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界线段的沉积地层学和古生物学方面。沉积领域的古生态学解释及其微量化石组合将被放置在生物地层学的背景下，从而增加了对地球历史中这一关键时间间隔的理解。现代沉积学重新评价和解释选定的关键部分序列和事件地层属性将确定主要的沉积环境，并提供关键的古环境参数。某些遗迹分类群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），从而提供了在其他无生命的沉积物中后生动物演化的数据。近年来，几种遗迹分类群已被成功地用作pC/C边界分带和全球对比的指标化石。在扬子地台沉积物的许多剖面中，真正的生物地层学标志（如疑源类、小壳化石和早期三叶虫）和保存完好的遗迹动物群的共同出现，这一独特的情况首次允许对某些跨越pC/C界线的遗迹动物群的真正生物地层学意义进行标定。

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.