Plancton foraminifera, biostratigraphy and palaeoclimatology across the Eocene/Oligocene boundary in Loburg 1/90 borehole (Sachsen-Anhalt)

Loburg 1/90 钻孔始新世/渐新世边界的浮游有孔虫、生物地层学和古气候学（萨克森-安哈尔特）

• 批准号: 204228204
• 负责人: Professor Dr. Michael Schudack (†)
• 金额: --
• 依托单位: Fachrichtung Paläontologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/204228204?language=en
• 关键词: Plancton; foraminifera; biostratigraphy; palaeoclimatology; across

Borehole Loburg 1/90 (Sachsen-Anhalt, Germany) records the Eocene/Oligocene transition beds of the southeastern part of the ancient North Sea quite completely. The worldwide temperature drop of that interval of time is currently under multidisciplinary investigation by several groups of scientists. Our own stable isotope research has already shown that such a considerable temperature drop has alreay existed in the North Sea Basin of that time, but its exact stratigraphic position has been under intensive discussion (and with conflicting opinions). Using benthic foraminifera for biostratigraphy in a former project, we have already been able to contradict previous opinions and date the time of the temperature drop into a stratigraphical interval somewhat above the Eocene/Oligocene boundary, which would coincide with the interruption of the palaeogeographic connection between the Tethys and the North Sea and thus the inflow (via Poland) of warm Tethyan watermasses.During this project´s research, we have been able to support these views by our new biostratigraphy using plancton foraminifera. Moreover, we have been able to date the Eocene/Oligocene boundary into the uppermost part of the Upper Schönwalde Formation. Additional information about the separation of ocean current vs. antarctic glaciation influences onto the dO18 curve (leading vs. heavier values) has been derived from Mg/Ca analysis of calcite shells (pointing to the same explication as described above). In the final phase of our research on the Loburg foraminifera, we intend to carry out more Mg/Ca measurements (again in order to decipher the two possible influences onto the dO18 trend from each other) and also use strontium isotope stratigraphy in order to confirm (if possible) our stratigraphical conclusions derived from the foraminifera (both benthic and planctic). Final goal of the project is a summarizing interpretation, based on a set of interdisciplinary and solid data, of the palaeoclimatic and palaeooceanographic evolution of the ancient North Sea across the Eocene/Oligocene transition.

Borehole Loburg 1/90（德国萨克森-安哈尔特）相当完整地记录了古北海东南部的始新世/渐新世过渡层，目前多个科学家小组正在对这一时期的全球气温下降进行多学科研究。我们自己的稳定同位素研究已经表明，当时的北海盆地已经存在如此大的温度下降，但其确切的地层位置一直在激烈讨论（并且存在相互矛盾的问题）。在以前的项目中使用底栖有孔虫进行生物地层学，我们已经能够反驳以前的观点，并将温度下降的时间确定为略高于始新世/渐新世边界的地层区间，这与之间的古地理联系的中断相一致。特提斯海和北海，以及由此而来的特提斯温暖水团（经由波兰）的流入。在该项目的研究过程中，我们已经能够通过我们的研究来支持这些观点此外，我们还能够确定上 Schönwalde 地层最上部的始新世/渐新世边界。有关洋流与南极冰川作用对 dO18 曲线影响的分离的更多信息。重值）是从方解石壳的 Mg/Ca 分析中得出的（与上述相同的解释）。 Loburg foraminifera，我们打算进行更多的 Mg/Ca 测量（再次是为了破译彼此对 dO18 趋势的两种可能影响），并使用锶同位素地层学来确认（如果可能的话）我们从该项目的最终目标是基于一组跨学科和可靠的数据对有孔虫（底栖和浮游）进行总结性解释。古北海始新世/渐新世过渡时期的古气候和古海洋演化。