sign in sign up
<<
Home , Baltica, Pannotia, Rheic Ocean, Rodinia

Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Pannotia to : and Orogenic Cycles in the Circum-Atlantic : A celebration of the career of Damian Nance

J. Brendan Murphy1,2*, Robin A. Strachan3 and Cecilio Quesada4 1Department of Sciences, St Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada 2Earth Dynamics Research Group, the Institute for Geoscience Research (TIGeR), School of Earth and Planetary Sciences, Curtin University, WA 6845, 3School of the Environment, Geography and Geosciences, University of Portsmouth, Portsmouth PO1 3QL, UK 4Instituto Geológico y Minero de España (IGME), C/Ríos Rosas, 23, 28003 Madrid, Spain JBM, 0000-0003-2269-1976 *Correspondence: [email protected]

Special Publication 503 celebrates the career of between tectonic events and biogeochemical cycles, R. Damian Nance. It features 27 articles, with more as exemplified in the late Neoproterozoic–Early than 110 authors based in 18 different countries. by the amalgamation of span- The wide range of topics presented in this volume ning a time interval characterized by dramatic climate mirrors the breadth and depth of Damian’s contribu- swings, profound changes in the chemistry of the tions, interests and expertise. Like Damian’s papers, and atmosphere, and the of multi- the contributions range from the predominantly con- cellular animals (see Hoffman 1991; Hoffman et al. ceptual to detailed field work, but all are targeted at 1998; Narbonne 2010; Knoll 2013). understanding important tectonic processes. Their As reconstructions became more refined, scope not only varies in scale from global to regional several authors proposed that Gondwana was part to local, but also in the range of approaches required of a larger entity called that included Lau- to gain that understanding. Thus, there are contribu- rentia, and possibly (e.g. Stump tions on the processes responsible for the formation 1987; Dalziel 1997). Recent syntheses have con- and breakup of , the controversial tested the status of Pannotia as an super- amalgamation of Pannotia, the generation and continent because of its small size relative to destruction of Paleozoic oceans, and the development Pangaea (about half) and limited duration (it was of the Appalachian–Ouachitan–Caledonide–Varis- probably breaking up in its centre as can orogens (Fig. 1). In addition to field work, the were colliding with its margins). , which approaches to gain that understanding include exam- amalgamated during global-scale c. 1.1–0.9 Ga oro- ining the relationships between stratigraphy and genesis, is arguably the most widely accepted of the structural geology, precise geochronology, geo- pre-Pangaean supercontinents (McMenamin and chemical and isotopic fingerprinting, geodynamic McMenamin 1990; Li et al. 2008). Many syntheses modelling, regional syntheses, palaeogeographic claim that the transition from Rodinia to Pangaea modelling, and plain, old-fashioned arm-waving! represents a single cycle (e.g. Li et al. 2019). Resolution of the ‘Pannotia contro- versy’ is fundamental to understanding the supercon- The Pannotia controversy tinent cycle. If the transition from Rodinia to Pangaea represents a single , When Damian with Tom Worsley and Judith Moody then Pangaea probably formed by extroversion, i.e. proposed the existence of a supercontinent cycle with predominantlysubductionof the exterior oceansystem a series of papers in the 1980s (Nance et al. 1986; that surrounded Rodinia (Li et al. 2019). In contrast, Moody et al. 1988), the amalgamation of Gondwana Murphy and Nance (2008) maintain that Pannotia in the Neoproterozoic, as evidenced by the collisional formed by the amalgamation of the exterior to Pan-African orogenic events, was arguably their best Rodinia (extroversion), but that Pangaea was formed defined pre-Pangaean supercontinent. These early from Pannotia by closure of the interior Iapetus and publications examined the potential relationship Rheic oceans (introversion).

From: Murphy, J. B., Strachan, R. A. and Quesada, C. (eds) 2020. Pannotia to Pangaea: Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region. Geological Society, London, Special Publications, 503, https://doi.org/10.1144/SP503-2020-213 © 2020 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

J. B. Murphy et al.

Gondwanan margin beginning at c. 0.6 Ga. Candi- dates for plume magmatism are identified that require testing by detailed field, geochemical and isotopic studies. Heron et al. (2020) present 3-D global convec- tion models showing increased core–mantle heat flux during the convergence that led to Pan-African collisions and amalgamation of Pannotia. This heat flux is similar in magnitude to that associated with convergence and assembly of Rodinia and Pangaea, implying that Pannotia assembly may have impacted mantle circulation patterns in a similar manner. Evans (2020) argues against the existence of Pannotia as a landmass, claiming that its existence is not supported by either the geological record or indirect proxies (e.g. biological diversity, palaeo- climate, sea-level, magmatism and palaeoenviron- mental indicators). Evans does agree with Murphy Fig. 1. Palaeocontinental reconstruction (c. 500 Ma; at al. and Heron et al. that the assembly of Gondwana after Domeier 2016) showing the relative locations of was probably a geodynamically significant event on the contributions to this volume. Events in many of the a global scale and merits the status of ‘semi- papers span a considerable duration of time, or may supercontinent’ (see Evans et al. 2016). deviate in time from c. 500 Ma so that the location et al. shown on this map is not necessarily intended to Kroner (2020) test the hypothesis of a provide a geological context for tectonic events Pannotian supercontinent by combining geological documented in the papers. Papers 1–4 (Murphy et al., and palaeogeographical constraints from different Heron et al., Evans and Kroner et al.) are global studies . They reconstruct the Paleozoic kinematics and their locations are not shown. 5, Hoffman; 6, van of , Gondwana, Siberia and the peri- Staal et al.; 7, Arenas et al.; 8, Lindner et al.; 9, Errami Gondwanan relative to the East European et al.; 10, Andresen; 11, Dalslåen et al.; 12, Slagstad (including Baltica). Their approach is to et al.; 13, Walker et al.; 14, McConnell et al.; 15, ‘back-rotate’ from a Pangaea-A configuration to Archibald and Murphy; 16, Schofield et al.; 17, Dostal et al.; 18, Hildebrand and Whalen; 19, Piper and accommodate the Paleozoic opening of the Iapetus, Pe-Piper; 20, Park and Hinds; 21, Dennis, 22., Rheic and Paleo-Arctic oceans. These back rotations Juárez-Zúñiga et al.; 23, Álvaro et al.; 24, Sánchez achieve a Pannotia configuration, thus supporting Martinez et al.; 25, Gutiérrez-Alonso et al.; 26, their interpretation of its status as a supercontinent Paslawski et al.; 27, Pereira et al. Abbreviations: FA, and indicating that the transition from Rodinia to Pan- Famatina; MX, Mexico; CA, Carolinia; WA, West gaea represents two complete supercontinent cycles. ; EA, East Avalonia; IB, Iberia; AM, They also identify two fundamental phases of Iapetus Armorica; CH, Clew Bay-Highland Border; MV, Ocean opening and closure. Midland Valley–South Mayo; DW, Dashwoods; LB, Lushes Bight; PI, Eastern ; CU, . Regional Neoproterozoic tectonics In this volume, four papers (Murphy et al., Heron et al., Evans and Kroner et al.) tackle the con- The Neoproterozoic Era was characterized by colli- troversial status of Pannotia as an Ediacaran super- sional (Pan-African) orogenic belts as Gondwana continent. Murphy et al. (2020) point out that an amalgamated, and by -related orogenesis over-arching question is whether the assembly of along its periphery. In the Pan-African collisional the Gondwanan portion of Pannotia influenced belt of Namibia, Hoffman (2020) describes the global-scale mantle convection patterns (Nance and stratigraphic and structural record of a lithospheric Murphy 2019; Pastor-Galán et al. 2019). Such pat- cusp (or syntaxis). Such cusps (where arcs are terns, if they existed, must be factored into models joined end-to-end) are features of modern arc sys- for the amalgamation of Pangaea. Deducing the tems, associated with the buckling of subducted mantle legacy (mantle convection patterns) of Pan- slabs, but are rarely identified in the geological notia’s amalgamation is fundamental to resolving record. Hoffman describes a potential cusp where this controversy. Murphy et al. propose a testable sce- the Kaoko belt and the Damara orogen meet at nario involving feedback between the supercontinent right angles. In the vicinity of the hypothesized cycle and global mantle convection patterns. This cusp, the regional stratigraphy dominated by marine predicts upwellings beneath the Gondwanan portion carbonates was uplifted to form a megakarst - of Pannotia and the arrival of plumes along the entire scape with associated mass slides and was then Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region rapidly buried by foredeep syn-orogenic deposits. supra-subduction zone geochemical signatures. The Abrupt drowning of the carbonate platform and bur- oldest known ophiolite (the c. 697 Ma Bou Azzer ial by foredeep deposits is interpreted to reflect lith- ophiolite) occurs in the Anti-Atlas Mountains, and ospheric flexure and aborted subduction beneath the the remainder are exposed in Iberia. Arenas et al. promontory of the . The timing of attribute the c. 100 Ma time intervals to cyclic events these events suggests that they occurred about of mantle upwelling, possibly related to episodic 50 myr before terminal Pan-African collision. deep mantle convection patterns. As Gondwana amalgamated, subduction zones Lindner et al. (2020) present new U–Pb and between the colliding blocks were expunged and geochemical data from a region in the eastern Bohe- arc magmatism became established along much of mian massif that preserves an unusually protracted Gondwana’s periphery producing orogens character- Neoproterozoic history. These rocks include orthog- ized by a diverse collage of arcs and back-arc basins. neisses which are rare examples of For nearly 35 (e.g. Nance 1986a; Nance et al. , paragneisses which preserve evidence of an 1991, 2002, 2008, 2012), one focus of Damian’s early Neoproterozoic platformal sequence, and late research has been the evolution of the ‘peri- Neoproterozoic volcanic-arc granitoids typical of Gondwanan’ terranes that were distributed along Avalonia. U–Pb age data from orthogneiss and para- the northern margin of Gondwana in the late Neopro- gneiss yield ages that can be readily correlated with terozoic and early Paleozoic. This volume has sev- rock units in West Amazonia such as the Rondonia– eral contributions from these terranes. San Ignácio (1.55–1.3 Ga) and Sunsás (1.3–1.1 Ga) van Staal et al. (2020) propose a model to explain tectonic provinces. Their interpretation supports pre- the Neoproterozoic–Early Cambrian evolution of vious studies that proposed Amazonian affinities West Avalonia. Obduction of the c. 760 Burin ophio- (e.g. Friedl et al. 2000; Keppie et al. 2008a, 2012; lite of SE Newfoundland (Krogh et al.1988; Murphy Nance et al. 2009) as well as models for along- et al. 2008) onto a continental ribbon before 750 Ma margin transport (Fernández-Suárez et al. (compare Henderson et al. 2016) was followed by sev- 2002; Linnemann et al. 2012; Nance et al. 2012) eral pulses of island arc magmatism, including the from Amazonia to positions outboard of the West main phase between c. 640 and 565 Ma. Most recon- African craton. structions for the peri-Gondwanan terranes during Recently published geochemical and geochrono- this main phase (including papers in this volume) posi- logical data have provided new insights into the tion them along the northern Gondwanan margin out- genetic relationship between the Anti-Atlas of board of Amazonia, West and the Saharan Morocco and the Variscan massifs of continental metacraton. According to the van Staal et al. model, . Errami et al. (2020) provide new U–Pb however, West Avalonia and were posi- detrital and magmatic zircon ages from late Edia- tioned at this time on opposite sides of a shrinking caran stratigraphic successions in the Eastern Saghro (Puncoviscana) ocean with oppositely verging sub- massif of the Anti-Atlas Mountains. The detrital age duction zones. In the late Ediacaran, West Avalonia populations can be assigned to Neoproterozoic tecto- accreted to Amazonia in a position that was outboard nothermal events in peri-Gondwanan terranes and to ofGanderia but along-strike from East Avalonia. Mag- input from nearby Eburnian (c. 2.1 Ga) . matism was terminated by strike-slip activity that shuf- Deformation of the Saghro Group reflects closure fledtheperi-Gondwananterranes alongthecontinental of a back-arc basin prior to intrusion of 603 Ma margin prior to the diachronous opening of the Rheic granitoid bodies and is attributed to Pan-African Ocean beginning at c. 500 Ma during which Avalonia transpressive collision that had finished by and Ganderia separated from the Gondwana (e.g. c. 600 Ma. This sequence was followed by deposi- Nance and Linnemann 2008; van Staal et al. 2012). tion of the M’gouna and Ouarzazate groups in a The geology of the peri-Gondwanan terranes transtensional regime (Thomas et al. 2002) related dominates many of the Variscan massifs of conti- to the c. 570 Ma onset of Cadomian subduction. nental Europe. These massifs preserve a complex evolution of arc-related orogenesis in the late Neo- and early Paleozoic that was overprinted Caledonides in the late Paleozoic by tectonothermal events asso- ciated with the amalgamation of Pangaea. Arenas The breakup of Pannotia from c. 615 Ma onwards et al. (2020) maintain that the Neoproterozoic to occurred as Laurentia, Gondwana and Baltica rifted evolution of Gondwana’s West African– from each other to form the (Tegner Iberia margin includes the generation and emplace- et al. 2019 and references therein). The ocean wid- ment of ophiolite sequences at c. 100 myr intervals ened until the Late Cambrian, and then started to between 700 and 400 Ma. During much of this close following the initiation of east-dipping sub- time interval, this portion of the northern Gond- duction zones (present reference frame) close to the wanan margin was active and all ophiolites have margin of Laurentia (Cocks and Torsvik 2006). Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

J. B. Murphy et al.

Accretion of magmatic arcs to the margin of Lauren- (2020) utilize the Lu–Hf and Sm–Nd dating of meta- tia during the Early to Mid- was followed morphic garnets to similarly demonstrate multiple by development of a west-dipping subduction sys- Neoproterozoic and Ordovician tectonic events tem and further closure of Iapetus (Dewey and prior to Scandian thrusting and debate the possible Ryan 1990). Avalonia rifted from Gondwana in significance of the transcurrent Walls Boundary the Early Ordovician and collided with Baltica in Fault. Understanding the Neoproterozoic evolution the Late Ordovician (Fortey and Cocks 2003). The of the eastern Laurentian margin represents a composite continent then converged obliquely with continuing challenge. Laurentia through the (Soper et al. 1992). McConnell et al. (2020) demonstrate that in the The culminating Mid to Late Silurian Scandian orog- Irish sector of the Iapetus Ocean, subduction of eny formed the Caledonides, exposed in Scandina- oceanic lithosphere continued under both the Lau- via, Greenland, Britain and Ireland. rentian and Ganderian continental margins until Andresen (2020) provides a new interpretation final ocean closure in Wenlock time. There is there- of the relatively poorly known Late Ordovician con- fore a single in Ireland, in contrast to the east- vergence zone between Baltica and Avalonia, based ern Appalachians where separate Ordovician and on structural mapping and published detrital zircon Silurian sutures are recognized (van Staal et al. studies in the Hardangervidda region of central 2009). Emplacement of the late Caledonian Silu- south Norway. It is argued that a thin-skinned thrust rian–Devonian ‘Newer ’ suite of Scotland belt developed owing to underthrusting of Baltica and Ireland followed closure of the Iapetus Ocean. beneath Avalonia, and that whereas Cambrian strata These granitoid rocks have been interpreted to reflect were derived from Baltica sources, Middle to Late slab breakoff (also known as slab failure) in the latest Ordovician sedimentary rocks have a Gondwanan stages or immediately after the Scandian provenance. Docking of these two continents was (Atherton and Ghani 2002). The Donegal composite not therefore ‘soft’ (Torsvik and Rehnstrøm 2003) batholith in NW Ireland is a classic composite but affected a large area of SW Baltica both structur- batholith of late Caledonian (430–400 Ma) age that ally and sedimentologically. intruded the Neoproterozoic Dalradian Supergroup. The Norwegian–Swedish sector of the Caledo- Archibald and Murphy (2020) present a synthesis nides contains a cross-section from the Baltica of new lithogeochemical data from individual plu- foreland structurally upwards and westwards into tons to determine their tectonic setting using recently para-autochthonous thrust sheets, Iapetan oceanic published tectonic discrimination diagrams designed terranes and continental allochthons thought to have to detect slab failure granites (e.g. Whalen and Hilde- been derived from Laurentia (Stephens and Gee brand 2019). They show that its geochemical and 1985). A common theme in recent publications has isotopic features are compatible with post-collisional been the increased tectonic complexity now recog- slab failure followed by upwelling of asthenosphere nized within this framework. Dalslåen et al. (2020) which melted the subcontinental lithospheric mantle document the Early to Middle Ordovician and/or the base of the crust to generate the magmas Trolhøtta–Kinna basin within the Trondheim Nappe that formed the batholith. Complex of western Norway. The alternating silici- In NW Wales, the island of Anglesey consists of clastic and bimodal volcanic rocks are interpreted to a collage of allochthonous terranes, collectively have accumulated in a marginal basin that probably termed the ‘Monian Composite Terrane’ (Gibbons developed along the margin of Laurentia or an asso- and Horák 1990), that was assembled along strike- ciated microcontinent. The distinctive, highly slip faults in the Early Ordovician. These rocks dis- enriched geochemistry is inferred to result from melt- play many similarities with peri-Gondwanan ter- ing of a heterogeneous mantle source that had been ranes of the northern Appalachians (Waldron et al. previously metasomatized by continental material. 2014, 2019; Schofield et al. 2016). Schofield et al. Slagstad et al. (2020) investigate the Rödingsfjället (2020) provide a synthesis of this complex geology Nappe Complex, an exotic continental unit in western that includes late Neoproterozoic accretionary com- Norway. Their data reveal a complex late Neoproter- plexes and Cambrian -related continental margin ozoic to Ordovician tectono-magmatic history, strata with a West African provenance and thought consistent with either a peri-Laurentian or peri-Gond- be part of Megumia (Waldron et al. 2011), which wanan parentage. They hypothesize that superconti- is only unequivocally exposed in mainland Nova nent fragmentation in the Neoproterozoic probably Scotia (see also Braid et al. 2012; Nance et al. resulted in numerous, coeval active margins, produc- 2015). Early Ordovician (Monian) deformation is ing a variety of peri-continental terranes. Along- the dominant map-scale structural feature of Angle- strike to the SW, the Caledonides of Shetland, Scot- sey, and its potential relationship with the coeval land, comprise polydeformed Laurentian metasedi- Penobscottian orogeny of New England is discussed. mentary rocks and associated meta-igneous rocks, A Floian overstep sequence was followed by contin- overlain by an Ordovician ophiolite. Walker et al. ued subsidence until collision with Laurentia in the Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region

Late Silurian, which resulted in SSE-verging folding In his many years of field work in Maritime Can- and thrusting. ada, Damian and his students spent a lot of time try- ing to understand the evolution of the Minas Fault Zone, which defines the boundary between the Ava- Appalachians–Mexico lon and Meguma terranes and is exposed primarily in mainland Nova Scotia and southern New Brunswick. After completion of his PhD, Damian cut his teeth on We have two updated syntheses from regions Appalachian geology with several field campaigns in affected by the Minas Fault Zone, the Cobequid southern New Brunswick in the 1970s, and in the Highlands of Nova Scotia and the southern coastal Cobequid Highlands of mainland Nova Scotia in sections of New Brunswick. Piper and Pe-Piper the 1980s. In the late 1990s he was lured by Duncan (2020) point out that the Cobequid Highlands lie at Keppie to southern Mexico to work on the Acatlán the intersection of NE–SW and east–west major Complex, which is an inlier of Paleozoic rocks intra-continental shear systems. The NE–SW system with an outcrop area the size of Massachusetts (e.g. was probably initiated in the late Neoproterozoic and Ortega-Gutiérrez et al. 1999). By linking its develop- guided the emplacement of bimodal plutons in the ment to that of the , the Paleo-Pacific Late Devonian–Early . The east–west and the Gulf of Mexico (Nance et al. 2006; Keppie Minas Fault Zone formed in the Late Carboniferous et al. 2008b), his research provided genetic linkages as a response to collision between Africa and Lau- between the Acatlán Complex and Appalachian rentia. The ages and changing style of the earlier geology as well as with the assembly and breakup Late Devonian–Early Carboniferous deformational of Pangaea. It is appropriate that this special publica- events are documented by the U–Pb crystallization tion has contributions from each of these regions. ages of synkinematic plutons and for the Late Car- Dostal et al. (2020) present new geochemical boniferous–Early Permian events by biostratigraphic data from felsic rocks in the Uppermost Silurian– studies of syntectonic strata as well as by dated igne- Lower Devonian Tobique Group in northern New ous rocks and minerals in faults and veins. Brunswick, Canada. These rocks are part of a bimo- In 1986, Damian proposed that the Late Carbon- dal sequence that oversteps the boundaries between iferous tectonostratigraphic evolution of southern peri-Gondwanan terranes accreted to composite Lau- New Brunswick could be explained by the develop- rentia as the Iapetus Ocean closed. Previous work ment of a positive flower structure during dextral (e.g. Dostal et al. 2016) shows that the mafic rocks transpressive motion of the relative are continental tholeiites. The felsic rocks have geo- to the Avalon terrane (Nance 1986b). Park and chemical characteristics typical of post-collisional Hinds (2020) present a detailed regional strati- and extensional A2-type granites (Eby 1992) gener- graphic and structural analysis, integrated with ated by crustal anatexis. The authors attribute the recent geochronology, that verifies this overall rapid transition from compressional to extensional model. Additionally, they find evidence for three magmatism to reflect a slab breakoff event in the major transpressive flower structures that developed aftermath of the accretion of Ganderia to Laurentia. diachronously, as well as for kinematic linkages of In recent years, a consensus model for the these flower structures with regional fault systems. Upper Ordovician Taconic Orogeny in New England They present an integrated model that explains the and western New York involves development origin of these structures from the perspective of a of a Lower–Middle Ordovician island arc over an regional dextral strike-slip regime. eastward-dipping subduction zone, its accretion to Dennis et al. (2020) describe for the first time the Laurentia at c. 470 Ma, and then a subduction polar- origin and setting of the youngest rocks in the Appa- ity flip which produced Upper Ordovician arc mag- lachians of wholly Gondwanan origin. They identify matism beneath the amalgamated continental sedimentary successions in the margin. However, some features that are expected which they assign to both upper-plate and lower- outcomes of this model (Early Ordovician deforma- plate asymmetric fragments that tion, foreland basin development and tuffs deposited rifted from Gondwana in the Late Cambrian when on the Laurentian carbonate platform) are notably the Rheic Ocean formed. The upper plate succession absent (Karabinos et al. 2017). In an attempt to consists of 1–2 km thick Middle Cambrian - resolve these issues, Hildebrand and Whalen bearing mudstones whereas the lower plate succes- (2020) show that the post-Taconic igneous rocks sion is dominated by clastic rocks with western Ama- have compositions typical of a post-collisional slab zonian detritus that overlies Carolinian volcanic failure setting, obviating the need for a post-Taconic arc basement. west-dipping subduction zone. In this model, the The late Paleozoic evolution of southern Mexico Late Ordovician Taconic orogeny is the result of is critical to our understanding of late Paleozoic– an arc–continent collision above an east-dipping early Mesozoic palaeogeography along the western subduction zone followed by slab failure. margin of Pangaea during its amalgamation. Late Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

J. B. Murphy et al.

Paleozoic sequences have been variously interpreted new U–Pb zircon ages (498–492 Ma) from orthog- to reflect subduction of Rheic Ocean lithosphere neiss and metagabbro of the Vila de Cruces ophiolite prior to Pangaea amalgamation (Ortega-Gutiérrez (NW Iberia). They also present data from two differ- et al. 2018) or subduction of Proto-Pacific oceanic ent metagabbro samples containing scattered zircon lithosphere after amalgamation (Keppie et al. grains with an average age of c. 1150 Ma, interpreted 2008b; Nance et al. 2010). Juárez-Zúñiga et al. as xenocrysts included in the gabbro during its ascent (2020) provide new petrographic and U–Pb–Hf (zir- along the Gondwana margin. The authors conclude con) analyses of felsic to intermediate volcanic peb- that an unexposed Mesoproterozoic basement bles in a conglomerate from the Matzitzi Formation, might have existed in this part of the Gondwanan whose provenance constrains this palaeogeography margin and the protolith of the Vila de Cruces ophio- (Centeno-García et al. 2009). The pebbles are attrib- lite formed as a section of oceanic or transitional uted to erosion of a Permian arc that was probably lithosphere in a back-arc setting. Álvaro et al. itself emplaced over Mesoproterozoic (Oaxaquia) (2020) present a palaeogeographic restoration of basement along the margins of the Proto-Pacific the southwestern European margin of Gondwana Ocean. during Cambrian–Ordovician time. The reconstruc- tion relies on the relative positions of Variscan tectonostratigraphic units as indicated by four palae- Variscides ogeographic proximal-to-distal transects, which per- mit recognition of: (1) a Furongian (Toledanian or The Variscan belt in Europe and NW Africa repre- ‘lacaune normande’) breakup unconformity (Ossa- sents the eastern extremity of the broad Ouachita– Morena/North-Armorican and Central Iberian/ Alleghanian–Variscan orogenic system that formed Central-Armorican belts and (2) a Mid–Ordovician by closure of the Rheic Ocean and led to the amal- (Sardic) unconformity across the Occitan and Pyre- gamation of Pangaea via the progressive collision nean Domains and SW Sardinia. In support of their of north Gondwana with the southern outer margin model, the authors also report similar palaeogeo- of Laurussia (Nance et al. 2010). Gondwana–Laur- graphic variations in zircon provenance patterns, ussia collision probably began at c. 400 Ma when a the occurrence of climatically sensitive subtropical promontory in north Gondwana collided with Laur- facies, mineral indicators across platform-to-basinal ussia (Matte 1986; Quesada 1991; Kroner and transects, and the migration of peaks in trilobite Romer 2013; Arenas et al. 2014; Wu et al. 2020). and cinctan (echinoderm) diversity. This severed continuity of the Rheic Ocean and the At the core of the broad Ibero-Armorican arc, a convergence zone was transformed into a complex tight late Variscan orocline (Cantabrian orocline) Mediterranean-style tectonic environment (Murphy has been documented in detail (Weil et al. 2019 and et al. 2016). The collisional suture is discontinuously references therein). The Cantabrian zone of the Ibe- exposed around a broad curvilinear structure (Ibero- rian massif represents the Variscan foreland on the Armorican arc) from SW Iberia, through NW Iberia, Gondwanan side of the suture. For this area, Gutiér- SW England and France to the rez-Alonso et al. (2020) present a multidimensional (e.g. Martínez Catalán et al. 2007). Evidence of the analysis of new and published detrital zircon ages suture has been reported from the Pontides in Turkey from samples covering the continuous stratigraphic and the Alborz mountains in Iran, but detailed char- record (Ediacaran–Carboniferous) with the aims of acterization is obscured by severe overprinting dur- detecting possible changes in the provenance of sed- ing the Cenozoic (e.g. Dokuz et al. iments through time and examining the role of sedi- 2011). Overprinting also obscures original relation- ment recycling. The analysis allows recognition of ships along the eastern flank of the aforementioned a continuous source of sediments from the Ediacaran Gondwanan promontory facing the Paleotethys to the Late Devonian punctuated by a sudden ephem- Ocean, with the exception of Corsica and Sardinia eral change in the Early Cambrian that the authors (Avigad et al. 2012). In these two Mediterranean attribute to local causes during the inception of the islands, evidence of subduction starting c. 360 Ma Paleozoic passive margin of Gondwana. ago is provided by high-pressure metamorphic units Finally, two papers deal with aspects of the geol- and dismembered ophiolites, which are also recog- ogy of the South Portuguese zone (SPZ) of SW Ibe- nized in the Alps despite pervasive Alpine overprint- ria. The SPZ has Laurussian affinity and collided ing. Therefore, the Variscan orogeny is not only due with the southwestern margin of the Gondwanan to the closure of the Rheic Ocean; at some stage in promontory after complete subduction of the relict the Gondwana–Laurussia collision process the Paleo- Rheic Ocean in Late Mississippian time (see Oliveira tethys was subducted beneath the promontory and et al. 2019; Quesada et al. 2019, and references eventually beneath Laurussia (Wu et al. 2020). therein). Paslawski et al. (2020) describe the bimo- Variscan pre-collisional stages are investigated in dal, predominantly submarine volcanic succession two papers. Sánchez Martínez et al. (2020) present with which the -famous Iberian Pyrite belt Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region massive sulfide province is associated. Volcanic References rocks are intruded by the Sierra Norte Batholith (Gladney et al. 2014). Based on their field and U– Arenas, R., Díez Fernández, R., Sánchez Martínez, S., Pb zircon data, the authors propose that the emplace- Gerdes, A., Fernández-Suárez, J. and Albert, R. 2014. Two-stage collision: exploring the birth of Pangea in ment of the Iberian Pyrite belt igneous rocks was the Variscan terranes. Gondwana Research, 25, both pre- and syn-collisional, with protracted mag- 756–763, https://doi.org/10.1016/j.gr.2013.08.009 matic activity in both subaerial and subaqueous set- Álvaro, J.J., Casas, J.M. and Quesada, C. 2020. Recon- tings from c. 370 to c. 338 Ma. In their model, structing the pre-Variscan puzzle of Cambro–Ordovi- magmatism was initiated primarily by lithospheric cian basement rocks in the south-western European delamination related to tectonic escape and crustal margin of Gondwana. The Geological Society of Lon- thinning of the lower plate. Pereira et al. (2020) don, Special Publications, 503, https://doi.org/10. / present new isotopic data from Carboniferous 1144 SP503-2020-89 syn-orogenic turbidites in the SPZ. These data are Andresen, A. 2020. Lithostratigraphic and structural data from Hardangervidda, S Norway, support extended consistent with the progressive denudation of a con- interaction between Avalonia and Baltica. The Geolog- tinental magmatic arc built on the Laurussian mar- ical Society of London, Special Publications, 503, gin. The oldest strata (Mértola turbidites) inherited https://doi.org/10.1144/SP503-2020-79 their geochemical and isotopic characteristics from Archibald, D.B. and Murphy, J.B. 2020. A slab failure ori- a dissected Middle–Late Devonian continental mag- gin for the Donegal composite batholith, Ireland as indi- matic arc with an intermediate–felsic composition. cated by trace-element geochemistry. The Geological The progressive erosion of its plutonic roots and Society of London, Special Publications, 503, https:// / / older continental basement rocks is consistent with doi.org 10.1144 SP503-2020-6 the increasing contribution of recycled ancient conti- Arenas, R. and Sánchez Martinez, S. et al. 2020. 100 myr cycles of oceanic lithosphere generation in peri- nental crust evident in the younger Mira and Brejeira Gondwana: Neoproterozoic–Devonian ophiolites from formations. The pronounced similarity between the the NW African–Iberian margin of Gondwana and the Nd TDM model ages and detrital zircon populations Variscan Orogen. The Geological Society of London, of the younger formations suggests that they share Special Publications, 503, https://doi.org/10.1144/ a common Laurussian (West Avalonia/Meguma SP503-2020-3 terrane) type source but a contribution from Gond- Atherton, M.P. and Ghani, A.A. 2002. Slab breakoff: a wanan (Ossa–Morena) type sources cannot be model for Caledonian, Late Granite syn-collisional ruled out. magmatism in the orthotectonic (metamorphic) zone of Scotland and Donegal, Ireland. Lithos, 62,65–85, https://doi.org/10.1016/ S0024-4937(02)00111-1 Avigad, D., Gerdes, A., Morag, N. and Bechstädt, T. 2012. Acknowledgements We thank all of the authors and Coupled U–Pb–Hf of detrital zircons of Cambrian sand- reviewers for their willingness to contribute to this special stones from Morocco and Sardinia: implications for publication dedicated to Damian Nance, and to all those provenance and crustal evolution of who attended the special session at the Geological Associ- – – North Africa. Gondwana Research, 21, 690 703, ation of Canada Mineralogical Association of Canada Joint https://doi.org/10.1016/j.gr.2011.06.005 Assembly in Quebec City in 2019. We believe that this pub- Braid, J.A., Murphy, J.B., Quesada, C., Bickerton, L. and lication is a fitting tribute to Damian’s career and wish him ‘ ’ Mortensen, J.K. 2012. Probing the composition of well on his retirement . We are also indebted to the Geo- unexposed basement, South Portuguese Zone, Southern logical Society of London, especially to Randell Stephen- Iberia: implications for the connections between the son for his stewardship and expertise as Books Editor, Appalachian and Variscan orogens. Canadian Journal Bethan Phillips (Associate Commissioning Editor), of Earth Sciences, 49, 591–613, https://doi.org/10. Rachael Kriefman (Production Editor) and all at GSL for 1139/e11-071 making our task as editors easy and rewarding. This volume Centeno-García, E., Mendoza-Rosales, C.C. and is a contribution to IGCP Project 648, Supercontinent Silva-Romo, G. 2009. Sedimentología de la Forma- Cycles & Global . ción Matzitzi (Paleozoico superior) y significado de sus componentes volcánicos, región de Los Reyes Metzontla–San Luis Atolotitlán, Estado de Puebla. Author contributions JBM: conceptualization Revista Mexicana de Ciencias Geológicas, 26, (equal); RAS: conceptualization (equal); CQ: conceptuali- 18–36, http://www.scielo.org.mx/pdf/rmcg/v26n1/ zation (equal). v26n1a3.pdf Cocks, L.M.R. and Torsvik, T.H. 2006. European geogra- phy in a global context from the Vendian to the end Funding This work was funded by a grant from Natural of the Palaeozoic. Geological Society, London, Mem- Sciences and Engineering Research Council of Canada to oirs, 32,83–95, https://doi.org/10.1144/GSL.MEM. J. Brendan Murphy. 2006.032.01.05 Dalslåen, B.H., Gasser, D., Grenne, T., Augland, L.E. and Andresen, A. 2020. Early–Middle Ordovician sedimen- Data availability There are no new data. tation and bimodal volcanism at the margin of Iapetus: Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

J. B. Murphy et al.

the Trollhøtta–Kinna Basin of the central Norwegian 204,75–88, https://doi.org/10.1016/S0012-821X Caledonides. The Geological Society of London, (02)00963-9 Special Publications, 503, https://doi.org/10.1144/ Fortey, R.A. and Cocks, L.M.R. 2003. Palaeontological evi- SP503-2020-37 dence bearing on global Ordovician–Silurian continental Dalziel, I.W.D. 1997. Neoproterozoic–Paleozoic geogra- reconstructions. Earth-Science Reviews, 61,245–307, phy and tectonics: review, hypothesis, environmental https://doi.org/10.1016/S0012-8252(02)00115-0 speculation. Geological Society of America Bulletin, Friedl, G., Finger, F., McNaughton, N.J. and Fletcher, I.R. 108,16–42, https://doi.org/10.1130/0016-7606(1997) 2000. Deducing the ancestry of terranes: SHRIMP 109,0016:ONPGAT.2.3.CO;2 evidence for -derived Gondwana frag- Dennis, A.J., Miller, B.V., Hibbard, J.P., Tappa, E. and ments in central Europe. Geology, 28, 1035–1038, Thunell, R.C. 2020. Gondwanan fragments in the https://doi.org/10.1130/0091-7613(2000)28,1035: southern Appalachians. The Geological Society of Lon- DTAOTS.2.0.CO;2 don, Special Publications, 503, https://doi.org/10. Gibbons, W. and Horák, J.M. 1990. Contrasting metamor- 1144/SP503-2019-249 phic terranes in north-west Wales. Geological Society, Dewey, J.F. and Ryan, P.D. 1990. The Ordovician evolu- London, Special Publications, 51, 315–327, https:// tion of the South Mayo Trough, western Ireland. Tec- doi.org/10.1144/GSL.SP.1990.051.01.20 tonics, 9, 887–903, https://doi.org/10.1029/TC009i Gladney, E., Braid, J.A., Murphy, J.B., Quesada, C. and 004p00887 McFarlane, C. 2014. The Late Paleozoic Gil Marquez Dokuz, A., Uysal, I.,̇ Kaliwoda, M., Karsli, O., Ottley, C.J. Pluton, southern Iberia: tectonic significance of mag- and Kandemir, R. 2011. Early abyssal- and late matism during continental collision and the amalgam- SSZ-type vestiges of the Rheic oceanic mantle in the ation of Pangea. International Journal of Earth Variscan basement of the Sakarya Zone, NE Turkey: Sciences, 103, 1433–1451, https://doi.org/10.1007/ implications for the sense of subduction and opening s00531-014-1034-5 of the Paleotethys. Lithos, 127, 176–191, https://doi. Gutiérrez-Alonso, G., Lopez-Carmona, A. et al. 2020. org/10.1016/J.LITHOS.2011.08.015 Neoproterozoic–paleozoic detrital sources in the Varis- Domeier, M. 2016. A plate tectonic scenario for the Iapetus can foreland of northern Iberia: primary v. recycled and Rheic oceans. Gondwana Research, 36, 275–295, sediments. The Geological Society of London, Special https://doi.org/10.1016/j.gr.2015.08.003 Publications, 503, https://doi.org/10.1144/SP503- Dostal, J., Keppie, J.D. and Wilson, R.A. 2016. Nd isotopic 2020-21 and trace element constraints on the source of Silurian– Henderson, B.J., Collins, W.J., Murphy, J.B., Gutiérrez- Devonian mafic lavas in the Chaleur Bay Synclinorium Alonso, G. and Hand, M. 2016. Gondwanan basement of New Brunswick (Canada): tectonic implications. terranes of the Variscan–Appalachian orogen: Baltican, Tectonophysics, 681, 364–375, https://doi.org/10. Saharan and West African hafnium isotopic fingerprints 1016/j.tecto.2015.10.002 in Avalonia, Iberia and the Armorican Terranes. Tecto- Dostal, J., Wilson, R.A. and Jutras, P. 2020. Petrogenesis of nophysics, 681,278–304, https://doi.org/10.1016/ Siluro-Devonian rhyolites of the Tobique Group in the j.tecto.2015.11.020 northwestern Appalachians (northern New Brunswick, Heron, P.J., Brendan Murphy, J., Damian Nance, R. and Canada): tectonic implications for the accretion history Pysklywec, R.N. 2020. Pannotia’s mantle signature: of peri-Gondwanan terranes along the Laurentian the quest for supercontinent identification. The Geolog- margin. The Geological Society of London, Special ical Society of London, Special Publications, 503, Publications, 503, https://doi.org/10.1144/SP503- https://doi.org/10.1144/SP503-2020-7 2019-229 Hildebrand, R.S. and Whalen, J.B. 2020. Arc and slab- Eby, N. 1992. Chemical subdivision of the A-type gran- failure magmatism of the Taconic Orogeny, western itoids: Petrogenetic and tectonic implications. Geology, New England, USA. The Geological Society of London, 20, 641–644, https://doi.org/10.1130/0091-7613 Special Publications, 503, https://doi.org/10.1144/ (1992)020,0641:CSOTAT.2.3.CO;2 SP503-2019-247 Errami, E., Linnemann, U. et al. 2020. From Pan-African Hoffman, P.F. 1991. Did the breakout of Laurentia turn transpression to Cadomian transtension at the West Gondwanaland inside-out? Science, 252, 1409–1412, African margin: new U–Pb zircon ages from the Eastern https://doi.org/10.1126/science.252.5011.1409 Saghro inlier (Anti-Atlas, Morocco). The Geological Hoffman, P.F. 2020. Cusp tectonics: an Ediacaran mega- Society of London, Special Publications, 503, https:// karst landscape and bidirectional mass slides in a Pan- doi.org/10.1144/SP503-2020-105 African syntaxis (NW Namibia). The Geological Soci- Evans, D.A.D. 2020. Pannotia under prosecution. The Geo- ety of London, Special Publications, 503, https://doi. logical Society of London, Special Publications, 503, org/10.1144/SP503-2019-253 https://doi.org/10.1144/SP503-2020-182 Hoffman, P.F., Kaufman, A.J., Halverson, G.P. and Schrag, Evans, D.A.D., Li, Z-X. and Murphy, J.B. 2016. Four- D.P. 1998. A Neoproterozoic . Science, dimensional context of Earth’s supercontinents. Geo- 281, 1342–1346, https://doi.org/10.1126/science. logical Society of London Special Publication, 424, 281.5381.1342 1–14, https://doi.org/10.1144/SP424.12 Juárez-Zúñiga, S., Solari, L.A. and Ortega-Obregon, C. Fernández-Suárez, J., Gutiérrez-Alonso, G. and Jeffries, 2020. Permian igneous clasts from the Matzitzi Forma- T.E. 2002. The importance of along-margin terrane tion, southern Mexico: isotopic constraints on the final transport in northern Gondwana: insights from detrital amalgamation of Pangaea. The Geological Society of zircon parentage in Neoproterozoic rocks from Iberia London, Special Publications, 503, https://doi.org/ and Brittany. Earth and Planetary Science Letters, 10.1144/SP503-2019-238 Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region

Karabinos, P., Macdonald, F.A. and Crowley, J.L. 2017. Martínez Catalán, J., Arenas, R. et al. 2007. Space and time Bridging the gap between the foreland and hinterland in the tectonic evolution of the northwestern Iberian I: geochronology and plate tectonic geometry of Ordo- Massif: implications for the Variscan belt. In: Hatcher, vician magmatism and terrane accretion on the Lauren- Jr. R.D., Carlson, M.P., McBride, J.H. and Martínez tian margin of New England. American Journal of Catalán, J.R. (eds) 4-D Framework of Continental Science, 317, 515–554, https://doi.org/10.2475/05. Crust. Geological Society of America, Boulder, CO, 2017.01 Memoirs, 200, Colorado, 403–423. Keppie, J.D., Dostal, J., Murphy, J.B. and Nance, R.D. Matte, P. 1986. Tectonics and model for 2008a. Synthesis and tectonic interpretation of the the Variscan belt of Europe. Tectonophysics, 126, westernmost Paleozoic Variscan orogen in southern 329–374, https://doi.org/10.1016/0040-1951(86) Mexico: from rifted Rheic margin to active Pacific mar- 90237-4 gin. Tectonophysics, 461, 277–290, https://doi.org/10. McConnell, B., Riggs, N. and Fritschle, T. 2020. Tectonic 1016/j.tecto.2008.01.012 history across the Iapetus suture zone in Ireland. The Keppie, J.D., Dostal, J. et al. 2008b. Ordovician–earliest Geological Society of London, Special Publications, Silurian rift tholeiites in the Acatlán Complex, southern 503, https://doi.org/10.1144/SP503-2019-233 Mexico: evidence of rifting on the southern margin of McMenamin, M.A. and McMenamin, D.L. 1990. The the Rheic Ocean. Tectonophysics, 461, 130–156, Emergence of Animals: The Cambrian breakthrough. https://doi.org/10.1016/j.tecto.2008.01.010 Columbia University Press, 217pp. Keppie, J.D., Murphy, J.B., Nance, R.D. and Dostal, J. Moody, J.B., Nance, R.D. and Worsley, T.R. 1988. The 2012. Mesoproterozoic Oaxaquia-type basement in supercontinent cycle. Scientific American, 259,72–79, peri-Gondwanan terranes of Mexico, the Appala- https://doi.org/10.1038/scientificamerican0788-72 chians, and Europe: TDM age constraints on extent Murphy, J.B. and Nance, R.D. 2008. The Pangea conun- and significance. International Geology Review, 54, drum. Geology, 36, 703–706, https://doi.org/10. 313–324, https://doi.org/10.1080/00206814.2010. 1130/G24966A.1 543783 Murphy, J.B., McCausland, P.J.A., O’Brien, S.J., Pisarev- Knoll, A.H. 2013. Systems paleobiology. Geological Soci- sky, S. and Hamilton, M.A. 2008. Age, geochemistry ety of America Bulletin, 125,3–13, https://doi.org/10. and Sm–Nd isotopic signature of the 0.76 Ga Burin 1130/B30685.1 Group: compositional equivalent of Avalonian base- Krogh, T.E., Strong, D.F., O ’Brien, S.J. and Papezik, V.S. ment? Precambrian Research, 165,37–48, https:// 1988. Precise U–Pb dates from the Avalon terrane in doi.org/10.1016/j.precamres.2008.05.006 Newfoundland. Canadian Journal of Earth Sciences, Murphy, J.B., Braid, J.A., Quesada, C., Dahn, D., Gladney, 25, 442–453, https://doi.org/10.1139/e88-045 E. and Dupuis, N. 2016. An eastern Mediterranean ana- Kroner, U. and Romer, R. 2013. Two plates – many sub- logue for the Late Palaeozoic evolution of the Pangaean duction zones: the Variscan orogeny reconsidered. suture zone in SW Iberia. Geological Society, London, Gondwana Research, 24, 298–329, https://doi.org/ Special Publications, 424, 241–263, https://doi.org/ 10.1016/j.gr.2013.03.001 10.1144/SP424.9 Kroner, U., Stephan, T., Romer, R.L. and Roscher, M. Murphy, J.B., Nance, R.D. et al. 2020. Pannotia: in defence 2020. Paleozoic plate kinematics during the Pannotia– of its existence and geodynamic significance. The Geo- Pangaea supercontinent cycle. The Geological Society logical Society of London, Special Publications, 503, of London, Special Publications, 503, https://doi. https://doi.org/10.1144/SP503-2020-96 org/10.1144/SP503-2020-15 Nance, R.D. 1986a. Precambrian evolution of the Avalon Li, Z.-X., Bogdanova, S.V. et al. 2008. Assembly, config- terrane in the Northern Appalachians: a review. Mari- uration, and break-up history of Rodinia: a synthesis. time Sediments and Atlantic Geology, 22, 214–238, Precambrian Research, 160, 179–210, https://doi. https://doi.org/10.4138/1608 org/10.1016/j.precamres.2007.04.021 Nance, R.D. 1986b. Late Carboniferous tectonostratigra- Li, Z.X., Mitchell, R.N., Spencer, C.J., Ernst, R., Pisarev- phy in the Avalon terrane of southern New Brunswick. sky, S., Kirscher, U. and Murphy, J.B. 2019. Decoding Maritime Sediments and Atlantic Geology, 22, Earth’s rhythms: modulation of supercontinent cycles 308–326. by longer episodes. Precambrian Research, Nance, R.D. and Linnemann, U. 2008. The Rheic Ocean: 323,1–5, https://doi.org/10.1016/j.precamres.2019. origin, evolution, and significance. GSA Today, 18, 01.009 4–12, https://doi.org/10.1130/GSATG24A.1 Lindner, M., Dörr, W., Reither, D. and Finger, F. 2020. The Nance, R.D. and Murphy, J.B. 2019. Supercontinents and Dobra Gneiss and the Drosendorf Unit in the southeast- the case for Pannotia. Geological Society, London, Spe- ern Bohemian Massif, Austria: West Amazonian crust cial Publications, 470,65–85. in the heart of Europe. The Geological Society of Lon- Nance, R.D., Worsley, T.R. and Moody, J.B. 1986. Post- don, Special Publications, 503, https://doi.org/10. biogeochemical cycles and long-term episo- 1144/SP503-2019-232 dicity in tectonic processes. Geology, 14, 514–518, Linnemann, U., Herbosch, A., Liégeois, J.-P., Pin, C., Gärt- https://doi.org/10.1130/0091-7613(1986)14,514: ner, A. and Hofmann, M. 2012. The Cambrian to PBCALE.2.0.CO;2 Devonian odyssey of the Brabant Massif within Avalo- Nance, R.D., Murphy, J.B., Strachan, R.A., D’Lemos, R.S. nia: a review with new zircon ages, geochemistry, and Taylor, G.K. 1991. Late Proterozoic tectonostrati- Sm-Nd isotopes, stratigraphy and palaeogeography. graphic evolution of the Avalonian and Cadomian ter- Earth-Science Reviews, 112, 126–154, https://doi. ranes. Precambrian Research, 53,41–78, https://doi. org/10.1016/j.earscirev.2012.02.007 org/10.1016/0301-9268(91)90005-U Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

J. B. Murphy et al.

Nance, R.D., Murphy, J.B. and Keppie, J.D. 2002. A Cor- Pastor-Galán, D., Nance, R.D., Murphy, J.B. and Spencer, dilleran model for the evolution of Avalonia. Tectono- C.J. 2019. Supercontinents: myths, mysteries and mile- physics, 352,11–31, https://doi.org/10.1016/S0040- stones. Geological Society, London, Special Publica- 1951(02)00187-7 tions, 470,39–64. Nance, R.D., Miller, B.V., Keppie, J.D., Murphy, J.B. Pereira, M.F., Gama, C., da Silva, I.D., Fuenlabrada, J.M., and Dostal, J ., 2006. The Acatlan Complex, southern Silva, J.B. and Medina, J. 2020. Isotope geochemistry Mexico: record spanning the assembly and breakup of evidence for Laurussian-type sources of South Portu- Pangea. Geology, 34, 867–860, https://doi.org/10. guese Zone Carboniferous turbidites (Variscan Orog- 1130/G22642.1 eny). The Geological Society of London, Special Nance, R.D., Murphy, J.B. et al. 2008. Neoproterozoic– Publications, 503, https://doi.org/10.1144/SP503- early Palaeozoic and palaeogeogra- 2019-163 phy of the peri-Gondwanan terranes: Amazonian Piper, D.J.W. and Pe-Piper, G. 2020. Evolution of late v. West African connections. Geological Society, Lon- Paleozoic shearing in the Cobequid Highlands: con- don, Special Publications, 297, 345–383, https://doi. straints on the fragmentation of the Appalachian Orogen org/10.1144/SP297.17 in Nova Scotia along intra-continental shear zones. The Nance, R.D., Keppie, J.D., Miller, B.V., Murphy, J.B. and Geological Society of London, Special Publications, Dostal, J. 2009. Palaeozoic palaeogeography of 503, https://doi.org/10.1144/SP503-2019-239 Mexico: constraints from detrital zircon age data. Geo- Quesada, C. 1991. Geological constraints on the Paleozoic logical Society, London, Special Publications, 327, tectonic evolution of tectonostratigraphic terranes in the 239–269, https://doi.org/10.1144/SP327.12 Iberian Massif. Tectonophysics, 185, 225–245, https:// Nance, R.D., Gutiérrez-Alonso, G. et al. 2010. Evolution of doi.org/10.1016/0040-1951(91)90446-Y the Rheic Ocean. Gondwana Research, 17, 194–222, Quesada, C., Braid, J.A. et al. 2019. SW Iberia suture zone: https://doi.org/10.1016/j.gr.2009.08.001 oceanic affinity units. In: Quesada, C. and Oliveira, J.T. Nance, R.D., Gutiérrez-Alonso, G. et al. 2012. A brief his- (eds) The Geology of Iberia: A geodynamic Approach. tory of the Rheic Ocean. Geoscience Frontiers, 3, Springer, Cham, 2, 131–171, https://doi.org/10.1007/ 125–135, https://doi.org/10.1016/j.gsf.2011.11.008 978-3-030-10519-8_5 Nance, R.D., Neace, E.R., Braid, J.A., Murphy, J.B., Sánchez Martínez, S., Arenas, R., Albert, R., Gerdes, A. Dupuis, N. and Shail, R.K. 2015. Does the Meguma and Fernández-Suárez, J. 2020. Updated geochronol- Terrane extend into SW England? Geoscience Canada, ogy and isotope geochemistry of the Vila de Cruces 42,61–76, https://doi.org/10.12789/geocanj.2014. Ophiolite: a case study of a peri-Gondwanan back-arc 41.056 ophiolite. The Geological Society of London, Special Narbonne, G.M. 2010. Ocean chemistry and early animals. Publications, 503, https://doi.org/10.1144/SP503- Science, 328,53–54, https://doi.org/10.1126/science. 2020-8 1188688 Schofield, D.I., Potter, J., Barr, S.M., Horák, J.M., Millar, Oliveira, J.T., Quesada, C. et al. 2019. South Portuguese I.L. and Longstaffe, F.J. 2016. Reappraising the terrane: a continental affinity exotic unit. In: Quesada, Neoproterozoic ‘East Avalonian’ terranes of southern C. and Oliveira, J.T. (eds) The Geology of Iberia: A Great Britain. Gondwana Research, 35, 257–271, Geodynamic Approach. Springer, Cham, 2, 173–206. https://doi.org/10.1016/j.gr.2015.06.001 https://doi.org/10.1007/978-3-030-10519-8_6 Schofield, D.I., Leslie, A.G., Wilby, P.R., Dartnall, R., Ortega-Gutiérrez, F., Elias-Herrera, M., Reyes-Salas, M., Waldron, J.W.F. and Kendall, R.S. 2020. Tectonic evo- Macias-Romo, C. and López, R. 1999. Late Ordovi- lution of Anglesey and adjacent mainland North Wales. cian–Early Silurian continental collision orogeny in The Geological Society of London, Special Publica- southern Mexico and its bearing on Gondwana–Lauren- tions, 503 https://doi.org/10.1144/SP503-2020-9 tia connections. Geology, 27, 719–722, https://doi. Slagstad, T., Saalmann, K. et al. 2020. Late Neoprotero- org/10.1130/0091-7613(1999)027,0719:LOESCC.2. zoic–Silurian tectonic evolution of the Rödingsfjället 3.CO;2 Nappe Complex, orogen-scale correlations and impli- Ortega-Gutiérrez, F., Elías-Herrera, M., Morán-Zenteno, cations for the Scandian suture. The Geological Society D.J., Solari, L., Weber, B. and Luna-González, L. of London, Special Publications, 503, https://doi.org/ 2018. The pre-Mesozoic metamorphic basement of 10.1144/SP503-2020-10 Mexico, 1.5 billion years of crustal evolution. Earth Soper, N.J., Strachan, R.A., Holdsworth, R.E., Gayer, R.A. Science Reviews, 183,2–37, https://doi.org/10. and Greiling, R.O. 1992. Sinistral transpression and the 1016/j.earscirev.2018.03.006 Silurian closure of Iapetus. Journal of the Geological Park, A.F. and Hinds, S.J. 2020. Structure and stratigraphy Society, London, 149, 871–880, https://doi.org/10. in the Pennsylvanian tectonic zone of southern New 1144/gsjgs.149.6.0871 Brunswick, Canada: the ‘Maritime coastal disturbance’ Stephens, M.B. and Gee, D.G. 1985. A plate tectonic model revisited. The Geological Society of London, Special for the evolution of the eugeoclinal terranes in the cen- Publications, 503, https://doi.org/10.1144/SP503- tral . In: Gee, D.G. and Sturt, 2019-234 B.A. (eds) The Caledonide Orogen – Scandinavia and Paslawski, L.E., Braid, J.A., Quesada, C. and McFarlane, Related Areas. Wiley, Chichester, 953–978. C.M. 2020. Geochronology of the Iberian Pyrite Belt Stump, E. 1987. Construction of the Pacific margin of and the Sierra Norte Batholith: lower plate magmatism Gondwanaland during the Pannotios cycle. In: McKen- during supercontinent amalgamation? The Geological zie, G.D. (ed.) Gondwana Six: Structure, Tectonics and Society of London, Special Publications, 503, https:// Geophysics. American Geophysical Union, Mono- doi.org/10.1144/SP503-2020-5 graphs, 40,77–87. Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021

Neoproterozoic and Paleozoic Orogenic Cycles in the Circum-Atlantic Region

Tegner, C., Andersen, T.B. et al. 2019. A Mantle Plume Terrane, Nova Scotia, Canada, and Harlech Dome, Origin for the Scandinavian Dyke Complex: a ‘piercing North Wales, UK: dispersed fragments of a peri- point’ for 615 Ma of Baltica? Geo- Gondwanan basin? Journal of the Geological Society, chemistry, Geophysics, Geosystems, 20, 1075–1094, London, 168,83–98, https://doi.org/10.1144/0016- https://doi.org/10.1029/2018GC007941 76492010-068 Thomas, R.J., Chevallier, L.C. et al. 2002. Precambrian Waldron, J.W.F., Schofield, D.I., Murphy, J.B. and Tho- evolution of the Siroua Window, Anti-Atlas Orogen, mas, C. 2014. How was the Iapetus Ocean infected by Morocco. Precambrian Research, 118,1–57, https:// subduction? Geology, 42, 1095–1098, https://doi. doi.org/10.1016/S0301-9268(02)00075-X org/10.1130/G36194.1 Torsvik, T.H. and Rehnstrøm, E.F. 2003. The Tornquist Waldron, J.W.F., Schofield, D.I. and Murphy, J.B. 2019. Sea and Baltica–Avalonia docking. Tectonophysics, Diachronous Palaeozoic accretion of peri-Gondwanan 362,67–82, https://doi.org/10.1016/S0040-1951(02) terranes at the Laurentian margin. Geological Society, 00631-5 London, Special Publications, 470–411. van Staal, C.R., Whalen, J.B., Valverde-Vaquero, P., Walker, S., , A.F., Thirlwall, M.F. and Strachan, R.A. Zagorevski, A. and Rogers, N. 2009. Pre-Carbonifer- 2020. Caledonian and Pre-Caledonian orogenic events ous, episodic accretion-related, orogenesis along the in Shetland, Scotland: evidence from garnet Lu–Hf Laurentian margin of the northern Appalachians. Geo- and Sm–Nd geochronology. The Geological Society logical Society, London, Special Publications, 327, of London, Special Publications, 503, https://doi. 271–316, https://doi.org/10.1144/SP327.13 org/10.1144/SP503-2020-32 van Staal, C.R., Barr, S.M. and Murphy, J.B. 2012. Prove- Weil, A., Pastor-Galán, D., Johnston, S.T. and Gutiérrez nance and tectonic evolution of Ganderia: constraints Alonso, G. 2019. Late/post Variscan orocline forma- on the evolution of the Iapetus and Rheic oceans. Geol- tion and widespread magmatism. In: Quesada, C. and ogy, 40, 987–990, https://doi.org/10.1130/G33302.1 Oliveira, J.T. (eds) The Geology of Iberia: A Geody- van Staal, C.R., Barr, S.M., McCausland, P.J.A., Thomp- namic Approach. Springer, Cham, 2, 527–542, son, M.D. and White, C.E. 2020. –Ediacaran https://doi.org/10.1007/978-3-030-10519-8_14 tectonomagmatic evolution of West Avalonia and its Whalen, J.B. and Hildebrand, R.S. 2019. Trace element dis- Ediacaran–early Cambrian interactions with Ganderia: crimination of arc, slab failure, and A-type granitic an example of complex terrane transfer due to arc–arc rocks. Lithos, 348–349, 105179, https://doi.org/10. collision? The Geological Society of London, Special 1016/j.lithos.2019.105179 Publications, 503, https://doi.org/10.1144/SP503- Wu, L., Murphy, J.B. et al. 2020. The amalgamation of 2020-23 Pangea: paleomagnetic and geological observations Waldron, J.W.F., Schofield, D.I., White, C.E. and Barr, revisited. Geological Society of America Bulletin, S.M. 2011. Cambrian successions of the Meguma https://doi.org/10.1130/B35633.1