Collaborative Research: Stratigraphic, geochemical, and paleobiological tests of the co-evolution of multicellular life and environment in the late Ediacaran Period

埃迪卡拉纪晚期多细胞生命和环境共同演化的地层学、地球化学和古生物学测试艾伦·J·考夫曼、马里兰大学肖舒海分校、弗吉尼亚理工学院和俄罗斯科学院迪马·格拉日丹金州立大学PIS将对西伯利亚北部偏远地区以碳酸盐为主的哈特斯皮特组进行盆地范围的地层、地球化学和古生物学研究。该单元中的埃迪卡拉纪化石被显著保存在细粒碳酸盐中，有望大大增强对地球上最早的动物的解剖和古生态观点。鉴于埃迪卡拉纪生物群可能需要大量的自由氧来维持代谢活动，我们假设它们的分布可能跟踪环境条件，并建议通过对Khatyspyt沉积盆地多个等效剖面的碳和硫同位素以及其他氧化还原条件的生物、元素和同位素指标的高分辨率时间序列分析来测试这种联系。Khatyspyt组包含各种独特的碳酸盐寄主埃迪卡拉纪生物，以及碳质大型化石、小壳化石、遗迹化石和浮游微型化石，所有这些都是沿着Olenek、KhorBosuonka和Lena河连续产出的一个450米厚的连续序列。研究结果将为软组织保存现象提供洞察力，提高埃迪卡拉纪-寒武纪过渡的生态分辨率，并为地球最早的后生动物及其起源、多样化和最终灭绝的海洋的历史提供重要的制约因素。这一现场和实验室建议的主要目的是测试复杂多细胞生命中地质上简短的埃迪卡拉实验是否受控于浅海环境的氧化状态。这项拟议的研究将与俄罗斯的同事建立新的国际合作，并需要在西伯利亚北部的北极圈上空进行为期两个月的野外季节。这两所美国大学的研究生将在现场陪同PI，为他们提供增强的学习体验，促进科学和文化交流。

Stratigraphic, Geochemical, and Paleobiological Tests of the Co-Evolution of Multicellular Life and Environment in the Late Ediacaran Period Alan J. Kaufman, University of Maryland Shuhai Xiao, Virginia Polytechnic Institute and State University Dima Grazhdankin, Russian Academy of Sciences The PIs will undertake a basin-wide stratigraphic, geochemical, and paleobiological study of the carbonate-dominated Khatyspyt Formation in remote northern Siberia. Ediacaran fossils in this unit are remarkably preserved in fine-grained carbonates, promising a much enhanced anatomical and paleoecological view of Earths earliest animals. Insofar as the Ediacaran biota may have required abundant free oxygen to sustain metabolic activities, we hypothesize that their distribution may track environmental conditions, and propose tests of this linkage through high resolution time-series analyses of carbon and sulfur isotopes in multiple equivalent sections across the Khatyspyt depositional basin as well as other biological, elemental and isotopic indicators of redox conditions. The Khatyspyt Formation contains a wide range of unique carbonate-hosted Ediacaran organisms, as well as carbonaceous macrofossils, small shelly fossils, trace fossils and planktonic microfossils all in a single, 450-m-thick continuous succession cropping out along the Olenek, Khorbosuonka and Lena rivers. Results of the study should provide insights to the phenomenon of soft tissue preservation, increase the ecological resolution of the Ediacaran-Cambrian transition, and provide important constraints on the history of Earths earliest metazoans and the oceans in which they originated, diversified, and ultimately perished. The primary aim of this field and laboratory based proposal is to test whether the geologically brief Ediacaran experiment in complex multicellular life was controlled by the oxidation state of shallow marine environments. The proposed research will establish a new international collaboration with colleagues in Russia, and require two month-long field seasons above the Arctic Circle in northern Siberia. Graduate students from both U.S. institutions will accompany the PIs in the field, providing them with an enhanced learning experience that will promote both scientific and cultural exchange.