Benthic mass-mortality events on a Middle Miocene incised-valley tidal-flat (North Alpine Foredeep Basin)

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• 作者：Oleg Mandic ; Mathias Harzhauser ; Reinhard Roetzel and Paul Tibuleac
• 关键词：Sarmatian ; Estuary ; Green ; tide ; Hypoxia ; Molluscs ; Hermit crabs ; Solenid bivalves
• 刊名：Facies
• 出版年：2008
• 出版时间：August, 2008
• 年：2008
• 卷：54
• 期：3
• 页码：343-359
• 全文大小：1.1 MB

文摘

A sedimentological and palaeontological description of the Middle Miocene marine tidal-flat deposits in a ca. 50-km-long incised valley in the eastern part of the North Alpine Foreland Basin is presented. The investigated outcrop documents the environmental shifts in the middle part of this extremely long, narrow, and shallow embayment of the Central Paratethys Sea during the Sarmatian. Sedimentological features point to some tidal influence at that time. The section yields an outstanding Fossillagerst?tte with census assemblages of solenid bivalves and potentially pagurized batillariid gastropods in death position. The position of the fossils and the adjoining concretions of former iron-sulfide point to hypoxic events as causes for the benthic mass-mortalities. Based on comparison with modern estuaries, eutrophication and subsequent blooms of macro-algae washing ashore might have triggered the hypoxia in the intertidal zone. The position of the obliquely buried batillariid gastropod shells hints at the occurrence of otherwise completely unrecorded hermit crabs in the highly endemic fauna of the Paratethys Sea during the Sarmatian.