Johnstone, G.S. and Smith, D.I. (1965) Geological observations 29 concerning the Breadalbane Hydroelectric Project, 30 Perthshire. Bulletin of the Geological Survey of Great Britain, 31 22, 1–52. 32 Johnstone, G.S. and Wright, J.E. (1957) The Geology of the tunnels 33 of the Loch Sloy hydroelectric scheme. Bulletin of the Geological 34 Survey of Great Britain, 12, 1–17. 35 Jones, K.A. (1959) The tectonic and metamorphic history of the Ben 36 More–Am Binnein area, Western Perthshire. Unpublished PhD thesis, 37 University of Wales, Swansea. 38 39 Kearns, S. (1989) Metamorphism of calc-silicate and related rocks 40 from the Dalradian of N.E. Scotland. Unpublished PhD thesis, 41 Derbyshire College of Higher Education. 42 Kennedy, M.J. (1975) The Fleur de Lys Supergroup: stratigraphic 43 comparison of Moine and Dalradian equivalents in Newfoundland with 44 the British Caledonides. Journal of the Geological Society, 45 London, 131, 305–10. 46 Kennedy W.Q. (1946) The Great Glen Fault. Quarterly Journal of the 47 Geological Society of London, 102, 41–76. 48 Kennedy, W.Q. (1948) On the significance of thermal structure in 49 the Scottish Highlands. Geological Magazine, 85, 229–34. 50 Kessler, L.G. and Gollop, I.G. (1988) Inner shelf/shoreface– 51 intertidal transition, Upper Precambrian, Port Askaig Tillite, 52 Isle of Islay, Argyll, Scotland. In Tide Influenced Sedimentology, 53 Environments and Facies (eds. de Boer, P. L., van Gelder, A. and 54 Nio, S. D.), Reidal, Dohdrecht, pp. 341–58. 55 Key, R.M., Clark, G.C., May, F., Phillips, E.R., Chacksfield, B.C. 56 and Peacock, J.D. (1997). Geology of the Glen Roy district. Memoir 57 of the British Geological Survey, Sheet 63W (Scotland). 58 Kilburn, C., Pitcher, W.S. and Shackleton, R.M. (1965) The 59 stratigraphy and origin of the Portaskaig Boulder Bed series 60 (Dalradian). Geological Journal, 4, 343–60. 61 62 63 64 65 1 2 3 4 Kinny, P.D., Friend, C.R.L., Strachan, R.A., Watt, G.R. and Burns, 5 I.M. (1999) U-Pb geochronology of regional migmatites in East 6 Sutherland, Scotland; evidence for crustal melting during the 7 Caledonian Orogeny. Journal of the Geological Society, London, 8 156, 1143–52. 9 Kinny, P.D., Strachan, R.A., Friend, C.R.L., Kocks, H., Rogers, G. 10 and Paterson, B.A. (2003a) U-Pb geochronology of deformed 11 metagranites in central Sutherland, Scotland; evidence for 12 widespread late Silurian metamorphism and ductile deformation of 13 the Moine Supergroup during the Caledonian orogeny. Journal of the 14 Geological Society of London, 160, 259–69. 15 Kinny, P.D., Strachan, R.A., Kocks, H. and Friend, C.R.L. (2003b) 16 U-Pb geochronology of late Neoproterozoic augen granites in the 17 Moine Supergroup, NW Scotland: dating of rift-related, felsic 18 magmatism during supercontinent break-up? Journal of the 19 Geological Society of London, 160, 925–34. 20 Klein, G.D.V. (1970) Tidal origin of a Precambrian quartzite – the 21 Lower Fine-grained Quartzite (Middle Dalradian) of Islay, 22 Scotland. Journal of Sedimentary Petrology, 40, 973–85. 23 Klein, G.D.V. (1971) Tidal origin of a Precambrian quartzite – the 24 Lower Fine-grained Quartzite (Middle Dalradian) of Islay, 25 Scotland: Reply. Journal of Sedimentary Petrology, 41, 886–9. 26 Kneller, B.C. (1985) Dalradian basin evolution and 27 metamorphism. Journal of the Geological Society of London, 142, 4 28 (abstract). 29 Kneller, B.C. (1987) A geological history of NE Scotland. 1–50. 30 In Excursion guide to the geology of the Aberdeen area. Trewin, 31 H.N., Kneller, B.C. and Gillen, C. (editors). Scottish Academic 32 Press for Geological Society of Aberdeen, Edinburgh. 33 Kneller, B.C. (1988) The geology of part of Buchan. Unpublished 34 PhD thesis, University of Aberdeen. 35 Kneller, B.C. and Aftalion M. (1987) The isotopic and structural 36 age of the Aberdeen Granite. Journal of the Geological Society of 37 London 144, 717–21. 38 Kneller, B.C. and Leslie, A.G. (1984) Amphibolite facies 39 metamorphism in shear zones in the Buchan area of NE Scotland. 40 Journal of Metamorphic Geology 2, 83–94. 41 Knill, J.L. (1959) Palaeocurrents and sedimentary facies of the 42 Dalradian metasediments of the Craignish–Kilmelfort district. 43 Proceedings of the Geologists’ Association, 70, 273–84. 44 Knill, J.L. (1960) The tectonc pattern in the Dalradian of the 45 Craignish–Kilmelfort District, Argyllshire. Quarterly Journal of 46 the Geological Society of London, 115, 339–64. 47 Knill, J.L. (1963) A sedimentary history of the Dalradian Series. 48 In The British Caledonides. (eds Johnson, M.R.W. and Stewart, 49 F.H.). Oliver and Boyd, Edinburgh, pp. 99–121. 50 Krabbendam, M. and Leslie, A.G. (1996) Folds with vergence opposite 51 to the sense of shear. Journal of Structural Geology, 18, 777–81. 52 Krabbendam, M., Leslie, A.G., Crane, A. and Goodman, S. (1997) 53 Generation of the Tay Nappe, Scotland, by large-scale SE-directed 54 shearing. Journal of the Geological Society, London, 154, 15–24. 55 Krabbendam, M., Prave, A.R. and Cheer, D.A. (2008) A fluvial origin 56 for the Neoproterozoic Morar Group, NW Scotland; implications for 57 Torridon–Morar Group correlation and the Grenville Orogen foreland 58 basin. Journal of the Geological Society, London, 165, 379–94. 59 60 61 62 63 64 65 1 2 3 4 Kruhl, J. and Voll, G. (1975) Large scale pre-metamorphic and pre- 5 cleavage inversion at Loch Leven, Scottish Highlands. Neues 6 Jahrbuch für Mineralogie, 2, 71–8. 7 Kynaston, H. and Hill J.B. (1908) The Geology of the country near 8 Oban and Dalmally. Memoir of the Geological Survey, Sheet 45 9 (Scotland). 10 11 Lambert, R.St. J. (1975) Discussion of Moine–Dalradian 12 relationships in the River Leven. Journal of the Geological 13 Society of London, 131, 327–8. 14 Lambert, R.St.J., Holland, J.G. and Winchester, J.A. (1982) A 15 geochemical comparison of the Dalradian Leven Schists and the 16 Grampian Division Monadhliath Schists of Scotland. Journal of the 17 Geological Society of London, 139, 71–84. 18 Lambert, R.St.J. and McKerrow, W.S. (1976) The Grampian Orogeny. 19 Scottish Journal of Geology, 12, 271–92. 20 Lambert, R.St.J, Winchester, J.A. and Holland, 21 J.G. (1981) Comparative geochemistry of pelites from the Moinian 22 and Appin Group (Dalradian) of Scotland. Geological Magazine, 23 118, 477–90. 24 Lawson, J. D. and Weedon, D. S. (editors) (1992) Geological 25 Excursions around Glasgow and Girvan. Geological Society of 26 Glasgow, Glasgow. 27 Leake, B.E. (1982) Volcanism in the Dalradian. In Igneous rocks 28 of the British Isles. Sutherland, D. S. (editor). John Wiley and 29 Sons, Chichester, pp. 45–50. 30 Leake, B.E. and Tanner, P.W.G. (1994) The Geology of the Dalradian 31 and Associated Rocks of Connemara, Western Ireland: a report to 32 accompany the 1:63360 geological map and cross sections. Royal 33 Irish Academy, Dublin. 34 Lee, G.W. and Bailey, E.B. (1925) The pre-Tertiary geology of Mull, 35 Loch Aline and Oban. Memoir of the Geological Survey of Great 36 Britain, Sheet 44 (Scotland). 37 Leggo, P.J., Tanner, P.W.G. and Leake, B.E. (1969) Isochron study 38 of Donegal Granite and certain Dalradian rocks of Britain. In 39 North Atlantic-geology and Continental Drift, a symposium (ed. M. 40 Kay), Memoir of the American Association of Petroleum Geologists, 41 12, pp. 354–62. 42 Le Maitre, R.W (editor) (2002). Igneous Rocks: a Classification and 43 Glossary of Terms; Recommendations of the International Union of 44 Geological Sciences Subcommission on the Systematics of Igneous 45 Rocks. Cambridge University Press, Cambridge, 236 pp. 46 Leslie, A.G., Chacksfield, B.C., Smith, M. and Smith, R.A. (1999). 47 The Geophysical signature of a major shear zone in the Central 48 Highlands of Scotland. British Geological Survey Technical Report 49 No. WA/99/32R. 50 Leslie, A.G., Krabbendam, M. and Smith, R.A. (2006) The Gaick Fold 51 Complex: large-scale recumbent folds and their implications for 52 Caledonian structural architecture in the Central Grampian 53 Highlands. Scottish Journal of Geology, 42, 149–60. 54 Leslie, A.G., Smith, M. and Soper, N.J. (2008) Laurentian margin 55 evolution and the Caledonian orogeny–a template for Scotland and 56 East Greenland. In The Greenland Caledonides: Evolution of the 57 Northeast Margin of Laurentia. Higgins, A.K., Gilotti, J.A. and 58 Smith, M.P. (editors), Geological Society of America Memoir, 202, 59 307–43. 60 61 62 63 64 65 1 2 3 4 Lindsay, N.G. (1988) Contrasts in Caledonian tectonics of the 5 Northern and Central Highlands. Unpublished PhD thesis, University 6 of Liverpool. 7 Lindsay, N.G., Haselock, P.J. and Harris, A.L. (1989). The extent 8 of Grampian orogenic activity in the Scottish Highlands. Journal 9 of the Geological Society of London, 146, 733–5. 10 Litherland, M. (1970) The stratigraphy and structure of the 11 Dalradian rocks around Loch Creran, Argyll. Unpublished PhD 12 thesis, University of Liverpool. 13 Litherland, M. (1975) Organic remains and traces from the Dalradian 14 of Benderloch, Argyll. Scottish Journal of Geology, 11, 47–50. 15 Litherland, M. (1980) The stratigraphy of the Dalradian rocks 16 around Loch Creran, Argyll. Scottish Journal of Geology, 16, 105– 17 23. 18 Litherland, M. (1982) The structure of the Loch Creran Dalradian 19 and a new model for the SW Highlands. Scottish Journal of Geology, 20 18, 205–25. 21 Loudon, T.V. (1963) The sedimentation and structure in the Macduff 22 District of North Banffshire and Aberdeenshire. Unpublished PhD 23 thesis, University of Edinburgh. 24 Lowe, D. R. 1976. Subaqueous liquified and fluidised sediment flows 25 and their deposits. Sedimentology, 23, pp. 285-308. 26 Lyubetskaya, T. and Ague, J.J., 2010. Modeling metamorphism in 27 collisional orogens intruded by magmas: fluid flow and 28 implications for Barrovian and Buchan metamorphism, Scotland. 29 American Journal of Science, 310, 459-491. 30 31 McAteer, C.A., Daly, J.S., Flowerdew, M.J., Connelly, J.N., Housh, 32 T.B. and Whitehouse, M.J. (2010) Detrital zircon, detrital 33 titanite and igneous clast U-Pb geochronology and basement-cover 34 relationships of the Colonsay Group, SW Scotland: Laurentian 35 provenance and correlation with the Neoproterozoic Dalradian 36 Supergroup. Precambrian Research, 181, 21-42. 37 McCallien, W.J. (1925) Notes on the Geology of the Tarbet district 38 of Loch Fyne. Transactions of the Geological Society of Glasgow, 39 17, 233–63. 40 McCallien, W.J. (1926) The structure of South Knapdale (Argyll). 41 Transactions of the Geological Society of Glasgow, 17, 377–94. 42 McCallien, W.J. (1929) The metamorphic rocks of 43 Kintyre. Transactions of the Royal Society of Edinburgh, 56, 409– 44 36. 45 Mccallien, W.J. (1938) The Geology of Bute. Transactions of the 46 Buteshire Natural History Society, 12, 84–112. 47 McCay, G.A., Prave, A.R., Alsop, G.I. and Fallick, A.E. (2006) 48 Glacial trinity: Neoproterozoic Earth history within the British– 49 Irish Caledonides. Geology, 34, 909–12. 50 McClay, K.R. (1987) The Mapping of Geological Structures. 51 Geological Society of London Handbook, Open University Press, 52 Milton Keynes, 161 pp. 53 McClay K.R., Norton M.G., Cony P. and Davis G.H. (1986) Collapse of 54 the Caledonian Orogen and the Old Red Sandstone. Nature, London 55 323, 147–9. 56 MacCulloch, J. (1814) Remarks on several parts of Scotland which 57 exhibit quartz rock, and on the nature and connexions of this rock 58 in general. Transactions of the Geological Society, 2, 450–87. 59 MacCulloch, J. (1819) A description of the western islands of 60 Scotland including the Isle of Man: comprising an account of their 61 62 63 64 65 1 2 3 4 geological structure; with remarks on their agriculture, scenary 5 and antiquities. 3 volumes. Constable, London. 6 MacDonald, J.G. and Herriot, A. (1983) Macgregor’s excursion guide 7 to the geology of Arran. (3rd edition). Geological Society of 8 Glasgow and University of Glasgow, Glasgow. 9 Macdonald, R. and Fettes, D.J. (2007) The tectonomagmatic evolution 10 of Scotland. Transactions of the Royal Society of Edinburgh: Earth 11 Sciences, 97, 213–95. 12 Macdonald, R., Fettes, D.J., Stephenson, D. and Graham, C.M. (2005) 13 Basic and ultrabasic volcanic rocks from the Argyll Group 14 (Dalradian) of NE Scotland. Scottish Journal of Geology, 41, 159– 15 74. 16 MacGregor, A.G. (1948) British regional geology: the Grampian 17 Highlands (2nd edition), HMSO for Geological Survey and Museum, 18 Edinburgh. 19 MacGregor, A.R. (1996) Edzell and Glen Esk. 93–108 in Fife and 20 Angus Geology, an excursion guide (3rd edition) by A.R. MacGregor, 21 Pentland Press, Durham. 22 MacGregor, S.M.A. and Roberts, J.L. (1963) Dalradian pillow lavas, 23 Ardwell Bridge, Banffshire. Geological Magazine, 100, 17–23. 24 McIntyre, D.B. (1950) Lineation, boudinage and recumbent folding in 25 the Struan Flags (Moine), near Dalnacardoch, Perthshire. 26 Geological Magazine, 87, 205–25. 27 McIntyre, D.B. (1951) The tectonics of the area between Grantown 28 and Tomintoul (mid-Strathspey). Quarterly Journal of the 29 Geological Society of London, 107, 1–22. 30 McKenzie, D.P. and Bickle, M.J. (1988). The volume and composition 31 of melt generated by the extension of the lithosphere. Journal of 32 Petrology, 29, 625–79. 33 McKie, T. (1990) Tidal and storm-influenced sedimentation from a 34 Cambrian transgressive passive margin sequence. Journal of the 35 Geological Society, London, 147, 785–94. 36 Mackie, W. (1908) Evidence of contemporaneous volcanic action in 37 the Banffshire schists. Transactions of the Edinburgh Geological 38 Society, 9, 93–101. 39 McLellan, E.L. (1983) Barrovian migmatites and the thermal history 40 of the south-eastern Grampians. Unpublished PhD thesis, University 41 of Cambridge. 42 McLellan, E.L., 1985. Metamorphic reactions in the kyanite and 43 sillimanite zones of the Barrovian type area, Journal of 44 Petrology, 26, 789-818. 45 Macnair, P. (1896) The altered clastic rocks of the Southern 46 Highlands: their structure and succession. Geological Magazine, 47 Decade 4, 3, 167–174, 211–217. 48 Macnair, P. (1906) On the development of the great axial lines of 49 folding in the Highland schists. Proceedings of the Royal 50 Philosophical Society of Glasgow Vol. 37, 129–xxx. 51 Macnair, P. (1908) The Geology and Scenery of the Grampians and the 52 Valley of Strathmore, James MacLehose and Sons, Glasgow, 2 53 volumes, 256 pp. 54 Marcantonio, F., Dickin, A.P., McNutt, R.H. and Heaman, L.M. 55 (1988). A 1880-million year old Proterozoic gneiss terrane in 56 Islay with implications for crustal evolution of Britain. Nature, 57 335, 62–64. 58 Mather, J.D. (1968) A geochemical, mineralogical and petrological 59 study of rocks of lower greenschist facies from the Dalradian of 60 Scotland. Unpublished PhD thesis, University of Liverpool. 61 62 63 64 65 1 2 3 4 May, F. (1970) Movement, metamorphism and migmatization in the 5 Scalloway region of Shetland. Bulletin of the Geological Survey of 6 Great Britain, 31, 205–26. 7 May, F. and Highton, A.J. (1997) Geology of the Invermoriston 8 district. Memoir of the British Geological Survey. Sheet 73W 9 (Scotland). 10 Melezhik, V.A., Gorokhov, I.M., Kuznetsov, A.B. and Fallick, A.E. 11 (2001). Chemostratigraphy of Neoproterozoic carbonates: 12 implications for ‗blind dating‘. Terra Nova, 13, 1–11. 13 Mendum, J.R. 1987. Dalradian of the Collieston coast section. 161– 14 172 in Excursion guide to the geology of the Aberdeen 15 area. Trewin, N H, Kneller, B C, and Gillen, C (editors). 16 (Edinburgh: Scottish Academic Press for Geological Society of 17 Aberdeen.) 18 Mendum, J.R., Barber, A.J., Butler, R.W.H., Flinn, D., Goodenough, 19 K.M., Krabbendam, M., Park, R.G. and Stewart, A.D. (2009) 20 Lewisian, Torridonian and Moine rocks of Scotland, Geological 21 Conservation Review Series, No. 34, Joint Nature Conservation 22 Committee, Peterborough, 722 pp. 23 Mendum, J.R. and Fettes, D.J. (1985) The Tay nappe and associated 24 folding in the Ben Ledi–Loch Lomond area. Scottish Journal of 25 Geology, 21, 41–56. 26 Mendum, J.R. and Noble, S.R. (2010) Mid-Devonian sinistral 27 transpression on the Great Glen Fault: the rise of the Rosemarkie 28 Inlier and the Acadian Event in Scotland. In Continental tectonics 29 and mountain building: the legacy of Peach and Horne. (eds R.D. 30 Law, R.W.H. Butler, R.E. Holdsworth, M. Krabbendam and R.A. 31 Strachan), Geological Society, London, Special Publication, No. 32 335, pp. 161-187. 33 Mendum, J.R. and Thomas, C.W. (1997) Discussion on the generation 34 of the Tay Nappe, Scotland, by large-scale SE-directed shearing. 35 Journal of the Geological Society, London, 154, 581–3. 36 Miall, A. D. 1985. Architectural-element analysis: a new method of 37 facies analysis applied to fluvial deposits. Earth Science 38 Reviews, 22, pp. 261-308. 39 Miall, A. D. 1992. Alluvial Deposits. In: Walker, R. G. & James, N. 40 P. (eds), Facies models – response to sea level changes. 41 Geoscience Canada, pp. 119-1992. 42 Millar, I.L. (1999) Neoproterozoic extensional basic magmatism 43 associated with the West Highland granite gneiss in the Moine 44 Supergroup of NW Scotland. Journal of the Geological Society, 45 London 156, 1153–62. 46 Moffat, D.T. (1987) The serpentinized ultramafites of the Shetland 47 Caledonides. Unpublished PhD thesis, University of Liverpool. 48 Moig, N.A.W. (1986) A structural study of the Dalradian rocks of 49 the Banff coastal transect, NE Scotland. Unpublished PhD thesis, 50 University of Dundee. 51 Moles, N.R. (1985a) Geology, geochemistry and petrology of the Foss 52 stratiform baryte–base metal deposit and adjacent Dalradian 53 metasediments, near Aberfeldy. Unpublished PhD thesis, University 54 of Edinburgh. 55 Moles, N.R. (1985b) Metamorphic conditions and uplift history in 56 central Perthshire: evidence from mineral equilibria in the Foss 57 celsian-barite-sulphide deposit, Aberfeldy. Journal of the 58 Geological Society of London, 142, 39–52. 59 60 61 62 63 64 65 1 2 3 4 Möller, C. (1998) Decompressed eclogites in the Sveconorwegian 5 (Grenvillian) Orogen of SW Sweden; petrology and tectonic 6 implications. Journal of Metamorphic Geology, 16, 641–56. 7 Molyneux, S.G. 1998. An upper Dalradian microfossil reassessed. 8 Journal of the Geological Society, London, 155, 740–743. 9 Morgan, W.C. (1966) The metamorphic history of the Dalradian rocks 10 between Tomintoul and Loch Builg, Banfshire. Unpublished Ph D 11 thesis, University of Aberdeen. 12 Morris, G.A. and Hutton, D.H.W. (1993) Evidence for sinistral shear 13 associated with the emplacement of the early Devonian Etive dyke 14 swarm. Scottish Journal of Geology, 29, 69–72. 15 Mould, D.D.C.P. (1946) The geology of the Foyers ‗granite‘ and the 16 surrounding country. Geological Magazine, 83, 249–65. 17 Muir, R.J. (1990) The Precambrian basement and related rocks of the 18 southern Inner Hebrides, Scotland. Unpublished PhD thesis, 19 University of Wales, Aberystwyth. 20 Muir, R.J., Fitches, W.R. and Maltman, A.J. (1989) An Early 21 Proterozoic link between Greenland and Scandinavia in the Inner 22 Hebrides of Scotland. Terra Abstract, 1, 5. 23 Muir, R.J., Fitches, W.R. and Maltman, A.J. (1992). Rhinns Complex: 24 a missing link in the Proterozoic basement of the North Atlantic 25 region. Geology, 20, 1043–6. 26 Muir, R.J., Fitches, W.R. and Maltman, A.J. (1994a). The Rhinns 27 Complex: Proterozoic basement on Islay and Colonsay, Inner 28 Hebrides, Scotland, and on Inishtrahull, NW Ireland. Transactions 29 of the Royal Society of Edinburgh: Earth Sciences, 85, 77–90. 30 Muir, R.J., Fitches, W.R., Maltman, A.J. and Bentley, M.R. (1994b) 31 Precambrian rocks of the southern Inner Hebrides–Malin Sea region: 32 Colonsay, west Islay, Inishtrahull and Iona. In: Gibbons, W. and 33 Harris, A.L. (eds) A revised correlation of Precambrian rocks in 34 the British Isles. Geological Society, London, Special Report 22, 35 54–58. 36 Muir, R.J., Fitches, W.R. and Maltman, A.J. (1995). The Colonsay 37 Group and basement–cover relationship on the Rhinns of Islay, 38 Inner Hebrides. Scottish Journal of Geology, 31, 125–30. 39 Munro, M. (1986) Geology of the country around Aberdeen. Memoir of 40 the British Geological Survey, Sheet 77 (Scotland). 41 Munro, M. and Gallagher, J W. (1984) Disruption of the ‗Younger 42 Basic‘ masses in the Huntly–Portsoy area, Grampian 43 Region. Scottish Journal of Geology, 20, 361–82. 44 Murchison, R.I. (1851) On the Silurian rocks of the south of 45 Scotland. Quarterly Journal of the Geological Society of London, 46 7, 139–78. 47 Murchison, R.I. (1859) Siluria: the History of the Oldest Known 48 Rocks Containing Organic Remains, With a Brief Sketch of the 49 Distribution of Gold Over the Earth. 3rd edition. John Murray, 50 London. 51 Murchison, R.I. and Geikie, A. (1861) On the altered rocks of the 52 Western Islands of Scotland and the North-Western and Central 53 Highlands. Quarterly Journal of the Geological Society of London 54 17, 171– ??. 55 Mutti, E. and Normark, W.R. (1987) Comparing examples of modern and 56 ancient turbidite systems: problems and concepts. In Marine 57 Clastic Sedimentology (eds. Legget, J.K and Zuffa, G.G.), Graham 58 and Trotman, pp.1–38. 59 Mykura, W. (1976) British Regional Geology: Orkney and Shetland. 60 HMSO, Edinburgh for the Institute of Geological Sciences. 61 62 63 64 65 1 2 3 4 5 Nell, P.A.R. (1984) The geology of lower Glen Lyon. Unpublished PhD 6 thesis, University of Manchester. 7 Nell, P.A.R. (1986) Discussion on the Caledonian metamorphic core: 8 an Alpine model. Journal of the Geological Society of London, 9 143, 723–8. 10 Nesbitt, R.W. and Hartmann, L.A. (1986) Comments on ‗A peridotitic 11 komatiite from the Dalradian of Shetland‘ by D. Flinn and D.T. 12 Moffat. Geological Journal, 21, 201–5. 13 Nicol, J. (1844) Guide to the geology of Scotland: Containing an 14 Account of the Character, Distribution and More Interesting 15 Appearances of its Rocks and Minerals. Oliver and Boyd, Edinburgh. 16 Nicol, J. (1852) On the geology of the southern portion of the 17 peninsula of Cantyre, Argyllshire. Quarterly Journal of the 18 Geological Society of London, 8, 406–25. 19 Nicol J. (1863) On the geological structure of the Southern 20 Grampians. Quarterly Journal of the Geological Society of London 21 19, 180–209. 22 Noble, S.R., Hyslop, E.K. and Highton, A.J. (1996). High-precision 23 U-Pb monazite geochronology of the c. 806 Ma Grampian Shear Zone 24 and the implications for evolution of the Central Highlands of 25 Scotland. Journal of the Geological Society, London, 153, 511–14. 26 27 Okonkwo, C.T. (1985). The geology and geochemistry of the 28 metasedimentary rocks of the Loch Laggan–Upper Strathspey area, 29 Inverness-shire. Unpublished PhD thesis, University of Keele. 30 Okonkwo, C.T. (1988). The stratigraphy and structure of the 31 metasedimentary rocks of the Loch Laggan–Upper Strathspey area, 32 Inverness-shire. Scottish Journal of Geology, 24, 21–34. 33 Oldroyd, D.R. and Hamilton, B.M. (2002) Themes in the early history 34 of Scottish geology. In: Trewin N. H. (ed.) The Geology of 35 Scotland. The Geological Society, London, pp. 27–43. 36 Oliver, G.J.H. (2001) Reconstruction of the Grampian episode in 37 Scotland: its place in the Caledonian Orogeny. Tectonophysics, 38 332, 23–49. 39 Oliver, G.J.H. (2002) Chronology and terrane assembly, new and old 40 controversies. In The Geology of Scotland (edited by Trewin, N. 41 H.) The Geological Society, London, 201–11. 42 Oliver, G.J.H., Chen, F., Buchwald, R. and Hegner, E. (2000) Fast 43 tectonometamorphism and exhumation in the type area of the 44 Barrovian and Buchan zones. Geology, 28, 459–62. 45 Oliver, G.J.H., Simon, A.W., Wan, Y., 2008. Geochronology and 46 geodynamics of Scottish granitoids from the late Neoproterozoic 47 break-up of Rodinia to Palaeozoic collision. Journal of the 48 Geological Society, London, 165, 661-674. 49 50 Pankhurst, R.J. (1970) The geochronology of the basic igneous 51 complexes. Scottish Journal of Geology, 6, 83–107. 52 Pankhurst, R.J. and Pidgeon, R.T. (1976) Inherted isotope systems 53 and the source region prehistory of the early Caledonian granites 54 in the Dalradian Series of Scotland. Earth and Planetary Science 55 Letters, 31, 58–66. 56 Pantin, H.M. (1952) Part 1: The petrology and structure of the Ben 57 Vrackie epidiorite. Part 2: Some new observations on Dalradian 58 stratigraphy and tectonics. Unpublished PhD thesis, University of 59 Cambridge. 60 61 62 63 64 65 1 2 3 4 Pantin H.M. (1961) The stratigraphy and structure of the Blair 5 Atholl–Ben a‘ Gloe area, Perthshire, Scotland. Transactions of the 6 Royal Society of New Zealand, 88, 597–622. 7 Park, R.G. (1992) Plate kinematic history of Baltica during the 8 Middle to Late Proterozoic: a model. Geology 20, 725–8. 9 Park, R.G. (1994) Early Proterozoic tectonic overview of the 10 northern British Isles and neighbouring terrains in Laurentia and 11 Baltica. Precambrian Research, 68, 65–79. 12 Parson, L M. (1982) The Precambrian and Caledonian geology of the 13 ground near Fort Augustus, Inverness-shire. Unpublished PhD 14 thesis, University of Liverpool. 15 Paterson, I.B., Hall, I.H.S. and Stephenson, D. (1990) Geology of 16 the Greenock district. Memoir of the British Geological Survey, 17 Sheet 30W and part of Sheet 29E (Scotland). 18 Pattrick, R.A. and Treagus, J.E. (1996) Economic geology of the 19 Schiehallion district, central highlands of Scotland. British 20 Geological Survey Technical Report No. WA/96/89. 21 Peach, B.N. (1904) Summary of Progress of the Geological Survey of 22 the United Kingdom for 1903, 69. 23 Peach, B.N. and Horne, J. (1930) Chapters on the Geology of 24 Scotland, Oxford University Press, London. 25 Peach, B.N., Kynaston, B.A. and Muff, H.B. (1909) The geology of 26 the seaboard of mid Argyll including the islands of Luing, Scarba, 27 the Garvellachs, and the Lesser Isles, together with the northern 28 part of Jura and a small portion of Mull. Memoirs of the 29 Geological Survey of Scotland, Sheet 36. 30 Peach, B.N., Wilson, J.G.S., Hill, J.B., Bailey, E.B. and Grabham, 31 G.W. (1911) The Geology of Knapdale, Jura and North Kintyre. 32 Memoirs of the Geological Survey of Scotland, Sheet 28. 33 Peach, B.N. and Horne, J. (1930) Chapters on the Geology of 34 Scotland, Oxford University Press, Oxford. 35 Peacock, J.D., Berridge, N.G., Harris, A.L. and May, F. (1968) The 36 geology of the Elgin district. Memoir of the Geological Survey of 37 Scotland, Sheet 95 (Scotland). 38 Phillips, E.R. (1996) The mineralogy and petrology of the igneous 39 and metamorphic rocks exposed in the Macduff district (Sheet 96E), 40 Northeast Scotland. British Geological Survey, Mineralogy and 41 Petrology Technical Report, WG/96/26. 42 Phillips, E.R. and Auton, C.A. (1997) Ductile fault rocks and 43 metamorphic zonation in the Dalradian of the Highland Border SW of 44 Stonehaven, Kincardineshire. Scottish Journal of Geology, 33, 83– 45 93. 46 Phillips, E.R., Clark, G.C. and Smith, D.I. (1993) Mineralogy, 47 petrology, and microfabric analysis of the Eilrig Shear Zone, Fort 48 Augustus, Scotland. Scottish Journal of Geology, 29, 143–58. 49 Phillips, E.R., Hyslop, E.K., Highton, A.J and Smith, M. (1999). 50 The timing and P-T conditions of regional metamorphism in the 51 Central Highlands. Journal of the Geological Society, London, 156, 52 1183–93. 53 Phillips, F.C. (1930) Some mineralogical and chemical changes 54 induced by progressive metamorphism in the Green Bed group of the 55 Scottish Dalradian. Journal of the Mineralogical Society, 22, 240– 56 256. 57 Phillips, F.C. (1954) The Use of Stereographic Projection in 58 Structural Geology, Arnold, London. 59 60 61 62 63 64 65 1 2 3 4 Phillips, W.E.A., Stillman, C.J. and Murphy, T. (1976) A Caledonian 5 plate tectonic model. Journal of the Geological Society of London, 6 132, 579–609. 7 Piasecki M.A.J. (1975) Tectonic and metamorphic history of the 8 Upper Findhorn, Inverness-shire, Scotland. Scottish Journal of 9 Geology, 11, 87–115. 10 Piasecki, M.A.J. (1980). New light on the Moine rocks of the 11 Central Highlands of Scotland. Journal of the Geological Society 12 of London, 137, 41–59. 13 Piasecki, M.A.J. and van Breemen, O. (1979a) A Morarian age for 14 the ―younger Moines‖ of central and western Scotland. Nature, 15 London, 278, 734–6. 16 Piasecki, M.A.J. and van Breemen, O. (1979b). The ‗Central Highland 17 Granulites‘: cover-basement tectonics in the Moine. In The 18 Caledonides of the British Isles - reviewed. (editors. Harris, 19 A.L., Holland, C.H. and Leake, B.E.), The Geological Society of 20 London, Special Publications, 8, 139–44. 21 Piasecki, M.A.J. and van Breemen, O. (1983) Field and isotopic 22 evidence for a c. 750 Ma tectonothermal event in Moine rocks in 23 the Central Highland region of the Scottish Caledonides. 24 Transactions of the Royal Society of Edinburgh: Earth Sciences, 25 73, 119–34. 26 Piasecki, M.A.J., van Breemen, O. and Wright, A.E. (1981) Late 27 Precambrian geology of Scotland, England and Wales. In Geology of 28 the North Atlantic Borderlands, Kerr, J.W. and Fergusson, A.J. 29 (eds). Memoir of the Canadian Society of Petroleum Geologists, 7, 30 57–94. 31 Piasecki, M.A.J. and Temperley, S. (1988a). The Central Highland 32 Division. In: Winchester, J.A. (ed) Later Proterozoic stratigraphy 33 of the Northern Atlantic regions. Blackie, Glasgow and London, 46– 34 53. 35 Piasecki, M.A.J. and Temperley, S. (1988b). The northern sector of 36 the central Highlands. 51-68 in An excursion guide to the Moine 37 geology of the Scottish Highlands. Allison, I, May, F, and 38 Strachan, R A (editors). (Edinburgh: Scottish Academic Press for 39 Edinburgh Geological Society and Geological Society of Glasgow.) 40 Pickering K.T., Bassett M.G., and Siveter D.J. (1988) Late 41 Ordovician–early Silurian destruction of the Iapetus Ocean: 42 Newfoundland, British Isles and Scandinavia: A discusion. 43 Transactions of the Royal Society of Edinburgh: Earth Sciences, 44 79, 361–82. 45 Pickett, E.A. (1997) An introduction to the Green Beds of the 46 Southern Highland Group: previous research and an account of 47 preliminary work carried out in 1997. British Geological Survey 48 Technical Report WA/97/92. 49 Pickett, E.A., Hyslop, E.K. and Petterson, M.G. (2006) The Green 50 Beds of the SW Highlands: deposition and origin of a basic 51 igneous-rich sedimentary sequence in the Dalradian Supergroup of 52 Scotland. Scottish Journal of Geology, 42, 43–57. 53 Pidgeon R.T. and Compston W. (1992) A Shrimp ion microprobe study 54 of inherited and magmatic zircon from Scottish Caledonian 55 granites. Transactions of the Royal Society, Edinburgh: Earth 56 Sciences, 83, 473–83. 57 Pitcher, W.S. and Berger, A.R. (1972) The Geology of Donegal: a 58 study of granite emplacement and unroofing. Wiley-Interscience, 59 New York, 435 pp. 60 61 62 63 64 65 1 2 3 4 Plant, J.A., Stone, P. and Mendum, J.R. (1999) Regional 5 geochemistry, terrane analysis and metallogeny in the British 6 Caledonides. In Continental Tectonics. MacNiocaill, C and Ryan, 7 P.D. (editors), Geological Society, London, Special Publication No 8 164, 109–26. 9 Plant, J.A., Watson, J.V. and Green, P.M. (1984) Moine–Dalradian 10 relationships and their palaeotectonic significance. Proceedings 11 of the Royal Society, 395a, 185–202. 12 Powell, R. and Evans, J.A. (1983). A new geobarometer for the 13 assemblage biotite-muscovite-chlorite-quartz. Journal of 14 Metamorphic Geology, 1, 331–6. 15 Power, M.R. and Pirrie, D. (2000) Platinum-group mineralization 16 within ultramafic rocks at Corrycharmaig, Perthshire: implications 17 for the origin of the complex. Scottish Journal of Geology, 36, 18 143–50. 19 Prave, A.R. (1999) The Neoproterozoic Dalradian Supergroup of 20 Scotland: an alternative hypothesis. Geological Magazine, 136, 21 609–17. 22 Prave, A.R., Fallick, A.E., Thomas, C.W. and Graham, C.M. (2009a) A 23 composite C-isotope profile for the Neoproterozoic Dalradian 24 Supergroup of Scotland and Ireland. Journal of the Geological 25 Society, 166, 845-857. 26 Prave, A.R., Strachan, R.A. and Fallick, A.E. (2009b) Global C 27 cycle perturbations recorded in marbles: a record of 28 Neoproterozoic Earth history within the Dalradian succession of 29 the Shetland Islands, Scotland. Journal of the Geological Society, 30 166, 129-135. 31 Pringle, I.R. (1972) Rb-Sr age determinations on shales 32 associated with the Varanger Ice Age. Geological Magazine, 109, 33 465–72. 34 Pringle, J. (1940) The discovery of Cambrian trilobites in the 35 Highland Border rocks near Callander, Perthshire (Scotland). 36 British Association for the Advancement of Science: Annual Report 37 for 1939–40, 1, 252. 38 Pumpelly, R., Wolff, J.E. and Dale, T.N. (1894) Geology of the 39 Green Mountains. United States Geological Survey Memoir, 23, 1– 40 157. 41 42 Rainbird, R.H., Hamilton, M.A. and Young, G.M. (2001) Detrital 43 zircon geochronology and provenance of the Torridonian, NW 44 Scotland. Journal of the Geological Society, London, 158, 15–27. 45 Ramsay, D.M. (1959) Structure and metamorphism of Glen Lyon. 46 Unpublished PhD thesis, University of Glasgow. 47 Ramsay, D.M. and Sturt, B.A. (1979) The status of the Banff 48 Nappe. In The Caledonides of the British Isles—reviewed. Harris, 49 A L, Holland, C H and Leake, B E (editors). Special Publication of 50 the Geological Society of London, No. 8. 145–151 51 Ramsay, J.G. (1958) Moine–Lewisian relations at Glenelg, Inverness- 52 shire. Quarterly Journal of the Geological Society of London 113, 53 487–523. 54 Rast, N. (1956) Tectonics of Central Perthshire. Unpublished PhD 55 thesis, University of Glasgow. 56 Rast, N. (1958) Metamorphic history of the Schiehallion complex, 57 Perthshire. Transactions of the Royal Society of Edinburgh, 64, 58 413–31. 59 60 61 62 63 64 65 1 2 3 4 Rast, N. (1963). Structure and metamorphism of the Dalradian rocks 5 of Scotland. In The British Caledonides. (editors. Johnson, M.R.W. 6 and Stewart, F.H.). Oliver and Boyd, Edinburgh, 123–42. 7 Rast, N. and Litherland, M. (1970) The correlation of the 8 Ballachulish and Perthshire (Islay) successions. Geological 9 Magazine, 107, 259–72. 10 Read, H.H. (1919) The two magmas of Strathbogie and Lower 11 Banffshire. Geological Magazine 56, 364–71. 12 Read, H.H. (1923) The geology of the country around Banff, Huntly, 13 and Turriff, Lower Banffshire and north-west Aberdeenshire. Memoir 14 of the Geological Survey, Scotland. Sheets 86 and 96 (Scotland). 15 Read, H.H. (1927) The igneous and metamorphic history of Cromar, 16 Deeside. Transactions of the Royal Society of Edinburgh, 55, 317– 17 53. 18 Read, H.H. (1928) The Highland Schists of middle Deeside and east 19 Glen Muick. Transactions of the Royal Society of Edinburgh, 55, 20 755–72. 21 Read, H.H. (1933). On quartz-kyanite rocks in Unst, Shetland 22 Islands, and their bearing on metamorphic differentiation. 23 Mineralogical Magazine, 23, 317–28. 24 Read, H.H. (1934) The metamorphic geology of Unst in the Shetland 25 Islands. Quarterly Journal of the Geological Society of London 90, 26 637–88. 27 Read, H.H. (1935) British Regional Geology: the Grampian Highlands 28 (1st edition). HMSO for Geological Survey and Museum, Edinburgh. 29 Read, H.H. (1936) The stratigraphical order of the Dalradian rocks 30 of the Banffshire coast. Geological Magazine, 73, 468–75. 31 Read, H.H. (1937) Metamorphic correlation in the polymetamorphic 32 rocks of the Valla Field Block, Unst, Shetland Islands. 33 Transactions of the Royal Society of Edinburgh, 59, 195–221. 34 Read, H.H. (1952) Metamorphism and migmatisation in the Ythan 35 Valley, Aberdeenshire. Transactions of the Edinburgh Geological 36 Society, 15, 265–79. 37 Read, H.H. (1955) The Banff nappe: an interpretation of the 38 structure of the Dalradian rocks of north-east Scotland. 39 Proceedings of the Geologists’ Association, 66, 1–29. 40 Read, H.H. (1960) North-east Scotland: the Dalradian. Geologists‘ 41 Association Guide, 31. Benham and Co., Colchester. 42 Read, H.H. and Farquhar, O.C. (1956) The Buchan Anticline of the 43 Banff Nappe of Dalradian rocks in north-east Scotland. Quarterly 44 Journal of the Geological Society of London, 112, 131–56. 45 Richardson, S.W. and Powell, R. (1976) Thermal causes of the 46 Dalradian metamorphism in the Central Highlands of 47 Scotland. Scottish Journal of Geology, 12, 237–68. 48 Ritchie, J.D. and Hitchen, K. (1993) Discussion on the location and 49 history of the Walls Boundary fault and Moine thrust north and 50 south of Shetland. Journal of the Geological Society, London, 150, 51 1003–8. 52 Roberts, J.L. (1959) Fold Structures in the Dalradian Rocks of 53 Knapdale, Argyllshire. Geological Magazine, 94, 221–9. 54 Roberts, J.L. (1963) The Dalradian of the southwest highlands of 55 Scotland. Unpublished PhD thesis, University of Liverpool. 56 Roberts, J.L. (1966a) Sedimentary affiliations and stratigraphic 57 correlation of the Dalradian rocks in the South-west Highlands of 58 Scotland. Scottish Journal of Geology, 2, 200–23. 59 Roberts, J.L. (1966b) The formation of similar folds by 60 inhomogeneous plastic strain, with reference to the fourth phase 61 62 63 64 65 1 2 3 4 of deformation affecting the Dalradian rocks in the southwest 5 Highlands of Scotland. Journal of Geology, 74, 831–55. 6 Roberts, J.L. (1974) The structure of the Dalradian rocks in the SW 7 Highlands of Scotland. Journal of the Geological Society of 8 London, 130, 93–124. 9 Roberts, J.L. (1976) The structure of the Dalradian rocks in the 10 north Ballachulish district of Scotland. Journal of the Geological 11 Society of London, 132, 139–54. 12 Roberts, J.L. (1977a) The evolution and transport of the Tay Nappe: 13 Discussion. Scottish Journal of Geology, 13, 79–80. 14 Roberts, J.L. (1977b) The Dalradian rocks of Rosneath and South- 15 east Cowal. Scottish Journal of Geology, 13, 101–11. 16 Roberts, J.L. (1977c) The Dalradian rocks of Knapdale and North 17 Kintyre. Scottish Journal of Geology, 13, 113–124. 18 Roberts, J.L. and Sanderson, D.J. (1974) Oblique fold axes in the 19 Dalradian rocks of the Southwest Highlands. Scottish Journal of 20 Geology, 9, 281–96. 21 Roberts, J.L. and Treagus, J.E. (1964) A reinterpretation of the 22 Ben Lui Fold. Geological Magazine, 101, 512–16. 23 Roberts, J.L, and Treagus, J.E. (1975) The structure of the Moine 24 and Dalradian rocks in the Dalmally district of Argyllshire, 25 Scotland. Geological Journal, 10, 59–74. 26 Roberts, J.L, and Treagus, J.E. (1977a) The Dalradian rocks of the 27 South-west Highlands–Introduction. Scottish Journal of Geology, 28 Vol. 13, 87–99. 29 Roberts, J.L. and Treagus, J.E. (1977b) The Dalradian rocks of the 30 Loch Leven area. Scottish Journal of Geology, 13, 165–184. 31 Roberts, J.L. and Treagus, J.E. (1977c) Polyphase generation of 32 nappe structures in the Dalradian rocks of the Southwest Highlands 33 of Scotland. Scottish Journal of Geology. 13, 237–254. 34 Roberts, J.L, and Treagus, J.E. (1979) Stratigraphical and 35 structural correlation between the Dalradian rocks of the SW and 36 Central Highlands of Scotland. 199–204 in The Caledonides of the 37 British Isles–reviewed. Harris, A.L., Holland, C.H., and Leake, 38 B.E.(editors). Special Publication of the Geological Society of 39 London. 8. 40 Roberts, J.L, and Treagus, J E. (1980) The structural 41 interpretation of the Loch Leven area. Scottish Journal of 42 Geology, 16, 73–5. 43 Robertson, S. (1991) Older granites in the south-eastern Scottish 44 Highlands. Scottish Journal of Geology, 27, 21–6. 45 Robertson, S. (1994) Timing of Barrovian metamorphism and ‗Older 46 Granite‘ emplacement in relation to Dalradian deformation. Journal 47 of the Geological Society of London, 151, 5–8. 48 Robertson, S. (1999) BGS Rock Classification Scheme Volume 2: 49 Classification of metamorphic rocks. British Geological Survey 50 Research Report, RR 99–02. 51 Robertson, S. and Smith, M. (1999) The significance of the Geal 52 charn–Ossian Steep Belt in basin development in the Central 53 Scottish Highlands. Journal of the Geological Society, London, 54 156, 1175–82. 55 Rock, N.M.S. (1985) A compilation of analytical data for 56 metamorphic limestones from the Scottish Highlands and Islands, 57 with lists of BGS registered samples, and comments on the 58 reproducibility and accuracy of limestone analyses by different 59 analytical techniques. Mineralogical and Petrological Report 60 British Geological Survey, No. 85/5. 61 62 63 64 65 1 2 3 4 Rock, N.M.S. (1986) Chemistry of the Dalradian (Vendian–Cambrian) 5 metalimestones, British Isles. Chemical Geology, 56, 289–311. 6 Rock, N.M.S., Macdonald, R. and Bower, J. (1986) The comparative 7 geochemistry of some Highland pelites (Anomalous local limestone– 8 pelite successions within the Moine outcrop; II). Scottish Journal 9 of Geology, 22, 107–26. 10 Rogers, G., Dempster, T.J., Bluck, B.J. and Tanner, P.W.G. (1989) A 11 high precision U-Pb age for the Ben Vuirich Granite: implications 12 for the evolution of the Scottish Dalradian Supergroup. Journal of 13 the Geological Society, London, 146, 789–98. 14 Rogers, G., Hyslop, E.K., Strachan, R.A., Paterson, B.A. and 15 Holdsworth, R.A. (1998) The structural setting and U-Pb 16 geochronology of the Knoydartian pegmatites of W Inverness-shire: 17 evidence for Neoproterozoic tectonothermal events in the Moine of 18 NW Scotland. Journal of the Geological Society, London, 155, 685– 19 96. 20 Rogers, G., Kinny, P.D., Strachan, R.A., Friend, C.R.L. and 21 Patterson, B.A. (2001) U-Pb geochronology of the Fort Augustus 22 granite gneiss, constraints on the timing of Neoproterozoic and 23 Paleozoic tectonothermal events in the NW Highlands of Scotland. 24 Journal of the Geological Society, London, 158, 7–14. 25 Rogers, G. and Pankhurst, R.J. (1993) Unravelling dates through the 26 ages: geochronology of the Scottish metamorphic complexes. Journal 27 of the Geological Society, London, 150, 447–64. 28 Rollin, K.E. (1994) Geophysical correlation of Precambrian rocks in 29 northern Britain. In A Revised Correlation of Precambrian Rocks in 30 the British Isles. Gibbons, W. and Harris, A.L. (eds.) Geological 31 Society, London, Special Report, 22, 65–74. 32 Rooney, A.D., Chew, D.M. and Selby, D. (2011) Re – Os geochronology 33 of the Neoproterozoic – Cambrian Dalradian Supergroup of Scotland 34 and Ireland: implications for Neoproterozoic stratigraphy, 35 glaciations and Re – Os systematics. Precambrian Research, 36 Rose, P.T.S. (1989) The emplacement of the Tay Nappe Scotland. 37 Unpublished PhD thesis, University of Liverpool. 38 Rose, P.T.S. and Harris, A.L. (2000) Evidence for the lower 39 Palaeozoic age of the Tay Nappe; the timing and nature of Grampian 40 events in the Scottish Highland sector of the Laurentian margin. 41 Journal of the Geological Society, London, 157, 789–98. 42 Rushton, A.W.A., Owen, A.W., Owens, R.M. and Prigmore, J.K. (1999) 43 British Cambrian and Ordovician stratigraphy, Geological 44 Conservation Review Series No. 18, Joint Nature Conservation 45 Committee, Peterborough. 46 Russell, M.J., Hall, A.J., Willan, R.C.R., Allison, I., Anderton, 47 R., and Bowes, G. (1984) On the origin of the Aberfeldy 48 celsian+barite+base metals deposits, Scotland. In Prospecting in 49 areas of glaciated terrain, 1984. Institution of Mining and 50 Metallurgy, London, pp. 159–170. 51 Ryan, P.D. and Soper, N.J. (2001) Modelling anatexis in intra- 52 cratonic basins: an example from the Neoproterozoic rocks of the 53 Scottish Highlands. Geological Magazine, 138, 577–588. 54 Ryan, P.D., Soper, N.J., Snyder, D.B., England, R.W. and Hutton, 55 D.H.W. (1995) The Antrim – Galway Line: a resolution of the 56 Highland Border Fault enigma of the Caledonides of Britain and 57 Ireland. Geological Magazine, 132, 171–184. 58 59 60 61 62 63 64 65 1 2 3 4 Saha, D. (1989) The Caledonian Loch Skerrols Thrust, SW Scotland: 5 Microstructure and Strain. Journal of Structural Geology, 11, 553– 6 568. 7 Schermerhorn, L.J.G. (1974) Late Precambrian mixtites: glacial 8 and/or non-glacial? American Journal of Science, 274, 673–824. 9 Schermerhorn, L.J.G. (1975) Tectonic framework of Late Precambrian 10 supposed glacials. In Ice Ages: Ancient and Modern (eds. Wright, 11 A.E. and Moseley, F.), proceedings of the Inter-University 12 Geological Congress (University of Birmingham) (1974), Geological 13 Journal special issue No. 6, 242–247. 14 Scott, R.A. (1987) Lithostratigraphy, structure and mineralization 15 of the Argyll Group Dalradian near Tyndrum, Scotland. Unpublished 16 PhD thesis, University of Manchester. 17 Scott, R.A., Pattrick, R.A.D., and Polya, D.A. (1991) Origin of 18 sulphur in metamorphosed stratabound mineralization from the 19 Argyll Group Dalradian of Scotland. Transactions of the Royal 20 Society of Edinburgh: Earth Sciences, Vol. 82, 91–98. 21 Scott, R.A., Polya, D.A., and Pattrick, R.A.D. (1988) Proximal Cu + 22 Zn exhalites in the Argyll Group Dalradian, Creag Bhocan, 23 Perthshire. Scottish Journal of Geology, Vol. 24, 97–112. 24 Seranne, M. (1992) Devonian extensional tectonics versus 25 Carboniferous inversion in the northern Orcadian basin. Journal of 26 the Geological Society, London, 149, 27–37. 27 Shackleton, R. M. 1958. Downward-facing structures of the Highland 28 Border. Quarterly Journal of the Geological Society, London, 113, 29 361–392. 30 Shackleton, R.M. (1979) The British Caledonides: comments and 31 summary. 299–304 in The Caledonides of the British Isles— 32 reviewed. Harris, A L, Holland, C H, and Leake, B E (editors). 33 Special Publication of the Geological Society of London, No. 8. 34 Shearman, D.J. and Smith, A.J. (1985) Ikaite, the parent mineral of 35 jarrowite-type pseudomorphs. Proceedings of the Geologists’ 36 Association, 96, 305–314. 37 Sibson, R.H. (1977) Fault rocks and fault mechanisms. Journal of 38 the Geological Society, London, Vol 133, 191–213. 39 Simpson, A. and Wedden, D. (1974) Downward-facing structures in the 40 Dalradian Leny Grits on Bute. Scottish Journal of Geology, 10, 41 257–267. 42 Skelton, A.D.L. (1993) Petrological, geochemical and field studies 43 of fluid infiltration during regional metamorphism of the 44 Dalradian of the SW Scottish Highlands. Unpublished PhD thesis, 45 University of Edinburgh. 46 Skelton, A.D.L., Bickle, M.J. and Graham, C.M. (1997) Fluid-flux 47 and reaction rate from advective-diffusive carbonation of mafic 48 sill margins in the Dalradian, southwest Scottish Highlands. Earth 49 and Planetary Science Letters, 146, 527–539 50 Skelton, A.D.L., Graham, C.M. and Bickle, M.J. (1995) Lithological 51 and structural constraints on regional 3-D fluid flow patterns 52 during greenschist facies metamorphism of the Dalradian of the SW 53 Highlands. Journal of Petrology, 36, 563–586. 54 Skevington, D. (1971) Palaeontological evidence bearing on the age 55 of the Dalradian deformation and metamorphism in Ireland and 56 Scotland. Scottish Journal of Geology, Vol. 7, 285–288. 57 Smallwood, J.R. (2007) Maskelyne‘s 1774 Schiehallion experiment 58 revisited. Scottish Journal of Geology, Vol. 43, 15–31. 59 Smith, A.J. and Rast, N. (1958) Sedimentary dykes in the Dalradian 60 of Scotland. Geological Magazine 95, 234 –240. 61 62 63 64 65 1 2 3 4 Smith, C.G., Gallagher, M.J., Coats, J.S. and Parker, M.E. (1984) 5 Detection and general characteristics of stratabound 6 mineralization in the Dalradian of Scotland. Transactions of the 7 Institution of Mining and Metallurgy (Section B: Applied Earth 8 Science), Vol. 93, B125–133. 9 Smith, C.G., Gallagher, M.J., Grout, A., Coats, J.S., Vickers, 10 B.P., Peachey, D., Pease, S.F., Parker, M.E. and Fortey, N.J. 11 (1988) Stratabound base-metal materialisation in Dalradian rocks 12 near Tyndrum, Scotland. Mineral Reconnaissance Programme Report, 13 British Geological Survey, No. 93. 14 Smith, C.G., Goodman, S. and Robertson, S. (2002) Geology of the 15 Ballater district. Memoir of the British Geological Survey, Sheet 16 65E (Scotland). 17 Smith, M., Robertson, S. and Rollin, K.E. (1999) Rift basin 18 architecture and stratigraphical implications for basement-cover 19 relationships in the Neoproterozoic Grampian Group of the Scottish 20 Caledonides. Journal of the Geological Society, London, 156, 1163– 21 1173. 22 Smith, R.A. (1980) The Geology of the Dalradian rocks around Blair 23 Atholl, Central Perthshire, Scotland. Unpublished PhD thesis, 24 University of Liverpool. 25 Smith, R.A. and Harris, A,L. (1976) The Ballachulish rocks of the 26 Blair Atholl District. Scottish Journal of Geology, Vol. 12, 153– 27 157. 28 Smith, T.E. (1968) Tectonics in Upper Strathspey, Inverness-shire. 29 Scottish Journal of Geology, 4, 68–84. 30 Snyder, D.B. and Flack, C.A. (1990) A Caledonian age for reflectors 31 within the mantle lithosphere north and west of Scotland. 32 Tectonics, 9, 903–922. 33 Soper N.J. (1994) Was Scotland a Vendian RRR junction? Journal of 34 the Geological Society, London, 151, 579–582. 35 Soper N.J. (1994) Neoproterozoic sedimentation on the northeast 36 margin of Laurentia and the opening of Iapetus. Geological 37 Magazine, 131, 291–299. 38 Soper, N.J. and Anderton, R. (1984) Did the Dalradian slides 39 originate as extensional faults? Nature, London, Vol. 307, 357– 40 360. 41 Soper, N.J. and England, R.W. (1995) Vendian and Riphean rifting in 42 NW Scotland. Journal of the Geological Society, London 152, 11–14. 43 Soper, N.J. and Evans, J.A., 1997. Discussion on metamorphism and 44 cooling of the NE Dalradian. Journal of the Geological Society, 45 London. 154, 357-360. 46 Soper N.J. and Hutton D.H.W. (1984) Late Caledonian sinistral 47 displacements in Britain: Implications for a three-plate collision 48 model. Tectonics 3, 781–794. 49 Soper, N.J., Ryan, P.D. and Dewey, J.F. (1999) Age of the Grampian 50 Orogeny in Scotland and Ireland. Journal of the Geological 51 Society, London 156, 1231–1236. 52 Soper N.J., Strachan R.A., Holdsworth R.E., Gayer R.A. and 53 O‘Greiling, R.O. (1992) Sinistral transpression and the Silurian 54 closure of Iapetus. Journal of the Geological Society, London 149, 55 871–880. 56 Spear, F.S. (1993) Metamorphic phase equilibria and pressure- 57 temperature-time paths. Mineralogical Society of America. 58 Spencer, A.M. (1971) Late Precambrian glaciation in Scotland. 59 Memoir of the Geological Society of London, No. 6. 60 61 62 63 64 65 1 2 3 4 Spencer, A.M. (1981) The late Precambrian Port Askaig Tillite in 5 Scotland. In Earth‘s pre-Pleistocene glacial record (eds. Hambrey, 6 M. J. and Harland, W. B.), pp. 632–636. Cambridge University 7 Press, Cambridge. 8 Spencer, A.M. (1985) Mechanisms and environments of deposition of 9 Late Precambrian geosynclinal tillites: Scotland and East 10 Greenland. Palaeogeography, Palaeoclimatology and Palaeoecology, 11 51, 143–157. 12 Spencer, A.M. and Pitcher, W.S. (1968) Occurrence of the Port 13 Askaig Tillite in north-east Scotland. Proceedings of the 14 Geological Society of London, No. 1650, 195–198. 15 Spencer, A.M. and Spencer, M. (1972) The Late Precambrian/Lower 16 Cambrian Bonnahaven Dolomite of Islay and its stromatolites. 17 Scottish Journal of Geology, 8, 269–282. 18 Spray J.G. and Dunning G.R. (1991) A U/Pb age for the Shetland 19 Islands oceanic fragment, Scottish Caledonides: evidence from 20 anatectic plagiogranites in ―layer 3‖ shear zones. Geological 21 Magazine 128, 667–671. 22 Stephenson, D. (1993) Amphiboles from Dalradian metasedimentary 23 rocks of NE Scotland: environmental inferences and distinction 24 from meta-igneous amphibolites. Mineralogy and Petrology, Vol. 25 49, 45–62. 26 Stephenson, D., Bevins, R.E., Millward, D., Highton, A.J., Parsons, 27 I., Stone, P. and Wadsworth, W.J. (1999) Caledonian Igneous rocks 28 of Great Britain. Geological Conservation Review Series No.17. 29 Joint Nature Conservation Committee, Peterborough. 648pp. 30 Stephenson, D. and Gould, D. (1995) British regional geology: the 31 Grampian Highlands (4th edition). HMSO for the British Geological 32 Survey, London. 33 Stewart, A.D. (1960) On the sedimentary and metamorphic history of 34 the Torridonian, and the later igneous intrusions of Colonsay and 35 Oronsay. Unpublished PhD thesis, University of Liverpool. 36 Stewart, A.D. (1962) On the Torridonian sediments of Colonsay and 37 their relationship to the main outcrop in north-west Scotland. 38 Liverpool and Manchester Geological Journal 3, 121–156. 39 Stewart, A.D. (1969) Torridonian rocks of Scotland reviewed. In 40 Kay, M. (ed.) North Atlantic-Geology and Continental Drift, a 41 symposium. Memoir of the American Association of Petroleum 42 Geologists 12, 595–608. 43 Stewart, A.D. (1975) ‗Torridonian‘ rocks of western Scotland. In: A 44 correlation of Precambrian rocks in the British Isles (eds. 45 Harris, A. L., Shackleton, R. M., Watson, J.V., Downie, C., 46 Harland, W. B. and Moorbath, S.) Geological Society, London, 47 Special Report, 6, 43–51. 48 Stewart, A.D. and Hackman, B.D. (1973) Precambrian sediments of 49 Islay. Scottish Journal of Geology, 9, 185–201. 50 Stewart, M., Strachan, R.A. and Holdsworth, R.E. (1999) Structure 51 and early kinematic history of the Great Glen fault zone, 52 Scotland. Tectonics 18, 326–342. 53 Stewart, M., Strachan, R.A., Martin, M.W. and Holdsworth, R.E. 54 (2001) Constraints on early sinistral displacements along the 55 Great Glen Fault Zone, Scotland; structural setting, U-Pb 56 geochronology and emplacement of the syn-tectonic Clunes Tonalite. 57 Journal of the Geological Society, London 158, 821–830. 58 Stoker, M.S., Howe, J.A. and Stoker, S.J. (1999) Late Vendian- 59 ?Cambrian glacially influenced deep-water sedimentation, Macduff 60 61 62 63 64 65 1 2 3 4 Slate Formation (Dalradian), NE Scotland. Journal of the 5 Geological Society, London, 156, 55–61. 6 Stone, M. (1957) The Aberfoyle Anticline, Callander, Perthshire. 7 Geological Magazine, 94, 265–276. 8 Stone, P., Plant, J.A., Mendum, J.R. and Green, P.M. (1999) A 9 regional geochemical assessment of some terrane relationships in 10 the British Caledonides. Scottish Journal of Geology, 35, 145–156. 11 Strachan, R.A. (2000) The Grampian Orogeny: Mid-Ordovician arc– 12 continent collision along the Laurentian margin of Iapetus. In: 13 Woodcock, N.H. and Strachan, R.A. (eds) Geological History of 14 Britain and Ireland. Blackwell Science Ltd, 88–106. 15 Strachan, R.A., Harris, A.L., Fettes D.J. and Smith, M. (2002) The 16 Northern Highland and Grampian terranes. In: Trewin N. H. (ed.) 17 The Geology of Scotland. (4th edition) The Geological Society, 18 London, pp. 81–148. 19 Strachan, R.A. and Holdsworth, R.E. (2000) Proterozoic 20 sedimentation, orogenesis and magmatism on the Laurentian Craton 21 (2700–750 Ma). In: Geological history of Great Britain and Ireland 22 (edited by Woodcock, N. and Strachan, R. A.) Blackwell Science. 23 Oxford, 52–72. 24 Stringer, P.J. (1957) Polyphase deformation in the Upper Dalradian 25 rocks of the Southern Highlands of Scotland. Unpublished PhD 26 thesis, University of Liverpool. 27 Stupavsky, M., Symons, D.T.A. and Gravenor, C.P. (1982) Evidence 28 for metamorphic remagnetisation of the upper Precambrian tillite 29 in the Dalradian Supergroup of Scotland. Transactions of the Royal 30 Society of Edinburgh, 73, 59–65. 31 Sturt, B.A. (1959) Studies in the metamorphic rocks of the Loch 32 Tummel district, Perthshire. Unpublished PhD thesis, University of 33 Wales, Aberystwyth. 34 Sturt, B.A. (1961) The geological structure of the area south of 35 Loch Tummel. Quarterly Journal of the Geological Society of 36 London, Vol. 117, 131–156. 37 Sturt, B.A. and Harris, A.L. (1961) The metamorphic history of 38 the Loch Tummel area. Liverpool and Manchester Geological 39 Journal, Vol. 2, 689–711. 40 Sturt, B.A., Ramsay, D.M., Pringle, I.R. and Teggin, 41 D.E. (1977) Precambrian gneisses in the Dalradian sequence of NE 42 Scotland. Journal of the Geological Society of London, Vol. 134, 43 41–44. 44 Sutton, J. and Watson, J.V. (1954) Ice-borne boulders in the 45 Macduff Group of the Dalradian of Banffshire. Geological 46 Magazine, Vol. 91, 391–398. 47 Sutton, J. and Watson, J.V. (1955) The deposition of the Upper 48 Dalradian rocks of the Banffshire coast. Proceedings of the 49 Geologists’ Association, Vol. 66, 101–133. 50 Sutton, J. and Watson, J.V. (1956) The Boyndie syncline of the 51 Dalradian of the Banffshire coast. Quarterly Journal of the 52 Geological Society of London, Vol. 112, 103–130. 53 54 Tanner, P. W. G. 1992. Rosneath Peninsula and Loch Long. In 55 Geological excursions around Glasgow and Girvan (eds. Lawson, J. 56 D. and Weedon, D. S.), pp. 159–185. Geological Society of Glasgow. 57 Tanner, P. W. G. 1995. New evidence that the Lower Cambrian Leny 58 Limestone at Callander, Perthshire, belongs to the Dalradian 59 Supergroup, and a reassessment of the ‗exotic‘ status of the 60 Highland Border Complex. Geological Magazine, 132, 473–483. 61 62 63 64 65 1 2 3 4 Tanner, P. W. G. 1996. Significance of the early fabric in the 5 contact metamorphic aureole of the 590 Ma Ben Vuirich Granite, 6 Perthshire, Scotland. Geological Magazine, 133, 683–695. 7 Tanner, P. W. G. 1997. The Highland Border controversy: Reply to a 8 Discussion of ‗New evidence that the Lower Cambrian Leny Limestone 9 at Callander, Perthshire, belongs to the Dalradian Supergroup, and 10 a reassessment of the ‗exotic‘ status of the Highland Border 11 Complex‘. Geological Magazine, 134, 565–570. 12 Tanner, P. W. G. 1998a. Interstratal dewatering origin for 13 polygonal patterns of sand-filled cracks: a case study from Late 14 Proterozoic metasediments of Islay, Scotland. Sedimentology, 45, 15 71–89. 16 Tanner, P W G. 1998b. Age of the Grampian event: Reply to a 17 Discussion of ‗New evidence that the Lower Cambrian Leny Limestone 18 at Callander, Perthshire belongs to the Dalradian Supergroup, and 19 a reassessment of the ‗exotic‘ status of the Highland Border 20 Complex‗. Geological Magazine, Vol. 135, 575–579. 21 Tanner, P. W. G. 2005. Discussion on evidence for a major 22 Neoproterozoic orogenic unconformity within the Dalradian 23 Supergroup of NW Ireland. Journal of the Geological Society, 24 London, 162, 221–224. 25 Tanner, P.W.G. 2007. The role of the Highland Border Ophiolite in 26 the ~ 470 Ma Grampian Event, Scotland. Geological Magazine Vol. 27 144, 597–602. 28 Tanner, P.W.G. 2008. Tectonic significance of the Highland Boundary 29 Fault. Journal of the Geological Society, London Vol. 165, 915– 30 921. 31 Tanner, P.W.G. and Bluck, B.J. (2011) Discussion of 'The Highland 32 Boundary Fault and the Highland Boundary Complex' by B.J. Bluck 33 Scottish Journal of Geology 46, 113-124. Scottish Journal of 34 Geolgy, 47, 89-93. 35 Tanner, P. W. G. and BLUCK, B. J. 1999. Current controversies in 36 the Caledonides. Journal of the Geological Society, London, 156, 37 1137–1141. 38 Tanner, P. W. G. and Evans, J. A. 2003. Late Precambrian U-Pb 39 titanite age for peak regional metamorphism and deformation 40 (Knoydartian Orogeny) in the western Moine, Scotland. Journal of 41 the Geological Society, London 160, 555–564. 42 Tanner, P. W. G. and Leslie, A. G. 1994. A pre-D2 age for the 590 43 Ma Ben Vuirich Granite in the Dalradian of Scotland. Journal of 44 the Geological Society, London, 151, 209–212. 45 Tanner P. W. G., Leslie A. G. and Gillespie M.R. 2006. Structural 46 setting and petrogenesis of a rift-related intrusion: the Ben 47 Vuirich Granite of the Grampian Highlands, Scotland. Scottish 48 Journal of Geology, Vol. 42, 113–136. 49 Tanner, P. W. G. and Pringle, M. 1999. Testing for a terrane 50 boundary within Neoproterozoic (Dalradian) to Cambrian siliceous 51 turbidites at Callander, Perthshire, Scotland. Journal of the 52 Geological Society, London, 156, 1205–1216. 53 Tanner, P.W.G. and Sutherland, S. 2007. The Highland Border 54 Complex, Scotland: a paradox resolved. Journal of the Geological 55 Society, London, 164, 111–116. 56 Tannner, P.W.G. and Thomas, P.R. (2010) Major nappe-like D2 folds 57 in the Dalradian rocks of the Beinn Udlaidh area, Central 58 Highlands, Scotland. Earth and Environmental Science Transactions 59 of the Royal Society of Edinburgh. 100, 371-389. 60 61 62 63 64 65 1 2 3 4 Temperley, S. (1990). The Late Proterozoic to Early Palaeozoic 5 geology of the Glen Banchor area in the Monadhliath Mountains of 6 Scotland, with particular reference to deformation in Knoydartian 7 shear zones and the Caledonian Central Highland steep belt. 8 Unpublished PhD thesis, University of Hull. 9 Thomas, C W. 1989. Application of geochemistry to the 10 stratigraphic correlation of Appin and Argyll Group carbonate 11 rocks from the Dalradian of northeast Scotland. Journal of the 12 Geological Society of London, Vol. 146, 631–647. 13 Thomas, C. W. 1993. Sources of Rare Earth elements in Appin Group 14 limestones, Dalradian, north-east Scotland. Mineralogy and 15 Petrology Vol. 49, 27–44 . 16 Thomas, C.W. (1995). The geochemistry of metacarbonate rocks from 17 the Monadhliath Project area. British Geological Survey Technical 18 Report. WA/95/40/R. 19 Thomas, C. W. (1999). The isotope Geochemistry and Petrology of 20 Dalradian Metacarbonate Rocks, Unpublished PhD thesis, University 21 of Edinburgh. 22 Thomas, C.W. and Aitchison (1998). Application of logratios to the 23 statistical analysis of the geochemistry of metamorphosed 24 limestones from the Northeast and Central Highlands of Scotland: 25 the case for Appin Group correlations. British Geological Survey 26 Technical Report, WA/98/03. 27 Thomas, C W, Aitken, A M, Pickett, E P, Mendum, J R, Hyslop, E K, 28 and Petterson, M.P. in press. Geology of the Aberfoyle District. 29 Sheet Description for the British Geological Survey, 1:50 000 30 Series Sheet 38E (Scotland). 31 Thomas, C. W., Graham, C. M., Ellam, R.M. and Fallick, A. E. 32 (2004). 87Sr/86Sr chemostratigraphy of Neoproterozoic Dalradian 33 limestones of Scotland: constraints on depositional ages and 34 timescales. Journal of the Geological Society, London 161, 223– 35 243. 36 Thomas, C.W., Smith, M. and Robertson, S. (1997). The geochemistry 37 of Dalradian metacarbonate rocks from the Schiehallion District 38 and Blargie, Laggan: implications for stratigraphical correlations 39 in the Geal Charn–Ossian Steep Belt. British Geological Survey 40 Technical Report, WA/97/81. 41 Thomas, P R. 1965. The structure and metamorphism of the Moinian 42 rocks in Glen Garry, Glen Tilt, and adjacent areas of Scotland. 43 Unpublished PhD thesis, University of Liverpool. 44 Thomas, P R. 1979. New evidence for a Central Highland Root Zone. 45 205–211 in The Caledonides of the British Isles –Reviewed. Harris, 46 A L, Holland, C H, and Leake, B E (editors). Special Publication 47 of the Geological Society, No. 8. 48 Thomas, P R. 1980. The stratigraphy and structure of the Moine 49 rocks north of the Schiehallion Complex, Scotland. Journal of the 50 Geological Society of London, Vol. 137, 469–482. 51 Thomas, P R. 1988. A9 road section—Blair Atholl to 52 Newtonmore. 39–50 in An excursion guide to the Moine geology of 53 the Scottish Highlands. Allison, I, May, F, and Strachan, R A 54 (editors). (Edinburgh: Scottish Academic Press for Edinburgh 55 Geological Society and Geological Society of Glasgow.) 56 Thomas, P R, and Treagus, J E. 1968. The stratigraphy and structure 57 of the Glen Orchy area, Argyllshire, Scotland. Scottish Journal of 58 Geology, Vol. 4, 121–134. 59 Thomson, J. 1877. On the geology of the Island of Islay. 60 Transactions of the Geological Society of Glasgow, 5, 200–222. 61 62 63 64 65 1 2 3 4 Tilley, C.E. (1925) A preliminary survey of metamorphic zones in 5 the southern Highlands of Scotland. Quarterly Journal of the 6 Geological Society of London, Vol. 81, 100–110. 7 Tollo R. P., Aleinikoff J. N., Bartholomew M. J. and Rankin D. W. 8 2004. Neoproterozoic A-type granitoids of the central and southern 9 Appalachians: intraplate magmatism associated with episodic 10 rifting of the Rodinian supercontinent. Precambrian Research, 128, 11 3–38. 12 Torsvik, T. H., Smethurst, M. A., Meert, J. G., Van der Voo, R., 13 McKerrow, W. S., Brasier, M. D., Sturt, B. A. and Walderhaug, H. 14 J. 1996. Continental break-up and collision in the Neoproterozoic 15 and Palaeozoic–a tale of Baltica and Laurentia. Earth Science 16 Reviews 40, 229–258. 17 Treagus, J. E. 1964a. The structural and metamorphic history of an 18 area of Moine and Dalradian rocks south of Loch Rannoch, 19 Perthshire. Unpublished PhD thesis, University of Liverpool. 20 Treagus, J E. 1964b. Notes on the structure of the Ben Lawers 21 Synform. Geological Magazine, Vol. 101, 260–270. 22 Treagus, J.E. (1969). The Kinlochlaggan Boulder Bed. Proceedings of 23 the Geological Society of London, 1654, 55–60. 24 Treagus, J E. 1974. A structural cross-section of the Moine and 25 Dalradian rocks of the Kinlochleven area, Scotland. Journal of the 26 Geological Society of London, Vol. 130, 525–544. 27 Treagus, J.E. (1981). The Lower Dalradian Kinlochlaggan Boulder 28 Bed, Central Scotland. In: Earth’s pre-Pleistocene glacial record. 29 (editors. Hambrey, J.M. and Harland, W.B.), Cambridge University 30 Press, 637–639. 31 Treagus, J E. 1987. The structural evolution of the Dalradian of 32 the Central Highlands of Scotland. Transactions of the Royal 33 Society of Edinburgh: Earth Sciences, Vol. 78, 1–15. 34 Treagus, J E. 1991. Fault displacements in the Dalradian of the 35 Central Highlands. Scottish Journal of Geology, Vol. 27, 135–145. 36 Treagus, J. E. (editor). 1992. Caledonian Structures in Britain 37 South of the Midland Valley, Geological Conservation Review Series 38 No. 3. London: Chapman and Hall. 39 Treagus, J.E. (1997) Discussion on a late Vendian age for the 40 Kinlochlaggan Boulder bed (Dalradian). Journal of the Geological 41 Society, London, 154, 917–919. 42 Treagus, J E. 1999. A structural reinterpretation of the Tummel 43 Belt and a transpressional model of evolution of the Tay Nappe in 44 the Central Highlands of Scotland. Geological Magazine, Vol. 136, 45 Pt 6, 643–660. 46 Treagus, J. E. 2000. The Solid Geology of the Schiehallion 47 District. Memoir of the British Geological Survey. Sheet 55W 48 (Scotland). 49 Treagus, J.E. 2009. The Dalradian of Scotland. Geologists’ 50 Association Guide No. 67. 202pp. 51 Treagus, J E, and King, G. 1978. A complete Lower Dalradian 52 succession in the Schiehallion district, central Perthshire. 53 Scottish Journal of Geology, Vol. 14, 157–166. 54 Treagus, J E, Pattrick, R A D, and Curtis, S F. 1999. Movement and 55 mineralization in the Tyndrum fault zone, Scotland and its 56 regional significance. Journal of the Geological Society, London, 57 Vol. 156, 591–604. 58 Treagus, J E. and Roberts, J L. 1981. The Boyndie Syncline, a D1 59 structure in the Dalradian of Scotland. Geological Journal, Vol. 60 16, 125–135. 61 62 63 64 65 1 2 3 4 Treagus, J E, Talbot, C J, and Stringer, P. 1972. Downward-facing 5 structures in the Birnam Slates, Dunkeld, Perthshire. Geological 6 Journal, Vol. 8, 125–128. 7 Treagus, J E, and Treagus, S H. 1971. The structures of the 8 Ardsheal peninsula, their age and regional significance. 9 Geological Journal, Vol. 7, 335–346. 10 Treagus, J E, and Treagus, S H. 1981. Folds and the strain 11 ellipsoid; a general model. Journal of Structural Geology, Vol. 3, 12 Pt 1, 1–17. 13 Trewin, N. H. (editor) 2002. The Geology of Scotland. (4th edition) 14 The Geological Society, London. 576 pp. 15 Trewin, N.H., Kneller, B.C. and Gillen, C. (1987) Excursion Guide 16 to the Geology of the Aberdeen area. (Edinburgh: Scottish Academic 17 Press, for Geological Society of Aberdeen). 18 Trewin, N.H. and Rollin, K. 2002. In: Trewin, N.H. (ed.) The 19 geology of Scotland.(4th edition) The Geological Society, London, 20 1–25. 21 Trewin, N.H. and Thirlwall, M.F. 2002. Old Red Sandstone. In: 22 Trewin N. H. (ed.) The Geology of Scotland. (4th edition) The 23 Geological Society, London, pp. 213–249. 24 Tyrrell, G.W. 1921. Some points in petrographic nomenclature. 25 Geological Magazine Vol. 58, 494–502. 26 27 Underhill, J.R. 1993. Discussion on the location and history of the 28 Walls Boundary fault and Moine thrust north and south of Shetland. 29 Journal of the Geological Society, London, 150, 1003–1008. 30 Upton, P.S., 1983. A stratigraphic, structural and metamorphic 31 study of the lower and middle Dalradian, between Braemar and the 32 Spittal of Glenshee, N.E. Scotland. Unpublished PhD thesis, 33 University of Manchester. 34 Upton, P S. 1986. A structural cross-section of the Moine and 35 Dalradian rocks of the Braemar area. Report of the British 36 Geological Survey, Vol. 17, No. 1, 9–19. 37 38 Van Breemen, O., Aftalion, M. and Johnson, M. R. 1979. Age of the 39 Loch Borrolan complex, Assynt and late movements along the Moine 40 Thrust Zone. Journal of the Geological Society of London 16, 489– 41 495. 42 Van de Kamp, P.C. 1968. Origins of para-amphibolites. Unpublished 43 PhD thesis, University of Bristol. 44 Van de Kamp, P C. 1970. The Green Beds of the Scottish Dalradian 45 Series: geochemistry, origin and metamorphism of mafic 46 sediments. Journal of Geology, Vol. 78, 281–303. 47 Van Staal, C. R., Dewey, J. F., McKerrow, W. S. and MacNiocaill, C. 48 1998. The Cambrian–Silurian tectonic evolution of the northern 49 Appalachians and British Caledonides: history of a complex, 50 southwest Pacific-type segment of Iapetus. In: Lyell: the Present 51 is in the Past (edited by Blundell, D. J. and Scott, A. C.). 52 Geological Society, London, Special Publication, 143, 199–242. 53 Vance, D., Strachan, R. A. and Jones, K. A. 1998. Extensional 54 versus compressional settings for metamorphism: Garnet chronometry 55 and pressure–temperature–time histories in the Moine Supergroup, 56 northwest Scotland. Geology 26, 927–930. 57 Viete, D.R., Forster, M.A. and Lister, G.S. (2011) The nature and 58 origin of the Barrovian metamorphism, Scotland: 40Ar/39Ar apparent 59 age patterns and the duration of metamorphism in the biotite zone. 60 Journal of the Geological Society, London, 168, 133-146. 61 62 63 64 65 1 2 3 4 Viete, D.R., Hermann, J., Lister, G.S. and Stenhouse, I.R. (2011) 5 The nature and origin of the Barrovian metamorphism, Scotland: 6 diffusion length scales in garnet and inferred thermal time 7 scales. Journal of the Geological Society, London, 168, 115-132. 8 Viete, D.R., Richards, S.W., Lister, G.S., Oliver, G.J.H. and 9 Banks, G.J. (2010) Lithospheric-scale extension during Grampian 10 orogenesis in Scotland. in Law, R.D., Butler, R.W.H., Holdsworth, 11 R.E., Krabbendam, M. and Strachan, R.A. (editors) Continental 12 Tectonics and Mountain Building: the Legacy of Peach and Horne. 13 Geological Society, London, Special Publications, 335, 121-160. 14 Viljoen, M. J and Viljoen, R. P. 1969. Evidence for the existence 15 of a mobile extrusive peridotite magma from the Komati Formation 16 of the Onverwacht Group. Geological Society of South Africa, 17 Special Publication No. 2, 87–112. 18 Vogt, T. 1930. On the chronological order of deposition in the 19 Highlands. Geological Magazine, 67, 68–76. 20 Voll, G. 1960. New work on Petrofabrics. Liverpool and Manchester 21 Geological Journal, 2, 503–567. 22 Voll, G. 1964. Deckenbau und fazies im Schottischen Dalradian. 23 Geologische Rundschau, Vol. 53, 590–612. 24 Vorhies, S.H. and Ague, J.J. (2011) Pressure – temperature 25 evolution and thermal regimes in the Barrovian zones, Scotland. 26 Journal of the Geological Society, London, 168, 1147-1166. 27 28 Wain, A. (1999). The petrography and metamorphic evolution of 29 metabasic rocks from the Lower Dalradian of the Central Highlands 30 area. British Geological Survey Technical Report No. WA/99/13. 31 Watkins, K.P. 1982. The structure and metamorphism of the 32 Balquhidder–Crianlarich region of the Scottish Dalradian. 33 Unpublished PhD thesis, University of Cambridge. 34 Watkins, K P. 1983. Petrogenesis of Dalradian albite porphyroblast 35 schists. Journal of the Geological Society of London, Vol. 140, 36 601–618. 37 Watkins, K P. 1984. The structure of the Balquhidder–Crianlarich 38 region of the Scottish Dalradian and its relation to the Barrovian 39 garnet isograd surface. Scottish Journal of Geology, Vol. 20, 53– 40 64. 41 Watkins, K.P. 1985. Geothermometry and geobarometry of inverted 42 metamorphic zones in the W. Central Scottish Dalradian. Journal of 43 the Geological Society of London, 142, 157–165. 44 Watson, J. V. 1984. The ending of the Caledonian Orogeny in 45 Scotland. Journal of the Geological Society of London 141, 193– 46 214. 47 Weiss, L E, and McIntyre, D B. 1957. Structural geometry of 48 Dalradian rocks at Loch Leven, Scottish Highlands. Journal of 49 Geology, Vol. 65, 575–602. 50 Wells, P. R. A. and Richardson, S. W. 1979. Thermal evolution of 51 metamorphic rocks in the Central Highlands of Scotland. In Harris, 52 A. L., Holland, C. H. and Leake, B. E. (editors), The Caledonides 53 of the British Isles–reviewed. Geological Society of London 54 Special Publication No. 8, published by Scottish Academic Press, 55 Edinburgh, 339–344. 56 Whalen J. B., Currie J. L. and Chappell B. W. 1987. A-type 57 granites: geochemical characteristics, discrimination and 58 petrogenesis. Contributions to Mineralogy and Petrology, 95, 407– 59 419. 60 61 62 63 64 65 1 2 3 4 Whitten, E H T. 1959. A study of two directions of folding; the 5 structural geology of the Monadhliath and mid-Strathspey. Journal 6 of Geology, Vol. 67, 14–47. 7 Whittles, K.H. 1981. The geology and geochemistry of the area west 8 of Loch Killin, Inverness-shire. Unpublished PhD thesis, 9 University of Keele. 10 Wilkinson, S. B. 1907. The geology of Islay. Memoirs of the 11 Geological Survey of Scotland, Sheets 19 and 27, and parts of 20. 12 Willan, R. C. R., and Coleman, M L. 1983. Sulphur isotope study of 13 the Aberfeldy barite, zinc, lead deposit and minor sulfide 14 mineralization in the Dalradian metamorphic terrain, Scotland. 15 Economic Geology, Vol. 78, 1619–1656. 16 Williamson, D. H., 1953. Petrology of chloritoid and staurolite 17 rocks north of Stonehaven, Kincardineshire. Geological Magazine, 18 90, 353–361. 19 Williamson, W O. 1935. The composite gneiss and contaminated 20 granodiorite of Glen Shee, Perthshire. Quarterly Journal of the 21 Geological Society of London, Vol. 91, 382–422. 22 Wilson, J.R. and Leake, B.E. 1972. The petrochemistry of the 23 epidiorites of the Tayvallich Peninsula, North Knapdale, 24 Argyllshire. Scottish Journal of Geology 8, 215–252. 25 Winchester, J.A. 1974. The zonal pattern of regional metamorphism 26 in the Scottish Caledonides. Journal of the Geological Society of 27 London, 130, 509–24. 28 Winchester, J.A. and Glover, B.W. (1988). The Grampian Group, 29 Scotland. In: Later Proterozoic stratigraphy of the Northern 30 Atlantic region. (editor Winchester, J.A.). Blackie, Glasgow and 31 London, 146–161. 32 Winchester, J.A. and Glover, B.W. (1991). Grampian Group: Pitlochry– 33 Loch Laggan–Glen Spean. In: The Late Precambrian Geology of the 34 Scottish Highlands and Islands. (editors Hambrey, M.J., Fairchild, 35 I.J., Glover, B.W., Stewart, A.D., Treagus, J.E. and Winchester, 36 J.A.). Geologists‘ Association Guide No. 44, 66–85. 37 Wiseman, J D H. 1934. The central and south-west Highland 38 epidiorites: a study in progressive metamorphism. Quarterly 39 Journal of the Geological Society of London, Vol. 90, 354–417. 40 Wood, D.S. 1964. Some structures in the Dalradian pillow lavas of 41 the Tayvallich Peninsula, Argyll. Geological Magazine, 101, 481 42 Woodcock, N. and Strachan, R. 2000. Geological History of Britain 43 and Ireland. Blackwell Science, Oxford. 44 Wright, A.E. 1976. Alternating subduction direction and the 45 evolution of the Atlantic Caledonides Nature, London 264, 156. 46 Wright, A. E. 1988. 15. The Appin Group. In Later Proterozoic 47 Stratigraphy of the Northern Atlantic Regions (editor Winchester, 48 J. A.), pp. 177–199. Blackie. 49 50 Yardley B. W. D. (1989) An introduction to metamorphic petrology. 51 Longman, Harlow. 52 Yardley, B.W.D. and Valley, J.W. 1997. The petrologic case for a 53 dry lower crust. Journal of Geophysical Research, 106 B6, 12173– 54 12185. 55 56 Zeh, A. and Millar, I. L. 2001. Metamorphic evolution of garnet- 57 epidote-biotite gneiss from the Moine Supergroup, Scotland, and 58 geotectonic implications. Journal of Petrology 42, 529–554. 59 Zenk, M. and Schulz, B. 2004. Zoned Ca-amphiboles and related P-T 60 evolution in metabasites from the classical Barrovian metamorphic 61 62 63 64 65 1 2 3 4 zones in Scotland. Mineralogical Magazine, 68, 769-786. 5 6 Figure 1 Map of the Highland Border region showing the main 7 stratigraphical divisions, axial plane traces of major folds, and 8 locations of the GCR sites. Only areas described in this regional 9 paper are ornamented; outcrop width of the Tayvallich Subgroup is 10 exaggerated in places. NB south-west of the Loch Tay Fault, the 11 pelitic rocks shown in the core of the Aberfoyle Anticline are 12 mostly assigned to the Aberfoyle Slate Formation, which is assumed 13 to be relatively low in the Southern Highland Group; north-east of 14 the Loch Tay Fault, the pelitic rocks are at lower structural 15 levels and hence are in higher parts of the succession, such as the 16 Birnam Slate and Grit Formation (see Figure 2). Based on BGS 1:250 17 000-scale maps and modified by P.W.G. Tanner in the light of recent 18 work. 19 Lines of section AA’– GG’ refer to Figure 4. 20 Axial plane traces of folds: AA Aberfoyle Anticline (F1–F2), BLA 21 Ben Ledi Antiform (F1–F2), BVS Ben Vane Synform (F1–F2), CA Cowal 22 Antiform (F4), HBD Highland Border Downbend (F4). 23 Faults: BBF Bridge of Balgie Fault, HBF Highland Boundary Fault, 24 LTF Loch Tay Fault, TF Tyndrum Fault. 25 GCR sites: 1 Ardscalpsie Point, 2 Cove Bay to Kilcreggan, 3 26 Portincaple, 4 Bealach nam Bo, 5 Duke’s Pass, 6 Keltie Water, 27 Callander, 7 Little Glen Shee, 8 Craig a’ Barns, 9 Rotmell, 10 28 Glen Esk, 11 Garron Point to Muchalls. 29 30 Figure 2 Stratigraphical columns (not to scale) showing 31 variations in Southern Highland Group stratigraphy along the length 32 of the Highland Border region and variations across the strike, 33 where present. N.B. in the Cowal to Loch Lomond area, equivalent 34 formations on the inverted north-west limb and the right-way-up 35 south-east limb of the Aberfoyle Anticline have different names and 36 are shown separately. Although these do reflect some facies 37 variations, the reason is largely historical, dating back to the 38 period before the anticline was recognized. Capital letters in 39 column headings refer to cross-sections in Figure 4. GCR sites are 40 numbered as on Figure 1. 41 42 Figure 3 ‘Gneiss Rock at Glenfinlas’, 1853-54 (pen, wash and 43 44 gouache on paper), John Ruskin (1819-1900) © Ashmolean Museum, University of Oxford. This picture took several months to complete 45 and lovingly and precisely depicts the tortuous shapes wrought by 46 weathering of the strongly developed S1/S2 cleavage typical of 47 Southern Highland Group rocks south-east of the Highland Border 48 49 Downbend. The site is in the River Turk, by Brig O’Turk (Greive, 50 1996), a few hundred metres north of the northern boundary of 51 Figure 18. 52 53 Figure 4 True-scale serial sketch cross-sections across the Tay 54 Nappe and Highland Border Downbend, as viewed to the south-west in 55 the plunge direction of the downbend. Limits of cross-sections and 56 lines of section as shown on Figure 1 are notional and do not 57 reflect current level of erosion. 58 AA’ Isle of Bute to Loch Fyne. 59 BB’ West side of Loch Lomond. 60 61 62 63 64 65 1 2 3 4 CC’ Aberfoyle to Loch Katrine. (after Section 1, BGS 1:50 000 5 Sheet 38E, Aberfoyle, 2005). 6 DD’ Callander. (unpublished cross-section by J.R. Mendum). 7 EE’ Dunkeld. (after Figure 24a). 8 FF’ Glen Shee. (after sections 1, 2 and 4, BGS 1:50 000 Sheet 9 56W, Glen Shee, 1999). 10 GG Stonehaven. (after Figure 33). 11 ’ Positions of GCR sites, projected onto the nearest equivalent 12 cross-section, are numbered as on Figure 1. 13

14 Figure 5 A composite figure prepared from C.T. Clough's field 15 16 sketches, as reproduced in the Geological Survey’s Cowal memoir 17 (Clough, in Gunn et al., 1897, figs 12 and 13). The individual 18 sketches are arranged diagrammatically with respect to their 19 inferred position on the Cowal Antiform. It is clear from these 20 sketches that Clough understood how to identify and unravel the 21 effects of polyphase deformation some sixty years before John 22 Ramsay demonstrated it at Glenelg (Ramsay, 1958). 23 24 Figure 6 Map showing the bedding-cleavage relationships in the 25 Dalradian rocks immediately north-west of a splay of the Highland 26 Boundary Fault, north of Ardscalpsie Point, Isle of Bute. A–F, 27 reference points on the line of cross-section shown in Figure 8. 28 29 Figure 7 30 (a) An inland exposure at Ardscalpsie Point (NS 0440 5766), 31 showing the bedding-cleavage relationship found typically on the 32 upper limb of the Tay Nappe at this GCR site. Bedding, which is 33 parallel to the hammer shaft, is cut by the spaced S1 cleavage 34 (seen as etched lines on the surface) that dips at a more-gentle 35 angle to the south-east (right on photo). Hammer shaft is 60 cm 36 long. (Photo: P.W.G. Tanner.) 37 (b) Photomicrograph showing the relatively undeformed nature of 38 the D1 metasandstone microlithons which, together with the 39 intervening thin dark cleavage domains, constitute the S1 cleavage 40 in (a). 41 (Photos: P.W.G. Tanner.) 42 43 Figure 8 A true-scale, NNW–SSE-trending cross-section, prepared 44 from field sketches, of the structures along the line A—F in Figure 45 6, Ardscalpsie Point GCR site. 46 47 Figure 9 Map of the southern end of the Rosneath peninsula, 48 including the Cove Bay to Kilcreggan GCR site, based on BGS 1:50 49 000 Sheet 30W (Greenock, 1990). 50 51 Figure 10 52 (a) Centimetre-wide microlithons, separated by narrow dark 53 anastomosing cleavage domains which, together form the main, SE- 54 dipping, S2 fabric in the metagreywacke unit of the Dunoon Phyllite 55 Formation near Barons Point (NS 223 808). The spaced S1 fabric can 56 be clearly seen locally within the microlithons, frozen in the act 57 of transformation to S2. The L2 intersection lineation occurs as a 58 ribbon lineation on the main fabric surface. 59 60 61 62 63 64 65 1 2 3 4 (b) Photomicrograph of the D2 microlithons in (a), reworking S1 5 pressure-solution stripes (shown in their original state in Figure 6 7b). 7 (Photos: P.W.G. Tanner.) 8 9 Figure 11 10 (a) Location map of the Portincaple GCR site. Bedrock is the 11 Beinn Bheula Schist Formation, cut by the few dykes shown. A–B, C– 12 D, lines of cross-section for (b). 13 (b) True-scale field sketch of a vertical cross-section, viewed 14 approximately down-plunge for F4, across the southern part of the 15 hinge-zone of the Highland Border Downbend (F4). The main fabric 16 in these rocks is a centimetre-spaced pressure-solution (or 17 dissolution) cleavage (S2). 18 (c) Equal-area stereographic projection showing poles to the S2 19 fabric that defines a best-fit great circle whose π axis plunges at 20 21 10° to 079°, parallel to the major F4 fold axis of the Highland 22 Border Downbend. 23 24 Figure 12 25 (a) A vertical rock face in the Bheinn Bheula Schist Formation at 26 Portincaple (NS 2297 9327), viewed to the north-east (054°), showing 27 asymmetrical, Z-shaped F3 folds on the southern limb of the 28 Highland Border Downbend. The D3 structures deform the main S2 29 spaced fabric; the poorly developed minor upright F4 folds are 30 accompanied by a near-vertical, crenulation cleavage that, although 31 restricted to the pelitic seams, is clearly imprinted on and hence 32 post-dates all of the other structures. Note the local 33 preservation of the S1 fabric within the S2 microlithons. (Photo: 34 P.W.G. Tanner.) 35 (b) An explanatory outline drawing of (a). 36 (c) Photomicrograph of the S4 crenulation cleavage at X on (b). 37 (Photo: P.W.G. Tanner.) 38 39 Figure 13 Cross-section from Callander due north to Loch Tay. 40 The section continues the Flat Belt from the southern end of the 41 section in Figure 3.3b and shows the position of the Keltie Water 42 (KW), Bealach nam Bo (BB) and Dukes Pass (DP) GCR sites within the 43 Steep Belt created by the F4 Highland Border Downbend. The 44 assumption is made that there is a single continuous unit of ‘green 45 beds’. 46 47 Figure 14 Map of the area around Bealach nam Bo, Loch Katrine, 48 Trossachs. Based upon mapping by the British Geological Survey, 49 19961998. 50 51 Figure 15 Sedimentological log through ‘green beds’ in the Loch 52 Katrine Volcaniclastic Formation, exposed in cliffs at Bealch nam 53 Bo. Adapted from Burt (2002). 54

55 Figure 16 F1 folds with axial planar cleavage picked out by 56 quartz veins in green beds and cleaner metasandstone in the Loch 57 ‘ ’ Katrine Volcaniclastic Formation at Bealach nam Bo (NN 478 075). 58 Lens cap is 50 mm diameter. (Photo: C.W. Thomas, BGS No. P 59 726593.) 60 61 62 63 64 65 1 2 3 4 5 Figure 17 F2 crenulation folds of the first cleavage in the 6 Creag Innich Sandstone Formation at NN 4777 0714, Bealach nam Bo 7 GCR site. Lens cap is 50 mm diameter. (Photo: C.W. Thomas, BGS 8 No. P 726594.) 9 10 Figure 18 Map of the area around the Duke’s Pass, Aberfoyle. 11 Based upon mapping by the British Geological Survey, 19961998. 12 13 Figure 19 Typical F1 fold in metasandstone of the Creag Innich 14 Sandstone Formation at NN 5144 0344 on the Duke’s Pass, Aberfoyle. 15 The coarse-grained base of a gritty metasandstone unit lies above 16 the hammer head, passing down into finer grained rock towards the 17 end of the handle. The rocks are inverted and the fold is downward 18 facing. Hammer shaft is 36 cm long. (Photo: C.W. Thomas. BGS No. 19 P 643897.) 20 21 Figure 20 Map of the Keltie Water, Callander GCR site. 22 Locations of photomicrographs (Figure 21, a–e) and the field 23 photograph (Figure 22) are indicated. The position of the putative 24 terrane boundary between the Grampian Terrane and the Highland 25 Border ‘exotic terrane’ (Brasier et al., 1992) is also shown for 26 reference. 27 The inset map shows three structural sub-areas sited across the 28 boundary between undoubted Dalradian rocks of the Ben Ledi Grit 29 Formation (A), and the lower part of the Keltie Water Grit 30 Formation, including the Transition Member (B). Sub-area C 31 consists mainly of gritty metasandstones of the Keltie Water Grit 32 Formation, comparable in lithology to the rocks in sub-area A. 33 Equal-area stereographic projections for each of these sub-areas 34 show the poles to the main cleavage, together with their computed 35 mean orientation shown as a great circle (solid line). 36

37 Figure 21 Photomicrographs of medium- to coarse-grained 38 metagreywackes from the Keltie Water section, and a related 39 exposure 5 km to the south-west. The photomicrographs illustrate 40 the similarities in petrography and strain state of samples from 41 (a) the Ben Ledi Grit Formation, (b) the Transition Member, (c) the 42 lower part of the Keltie Water Grit Formation, above the Transition 43 Member, (d) the Keltie Water Grit Formation above the Keltie 44 Limestone and Slate Member and (e) the upper part of the Keltie 45 Water Grit Formation above the Leny Limestone and Slate Member. 46 The selected photomicrographs are representative examples chosen 47 from over 100 thin sections and full details of the petrography 48 were given by Tanner and Pringle (1999). Locations of samples are 49 shown on Figure 20, except for (e) which is located at NN 6037 50 0858. All photomicrographs are at the same scale with a width 51 equivalent to approximately 4 mm. (Photos: P.W.G. Tanner.) 52

53 Figure 22 Spaced S1 cleavage, with microlithons 1–3 cm thick, 54 associated with a minor fold in gritty metasandstones of the Keltie 55 Water Grit Formation. Section viewed to the north-east. This 56 exposure (see Figure 20 for location) was removed totally by a 57 recent flood. (Photo: P.W.G. Tanner.) 58

59 60 61 62 63 64 65 1 2 3 4 Figure 23 Map of the Dunkeld  Pitlochry area to show the main 5 lithostratigraphical units, the main elements of the structure and 6 the locations of the Little Glen Shee, Craig a’Barns and Rotmell GCR 7 sites. Adapted from Rose and Harris (2000, figure 2). 8 9 Figure 24 10 (a) Schematic cross-section from Pitlochry to Dunkeld to show the 11 location of Figure 24b, and the position of the Little Glen Shee, 12 Craig a’Barns and Rotmell GCR sites in relation to the Tay Nappe. 13 (b) Schematic cross-section across the Flat Belt (FB), the 14 Highland Border Downbend (HBD), the Highland Border Steep Belt 15 (HBSB) and the Highland Boundary Fault (HBF) to show the position 16 of the Little Glen Shee, Craig a’Barns and Rotmell GCR sites in 17 relation to the detailed geology of the district. Adapted from a 18 drawing by P.T.S. Rose. 19

20 Figure 25 Geological relationships at the crag that comprises 21 the Little Glen Shee GCR site, to show the geometry of the folds 22 and the general direction of younging of the beds. Insets 1 and 2 23 show the detail of relations between bedding and the refracted 24 cleavage on alternate fold limbs. Locations of photographs, 25 Figures 26a and 26b, are shown. Adapted from a field sketch by 26 P.W.G. Tanner with insets from P.T.S. Rose. 27

28 Figure 26 Detailed sedimentological and structural features of 29 the Little Glen Shee GCR site at locations shown in Figure 25. 30 (a) Cleavage types and refraction related to rock type. A spaced 31 cleavage (S1p) occurs in metasandstones in the centre of the photo 32 and is refracted as it passes into a slaty cleavage (S1) in 33 metasiltstones on either side. To the right there is a sharp 34 lithological change at the base of the metasandstone unit, but to 35 the left the more gradual refraction brings out grading from one 36 lithology into another. Younging is to the left (north-north- 37 west). Coin is 1.2 cm in diameter. 38 (b) Detail of the minor fold-pair diagrammatically represented in 39 Figure 25 and discussed in the text. Coin is 1.2 cm in diameter. 40 (Photos: A.L. Harris.) 41

42 43 Figure 27 Location map of the Craig a’Barns GCR site, showing 44 the position of localities A–D described in the text and the 45 approximate trace of the Highland Border Downbend (HBD). 46 47 Figure 28 Detailed structural relationships at the Craig a’Barns 48 GCR site. 49 (a) Sketch taken from a photograph of the fold at locality B on 50 Figure 27, discussed in the text. A metasandstone bed contains 51 tight F2 folds of S1p showing consistent vergence on opposite limbs 52 of the Highland Border Downbend-related, step-like open fold. 53 (b) The association between the Highland Border Downbend-related 54 crenulation cleavage (overdrawn straight lines, labelled S4) and 55 folded bedding (S0), seen at or near the core of the downbend at 56 locality C on Figure 27. At the top of the photograph, bedding is 57 essentially parallel to both S1 and S2 but in the bottom left, S1p 58 is at a distinct angle to bedding. Looking north-east, width of 59 exposure about 60 cm. (Photo: A.L. Harris.) 60 61 62 63 64 65 1 2 3 4 (c) Detail of the crenulation cleavage related to the Highland 5 Border Downbend at locality C on Figure 27. Looking north-east, 6 width of exposure 20 cm. (Photo: A.L. Harris.) 7 8 Figure 29 Intense F2 folds of the S1p cleavage at the Rotmell 9 GCR site. Note the contrast in thickness between S1p microlithons 10 in the hinges of the F2 folds and those on the limbs. Top-to-the- 11 right (south-east) shear is inferred. Looking north-east at NO 12 0128 4118. Field of view is approximately 50 cm high. (Photo: 13 J.E. Treagus.) 14 15 Figure 30 Map of lower Glen Esk showing the full range of 16 regional metamorphic zones first erected by Barrow (1893, 1912). 17 Redrawn from Harte (1987), with modifications based on BGS 1:50 000 18 Sheet 66W (Aboyne, 1995). 19 20 Figure 31 Photomicrographs (a–d, f) and one field photo (e) 21 illustrating the sequence of Barrow’s Zones, as represented in the 22 Glen Esk GCR site. Rocks photographed come from the localities 23 described in the text, except for the sillimanite zone (f), which 24 is from a locality by Glen Effock (described by Harte, 1987). All 25 photomicrographs are at the same scale with a width equivalent to 26 approximately 4.5 mm. (Photos: B. Harte.) 27 (a) Chlorite Zone. Principal minerals are quartz, white 28 mica, chlorite and opaques (iron oxide and sulphide). The bedding 29 and main cleavage are approximately parallel to the top edge of 30 photo, and the upper (darker) half of the photo represents a 31 chlorite-rich layer, whilst the lower part is more quartz rich. A 32 later cleavage is visible as pale (white mica-rich) seams cutting 33 obliquely across the chlorite-rich layer. 34 (b) Biotite Zone. Biotite porphyroblasts (Bt) overgrow a 35 finer grained matrix of quartz, white mica, chlorite and opaque 36 iron minerals. The bedding and main cleavage are roughly parallel 37 to the top edge of the photo. 38 (c) Garnet Zone. Biotite (Bt) and garnet (Grt) 39 porphyroblasts in a finer grained matrix of quartz, white mica, 40 chlorite and opaque iron minerals. Areas in the matrix richer in 41 chlorite (Chl) have a darker appearance. 42 (d) Staurolite Zone. Porphyroblasts of garnet (Grt and 43 highest relief), staurolite(St and high relief) and biotite (Bt and 44 moderate relief) in a matrix of quartz and muscovite with a small 45 amount of opaque iron minerals. 46 (e) Kyanite Zone. Field photo of a vein dominantly of 47 quartz and kyanite; the label is in the centre of a rosette of 48 kyanites. Penknife is 10 cm long. 49 (f) Sillimanite Zone. A large (2 mm) porphyroblast of 50 garnet (Grt) in the centre, together with smaller porphyroblasts of 51 kyanite (Ky) and staurolite (St). The ‘Sill’ label is on a cluster 52 of sillimanite fibres (fibrolite). Darker areas to the left and 53 right of the garnet are of biotite intergrown with fibrolite. Pale 54 areas are dominated by muscovite and quartz. 55 56 Figure 32 Location of the coast section in Southern Highland 57 Group rocks from Garron Point to Muchalls, north of Stonehaven, 58 showing the principal structural and metamorphic features. After 59 BGS 1:50 000 Sheet 67 (Stonehaven, 1999), with approximate 60 61 62 63 64 65 1 2 3 4 locations of metamorphic mineral isograds based on Harte et al. 5 (1987, figure 2a). 6 7 Figure 33 Partly schematic structural cross-section of the coast 8 north of Garron Point, Stonehaven, showing the contrast in dip of 9 bedding in the Flat and Steep belts, the principle F1 and F4 folds 10 and the limits of D2 and D4 deformation in metasandstones. 11 Structures observed on the coast have been projected onto the line 12 A–A’ shown on Figure 27. Section is true scale (no vertical 13 exaggeration). After BGS 1:50 000 Sheet 67 (Stonehaven, 1999). 14 15 Figure 34 Cleavage/bedding relationships in Southern Highland 16 Group rocks of the Garron Point to Muchalls GCR site. 17 (a) Widely spaced S4 cleavage in calcsilicate-rock and psammite 18 at Hall Bay (NO 8994 8985). View to the south-west down the plunge 19 of the F4 folds. 20 (b) S1 cleavage is steeper than bedding in beds that young south 21 and are therefore inverted and downward facing on S1. Exposure at 22 high-water mark just south of promontory at edge of main part of 23 Perthumie Bay (NO 8908 8811). (Photos: C.W. Thomas, BGS Nos. P 24 726595 and P 726596.) 25 26 27 28

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Figure 4.1

700 200 TF

BBF e n A y F l a t B e LTF N F l t h ng c Lo Loch CA och o L BLA Loch Tay L H B Katrine S t e e B AA p B 3 BVS Cowal e l t C D 4 Luss HBD 2 5 6 1 B’ ’ Aberfoyle D’ A’ C Callander HBF Isle of Bute Loch Lomond Campbeltown

Isle of Arran 0 kilometres 20 200 300 700

Palaeogene intrusive igneous rocks Post-Dalradian sedimentary and volcanic rocks within area described in Chapter 4 800 Late-Caledonian intrusive igneous rocks N LTF 0 kilometres 20 green beds within the Southern Highland Group Dalradian SupergroupDalradian Southern Highland Group Loch Pelitic rocks within the Southern Highland Group Tay Pitlochry Fla F Tarfside Nappe t Belt 9 E 8 Tayvallich Subgroup Dunkeld HBD H Argyll Group 7 B S t e e p Crinan Subgroup B E’ e l t axial plane traces: ’ HBF F 10 fault F4 monoform Aberdeen HBD F4 antiform G 1 GCR site in Chapter 4 3 11 F1-F2 anticline 00 Forfar G’ Stonehaven F1-F2 syncline 8 400 00 Figure 4.2

SW NE (a) (b) (c) (d) (e) (f) (g) Cowal peninsula Aberfoyle Pitlochry to Dunkeld Glen Shee Glen Clova Glen Esk (Tarfside Nappe) to Loch Lomond C’-C E’-E F’-F to Stonehaven A’-A, B’-B G’-G North-west of the Aberfoyle Anticline

Ben Ledi Grit Fm Dunkeld Grit Fm Cairn Gibbs Psammite Rottal Schist Fm Glen Lethnot with green beds Grit Fm Beinn Bheula Schist Fm Fm with green beds Creag Innich Birnam Slate and Sandstone Fm Grit Fm Green Beds Loch Katrine Green Beds Volcaniclastic Fm Pitlochry Schist Fm Mount Blair Psammite with green beds Ardnandave and Semipelite Fm Longshank Gneiss Glen Effock Glen Sluan Schist Fm Sandstone Fm Fm Schist Fm Loch Tay Limestone Fm Loch Tay Limestone Loch Tay Limestone Fm Loch Tay Limestone Fm Dounalt/Water of Tarfside GCR sites 2 3 4 5 Fm 7 8 9 10 Tanar Limestone Fm 11 Psammite Fm

Callander Aberfoyle Anticline (* formations unique to SE limb) D’-D

*Bofrishlie Slate Fm *Keltie Water Grit Fm, Arran *Loch Ard Grit Fm including Keltie and Leny limestone and slate members *Toward Quay Grit Mbr Loch Tay Fault psammites/metagreywackes Ben Ledi Grit Fm North Sannox with rare green beds Ben Ledi Grit Fm, Grits Fm *Bullrock Greywacke Mbr including prominent pelites/semipelites pelites/semipelites

Loch Ranza NinianSt Fm Creag Innich Slate Fm Dunoon Phyllite Fm Sandstone Fm metalimestones (=Luss Slates) Aberfoyle Slate Fm volcaniclastic ‘green beds’ GCR sites 1 2 5 6 Figure 4.4

Cowal Antiform

SE NW Tay Nappe Highland Boundary A’ Fault A

Isle of Bute

e Highland Border clin nti A Downbend le e’ rm foy p ntifo er ap i A b N ed A ay L ‘T en B rm fo yn S e n B’ a B V n e B Loch Lomond Steep Belt Flat Belt

Aberfoyle C’ C Loch Tay Fault

D’ D

L

Highland Boundary Fault Callander

Capel Hill Syncline

E’ E Mount Blair Anticline

? Birnam 0 kilometres 5 ß

F’ Glen Shee F

unconformity G’ G Stonehaven Figure 4.5

SE NW

S1

S1

D2 microlithon S4

Cowal Antiform S2

S1 D4 minor fold pair S2

S2 D 2 m i cr ol ith on

S4 crenulation cleavage Figure 4.6

580 045 N quartz-dolerite dyke (Palaeogene) A 68 d unclassified dyke (?Early Carboniferous) 39 71 39 54 38 B 27 (?)basic sill (?Early Carboniferous) 36 SH Lower Carboniferous, Kinnesswood Formation 25 red sandstone and caliche 65 C T 47 Dalradian Supergroup, 39 T Southern Highland Group (SH) 54 58 and Trossachs Group (T) 40 D 40 37 t 59 aul dark grey slaty pelite 46 y F dar 54 un 55 Bo well-bedded metagreywacke nd 46 hla HWM E Hig 61 breccia associated with the splay from 42 F Ardscalpsie Point the Highland Boundary Fault d inclined bedding, dip in degrees inclined slaty and spaced S1 cleavage, dip in degrees 5 LWM, 75 d low and high tide marks HWM

0metres 200 fault LWM Figure 4.8

late fold-pair 2 m-thick N dolerite dyke F1 folds folds slaty cleavage late structure amalgamated bed flame structure f f f f f ff f f f f f f f

d A a c B C 100 metres approximately D

fault-breccia Highland vein quartz metagreywackes to 1 m-thick metagreywackes to Kinnesswood Boundary bedding in fault-zone 3 m thick fault-breccia 3 m thick Formation late fold-pair F1 folds ?f Fault-zone S gully individual bed, base dotted f f f f f f dyke direction of younging f SI cleavage b f D E e dyke F f fault black slaty pelite f a - f localities mentioned in the text Figure 4.9

G a r 6 e Rhu 84 48 L Knockderry o c Castle R h L o 35 o Rosneath c s h 38 45 n e 683 L o a 40 n 23 35 t g h Rosneath Bay p e Camsail 58 40 n 70 Bay 44 45 40 Cove i Cove Bay n 18 682 51 s u 22 40 50 40 l a 15

30 40 681 37 41 Barons Point 20 16 Highland Boundary Fault Southern limit 50 18 41 38 of D2 reworking 21 14 23 52 N 19 40 Kilcreggan 45 Portkil Bay 680

0 kilometres 2

222 223 224 225 226 227

Upper Devonian Rosneath Conglomerate Formation direction of younging

Dalradian Supergroup, Southern Highland Group inclined bedding, dip in degrees St Ninian Formation– Bullrock Greywacke Member inclined S1 cleavage, dip in degrees

Beinn Bheula Schist Formation inclined S2 cleavage, dip in degrees with basic meta-igneous rock

Dunoon Phyllite Formation with beds of metagreywacke Figure 4.11

(a) 223 N D g Groyne HTM n o C L (c) h c o L

D Jetty π B Path Portincaple D to A814 D A quartz-dolerite dyke 0 metres 200 (late Carboniferous) D felsic dykes (Caledonian) 692 = pole to S2

(b) N S Large F3 folds NE F3 folds Jetty

D C path SW F3 folds beach S2 fault gullychange in section line F3 folds Groyne B Sea microlithons F4 folds change in section line

F4 fold and S4 cleavage fault gully A S2 fabric erratics bedding 0 metres 10 approx. Dyke fault F4 folds & cleavage Figure 4.12b

S2

S1

S2

0 centimetres 10

S2 microlithon with F3 fold trace S1 preserved internally F4 fold trace Figure 4.13

N Flat Belt Highland Border Steep Belt S Old Red Sandstone

Loch Tay Loch Earn Ben Vorlich Keltie Water Callander Keltie Water Grit Ben Ledi Grit with Aberfoyle Slate etc. ? ? green beds BB Pitlochry Schist DP KW Loch Tay Limestone Ben Lui Schist

Ben Lawers Schist ? Ben Eagach Schist and Highland Border Downbend Ben Ledi Carn Mairg Quartzite Loch Tay Antiform Loch Tay Fault (?F4) Syncline Highland Ben Vane (F1) Aberfoyle Boundary Fault 0 kilometres 5 Anticline Anticline (F1) (F1) Figure 4.14

247 500 248 000 248 500 N

L o c h

K a 0 metres 300 t r i B Very thick-bedded n ea dark green beds e la ch 47 50 7 500 n 07 am g g B 50 o F1 70

F1 folds common in green beds in this area 50 85 60 g g S2 Abundant F2 folds F2 16 in coarse gritty 7 000 07 arenaceous metasandstones

Metasandstones very coarse g 80 and locally pebbly 60 g

0 500 65 Southern Highland Group overturned bedding, Ben Ledi dip in degrees Grit Formation axis of minor fold, Creag Innich Sandstone plunge in degrees. Formation F1: First folds Loch Katrine F2: Second folds Volcaniclastic Formation direction of younging geological boundary, g Ben Venue indicated by graded inferred bedding fault Figure 4.15 42 41 40 39 Metres 38 92 37 (Creag Innich 91 Sandstone 90 Formation) 33 metasandstones 60 32 green beds 59 31 D 30 58 29 57 28 56 27 55 26 54 25 53 24 52 8 51 7 50 6 49 5 48 4 47 3 46 2 45 1 44 0 43 f f c c vf vf m m vc vc silt silt

mud sand mud sand pebble pebble granule granule

quartz pebbles herringbone cross-lamination coarse sandstone cross-lamination lenses siltstone channelized/ clasts mudstone lenticular bed D dewatering

slumping Figure 4.18 2 2 2 k 51 52 53 r Creag u T

r Noran e 42 74 iv g S1 R 65 g e 59 lack Wat r Achray Loch Achray B Water S2 66 A821

706

S1 59 74

7 g 65 50 05 S1

S1 74 g g 75 66

Loch Drunkie 60 g 39 75 s 7 S1 as 04 g 41 P S1 s g ke g 74 u 86 D 80 g Creag a’ 61 Mhadaidh Lochan Reoidhte g Hill Cottage 27 55 g Loch Tay Fault Zone 7 Aberfoyle Quarries t 03 l 51 u 58 a g F S1

s Meall Ear s a P

s e 80 k g u D Creag 49 69 Gownan g S1 Craigmore 84 702 S1 42 60 g N 56 S1 lt au F ry da A821 un Bo d Aberfoyle an hl ig 0 kilometres 1 H

Southern Highland Group inclined bedding, dip in degrees road Ben Ledi Grit Formation inclined overturned bedding, pelite and semipelite dip in degrees geological boundary, inferred direction of younging; Ledard Burn Member g: graded bedding fault Creag Innich inclined first cleavage, S1 Sandstone Formation dip in degrees Aberfoyle Slate approximate southern limit of D2 Formation deformation in metasandstones Figure 4.4 key

Dalradian Supergroup: key units in approximate stratigraphical order, Lower Devonian, Upper Devonian and formed by combining the different sequences found on the limbs of the Lower Carboniferous (ORS facies) Tay Nappe (see Fig 4.2 for details). Highland Border Ophiolite L Keltie Water Grit Formation (with Leny Limestone, L) younging direction Birnam Slate and Grit Formation generalized younging direction Aberfoyle Slate Formation (=Luss Slates and Dunoon Phyllites) facing direction of early (F1) major fold Beinn Bheula Schist Formation, St Ninian Formation, Ben Ledi Grit Formation etc. form line (generally bedding) green beds axial plane trace of early fold Glen Sluan Schist Formation etc. axial plane trace of later fold Loch Tay Limestone Formation correlation tie-line ß fault-bounded panels of Lower Old Red Sandstone strata north-west of the Highland Boundary Fault. minor fault Figure 4.20 64 Structural sub-areas N 55 F F 26 A B 4.21a 29 Sròn Eadar a’ Chinn C

Allt Br 77 eac - 88 52 F nic 59 77 37 46 21 34 F F 37 77 F 20 F 57 F 50 F K 13 Subarea A: Main cleavage e l t i track 4.21b e 47 F W a t F e 42 r Subarea B: Main cleavage 46 72 61 58 40 54 31 F 59 4.21c 69 34 F 25 4.22 F N=9 22 F 61 34 39 F F Waterfall F 55 Subarea C: Main cleavage N=7 48 74 N 36 4.21d 42 Waterfall F 46 D

0 metres 300 D

4.21e 68 off map 64 N=16 12 Keltie Water Grit Formation Leny Limestone grey, purple and black slaty pelites D dolerite (Palaeogene) and Slate Member grey and white gritty metasandstones F felsite (Caledonian)

grey slaty pelites fault Keltie Limestone black slaty pelites with Keltie Limestone inclined bedding, dip in degrees and Slate Member inclined slaty/spaced cleavage, grey slaty pelites dip in degrees direction of younging grey and white gritty metasandstones putative terrane boundary green to pale gritty metasandstones Transition Member with some slaty pelites Lower Old Red Sandstone Ben Ledi Grit Formation green to grey-green gritty metasandstones with some slaty pelites green, grey and purple slaty pelites Figure 4.23

65 60 t N el B Old Red Sandstone ep 70 te 60 S el Southern Highland Group with Birnam Slates mm 20 Tu Tayvallich Limestone and Pitlochry 0 kilometres 5 5 Ben Lui Schist formations (undivided) 10 Easdale and Islay subgroups (undivided)

55 inclined S1 cleavage, dip in degrees 5 10 5 inclined S2 cleavage, dip in degrees 5 5 horizontal S2 cleavage R 15 iv e Deuchray r 50 5 vertical S2 cleavage T Hill a y 50 10 20 inclined foliation or banding, dip in degrees 10 30

Rotmell 15 F l a t axis of F1 fold, plunge in degrees B e l t 10 20 50 45 20 L2 lineation, plunge in degrees (after Stringer 1957) Craig a’ Barns 30 horizontal L2 lineation 75 Dunkeld

16 25 garnet isograd 40 fault 40 n raa 50 r B ive 30 45 R SE limit of strong D2 overprint

L i 60 (A) tt Highland Border Downbend, axial surface trace le G 20 45 le HBSB n S 35 h HBSB Highland Border Steep Belt e 40 e (B) t zones within the HBSB distinguished ul (A) (B) Fa by Rose and Harris (2000) y 25 ar nd ou B d an 30 hl ig H 90 95 00 05 Figure 4.24

NW SE

lt Little (a) e B p 0kilometres 10 Glen Shee e e t Craig a’ Barns S

l e m Rotmell D m B u

T H Present erosion surface Flat Belt Pitlochry

HBF Dunkeld Hinge inferred

(b) Dunkeld Grit/ Little Pitlochry Schist NW Rotmell Glen Shee SE Birnam Slate Craig a’ Barns FB Birnam Grit

F1 folds HBF HBSB F2 folds HBD axial surface 0 kilometres 1 direction of younging Figure 4.25

N S

2

Figure 4.26b

1 Figure 4.26a 0 metres 2

direction of younging Figure 4.27 02 fence 0-10 D HBD 50 44 65

Crag a’ C B Barns A

N car park

0 metres 400 Dunkeld Blairgowrie A953

inclined composite foliation of SØ, S1 and S2 on long limbs of F4 folds, generalized dip in degrees inclined S4 crenulation cleavage at Highland Border Downbend hinge-zone, generalized dip in degrees subhorizontal axis of F4 minor fold, showing direction of vergence axial plane trace of major F4 antiform general direction of younging, inferred from regional structure path Figure 4.28a

NW SE hinge of minor fold b related to HBD e d d i n g S Ø

F2 folds

0 centimetres 30 attenuated Slp cleavage Figure 4.30 356 357 358 359 Mi llden Regional metamorphic zones 6 GES Hillock sillimanite zone Sill 7 78 kyanite zone GES staurolite zone Sill GES GLGT garnet zone GES Ky GLGT 777 Ky GES biotite zone GES 5 GLGT chlorite zone

Craigoshina 776 geological boundary Craig of Weston St Gt GLGT R i fault, with sense of v 4 e r displacement shown by tick N N o (normal and reverse faults) r t h or arrows (wrench faults)

E 7 s 75 k isograd (Bi - biotite; Gt - almandine garnet; Bi St - staurolite; 0 kilometre 1 3 Ky - kyanite; Sill - sillimanite) GLGT 774 GLGT 3 described locally

GLGT 2 1 NOE

773 MARG MARG lt u a F k s E ORS h E t d r ze o ll 7 N 72 Dalbog ORS

Old Red Sandstone SILURIAN- ORS DEVONIAN Supergroup MARG Margie Formation Highland Border ORDOVICIAN Complex NOE North Esk Formation

GLGT Glen Lethnot Grit Formation Southern Dalradian NEOPROTEROZOIC (haematite-rich pelite shaded Highland Group Supergroup GES Glen Effock Schist Formation Figure 4.32 N Muchalls 92 Ritchie Shore

91 Doonie Point Flat Belt Castle Rock of Muchalls A

90 Hall Bay

CTD OUT 89 GNT+ST+BI CTD+BI Steep Belt CTD Red Man Perthumie Bay GNT

88 Skatie Shore Garron Point A’ 0 1 kilometres

8990 91 Highland Boundary Fault axial plane trace of Highland Border Downbend (F4) metamorphic mineral isograds, GNT: garnet, CTD: chloritoid, BI: biotite, ST: staurolite approximate line of section in figure 4.33 Figure 4.33

A A’ STEEP BELT; steep dips to the NNW ‘FLAT BELT’: Shallow, variable dips on F4 long fold limbs D4 dominates medium- and large-scale folding D2 and D4 deformation dominates D1 structures well seen up to the limit of D4 deformation. D2 minor folds abundant; S2 forms dominant cleavage D1 structures generally not well seen Bedding-cleavage and younging relationships clearly reveal D1 structures very rarely observed other than variably modified S1 cleavage. downward-facing character of D1 structures Rocks young towards downbend where metres Rocks are generally inverted where younging is observed younging observed metres D2 becomes strongly Approximate limit Approximate D2 limit 300 300 developed towards of D4 deformation in metasandstones Highland Highland Border the north Boundary Fault 200 Downbend ? 200

100 100

OD 1 OD 1 direction of younging 1 Cambro- -100 1 1 1 -100 axial plane trace of antiform 1 1 Ordovician 4 1 axial plane trace of synform 1 1 1 1 rocks -200 1 deformation episode 1 and Old Red -200 0 metres 300 1 Sandstone direction of facing of folds 1 -300 -300 Figure 4.3 colour Click here to download high resolution image Figure 4.7 colour Click here to download high resolution image Figure 4.10 colour Click here to download high resolution image Figure 4.12a + c Click here to download high resolution image Figure 4.16 colour Click here to download high resolution image Figure 4.17 colour Click here to download high resolution image Figure 4.19 colour Click here to download high resolution image Figure 4.21a Click here to download high resolution image Figure 4.21b Click here to download high resolution image Figure 4.21c Click here to download high resolution image Figure 4.21d Click here to download high resolution image Figure 4.21e Click here to download high resolution image Figure 4.22 colour Click here to download high resolution image Figure 4.26a Click here to download high resolution image Figure 4.26b colour Click here to download high resolution image Figure 4.28b Click here to download high resolution image Figure 4.28c Click here to download high resolution image Figure 4.29 colour Click here to download high resolution image Figure 4.31 a-f Click here to download high resolution image Figure 4.34a colour Click here to download high resolution image Figure 4.34b colour Click here to download high resolution image Figure 4.3 B&W Click here to download high resolution image Figure 4.10 B&W Click here to download high resolution image Figure 4.16 B&W Click here to download high resolution image Figure 4.17 B&W Click here to download high resolution image Figure 4.19 B&W Click here to download high resolution image Figure 4.22 B&W Click here to download high resolution image Figure 4.26b B&W Click here to download high resolution image Figure 4.29 B&W Click here to download high resolution image Figure 4.34a B&W Click here to download high resolution image Figure 4.34b B&W Click here to download high resolution image