High-resolution biometry and morphometric characterization of calcareous nannofossils during the Oceanic Anoxic Events 1a and 1d in a global context

基于其全球分布和对生态变化的敏感性，钙质纳米化石是重建过去气候条件的理想代用物。迄今为止，人们对钙质纳米化石组合的研究主要是为了了解其生态参数。近年来对单个物种的生物测量研究表明，球粒石的大小变化可能与生态变化有关。然而，对尺寸变化的驱动力的理解很差。因此，我们计划在海洋缺氧事件1a和1d （OAE 1a, 1d）的全球和剧烈影响下，对中白垩纪最常见的球石物种的尺寸变化进行高分辨率研究。在这两种情况下，将使用来自不同纬度和明确设置的材料。下Aptian OAE 1a的Boreal Realm将由四个地方代表（北海：North Jens-1和Adda-2；下萨克森州盆地：Alstätte 1和Hoheneggelsen KB09）。将获得的数据与特提斯的现有结果进行比较，将有助于更好、更广泛地了解气候变化和球粒岩尺寸变化的原因。OAE 1d的材料将从全球主要地区的三个地点进行调查：德国（Kirchrode I / Anderten I），大西洋（ODP Site 1052E）和印度洋（ODP Site 763B）。本研究的目的是：了解不同地点和环境下球岩石尺寸变化的原因；测试这些尺寸变化是否具有全球同步性；建立尺寸变化作为oae的生态指标。

Based on their global distribution and their sensitivity to ecologicalchanges, calcareous nannofossils are ideal proxies for reconstructing past climatic conditions. Up to now, calcareous nannofossil assemblageshave been studied particularly to understand ecological parameters. Biometric studies of individual species in recent years have shown, that size variations of coccoliths can be associated with ecological changes. The understanding of the driving forces of size variation is, however, poor. We therefore plan to do a highresolution study on the size variation of the most-common coccolith species of the mid-Cretaceous with respect to the global and radical impact of the Oceanic Anoxic Events 1a and 1d (OAE 1a, 1d). In both cases, material from different latitudes and well defined settings will be used. The lower Aptian OAE 1a of the Boreal Realm will be represented by four localities (North Sea: North Jens-1 and Adda-2; Lower Saxony Basin: Alstätte 1 and Hoheneggelsen KB09). A comparison of the data obtained with the existing results from the Tethys will lead to a better and broader understanding of the climatic changes and the reasons for the coccoliths size variation. Material of the OAE 1d will be investigated from three localities spanning major parts of the globe: Germany (Kirchrode I / Anderten I), the Atlantic (ODP Site 1052E) and the Indian Ocean (ODP Site 763B). The study aims at a) understanding the reasons for size variations of coccoliths from different sites and settings, b) testing whether these size variations are globally synchronous and c) establishing size variation as an ecological proxy for OAEs.