文章基本信息

标题：The Frasnian-Famennian events in a deep-shelf succession, Subpolar Urals: biotic, depositional, and geochemical records
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作者：ALEXANDRA B. YUDINA ; GRZEGORZ RACKI ; NORMAN M. SAVAGE 等
期刊名称：Acta Palaeontologica Polonica
印刷版ISSN：0567-7920
电子版ISSN：1732-2421
出版年度：2002
卷号：47
期号：2
页码：355-372
语种：English
出版社：Institute of Paleobiology PAS
摘要：The Frasnian-Famennian (F-F) boundary is well biostratigraphically documented in the Palmatolepis-rich deposits exposed along the Sywiu River in the lower slopes of the Subpolar Urals. The thin-bedded calcareous-clayey-siliceous deep-slope succession of the Vorota Formation appears to represent continuous Domanic-type deposition throughout the world-wide carbonate crisis time, without evidence for the basal Famennian hiatus or a large-scale sedimentary perturbation within a regressive setting. The northernmost Laurussian sequence exhibits many well known signatures throughout the broad F-F timespan: the appearance of organic- and clay-rich deposits, icriodontid and radiolarian blooms, and a correlative shift of several geochemical proxies towards hypoxic and high-productivity regimes, perfectly recorded by positive d13Ccarb excursions of +3.5 o/oo. Integrative biotic, microfacies and geochemical data substantiate a longer-term oceanographic destabilization, attributable to multiple Earth-bound triggering factors in (episodically enhanced?) greenhouse climate and punctuated eustatic sea-level highstands, superimposed on the elevated deposition of organic carbon-rich sediments during the Upper Kellwasser Event. Unsteady eutrophicated, and oxygen-depleted ecosystems during the F-F biotic crisis interval could be assumed, especially when intensified by various spasmodic tectono-volcanic phenomena in the incipiently closing Ural Ocean.
关键词：Frasnian;Famennian;Kellwasser Crisis;conodonts;microfacies;carbon isotopes;geochemistry;Timan- Pechora Basin