Dinoflagellate and calcareous nannofossil response to sea-level change in Cretaceous-Tertiary boundary sections
Dinoflagellate and calcareous nannofossil response to sea-level change in Cretaceous-Tertiary boundary sections
复制标题
白垩纪-第三纪边界剖面甲藻和钙质超微化石对海平面变化的响应
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
C. Kramer
中科院分区：
文献类型：
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作者：
D. Habib;S. Moshkovitz;C. Kramer
研究了阿拉巴马州中南部的地层剖面，以测试白垩纪-第三纪边界海平面变化的孢粉学证据。来自钙质纳米化石和鞭毛藻囊的新证据表明，阿拉巴马（1型层序边界）的区域不整合实际上位于K-T边界。这表明海平面下降可能导致了大灭绝事件。甲藻多样性在海岸覆盖的系统和组成部分之间存在差异。这个参数对于解释这部分剖面的海平面变化是有用的，因为鞭毛藻没有参与大灭绝。Braggs附近道路上的铱峰是最早的达尼安时代，其相对量级与Gubbio层型剖面中K-T边界正上方报道的较低值相对应。在新生代第一次海平面上升时期，富铱海洋侵入陆架时，在藻类有机质生产力较高的时期，铱集中在海洋泛洪面。
Stratigraphic sections in south-central Alabama were studied to test palynological evidence of sea-level change across the Cretaceous-Tertiary boundary. New evidence from both calcareous nannofossils and dinoflagellate cysts places the regional disconformity in Alabama (Type 1 sequence boundary) virtually at the K-T boundary. This suggests that sea-level fall may have contributed to the mass-extinction event. Dinofagellate diversity varies between systems tract components of coastal onlap. This parameter is useful for interpreting sea-level change in this part of the section, because dinoflagellates did not participate in the mass extinction. The iridium spikes in the roadcut near Braggs are of earliest Danian age and correlate in relative magnitude with the lower values reported from directly above the K-T boundary in the Gubbio stratotype section. Iridium was concentrated in marine flooding surfaces in episodes of higher productivity of algal organic matter at the time when the iridium-enriched ocean encroached on the shelf during the first Cenozoic episode of sea-level rise.