Mesozoic brachiopod migrations and the opening of the North Atlantic

Ager, Derek; Walley, Christopher D.

doi:10.1016/0031-0182(77)90007-4

Cited by 31 publications

(12 citation statements)

References 5 publications

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“…The incipient opening of the North Atlantic played an important role in the migration of Jurassic brachiopods, as recognized and illustrated by Ager & Walley (1977). Multicostate and sulcate terebratulids of Tethyan origin arrived in Southern England via the Maghrebian and western Portuguese zones in the Early and Middle Jurassic; the famous, perforate pygopides reached as far north as East Greenland (Ager 1967) along the Late Jurassic northern seaway.…”

Section: Changing Current Patternmentioning

confidence: 99%

Victims of the Early Toarcian anoxic event: the radiation and extinction of Jurassic Koninckinidae (Brachiopoda)

Vörös

2002

LET

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The significant mass extinction attributed to the Early Toarcian anoxic event had a severe impact on the phylum Brachiopoda. Beyond a serious decrease of species diversity, the extinction of the orders Spiriferidina and Athyridida is connected with this episode. The order Athyridida was represented by the family Koninckinidae in the Early Jurassic. The stratigraphical and geographical distribution of the three Early Jurassic koninckinid genera (Koninckella, Koninckodonta, Amphiclinodonta) shows a definite radiative pattern. The number of their nominal species increased from 2 to 17 from the Sinemurian to Early Toarcian; in the same time interval, their area increased from the Alpine region to the whole Mediterranean and the NW‐European domains. This radiative evolution can be explained as the result of different factors: (1) morphological adaptation to muddy bottoms, (2) fundamental changes in the current pattern in the Tethys/Laurasian Seaway, and, possibly, (3) utilization of methane‐based chemosynthesis as alternative food source. The radiation of koninckinids, leading from the cryptic habitats of the Tethyan rocky floors to the extensive muddy bottoms of the open European shelves, was abruptly terminated by the anoxic event in the Early Toarcian Falciferum Zone. The main causes of the extinction might be: (1) the excessive warming of Tethyan deep waters by thermohaline circulation, (2) the anoxic event, which was not survived by the spire‐bearers, handicapped by their stiff, calcareous spiralia. Brachiopoda, Early Jurassic, Europe, extinction, Koninckinidae, radiation, Tethys.

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Section: Changing Current Patternmentioning

confidence: 99%

Victims of the Early Toarcian anoxic event: the radiation and extinction of Jurassic Koninckinidae (Brachiopoda)

Vörös

2002

LET

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“…Many authors have postulated a circum‐global equatorial current system flowing through the Tethys–Atlantic–Caribbean Seaway beginning in the Middle or Late Jurassic (Ager & Walley, ; Vörös, ; Cottereau & Lautenschlager, ; Stille et al ., ; Pellenard et al ., ; Bombardiere & Gorin, ; Bill et al ., ; Leinfelder et al ., ; Hotinski & Toggweiler, ; Rais et al ., , ). Such a system is invoked to explain changes in global climate during the Callovian and Oxfordian (e.g.…”

Section: Possible Scenarios That Led To High Surface Fertility In Thementioning

confidence: 99%

Mesozoic radiolarites – accumulation as a function of sea surface fertility on Tethyan margins and in ocean basins

Baumgartner

2013

Sedimentology

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Radiolarites, commonly comprising chert‐shale couplets, feature prominently in the Mesozoic stratigraphy of the Neotethyan realm. The origin and significance of these deposits, especially with regard to understanding palaeoproductivity in that region, remains controversial. This study examines transport processes and accumulation rates of radiolarians/radiolarites, as well as the chronology of radiolarite sedimentation based on revised data from the Southern Alps and new data from the Balagne Nappes, Alpine Corsica. Results suggest that the spatio‐temporal distribution of carbonate and silica on Tethyan margins was governed by extensive lateral transport of radiolarian tests from topographic highs to basins. Palaeoclimatic, rather than palaeotectonic, changes seem to have triggered changes in surface fertility which, in turn, brought about major facies changes observed in Tethyan marginal basins: Regional platform demise – possibly due to eutrophication and onset of radiolarite deposition in the Early Bajocian – can be correlated with a positive shift in the carbon isotope curve, whereas platform recovery and the end of radiolarite accumulation correlates with a gradual decline in δ13C‐values. The existence of a vigorous trans‐Pangaean, equatorial current system that could have produced regional upwelling is questioned because of evidence for Middle Jurassic to Early Cretaceous oligotrophic conditions in the Proto‐Caribbean and the Central Atlantic. The ‘Caribbean River Plume Model’ is proposed as a possible alternative to upwelling in the Jurassic Western Tethys. Dissolved nutrients may have been dispersed in low salinity lids that originated from river plumes of rivers from tropical Africa and warm‐temperate Eurasia. Vast areas of the pre‐Late Cretaceous world ocean must have accumulated radiolarites at low rates (<4 g cm−2 10−3years) represented by the condensed, long‐lived (>50 Myr) radiolarite sections observed in many Circumpacific terranes. Radiolarian chert and claystone could be the normal pelagic sediment during Ordovician to Early Cretaceous time in far‐offshore, open oceanic settings, where dilution by terrigenous material and periplatform shallow‐water carbonates was absent.

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“…France and Great Britain (Ager and Walley, 1977;Elmi et al, 1982). Other examples include the spalial distribution of the arnmonite genus Hildoceratidae, described in the Lusitanian Basin, the Cordillera Ibérica,…”

Section: Late Pliensbachianmentioning

confidence: 99%

Pliensbachian–Toarcian ostracod biogeography in NW Europe: Evidence for water mass structure evolution

Arias

2007

Palaeogeography, Palaeoclimatology, Palaeoecology

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AbsfractThis paper examines fue role played by palaeoceanographic and c1imatic conditions on the palaeobiogeography of the Pliensbachian Toarcian ostracods (Early Jurassic) in the European Epicontinental Sea (BES). The infIuence of the palaeogeography, ocean currents and sea level, temperature and salinity variations on ostracod abundance, diversity and migration pattems is reconstructed. Ostracod migration follows an antic10cbvise circulation in the eastem side of the EES, with a leading northeast southwest movement, and fue frequent arrival ofTethyan falUlas into fue central and westem parts ofthe EES during the Pliensbachian. A three-fold c1assification ofwater masses based on salinity, temperature, lithological and fossil data is proposed. The repeated inflow ofTethyan ostracods into the EES ended by the earliest Toarcian. This ostracod event is related to the opening ofthe Hispanic Corridor and to the reorganization ofthe surface and deep circulations that may have generated a cold episode at the beginning of the Toarcian.

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Mesozoic brachiopod migrations and the opening of the North Atlantic

Cited by 31 publications

References 5 publications

Victims of the Early Toarcian anoxic event: the radiation and extinction of Jurassic Koninckinidae (Brachiopoda)

Victims of the Early Toarcian anoxic event: the radiation and extinction of Jurassic Koninckinidae (Brachiopoda)

Mesozoic radiolarites – accumulation as a function of sea surface fertility on Tethyan margins and in ocean basins

Pliensbachian–Toarcian ostracod biogeography in NW Europe: Evidence for water mass structure evolution

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