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Extinctions and survivals in a Mediterranean Early Jurassic brachiopod fauna (Bakony Mts, Hungary)

Vörös, Attila (1995) Extinctions and survivals in a Mediterranean Early Jurassic brachiopod fauna (Bakony Mts, Hungary). Hantkeniana, 1. pp. 145-154. ISSN 1219-3933

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Abstract

Detailed analysis of diversity, tumover and extinction rate has been undertaken for the Pliensbachian brachiopod fauna of the Bakony Mts (Hungary). There is an early peak of diversity in the Ibex Zone, then a steady decline to the Stokesi Zone and a second peak in the Margaritatus Zone. The Early Toarcian crisis is preceded by a rapid fali in the Spinatum Zone. The gradual decline of the Pliensbachian brachiopod fauna is thought to reflect decreasing food supply due to the gradual subsidence of the sea bottom in the Bakony area. The diversity peaks in the Ibex and Margaritatus Zones coincide with episodes of local tectonic movements along fault scarps bordering submarine horsts. These might produce fresh, empty rock surfaces and talus blocks at the foot of the escarpments. This sudden increase in the available rock surfaces greatly enhanced the growth of brachiopod communities. Another factor, possibly related to reiuvenation of tectonic movements, may be the activity of submarine cold seeps carrying nutrients to the starving environment and supporting chemosynthetically based communities.

Item Type: Article
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH526 Paleontology / őslénytan
Depositing User: Zsolt Baráth
Date Deposited: 13 Jan 2023 08:53
Last Modified: 13 Jan 2023 08:53
URI: http://real.mtak.hu/id/eprint/156428

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