Changes in the Early Palaeozoic geography as a possible factor of echinoderm higher taxa formation: Delayed larval development to cross the Iapetus Ocean

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stouge, S., Boyce, W. D., Christiansen, J. L., Harper, D. A., & Knight, I. (2002). Lower–Middle Ordovician stratigraphy of North-East Greenland. Geology of Greenland Survey Bulletin, 191, 117-125. https://doi.org/10.34194/ggub.v191.5138 _______________ The Upper Proterozoic (Riphean) to Lower Palaeozoic succession in North-East Greenland is exposed in a broad N–S-trending belt in the fjord region between 71°38´ and 74°25´N (Fig. 1). The succession comprises mainly marine sediments accumulated during the later stages of the break-up of the Rodinia supercontinent, the subsequent opening of the Iapetus Ocean and formation of the passive margin along the edge of the Laurentian palaeocontinent. Investigations of the sedimentary succession were initiated on Ella Ø in the summer of 2000 as part of a project to investigate the development of the Laurentian margin facing the Iapetus Ocean in the Early Palaeozoic, when studies of the uppermost formations of the Riphean Eleonore Bay Supergroup to the Lower Ordovician Antiklinalbugt Formation on Ella Ø were undertaken (Stouge et al. 2001). Ella Ø was revisited during the summer of 2001, with the focus on the Ordovician formations. In addition, investigations were undertaken in the Albert Heim Bjerge area where the uppermost part of the Ordovician succession is preserved (Fig. 1).

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A revised correlation of Silurian rocks in the Girvan district, SW Scotland

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593300000481 ◽

2002 ◽

Vol 93 (4) ◽

pp. 383-392 ◽

Cited By ~ 10

Author(s):

James D. Floyd ◽

Mark Williams

Keyword(s):

Depositional Environment ◽

Late Ordovician ◽

Important Research ◽

British Geological Survey ◽

Marine Fauna ◽

Comprehensive Review ◽

Iapetus Ocean ◽

Northern Side ◽

Lower Palaeozoic ◽

Early Palaeozoic

ABSTRACTIn late Ordovician and early Silurian times, the Girvan district lay in a shelf marinesetting on the margin of Laurentia, on the northern side of the Iapetus Ocean. The Lower Palaeozoic rocks of the Girvan district, and their shelly and graptolitic fossil fauna, were systematically described by Lapworth in 1882 and have formed an important research resource ever since. They provide valuable evidence for the depositional environment and geological setting of Girvan during the early Palaeozoic, in both regional and wider contexts, and demonstrate the long-recognised close affinity with contemporaneous Laurentian faunas. However, by late Ordovician and into Silurian times, the earlier Iapetus oceanic barrier to faunal migration had largely gone and there is good correlation between contemporaneous marine fauna throughout the British Isles and Scandinavia. Despite much recent research in the area, including resurvey work by the British Geological Survey, no comprehensive review of Silurian lithostratigraphy at Girvan has been published since the revision by Cocks and Toghill in 1973. The present review of the Silurian rocks addresses this need and complements the recently published (Fortey et al. 2000) revision of the underlying Ordovician rocks, thus bringing the entire Girvan Lower Palaeozoic succession up to modern standards of nomenclature.

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Introduction

Geological Society London Memoirs ◽

10.1144/gsl.mem.1992.013.01.02 ◽

1992 ◽

Vol 13 (1) ◽

pp. xi-xii

Keyword(s):

Plate Tectonics ◽

Time Interval ◽

British Isles ◽

Late Precambrian ◽

The Earth ◽

Iapetus Ocean ◽

Lower Palaeozoic ◽

The Subject ◽

Early Palaeozoic ◽

Early Maps

AbstractAlmost forty years have elapsed since Leonard Wills published his 'Palaeogeographical Atlas of the British Isles'; those forty years have seen a revolution in the earth sciences which has overturned many earlier ideas in geology. Palaeogeography has been affected just as much as other parts of the subject by this change.The advent of the plate tectonic theory has transformed our ideas of the Lower Palaeozoic palaeogeographical evolution of the British area and has rendered totally obsolete many aspects of Wills' maps. The application of plate tectonics has caused us to produce totally new palaeogeographical models for the late Precambrian and early Palaeozoic, and has emphasised that definitive palaeogeographies for this time interval cannot yet be compiled. Wills was at pains to point out that his Atlas was an 'Aunt Sally' at which to 'hurl one's own and other field observations'-our atlas too must be viewed in that light.The Precambrian and Lower Palaeozoic maps are separated for the northern and southern British Isles areas, because for much of that time the two areas were separated by the Iapetus Ocean. The recognition of important terrane boundaries in Scotland and Ireland has led to our attempt to reconstruct a map from the collage of terranes now in juxtaposition. These early maps owe much to Keith Ingham's experience of the Lower Palaeozoic-Keith would insist here that the maps are very much in the 'Aunt Sally' mould, and that his interpretations may not be able to stand the test of time-but they represent

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Scottish Ordovician ostracodes: a review of their palaeoenvironmental, biostratigraphical and palaeobiogeographical significance

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s0263593300008348 ◽

2000 ◽

Vol 91 (3-4) ◽

pp. 499-508 ◽

Cited By ~ 12

Author(s):

Mark Williams ◽

James D. Floyd ◽

C. Giles Miller ◽

David J. Siveter

Keyword(s):

Carbonate Rocks ◽

Species Level ◽

Border Region ◽

Baltic Region ◽

Shallow Marine ◽

Wide Geographical Distribution ◽

Iapetus Ocean ◽

Distributional Patterns ◽

Early Palaeozoic ◽

The Baltic

ABSTRACTOstracodes have a wide geographical distribution in the Ordovician of Scotland. They are known from the Southern Uplands, the Girvan district, the Highland Border region and the Inner Hebrides. Overall, more than forty species are recorded. They occur in clastic and carbonate rocks indicative of a range of shallow to deeper marine-shelf environments. Though many of the faunas are allochthonous, broad patterns of ostracode palaeoenvironmental distribution can be elucidated, and elements of the shallow marine Leperditella and open marineshelf Anisocyamus associations (previously recorded from N America) are present. Indigenous faunas are absent from the deep marine sediments of the Southern Uplands Northern Belt. Ostracodes are known from the Arenig, Llanvirn, Caradoc and Ashgill series in Scotland; those of the latter two series have widest biostratigraphical value. In the Girvan district the Caradoc species ‘Ctenobolbina’ ventrospinosa, Krausella variata, Balticella deckeri and Monoceratella teres have correlative value with N America, whilst the Ashgill species Kinnekullea comma appears to be a locum for the anceps graptolite Biozone in Britain, Ireland and possibly the eastern Baltic. The ostracodes are of typical Laurentian affinity, but show progressive generic links with the Baltic region during the late Llanvirn–Caradoc interval, and by Ashgill times display species-level links with southern Britain and Ireland. These distributional patterns suggest approaching geographical proximity for the early Palaeozoic continents of Laurentia, Baltica and Avalonia, and the ability of some Ordovician ostracodes to cross the Iapetus Ocean.

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Neodymium isotopic composition of Cambrian–Ordovician biogenic apatite in the Baltoscandian Basin: implications for palaeogeographical evolution and patterns of biodiversity

Geological Magazine ◽

10.1017/s0016756805000877 ◽

2005 ◽

Vol 142 (4) ◽

pp. 419-439 ◽

Cited By ~ 26

Author(s):

ULF STURESSON ◽

LEONID E. POPOV ◽

LARS E. HOLMER ◽

MICHAEL G. BASSETT ◽

SERGEI FELITSYN ◽

...

Keyword(s):

Sea Water ◽

Constant Factor ◽

Turnover Rates ◽

Benthic Assemblages ◽

The North ◽

Tectonic History ◽

Iapetus Ocean ◽

History Of ◽

Early Palaeozoic ◽

T Values

Biogenic apatite preserved in 148 samples of conodonts and organophosphatic-shelled brachiopods from Cambrian through Ordovician successions of the Baltoscandian Basin (Baltica Plate) preserves a sensitive record of early Palaeozoic sea-water chemistry interpreted via neodymium isotope ratios. Consistent ${\uvarepsilon}$Nd(t) values of −9.6 to −8.3 for Lower to Middle Cambrian samples suggest no significant lateral or temporal variation across the region. Average Upper Cambrian values are −7.2 to −7.7. Sedimentary analysis suggests that the influence of continental weathering from Baltica as a major source of radiogenic Nd was negligible. Ordovician samples show a rise to −5 to −6 in the early Arenig, early–mid Llanvirn and late Caradoc. Sea-water mixing from the southeast Iapetus Ocean was a constant factor throughout Cambrian–Ordovician times. The rise reflects erosion of obducted volcanic arc complexes along the Caledonian margin, and probably also relates to pollution of the Baltica sector of Iapetus from the approaching Avalonia Plate. Patterns of evolutionary biodiversity and palaeobiogeographical linkages support the geochemical signatures in interpreting the tectonic history of the region. Extinction of lingulate brachiopod faunas in the Tremadoc, followed by subsequent recovery and emergence of benthic assemblages typical of the Ordovician Evolutionary Fauna in the Billingen–early Volkhov regional stages coincide with significant changes in geochemical characteristics of water masses across the Baltoscandian basin. The early and mid Ordovician (Arenig to Llandeilo) brachiopod faunas of the North Estonian Confacies Belt are characterized by high endemism and low turnover rates, whereas increased immigration resulted in the extinction of a number of local lineages in the late Llanvirn. From the mid Caradoc to mid Ashgill, when Baltica was drifting on a course to collide eventually with Avalonia and gradually approach Laurentia, brachiopod assemblages were characterized by higher turnover rates. At the same time they gradually became more cosmopolitan and less influenced by the invasion of new faunas.

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Brittle fault evolution of the Montréal area (St Lawrence Lowlands, Canada): rift-related structural inheritance and tectonism approached by palaeostress analysis

Geological Magazine ◽

10.1017/s0016756803007283 ◽

2003 ◽

Vol 140 (2) ◽

pp. 157-172 ◽

Cited By ~ 9

Author(s):

MURIEL ROCHER ◽

ALAIN TREMBLAY ◽

DENIS LAVOIE ◽

ANDRÉ CAMPEAU

Keyword(s):

Tectonic Evolution ◽

Mechanical Twinning ◽

Strike Slip ◽

Passive Margin ◽

Upper Ordovician ◽

Structural Inheritance ◽

Relative Chronology ◽

Iapetus Ocean ◽

Northern Border ◽

Early Palaeozoic

The Montréal area belongs to the St Lawrence Lowlands, a Cambrian Early Ordovician passive margin of the Iapetus Ocean, later covered by Appalachian Middle to Upper Ordovician foreland deposits. A structural and palaeostress analysis has been carried out in order to reconstruct its tectonic evolution. The structural map has been revised with new data. Palaeostresses are reconstructed based on inversion of fault slip data, and these results are independently corroborated by the microstructural study of calcite mechanical twinning. Field relationships are used to establish the relative chronology of fractures and to deduce the motion on regional faults. The reconstructed structural and tectonic evolution brings to light some relationships between structural inheritance and tectonic events that have affected the area since Early Palaeozoic times. An early NW–SE extension is responsible for N040-trending faults along the northern border of the St Lawrence Lowlands, and for N090- and N120-trending faults cross-cutting the Montréal area. This extension is followed by WNW–ESE and NNW compressions, which have induced reverse motion on pre-existing faults and generated strike-slip conjugate faults. Subsequent NE–SW and NNW–SSE-directed extensions have reactivated previous faults with normal to strike-slip motions. A late NE–SW compression is recorded in the Monteregian plutons. Compressions in WNW–ESE and NNW directions are consistent with Appalachian collisional tectonism, but N040- and N090-trending faults cross-cut Appalachian folds and foreland deposits. Although the early NW–SE extension is consistent with the collapse of the Iapetan margin in Early Palaeozoic times, most of the present geometry of the St Lawrence Lowlands could be attributed to Mesozoic tectonism, recorded as nearly N–S-directed extensional events.

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Vendian stratigraphy and sedimentology of the East Greenland Caledonides

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v125.7900 ◽

1985 ◽

Vol 125 ◽

pp. 88-94

Author(s):

M.J Hambrey ◽

A.C.M Moncrieff

Keyword(s):

North Atlantic ◽

Depositional Environment ◽

Arctic Region ◽

Harvard University ◽

University Of Iowa ◽

East Greenland ◽

The North ◽

Iapetus Ocean ◽

Field Season ◽

Early Palaeozoic

The present two-year programme 1984-1985 on the Vendian Tillite Group in central East Greenland follows comprehensive investigations on similar sequences in eastern Svalbard. The project aims to establish through Vendian time the disposition of land masses and oceans in relation to the East Greenland depositional environment, and to erect detailed stratigraphic correlations with other parts of the North Atlantic - Arctic region. This is important for understanding the tectonic evolution of the region prior to the opening of the Iapetus Ocean. The work is a collaborative venture involving N. Abrahamsen (University of Aarhus, palaeomagnetism), G. Bylund (University of Lund, palaeomagnetism), A. H. Knoll (Harvard University, biostratigraphy), A. M. Spencer (Statoil, sedimentology), K. Swett (University of Iowa, sedimentology of bounding rock units) and G. Vidal (University of Lund, biostratigraphy). The authors were accompanied in the 1984 field season by Bylund and Vidal who undertook extensive sampling of the Late Proterozoic to Early Palaeozoic sequence.

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Lingulate brachiopods and the Early Palaeozoic history of the Iapetus Ocean

Lethaia ◽

10.1111/let.12068 ◽

2014 ◽

Vol 47 (4) ◽

pp. 456-468 ◽

Cited By ~ 4

Author(s):

Paul Winrow ◽

Mark D. Sutton

Keyword(s):

Iapetus Ocean ◽

History Of ◽

Early Palaeozoic

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The early Palaeozoic evolution of northwest England

Geological Magazine ◽

10.1017/s0016756800021026 ◽

1993 ◽

Vol 130 (5) ◽

pp. 711-724 ◽

Cited By ~ 31

Author(s):

A. H. Cooper ◽

D. Millward ◽

E. W. Johnson ◽

N. J. Soper

Keyword(s):

Foreland Basin ◽

Lake District ◽

Volcanic Group ◽

The North ◽

Iapetus Ocean ◽

Granitic Intrusions ◽

Deformation Event ◽

Lower Palaeozoic ◽

Early Palaeozoic ◽

Uplift And Erosion

AbstractThe Lake District and smaller Craven inliers of northwest England contain a Lower Palaeozoic sequence deposited on the Gondwanan side of the Iapetus Ocean, close to the junction with the Tornquist Sea. The Tremadoc to Llanvirn Skiddaw and Ingleton groups are deep water assemblages of turbidite, olistostrome and slump deposits, formed at a continental margin. They experienced uplift and erosion as a precursor to the eruption of two largely subaerial Llandeilo-Caradoc volcanic sequences: the tholeiitic Eycott Volcanic Group in the north and the calc–alkaline Borrowdale Volcanic Group in the central Lake District. The volcanic episodes are the earliest part of a major episode of magmatism, extending through to the early Devonian and responsible for a major batholith underpinning the Lake District. Subsidence in an intra-arc rift zone preserved the subaerial volcanic sequences. A marine transgression marks the base of the Windermere Group, which comprises a mixed carbonate–clastic shelf sequence of Ashgill age, passing upwards through the Silurian into a thick, prograding foreland basin sequence of Ludlow turbidites. Deformation of the Lower Palaeozoic sequences was possibly diachronous from north to south. It is attributed to the late Caledonian (Acadian) Orogeny and resulted in folding, cleavage and thrust development. Granitic intrusions, including those at Shap, Skiddaw and beneath the hydrothermal Crummock Water Aureole, are partly syntectonic and were therefore penecontemporaneous with this deformation event. Some thrust faulting post-dates the intrusive phase. Post-deformation Devonian conglomerates are also present locally.

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Lower Ordovician brachiopods from the Ben Suardal Limestone Formation (Durness Group) of Skye, western Scotland

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593300013948 ◽

1984 ◽

Vol 75 (3) ◽

pp. 301-310 ◽

Cited By ~ 5

Author(s):

Gordon B. Curry ◽

Alwyn Williams

Keyword(s):

New Species ◽

Plate Tectonic ◽

Iapetus Ocean ◽

Lower Ordovician ◽

Northwestern Margin ◽

Tectonic Position ◽

Early Palaeozoic ◽

Isle Of Skye

ABSTRACTTen silicified brachiopod taxa have been recovered from the Ben Suardal Limestone Formation (Durness Group) on the Isle of Skye, western Scotland. This Arenig fauna contains a new camerellid genus, Boreadocamara, and new species of each of the orthacean genera Archaeorthis, Fasciculina, and Oligorthis. Representatives of Billingsella, Finkelnburgia, Syntrophia, Syntrophopsis, and an indeterminate orthacean have also been recovered from etched residues of the Ben Suardal Limestone. The Skye fossils show strong affinities with the Scoto-Appalachian or American faunal province, in keeping with the inferred plate tectonic position of the Durness Group along the northwestern margin of the early Palaeozoic ‘Iapetus’ Ocean.

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