EAR-PF: The Silicification of Soft-Bodied Biotas: Reconstructing the Preservation, Ecology and Environments of Earth's Earliest Animal Communities

Lidya Tarhan博士获得了NSF地球科学博士后奖学金，在耶鲁大学和加州理工学院开展了一项研究和扩大参与计划，重点是复杂生命的多样化。她将通过一种多学科的方法，采用新的地球化学、岩石学、古生物学和实验技术，研究生物地球化学过程，特别是早期硅化在地球上最早的动物群落石化中的作用。异常保存的软体化石组合为了解古代群落和环境的生物、生态和化学提供了独特的窗口。开发模型来解释导致这种特殊保存的石化路径，对于重建生物多样性的初始步骤以及早期复杂生命辐射期间盛行的环境条件至关重要。此外，塔尔汉博士将使用的许多新兴分析技术可能不仅有助于揭示导致砂岩中化石异常保存的过程，还有助于揭示早期和晚期胶结作用在砂岩油藏孔隙度和渗透率发展中所起的作用。她的指导和外展工作将与耶鲁大学皮博迪博物馆的世界级藏品以及教育和外展项目相结合。例如，她将通过参与皮博迪进化课外计划以及指导本科生地球科学研究项目，促进科学研究和批判性思维技能的发展。地球上最早的动物生态系统埃迪卡拉生物群保存在全球埃迪卡拉晚期(约5.8亿-5.41亿年)地层中。埃迪卡拉化石组合包括保存完好的神秘形态和亲缘关系的软体形式。大部分埃迪卡拉化石组合以铸件和模具的形式保存在砂岩层中。然而，对于软体埃迪卡拉生物群和类似的砂岩托管的年轻生物群是如何保存下来的，几乎没有机械上的理解，这阻碍了重建这些开创性群落的生物学和生态的尝试。我们对这些生物的生态学知识--对于分析从埃迪卡拉生物群到显生宙(我们目前的地球历史上的亿万年)的过渡和解决埃迪卡拉纪-显生肖过渡的生态和生物地球化学特征至关重要的信息--目前是不完整的。充分了解地球历史上这段时期特有的石化途径，对于重建这些早期动物生态系统的复杂性至关重要。这项工作将阐明埃迪卡拉纪和早期显生宙古生物学中长期存在的问题，并阐明环境在地球上复杂生命的早期发展、辐射和保护中所起的作用。

Dr. Lidya Tarhan has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out a research and broadening participation plan, focused on the diversification of complex life, at Yale University and the California Institute of Technology. Through a multidisciplinary approach, employing novel geochemical, petrographic, paleobiological and experimental techniques, she will investigate the biogeochemical processes and particularly the role of early-stage silicification in the fossilization of Earth's earliest animal communities. Exceptionally preserved soft-bodied fossil assemblages offer unique windows into the biology, ecology and chemistry of ancient communities and environments. Developing models to explain the fossilization pathways responsible for this exceptional preservation is essential to reconstructing the initial steps in biological diversification, as well as the environmental conditions that prevailed during the radiation of early complex life. Further, many of the emerging analytical techniques Dr. Tarhan will utilize may help to shed light not only on the processes responsible for the exceptional preservation of fossils in sandstones, but also the role played by early- and late-stage cementation in the development of porosity and permeability in sandstone petroleum reservoirs. Her mentoring and outreach efforts will be carried out in association with the world-class collections and educational and outreach programs of Yale University's Peabody Museum. For instance, she will foster the development of scientific inquiry and critical thinking skills of student groups underrepresented in the sciences through participation in the Peabody's EVOLUTIONS after-school program, as well as by mentoring undergraduate geoscience research projects.The Ediacara Biota, Earth's earliest animal ecosystem, is preserved in terminal Ediacaran (~580-541 million years old) strata worldwide. Ediacara fossil assemblages consist of exceptionally preserved soft-bodied forms of enigmatic morphology and affinity. The majority of Ediacara fossil assemblages are preserved in situ as casts and molds in sandstone beds. However, there is little mechanistic understanding of how the soft-bodied Ediacara Biota and similar sandstone-hosted younger biotas were preserved, hindering attempts to reconstruct the biology and ecology of these seminal communities. Our knowledge of the ecology of these organisms-information that is essential to analyzing the transition from the Ediacara Biota to the faunas of the Phanerozoic (our current eon of Earth history) and to resolve the ecological and biogeochemical character of the Ediacaran-Phanerozoic transition-is currently incomplete. A full understanding of the fossilization pathways unique to this interval in Earth history is essential to reconstruct the complexity of these early animal ecosystems. This work will shed light on long-standing issues in Ediacaran and early Phanerozoic paleobiology, and also illuminate the role played by environment in the early development, radiation and preservation of complex life on Earth.