COLLABORATIVE RESEARCH: Presaging Paleoproterozoic Global Change: Geobiology of the Late Archean Eon

合作研究：预测古元古代全球变化：太古代晚期的地球生物学

• 批准号: 0418005
• 负责人: Alan Kaufman
• 金额: $ 6.49万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0418005&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Presaging; Paleoproterozoic; Global

Project will integrate geological, paleobiological and geochemical examination of a freshly-collected Archean sediment drill-core that will be obtained in the summer of 2004. This continuous core, ~ 1000 m in length, will sample the last ~ 250 million years of Archean stratigraphy in the Hamersley Basin of the Pilbara Craton, Western Australia. Sampled lithologies will include basalt, carbonate, chert and several kerogenous pyritic shale units.This proposal is possible because of an unprecedented opportunity for collaboration with the Astrobiology Drilling Program (ADP) of the NASA Astrobiology Institute. The ADP will fund acquisition of this core. The NSF funds will be used for initial characterization of core materials to include a detailed study of paleoecology and paleoenvironment in kerogenous sediments. Importantly, core recovery will be over-seen by PI Buick and is geared specifically toward the proposed research.Intellectual Merit: The general motivation of the proposed research is to characterize the nature of life and its environment in the late Archean, shortly before the rise of atmospheric oxygen. Many workers are examining the timing of this redox transition and its relationship to contemporaneous climatic oscillations that may include global ice ages. The team's interest, somewhat different but complementary, is to understand how the Archean biosphere set the stage for this singular environmental transformation. Specifically, a major goal of this project is to characterize the relative importance of different types of microbes in late Archean marine environments and, through lithofacies relationships, to study the envi-ronmental controls on their distributions. This goal will be achieved through integrated examination of hydrocarbon molecular biomarkers, redox indicators and biogeochemical cycling in kerogenous sediments.Clean drilling methods, immediate sampling and prompt analysis will allow us to unambiguously deter-mine if taxonomically diagnostic sterane and triterpenoid hydrocarbons are indigenous to these rocks. These compounds are abundant in existing, poorly-preserved Hamersley Basin drill core and, if not contaminants, constitute the earliest biomarkers of eukaryotes and cyanobacteria. Further, analysis of the new core should permit us to examine the relative abundances and isotopic compositions of such compounds in an environmental context, yielding information about ecological relationships. Additional goals are to characterize the status of major biogeochemical cycles in the late Archean and generate a robust baseline for future investigations by conducting sedimentological and biogeochemical reconnaissance of the entire core. Collectively, this work will test the hypothesis that oxygen-generating cyanobacteria and aerobic microorganisms were present in Archean ecosystems and that the environmental imprints of these me-tabolisms remained muted for hundreds of millions of years after their origins.Broader Impact: There are three areas of broader impact. First, ~ 6 graduate students will participate in an unusually integrative and multi-disciplinary research project spanning six major research universities. While each will be rooted in a single aspect of the program, these students will have substantive opportunities to bridge across subdisciplines and institutions. Second, because the planned drill core will ultimately be openly available in accordance with the ADP charter, this work will provide a lithological and chemostratigraphic framework of benefit to the wider research community. Third, it is hoped that this NSF-NASA collaboration will provide a positive precedent for future efforts by other investigators that might ultimately evolve into a broader inter-agency "Deep Time Drilling Program".

项目将在2004年夏季将新鲜收集的Archean Sediment钻孔的地质，古生物学和地球化学检查整合。这种连续的核心长度约为1000 m，将在西澳大利亚州Pilbara Craton的Hamersley盆地的最后约2.5亿年的Archean Stratergraphy进行样品。采样的岩性将包括玄武岩，碳酸盐，切特和几个动型黄铁质页岩单元。这项提案之所以可能，是因为与NASA天文学研究所的天体生物学钻探计划（ADP）合作的前所未有的机会。 ADP将资助该核心的收购。 NSF资金将用于核心材料的初始表征，包括对动态沉积物中古生物学和古环境的详细研究。重要的是，核心恢复将被Pi Buick过高，并专门针对拟议的研究。智能优点：拟议的研究的一般动机是在大气氧气崛起之前不久，在已故的大帝中表征生命及其环境的本质。许多工人正在研究这种氧化还原过渡的时机及其与可能包括全球冰河时代的同时气候振荡的关系。该团队的兴趣有些不同，但互补的是了解大帝生物圈如何为这种奇异的环境转变奠定基础。具体而言，该项目的主要目标是表征晚期大帝海洋环境中不同类型的微生物的相对重要性，并通过岩相关系来研究Envi-Ronentals对其分布的控制。该目标将通过整合碳氢化合物生物标志物，氧化还原指标和生物地球化学循环的整合检查来实现。清洁钻孔方法，即时抽样和及时的分析将使我们能够明确地探讨如果从分类上诊断出固醇和替代性的脑苯二甲苯甲苯甲苯甲酰基，则可以实现明确的探测。这些化合物在现有的，保存不稳的哈默斯利盆地钻芯中很丰富，如果不是污染物，则构成了真核生物和蓝细菌的最早生物标志物。此外，对新核心的分析应使我们能够在环境环境中检查此类化合物的相对丰度和同位素组成，从而产生有关生态关系的信息。其他目标是表征晚期大帝中主要的生物地球化学周期的状态，并通过对整个核心进行沉积和生物地球化学侦察来为未来的研究提供强大的基线。总的来说，这项工作将检验以下假设：生成氧气生成的蓝细菌和有氧微生物存在于大帝生态系统中，并且这些Me-Tebolism的环境烙印在起源后持续了数亿年。首先，约有6名研究生将参加一个跨越六个主要的研究工具的异常综合和多学科研究项目。尽管每个人都将植根于该计划的一个方面，但这些学生将有实质性的机会跨越子学科和机构。其次，由于计划的钻头芯最终将根据ADP宪章公开公开，因此这项工作将为更广泛的研究社区提供岩性和化学地层学框架。第三，希望这种NSF-NASA合作将为其他调查人员的未来努力提供积极的先例，这些调查人员可能最终发展成为更广泛的“深度时间钻探计划”。