Publication Date:
2021-04-25
Description:
The morphologically conspicuous bivalve Oxytoma (Palmoxytoma) cygnipes (Young & Bird, 1822), known for its palaeogeographically bipolar distribution, from a limestone bed in the boundary “Belemniten–Schichten”/Amaltheenton formation, Lower Jurassic, in N Germany is described. The occurrence of this palaeoceanographically significant bivalve points to an influx of cool seawater from the Arctic to the North-German Basin at the base of the Upper Pliensbachian, just before the deposition of the Amaltheenton formation. A review of previously reported occurrences on the NW European Shelf indicates two distinct stratigraphic intervals of occurrence of this taxon: the Rhaetian–Hettangian boundary and the Upper Pliensbachian. Whereas the former interval of occurrence may be related to short-term cooling in the course of the end-Triassic extinction event, the latter is interpreted as reflecting the influx of a cool water current to the eastern part of the NW European Shelf, which continued southwards parallel to the coast of the Bohemian–Vindelician High.
Keywords:
Bivalvia; Germany; Triassic–Jurassic boundary; Pliensbachian; Boreal; Bivalvia; Deutschland; Trias–Jura-Grenze; Pliensbachium; Boreal
;
551
;
Earth Sciences; Paleontology
Language:
English
Type:
article
,
publishedVersion
Format:
application/pdf
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