A Fresh Look at Lipid Biomarker Evidence for Neoproterozoic Animals
报告人（单位）
Gordon Love (University of California-Riverside)
报告时间
2022年2月14日（星期一）11:00 AM
主办方
中国古生物学会地球生物学分会
直播二维码
报告人介绍
Gordon is a Professor of Geochemistry and is currently the Chair of the Department of Earth & Planetary Sciences at University of California-Riverside. Gordon is an organic geochemist who analyzes lipid biosignatures preserved in the ancient sedimentary record. A major focus has been Proterozoic and Paleozoic biomarker records to track the evolutionary rise of eukaryotes, the protracted oxygenation of the ocean and the biological & environmental impact of mass extinctions. In this talk he will present and discuss proposed evidence for early animals from sterane biomarkers preserved in Neoproterozoic rocks, which is currently a hot topic.
报告摘要
Three C30 sterane compounds are typically found together in the Cryogenian and Ediacaran rock record. Both 24-isopropylcholestane (24-ipc) and 26-methylstigmastane (26-mes) are produced in abundance by multiple groups of demosponges and have been used as early animal biomarkers. Recently, it has been suggested that these C30 steranes are alternatively derived from either: i) biogenic C30 steroids from rhizarian protists, and/or ii) diagenetic modification of C29 sterol precursors made principally by ancient green algae. If correct, this undermines their robustness and the interpretative value of these steranes as early animal markers. A new analysis of Cryogenian and Ediacaran biomarker patterns from thermally immature rocks from South Oman strongly indicates C30 steranes in these rocks are primary signals, derived from ancient C30 sterol precursors. I will also discuss the controversial evidence published recently by others for putative Ediacaran steroids associated with Dickinsonia and Andiva fossils from White Sea region of Russia.