Sedimentary Environments and Biodiversity of Ichnofaunas at the pC/C-Boundary of the Yangtze Platform: Palaoecologic and Biostratigraphic Significance

该建议概述了扬子地台PC/C界线段的沉积学、地层学和古生物学方面的内容。对沉积领域及其遗迹化石组合的古生态解释将置于生物地层学的背景下，从而增加对地球历史上这一关键时间段的理解。现代沉积学重新评价和解释选定的有关层序和事件地层属性的关键剖面，将识别主要的沉积环境，并提供关键的古环境参数。某些遗迹类的首次出现以及典型遗迹组合的组成和分布反映了后生动物演化的各个阶段(行为、生活方式和策略、种间和种内关系等)，从而为其他未发现生命化石的沉积物中的后生动物演化提供了数据。最近，一些遗迹分类群被成功地用作PC/C界线分带和全球对比的指示化石。在扬子地台沉积的许多剖面中，真实的生物地层学标志(如尖晶石、小壳化石和早期三叶虫)与保存完好的鱼纲动物群共存的独特情况，首次使我们能够标定跨越PC/C界线的某些遗迹类的真实生物地层意义。

This proposal outlines sedimentologic-stratigraphic and palaeobiological aspects of the pC/C boundary interval of the Yantze Platform. Paleoecologic interpretations of the depositional realm and its trace fossil assemblage will be placed in a biostratigraphic context, thus adding to the understanding of this critical time interval in earth history. A modern sedimentological re-evaluation and interpretation of select key sections regarding sequence- and event-stratigrahic attributes will identify the dominant sedimentary environments and provide critical palaeoenvironmental parameters. The first appearances of certain ichnotaxa, and the composition and distribution of typical ichnoassemblages reflect evolutionary stages in the metazoan evolution (behavior, life styles and strategies, inter- and intraspecific relations etc.), and therefore supply data on the metazoan evolution in otherwise unfossilifeous sediments. Several ichnotaxa have recently been used with various succes as index fossils for pC/C boundary zonation and global correlation. The unique situation of a co-occurrence of true biostratigraphy markers (such as acritarchs, small shelly fossils and early trilobites) and well-preserved ichnofaunas in many sections of the Yangtze platform sediments allows, for the first time, the calibration of the true biostratigraphic significance of certain ichnotaxa occuring across the pC/C boundary.