The bipolar bivalve Oxytoma (Palmoxytoma) cygnipes (Young & Bird, 1822) in the Upper Pliensbachian of Germany
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 t...
| Published in: | Paläontologische Zeitschrift |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Springer-Verlag
2011
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| Subjects: | |
| Online Access: | https://doi.org/10.1007/s12542-011-0113-1 http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/6813 |
| Summary: | 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. |
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