Late Wenlock carbon isotope excursions and associated conodont fauna in the Podlasie Depression, eastern Poland: a not-so-big crisis?
Late Wenlock carbon isotope excursions and associated conodont fauna in the Podlasie Depression, eastern Poland: a not-so-big crisis?
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DOI：
10.1002/gj.2674
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发表时间：
2016-09-01
影响因子：
1.8
通讯作者：
Munnecke, Axel
中科院分区：
文献类型：
--
作者：
Jarochowska, Emilia;Munnecke, Axel
中志留世大危机指的是笔石灭绝事件和双峰正碳同位素漂移开始时的动物群更替。这场危机被认为会影响牙形刺，导致它们逐步灭绝的复杂古生态模型，被称为穆德事件。然而，这一事件对哥特兰和志留纪波罗的海盆地以外的牙形刺动物群的影响尚不清楚。在这里，它在Widowo IG-1核心(波兰东部)进行了检查。该岩芯的中志留世序列代表了东欧克拉通陆架上热带碳酸盐斜坡上的前滨、浅滩和泻湖环境。已经确定了三个正的C-13(Carb)漂移；上面的两个漂移与Mulde同位素异常和两个全球海平面回归相关。被认为受到灭绝事件影响的牙形刺物种要么没有被观察到，要么在整个灭绝间隔内排列不同。它们频率的变化可以用Widowo IG-1岩心文洛克晚期地层的层序地层学结构来很好地解释。这次大危机的影响很小，可能反映了整个研究区间的相均一性，支持了陆缘环境中文洛克晚期牙形刺的更替主要是由海平面控制的相移驱动的假说。版权所有(C)2015 John Wiley&Sons，Ltd.
The middle Silurian big crisis' refers to a graptolite extinction event and faunal turnover at the onset of a double-peaked positive carbon isotope excursion. The crisis has been proposed to affect conodonts, giving rise to a sophisticated palaeoecological model of their stepwise extinction, known as the Mulde Event. However, the impact of the event on conodont faunas outside Gotland and the Silurian Baltic Basin remains unknown. Here, it is examined in the Widowo IG-1 core (E Poland). The middle Silurian succession in this core represents foreshoal, shoal, and lagoonal settings on a tropical carbonate ramp on the shelf of the Eastern European Craton. Three positive C-13(carb) excursions have been identified; the two upper excursions correlate with the Mulde isotope anomaly and with two global eustatic regressions. Conodont species proposed to be affected by the extinction event either were not observed or ranged through the extinction interval. Changes in their frequencies are best explained by the sequence stratigraphic architecture of the late Wenlock strata in the Widowo IG-1 core. The little impact of the big crisis' may reflect facies homogeneity across the studied interval, supporting the hypothesis that the late Wenlock conodont turnover in epicontinental settings was primarily driven by eustatically controlled facies shifts. Copyright (c) 2015 John Wiley & Sons, Ltd.