DOCSLIB.ORG

The Geochemistry, Metasomatism and Petrogenesis of the Granites of the English Lake District

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Geochemistry, Metasomatism and Petrogenesis of the Granites of the English Lake District J. geol. Soc. London, Vol. 142, 1985, pp. 1139-1157, 15 figs, 5 tables. Printed in Northern Ireland The geochemistry, metasomatism and petrogenesis of the granites of the English Lake District C. O’Brien, J. A. Plant*, P. R. Simpson* & J. Tarney Department of Geology, The University, Leicester LE1 7RH, UK and *British Geological Survey, London, UK SUMMARY: New geochemical data for the Carrock, Threlkeld, Ennerdale, Shap, Skiddaw and Eskdale granites of the Lake District are presented and discussed with particular reference to the metasomatism and petrogenesis of the intrusions. The Caledonian granites of the Lake District have more associated hydrothermal activity and mineralizationthan their equivalents north of the Iapetussuture in Scotland. Pervasive high-temperaturemetasomatism which affects the Shap, Skiddaw and Eskdaleintrusions is accompanied by remobilization of the large ionic lithophile elements (K, Rb, Sr, U) and Li and B, although high field strength elements, including the rare earth elements, remain unaffected except near greisen and mineral veins. The Threlkeld intrusion appears to have suffered loss of Baand Sr duringa low-temperature event. However, there is no consistentrelationship between granite composition, hydrothermal activity and mineralization which could be used to supportthe granitecupola model for mineralization inthe province. Rather, the episodic mineralization which affects the Lake District may be related more to the broad geothermal field consequent upon the emplacement of the deeper Lake District batholith, identified from geophysical data. Despite the variable metasomatic perturbations of their primary chemistry, three distinct groups of intrusions can be recognized on geochemical grounds. The Carrock granophyre is a product of tholeiitic fractionation and the Threlkeld and Ennerdale bodies are more typical calc-alkaline intrusions, whereas the Eskdale, Shap and Skiddaw plutons show a progressive evolution towards more complex geochemical patterns, suggesting decreasing hornblende but increasing plagioclase control of fractionating processes. The culmination of this trend may have been the emplacement of a large, high heat production granite beneath the Lake District at the end of the Caledonian orogeny. The suggestion made on geophysical grounds that the Eskdale intrusion is a cupola of the Lake District batholith cannot be simply reconciled with geochemical modelling.None of theLake District graniteshas geochemical or isotopic characteristics which are convincingly S-type (i.e. formed by partial melting of a sedimentary protolith), and a model of subcrustal magmagenesis beneath an evolving arc or continental margin appears to be more appropriate. Renewedinterest in the British Caledoniangranites mineralization in the Caledonian. Hence a systematic has led to a number of detailed studies of intrusions in study of the trace element geochemistry and petrology Scotland, north of the Iapetus suture, using modern of the Carrock, Threlkeld, Ennerdale, Shap, Skiddaw trace and isotope data to understand their petrogene- and Eskdalegranites has been carried out in a sis, and particularly to constrain the extent of crustal collaborative study between Leicester University and involvement (e.g. Halliday 1984). In contrast, except the British Geological Survey (BGS).The study for some K-Ar and Rb-Sr geochronological data, few concerns the magmatic evolution of the Lake District studies have been made of the Caledonian granitoids granites in relationto models for the tectonic setting of of the southern plate, most of which outcrop in the the Lake District province during the Caledonian. The Lake District. Although broadly contemporaneous, geochemical effects of water-rock interaction, result- these granites were emplaced in a terrain related to a ing from the hydrothermal activity in the LakeDistrict different,southerly dipping subduction zone during geothermal field (which persistedfrom Devonian to the closure of Iapetus,and wereintruded into possibly as late as the Jurassic) has also been continental crust apparently considerably younger in investigated, with implications for the associated age and differentin character from that underlying mineralization. most of Scotland (Thorpe et al. 1984). An additional feature is that the LakeDistrict Caledonian province is Tectonic setting of the Lake considerably more mineralized thanthe Scottish District province. Comparisons between the two provinces may prove During the Caledonianorogeny theLake District useful in constraining models for granite genesis and formed part of theEuropean (or‘southern’) plate. Downloaded from http://pubs.geoscienceworld.org/jgs/article-pdf/142/6/1139/4888936/gsjgs.142.6.1139.pdf by guest on 30 September 2021 1140 C. O’Brien et al. This is believed to havebecome joined onto the Thesouthern province of the Caledonides is less unstable southeastern margin of the American-Green- well understood than the Scottish Caledonides, owing landic (or ‘northern’)continental plate (Williams mainly to the younger sedimentary cover over most of 1969) in a collision event which culminated during the England (Fig. 1). Seismic refraction studies (Bamford late Silurian-early Devonian, the suture being located 1979) and isotopicstudies of granites (Hampton & along the Solway line in southern Scotland. The Lake Taylor 1983; Pidgeon & Aftalion 1978) provide little District now lies immediately south of the suture and evidence in favour of widespreada Precambrian represents the most northerly exposure of the Caledo- gneissose basement comparable with that of northern nian rocks of the southern plate. To the north, in the Scotland. Instead, studies of isolated inliers indicate SouthernUplands of Scotland, is a thick prism of thatthe pre-Caledonianbasement of the southern LowerPalaeozoic sediments with ophiolitic compo- Caledonides consists of calc-alkaline volcanics and nents thought to have been tectonically accreted onto sediments,ranging in age from c. 700 to c. 500 Ma thenorthern continental plate duringnorthward (Patchett et al. 1980; Bath 1974; Beckinsale & Thorpe subduction of an oceanic plate (Leggett et al. 1979). 1979; Thorpe et al. 1984); and it has been suggested Post CaledonianPost cover.Borrowdale volcanics. Caledonian granites. .. .. ......... Silurlan sediments. HSkiddaw slates. 0. .. FIG. 1. Simplified geological map of the English Lake District with inset of schematic tectonic map of the British Caledonides. HBF = Highland Boundary Fault; SUF = Southern Uplands Fault. Downloaded from http://pubs.geoscienceworld.org/jgs/article-pdf/142/6/1139/4888936/gsjgs.142.6.1139.pdf by guest on 30 September 2021 GranitesEnglish of the Lake District 1141 TABLE1: Published isotopic dates for the major intrusions of the Lake District Intrusion Age (Mal Age Intrusion Method "Srta6Sr 60l8 Reference Skiddaw 392 * 4 K-Ar (biotite) 5.9-9.9 Shepherd et al. (1976) Shap 393 f 3 Rb-Sr 0.7077 11.0* Wadge et al. (1976) Carrock Fell 416 f 20 Rb-Sr 0.7071 Rundle (1979) granophyre Ennerdale 420 f 4 Rb-Sr 0.7057 Rundle (1979) Eskdale 429 f 4 Rb-Sr 0.7076 10.9* Rundle (1979) Threlkeld Rb-Sr 445 f 15 0.7055 Wadge et al. (1974) Carrock Fell K-Ar 468 f .l0 (biotite) Rundle (1979) gabbro * for Shap andEskdale from Harmon & Halliday (1980). (Le Bas 1982) that these rocks evolved as a series of exposed in a broad belt in the northern Lake District, island arcs and marginal basins. Evidence of a minor they also occur in isolated inliers south of the collision at c. 600 Ma in Anglesey, possibly due to the Borrowdale volcanics, suggesting that they may also closure of a marginal basin (Wright 1976; Barber & underliethe Borrowdale group. The Borrowdale Max 1979), may represent the final consolidation of volcanics are subaerial to subaqueous calc-alkaline the southern plate, which appears to have behaved lavas and tuffs compatible with a relatively evolved coherently from Cambrian times. continental margin environment(Fitton & Hughes During the Cambro-Ordovician, the relatively 1970); they have given a Sm-Nd mineral isochron age young andprobably thin southern continentalplate of c. 457 Ma (Thirlwall & Fitton 1983), consistent with became the site of sedimentation in the Welsh Basin a stratigraphic age of Llandeilo to Caradoc (Harland et and in theLake District,where the oldest rocks al. 1982). The Skiddaw andBorrowdale Groupsare presently exposed arethe Skiddaw Group. These unconformably overlain by limestones,shales, mud- consist of more than 3 km of graptoliticmudstones stones and greywackes of Upper Caradoc and Ash7ill with subsidiary greywacke and sandstones of Arenig to age. The rocks of theLake District are at lower Upper Llanvirn age (Wadge 1978) and have been greenschist metamorphic grade (Oliver et al. 1984) and interpreted as turbiditesequences deposited in re- are only weakly deformed in contrast to the Caledo- latively deep water(Jackson 1978). Inthe northern nides of N Scotland where Moine and Dalradian rocks Lake District, the Eycott Hill volcanics, which repre- are strongly deformedat greenschist to upper sent the earliest volcanism in the area, have tholeiitic amphibolite grade. affinities (Fitton & Hughes 1970) and are regarded as Granite magmatism occurred episodically in both primitive island arc lavas possibly extruded onan provinces of the Caledonides. Inthe Lake District immature, thinned continental crust. activity apparently commenced (see Table 1 and Fig. Sediments of the Skiddaw Group weredeformed 2) with the emplacement of the Threlkeld intrusion
Load more

Recommended publications
  • RR 01 07 Lake District Report.Qxp
    A stratigraphical framework for the upper Ordovician and Lower Devonian volcanic and intrusive rocks in the English Lake District and adjacent areas Integrated Geoscience Surveys (North) Programme Research Report RR/01/07 NAVIGATION HOW TO NAVIGATE THIS DOCUMENT Bookmarks The main elements of the table of contents are bookmarked enabling direct links to be followed to the principal section headings and sub-headings, figures, plates and tables irrespective of which part of the document the user is viewing. In addition, the report contains links: from the principal section and subsection headings back to the contents page, from each reference to a figure, plate or table directly to the corresponding figure, plate or table, from each figure, plate or table caption to the first place that figure, plate or table is mentioned in the text and from each page number back to the contents page. RETURN TO CONTENTS PAGE BRITISH GEOLOGICAL SURVEY RESEARCH REPORT RR/01/07 A stratigraphical framework for the upper Ordovician and Lower Devonian volcanic and intrusive rocks in the English Lake The National Grid and other Ordnance Survey data are used with the permission of the District and adjacent areas Controller of Her Majesty’s Stationery Office. Licence No: 100017897/2004. D Millward Keywords Lake District, Lower Palaeozoic, Ordovician, Devonian, volcanic geology, intrusive rocks Front cover View over the Scafell Caldera. BGS Photo D4011. Bibliographical reference MILLWARD, D. 2004. A stratigraphical framework for the upper Ordovician and Lower Devonian volcanic and intrusive rocks in the English Lake District and adjacent areas. British Geological Survey Research Report RR/01/07 54pp.
    [Show full text]
  • ON the ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society September 2018
    ON THE ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society September 2018 The Honister Slate Mine – starting point for the field trip described on page 12 Branch Organiser’s Musings CONTENTS 1. Rick’s musings Welcome to the third newsletter of the year. So far, we have had five absolutely 2. Tina in Norway amazing field trips, and have now been to Ingleton, Knaresborough, Bowland, 4. AGM Date 5. Castleton field trip Castleton and Settle. Over the next few newsletters you will see many of the write 10. Free beer in Spain ups for these trips. 12. Blencathra – day 4 16. Editor’s piece In the last newsletter both and Ann and myself spoke of the need to charge a small 16. Field trips etc fee of £2 for each field trip. So far this year we have collected in £104.10. This, to be honest, confuses me as someone has given me 10p extra, do we treat it as a charitable donation? Or would you like a refund? Either way the £104.00 will be a valuable contribution to help run the branch. Our next trip is to Norber and Crummackdale, which was the first trip I ever attended with the OUGS. It rained torrentially all day during which I can remember both Geoff and Peter using lots of new words none of which I understood! I had to ask what a syncline was, anticline, erratic and unconformity, the list was endless, but it will always hold a special place in my heart. The forthcoming trip in September will be self-led and follow the walk based on the Ramblings of Alan Stollery.
    [Show full text]
  • Crinkle Crags Excursion: Formation of the Scafell Caldera
    Crinkle Crags Excursion: formation of the Scafell caldera Author: Clive Boulter Photos: Clive Boulter unless otherwise acknowledged Photo: Crinkle Crags LOGISTICS • Please Note: for localities 2 & 7 you may feel more comfortable with a hard hat for close examination of the layer and grain characteristics. • Start at Three Shire Stone, Wrynose Pass [NY 278027]. • The climb is a fairly steady gradient towards Crinkle Crags, leave the path to skirt the western side of the first Crinkle, and from a height of 780m drop down to Locality 1 on the side of Adam-a-Cove at 710m. • Once Locality 2 is reached there is a string of localities at around the 750m contour though the last stop is just below Long Top at 850m. The return walk to Three Shire Stone takes just over an hour. • A brief pause at Red Tarn [NY 2674 0392] on the long climb up will allow inspection of the remnants of exploratory drilling for iron ore – small fragments of kidney ore can be found on spoil tips. This is just before the path takes a sharp left turn. From here down to the small stream draining Red Tarn the path is a ruddy colour highlighting the presence of haematite vein[s] in the saddle. There is an account dated 1709 that suggests iron was mined at Red Tarn to supply a furnace in Langdale. Exploration variously dated as 1860 or 1872 records test borings and shallow workings as well as a trial in 1922. The word red turns up in many Lake District place names.
    [Show full text]
  • These Route Descriptions Are Taken from a Variety of Sources Originally Published Between 1925 and 2000, They Have Not Been Updated/Checked
    These route descriptions are taken from a variety of sources originally published between 1925 and 2000, they have not been updated/checked. Vegetation grows, holds loosen and tastes change, in particular please treat any reference to in-situ gear with extreme caution. Duddon and Eskdale New Routes and comments Lickle River Crag SD 240 941 E Page: 194 This crag lies on the River Lickle twixt Dunnerdale & Torver. It is easily reached in 10 to 15 mins walk from the farm Stephenson Ground. Tilly 25m HS/MVS 4a/4b The centre of the crag is easily identified by a whitish coloured streak. There is at half height, a yew tree to the left and an overhang area to the right. The line of climb follows a direct line up the clean central wall starting from a prominent embedded flake and finishing directly with little variation at the highest point. Note: There is scope for further development particularly in the overhang/ bulge area for those keen enough to seek out this esoteric crag. Rick Gordon, Al Blackburn17/04/2008 "First climbed in 1977 by Dave Hannah, along with a couple of other lines, but not recorded at the time. Stonestar Crag Page: 196 The approach: Not obvious in summer when the bracken is high! To the right of parking area is an old iron fence. A good footpath starts here and leads up to below the crag. Ppi Cuppa 12m VD* The rib to the left of Patagonian Penguin gives a pleasant well-protected pitch. Make a hard start by gaining the front face of the 3 metre pinnacle from the left and climb to its top.
    [Show full text]
  • Radiohalos in the Shap Granite, Lake District, England: Evidence That Removes Objections to Flood Geology
    Answers in Depth, Vol. 4, (2009), Aug. 26, 2009. https://assets.answersingenesis.org/doc/articles/aid/v4/radiohalos-shap-granite.pdf Radiohalos in the Shap Granite, Lake District, England: Evidence that Removes Objections to Flood Geology Andrew A. Snelling, Ph.D., Answers in Genesis This paper was originally published in the Proceedings of the Sixth International Conference on Creationism, pp. 389–405 (2008) and is reproduced here with the permission of the Creation Science Fellowship of Pittsburgh (www.csfpittsburgh. org) and the Institute for Creation Research, Dallas. Abstract The Shap Granite in the Lake District of northern England intruded the surrounding host rocks as a magma that released hydrothermal fl uids as it crystallized and cooled. These hot fl uids in turn produced an atypically wide contact metamorphic and metasomatic aureole around the intrusion. There is no evidence at the boundary for tectonic emplacement of a primordial cold granite body. This study documents an abundance of Po radiohalos in the Shap Granite. These Po radiohalos had to have been produced in the granite after the hydrothermal fl uids released in the granite had assisted in the formation of the granite’s distinctive orthoclase feldspar megacrysts, and after the crystallized granite had subsequently cooled below the 150 °C annealing temperature of radiohalos. The abundance of Po radiohalos is consistent with the hydrothermal fl uid transport model for Po radiohalo formation and with catastrophically rapid granite formation. These features imply that the Shap Granite formed in 6–10 days and its Po radiohalos within hours to days once the granite cooled below 150 °C.
    [Show full text]
  • The Geology and Petrology of the Ennerdale
    THE GEOLOGY AND PETROLOGY OF THE ENNERDALE GRANOPHYRE. ITS__ METAMORPHIC AUREOLE __AND ASSOCIATED MINERALIZATION A Thesis presented for the Degree of Doctor of Philosophy by Lewis Clark. Department of Geology, The University of Leeds. June, 1963. a b s t r a c t The E n n e r d a l e G r a n o p h y r e occurs in the Latte District between Buttermere and Wasdale. It is a stocK shaped, composite intrusion which was emplaced at the close of the Caledonian earth movements. The country rocks of the granophyre are the Borrowdale Volcanic Series and the Skiddaw Slates. The oldest rocks in the Ennerdale Granophyre are a series of dioritic rocks which have been largely metasomatised by the later granophyre magma into a series of granodioritic hybrids. Eighty percent of the outcrop of the Ennerdale Granophyre is occupied by a fine grained granophyre, the Main Granophyre. The youngest rocks associated with the granophyre: are a series of fine aplitic microgranites and rhyolitic felsites. Metamorphism by the granophyre has been very slight. The main changes in the Skiddaw Slates are a change in colour and an increase in hardness, but the slates in places in Ennerda.le have been soda—metasomatised. Macroscopic changes in the Berrowdale /olcanic Series are negligible, but there have been important mineralogicalL changes within a narrow aureole adjacent to the granophyre. ACKNOWLEDGEMENTS This research was made possible by the award of a D.S.I.R. Research Studentship. I am extremely grateful to the Department of Scientific and Industrial Research and Professor W.
    [Show full text]
  • Bothy Welcome Folder
    Welcome to Woodend We welcome you to your stay at Woodend and hope it will be a memorable one. Please bear in mind that we are situated within a working sheep and cattle farm. Other than the field that we own (further information on Page 5 and 24), the farm fields are out of bounds to guests and dogs. If you haven’t yet found our website, then please check it out at www.woodendhouse.co.uk as there is useful information on things to do in the area. Please read the notes which follow - they're important and we hope you'll find them useful and informative. We pride ourselves in combining comfortable and cosy accommodation within a quiet relaxing environment and we aim to provide everything you are likely to need for your stay. If you have any problems during your stay then we will try our best to resolve them but please remember, we can only help if you ask, so please don’t put up with something that you are unhappy with and only tell us on your return home! The origins of Woodend go back to the 16th century and being located high on Birker Fell you have incredible views, (weather permitting), towards Scafell Pike, Crinkle Craggs and Bowfell. We hope that you enjoy your break and will return. Paul and Jella The Schoolhouse - Woodend Page 1 Contents General Parking 4 Garden Room 6 Information Laundry 4 Rubbish & Recycling 7 Smoking 4 Pets 9 Walking 4 Breakages & Damage 10 Services Gas 10 Bulbs and Batteries 18 Gas Cooker 10 Telephone 18 Dishwasher 11 Outside Lights 19 Log Burning Stove 12 Television 19 Logs 13 Sky Remote 20 Heating 13 Fuse
    [Show full text]
  • Harter Fell [Duddon Valley]
    Harter Fell [Duddon Valley] Cumberland Geological Society Photo from Muncaster Fell Field Meeting 18.05.2019 highlighting the contrast Leader: Clive Boulter between the andesite lava flows and the stratified rocks. Locality Map Meet at Birks Bridge, Forestry Commission parking area. SD 2350 9955 10h00 start. Base map from N Ordnance Survey OpenData. Kilometre grid. Background Information on geology seen at Brandy Crag [Location 1] This excursion is entirely within the Birker Fell Formation which dominates the lowermost part of the Borrowdale Volcanic Group. The unit is up to 2700 m thick and about 60% is andesite lava flows [plus sills] but it also contains basalt, basaltic andesite, and dacite lava flows as well as pyroclastics [ignimbrites and airfall tuff] and reworked material [fluviatile and lacustrine]. Classic images of volcanic cones should be side-lined as this assemblage formed a low-profile plateau volcanic field mainly fed by fissure eruptions. The andesite lava flows are normally tens of metres thick but individual flows can be 200 m thick. Most flows can be traced for no more than five kilometres. The typical flow has blocky autobrecciated margins and on the upper flow surface the cavities between fragments became infilled with sediment either washed in as pyroclastics were reworked or settled in from air-fall pyroclastic events. An overall extensional setting is the only way such a thick pile of subaerial volcanic material can accumulate and be preserved. Convergent tectonics, such as subduction at a continental margin, readily provide such opportunities as most arc systems are in tension [slab roll-back]. The main focus for the field meeting is the two prominent felsic marker horizons within this otherwise monotonous pile of andesites and derived materials.
    [Show full text]
  • ON the ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society June 2019
    ON THE ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society June 2019 The cliff at Fleswick, St Bees Head, Cumbria, looking southeast. The cliffs are St Bees Sandstone, which are Early Triassic (approx. 250Ma). BGS describe the cliff composition as sheetflood sandstone (60%), playa mudflat (30%) and minor channel sandstones (10%). There are many examples of the interesting erosional patterns on the beach and under the cliff. More information can be found on the West Cumberland Mining Factsheet here. (Peter Roberts 19.3.18 Grid Ref: NX945133) Editor’s piece Welcome to the latest newsletter. I’m afraid that for personal reasons there is no CONTENTS Branch Organiser’s Musings this time, but Rick is hoping to let us have members’ thoughts on the future of the Branch and possible amalgamation with North East 1. Editor’s piece Branch shortly. If you have not let him have yours yet, there is still time to email him. 2. Blencathra Day 2 5. Day out at Royston We have a report on Day 2 of last year’s Blencathra trip by Helen Cuffe and Day 4 by 8. Blencathra Day 4 Earl Howarth, while Tony Felski offers the New Monckton Collieries spoil heap at 11. Branch field trips Royston near Barnsley as a suitable day out for anyone with children or grandchildren. 12. Your committee Thank you to them and to Peter Roberts for the stunning photo above. On page 11 is a list of this year’s Branch field trips which will include some from Alan Stollery’s Ramblings which were mentioned in the March newsletter.
    [Show full text]
  • Radiohalos in the Shap Granite, Lake District, England: Evidence That Removes Objections to Flood Geology
    The Proceedings of the International Conference on Creationism Volume 6 Print Reference: Pages 389-405 Article 33 2008 Radiohalos in the Shap Granite, Lake District, England: Evidence that Removes Objections to Flood Geology Andrew A. Snelling Answers in Genesis Follow this and additional works at: https://digitalcommons.cedarville.edu/icc_proceedings DigitalCommons@Cedarville provides a publication platform for fully open access journals, which means that all articles are available on the Internet to all users immediately upon publication. However, the opinions and sentiments expressed by the authors of articles published in our journals do not necessarily indicate the endorsement or reflect the views of DigitalCommons@Cedarville, the Centennial Library, or Cedarville University and its employees. The authors are solely responsible for the content of their work. Please address questions to [email protected]. Browse the contents of this volume of The Proceedings of the International Conference on Creationism. Recommended Citation Snelling, Andrew A. (2008) "Radiohalos in the Shap Granite, Lake District, England: Evidence that Removes Objections to Flood Geology," The Proceedings of the International Conference on Creationism: Vol. 6 , Article 33. Available at: https://digitalcommons.cedarville.edu/icc_proceedings/vol6/iss1/33 In A. A. Snelling (Ed.) (2008). Proceedings of the Sixth International Conference on Creationism (pp. 389–405). Pittsburgh, PA: Creation Science Fellowship and Dallas, TX: Institute for Creation Research. Radiohalos in the Shap Granite, Lake District, England: Evidence that Removes Objections to Flood Geology Andrew A. Snelling, Ph.D., Director of Research, Answers in Genesis, P. O. Box 510, Hebron, KY, 41048 Abstract The Shap Granite in the Lake District of northern England intruded the surrounding host rocks as a magma that released hydrothermal fluids as it crystallized and cooled.
    [Show full text]
  • Three Shire Stone to Side Pike [The Langdale Caldera]
    Three Shire Stone to Side Pike [The Langdale Caldera] A reassessment of the Side Pike Complex concept. Cumberland Geological Society Excursion Saturday July 7th 2018 Meet at 10h00 at Three Shire Stone NY 2770 0273 [arrangements need to be made to leave some cars at Side Pike to take drivers back to vehicles] INTRODUCTION Initially the excursion route will take us through familiar stratigraphy from the Birker Fell Formation andesites into the two components of the Whorneyside Formation: the lower Wet Side Edge Member [andesitic welded ignimbrite] and the upper bedded tuff [air fall deposits from a gigantic phreatoplinian eruption]. We then move into uncharted territory where, in the 1980s/1990s resurvey, the deposits in a 5 km2 area could not be tied into the regional stratigraphy and the notion of the Side Pike Complex was introduced [Branney 1988]. It was believed that the differences between this small area and its surrounds were created when flank failure of the volcanic edifice led to blocks, 100s of metres to around a kilometre in size, sliding in from parts of the stratigraphy no longer exposed. The blocks in this megabreccia were considered to be exotic. However, very detailed work on part of the established stratigraphy of the Scafell Caldera was extended to the excursion area with dramatic consequences for the stratigraphy of the Borrowdale volcanics and its volcanological model [Brown 2001]. At Excursion Stop 4, within the Side Pike Complex, five metres of stratigraphy are so distinctive that Brown [2001] could identify them as being part of the uppermost Seathwaite Fell Formation which is the sedimentary infill of the Scafell Caldera.
    [Show full text]
  • The Lower Palaeozoic Igneous Rocks and Quaternary Deposits of the Area Between Haweswater and Shap (Part of Sheets 30 and 39, England and Wales)
    The Lower Palaeozoic igneous rocks and Quaternary deposits of the area between Haweswater and Shap (part of Sheets 30 and 39, England and Wales) Integrated Geoscience Surveys (North) Research Report RR/02/02 NATURAL ENVIRONMENT RESEARCH COUNCIL BRITISH GEOLOGICAL SURVEY Research Report RR/02/02 The Lower Palaeozoic igneous rocks and Quaternary deposits of the area between Haweswater and Shap (part of Sheets 30 and 39, England and Wales) The National Grid and other Ordnance Survey data are used D Millward with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number GD 272191/2003. Cover illustration Haweswater and Harter Fell. Bibliographical reference MILLWARD, D. 2003. The Lower Palaeozoic igneous rocks and Quaternary deposits of the area between Haweswater and Shap (part of Sheets 30 and 39, England and Wales). British Geological Survey Research Report, RR/02/02. 48 pp. ISBN 0 85272 418 7 Copyright in materials derived from the British Geological Survey's work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining NERC permis- sion. Contact the BGS Copyright Manager, Keyworth, Nottingham. You may quote extracts of a reasonable length without prior permission, provided a full acknowledge- ment is given of the source of the extract. © NERC 2003. All rights reserved Keyworth, Nottingham British Geological Survey 2003 BRITISH GEOLOGICAL SURVEY ACKNOWLEDGEMENTS The full range of Survey publications is available from the BGS The farmers, landowners and the Lake District National Park Sales Desks at Nottingham, Edinburgh and London; see contact are thanked for their co-operation and assistance during the details below or shop online at www.geologyshop.com survey.
    [Show full text]