Multistratigraphic framework for continental Permian-Triassic boundary sections of northern Pangaea: key to a better understanding of the ecological consequences of the end-Permian crisis in the terrestrial realm

二叠纪-三叠纪边界（PTB）的全球过程造成了已知最严重的生物多样性危机。为了了解这次大灭绝的触发机制，需要对海洋和陆地生态系统进行多学科研究。在海洋领域，连续的化石记录可以实现高分辨率的生物地层学，而在陆地领域，由于不连续的沉积作用，时间分辨率通常受到限制。因此，海洋-陆地远程联系很难被发现，因此是一个极具争议的话题。此外，盘古大陆北部大部分陆地结核剖面的特征是在关键结核间隔处出现断裂。因此，中欧，俄罗斯向斜，西伯利亚和中国北部的少数完整的陆地PTB部分对于破译二叠纪末期危机的触发过程至关重要。因此，项目目标是：A)项目目标是利用多地层方法检测PTB在大陆系列中的位置，并将大陆边界剖面与海洋参考剖面相关联。生物地层学研究将集中于壳甲纲。目前基于螺壳类的对比方案需要通过火山碎屑的放射性定年以及磁和化学地层（d13C-、d18O-、d34s -同位素）数据的整合来完善和校准。B)此外，该项目的目的是详细阐述生物和非生物数据，这些数据适用于在不同的大地构造和气候背景下描述海洋-大陆混合以及纯大陆PTB剖面的环境变化。重点放在孢粉相、相结构和古土壤的文献以及同位素和沉积物地球化学上。选取的边界剖面构成了从梅山海相层型剖面到中国南部海陆混合剖面到中国北部纯大陆剖面的样带。这些边界剖面可以通过海洋化石（牙形刺、镰状刺）和火山碎屑的辐射测量数据进行精确的对比。该样带由俄罗斯向斜的大陆PTB剖面延续，具有精确的四足动物和磁/同位素地层格架，并通过匈牙利和波兰到达中欧盆地的连续PTB剖面。所有这些剖面都在关键的PT转换（自己的初步工作）中发现了贝壳类动物，这将使海洋-陆地的精确对比成为可能。此外，样带还跨越了不同的大地构造单元和不同的生物群系。因此，有可能将区域构造和区域气候过程（古纬度的影响）与PTB的全球过程区分开来。所获得的数据将有助于对关于PTB事件及其触发机制的现有假设进行批判性分析，最后将有助于了解引起生态系统重大扰动的全球过程。

Global processes at the Permian-Triassic boundary (PTB) caused the most severe biodiversity crisis known. In order to understand the triggering mechanisms of this mass extinction, multidisciplinary research on marine and terrestrial ecosystems is required. Within the marine realm a continuous fossil record enables high-resolution biostratigraphy, whereas time resolution is usually limited in the terrestrial realm due to discontinuous sedimentation. Thus, marine-terrestrial teleconnections are difficult to detect and therefore a highly controversial topic. Additionally, the majority of terrestrial PT sections of northern Pangaea are characterized by a hiatus at the critical PTB interval. Consequently, the few complete terrestrial PTB sections of central Europe, the Russian syncline, Siberia and N China are pivotal for deciphering the triggering processes of the end-Permian crisis. Accordingly, project aims are:A) The project aims to detect the position of the PTB in continental series using a multistratigraphic approach, and to correlate continental boundary sections with marine reference sections. Biostratigraphic investigations will focus on conchostracans. The current correlation schemes based on conchostracans need to be refined and calibrated by radiometric dating of pyroclastics as well as by integrating magneto- and chemostratigraphic (d13C-, d18O-, d34S-isotope) data. B) Furthermore, the project aims to elaborate biotic and abiotic data which are suited to characterize environmental changes in mixed marine-continental as well as in exclusively continental PTB sections within different geotectonic and climatic settings. The focus is set on palynofacies, documentation of facies architectures and palaeosoils as well as on isotopic and sediment geochemistry. The selected boundary sections form a transect from the marine stratotype section in Meishan (S China) via mixed marine-continental sections in S China to pure continental sections in N China. These boundary sections can be precisely correlated by marine fossils (conodonts, fusulinids) and radiometric data from pyroclastics. The transect is continued by continental PTB sections of the Russian syncline with a precise tetrapod- and magneto-/isotope-stratigraphic framework, and via Hungary and Poland to the continuous PTB section of the Central European basin. All these sections yield conchostracans in the critical PT transition (own preliminary work) which will enable precise marine-terrestrial correlations. Furthermore, the transect crosses different geotectonic units and different biomes. Thus, it will be possible to distinguish regional tectonical and regional climatic processes (effects of palaeolatitude) from global processes across the PTB. The data obtained will enable a critical analysis of existing hypotheses on the PTB event and its triggering mechanisms and finally, will contribute to the understanding of global processes causing major perturbation of ecosystems.