Astronomical signatures in Late Devonian black shales of the Rhenish Massif.

莱茵地块晚泥盆世黑色页岩的天文特征。

• 批准号: 451461400
• 负责人: Professor Dr. David De Vleeschouwer, Ph.D.
• 金额: --
• 依托单位: Analytical, Environmental, and Geo-Chemistry (AMGC) Research Unit
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/451461400?language=en
• 关键词: Astronomical; signatures; Late; Devonian; black

The Late Devonian (380 – 359 million years ago (Ma)) was a time of dynamic climate change, episodic ocean anoxia, biodiversity loss and innovation. The entanglement of these developments is best illustrated by the Late Devonian mass extinction event at the Frasnian–Famennian boundary (374 Ma). Yet, the entire Late Devonian represents a complete reorganization of marine ecosystems, in a series of extinction events associated with ocean anoxia (e.g. Kellwasser, Annulata, Dasberg and Hangenberg crises). In the Rhenish Massif, the sedimentologic expression of this series of extinctions has been studied since almost 200 years (von Dechen, 1823), which makes the Rhenish Massif extremely well-documented in terms of lithostratigraphy, microfacies, biostratigraphy and faunal assemblages. The next important step is understanding the cyclicity of Devonian sedimentary sequences in the Rhenish Massif, first to refine the geological time scale and second to provide paleoclimate insights for this high-CO2 world. With this proposal, I am requesting the means to construct accurate and consistent astrochronologies for three Late Devonian time slices at three different field sites: The Kellwasser events at the Winsenberg roadcut near Diemelsee-Adorf; the Annulata and Dasberg crises at the Effenberg Quarry; and the Hangenberg crisis at the Borkewehr section. The research team will seek to combine cyclostratigraphic age-depth models with well-established biostratigraphies to provide global correlations towards other Late Devonian reference sections. This approach could yield valuable new constraints for the geologic time scale. However, the main objective of this proposal resides with the fact that accurate astrochronologies constitute a prerequisite to quantify rates and durations of Late Devonian climate and carbon-cycle processes. For example, the development of ocean anoxic conditions. This proposal provides a unique opportunity to evaluate the role of astronomical Milankovitch forcing in prompting and pacing Late Devonian carbon cycle perturbations and extinction pulses.

泥盆纪晚期（3.8亿-3.59亿年前（Ma））是一个气候动态变化、海洋缺氧、生物多样性丧失和创新的时期。这些发展的纠缠是最好的说明了晚泥盆世的大规模灭绝事件在弗拉斯阶-法门阶边界（374马）。然而，整个晚泥盆世代表了一个完整的重组海洋生态系统，在一系列灭绝事件与海洋缺氧（例如Kellwasser，Annulata，Dasberg和Hangenberg危机）。在莱茵地块，这一系列沉积的沉积学表现已经研究了近200年（von Dechen，1823年），这使得莱茵地块在岩石地层学、微相、生物地层学和动物群组合方面得到了非常好的记录。下一个重要的步骤是了解莱茵地块泥盆纪沉积序列的旋回性，首先是细化地质时间尺度，其次是为这个高二氧化碳世界提供古气候见解。有了这个建议，我要求的手段，以构建准确和一致的天文年表的三个晚泥盆世的时间片在三个不同的现场：在迪梅尔塞-阿多夫附近的文森堡道路切割的Kellwasser事件;在埃芬贝格采石场的环形和达斯贝格危机;和Hangenberg危机在Borkewehr部分。该研究小组将寻求将联合收割机旋回地层年龄-深度模型与成熟的生物地层学相结合，以提供与其他晚泥盆世参考剖面的全球对比。这种方法可以产生有价值的新的地质时间尺度的限制。然而，这一建议的主要目标在于准确的天体年代学是量化晚泥盆世气候和碳循环过程的速率和持续时间的先决条件。例如，海洋缺氧条件的发展。这一建议提供了一个独特的机会，以评估天文米兰科维奇强迫的作用，促进和起搏晚泥盆世碳循环扰动和灭绝脉冲。