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Evidence from Paleosols for Acid Rain at the Cretaceous- Tertiary Boundary

白垩纪-第三纪边界酸雨的古土壤证据

基本信息

批准号：
9103178
负责人：
Gregory Retallack
金额：
$ 3.32万
依托单位：
University of Oregon Eugene
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1991
资助国家：
美国
起止时间：
1991-06-01 至 1992-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9103178&HistoricalAwards=false
关键词：
Evidence Paleosols Acid Rain Cretaceous

项目摘要

This proposal is for a small grant for exploratory research (SGER): a pilot study of buried soils to attempt to detect mobilization of heavy trace metals, decalcification and podzolization that should have accompanied the nitric acid rain predicted by some scenarios of extraterrestrial impact at the Cretaceous-Tertiary boundary. A suitably complete sequence of buried soils across this geological boundary has been located and sampled in Bug Creek, eastern Montana. Analyses of selected paleosols will be performed by AA (major and trace elements), isotopic dilution mass spectrometry (for Pb) and Walkley-Black (for organic carbon) techniques. Petrographic studies also will be undertaken in order to complete documentation of the subsurface clayey (Bt) horizons and other paleoenvironmentally significant features of the paleosols. Nitric acid rain would be indicated by strong depletion of the paleosol at the boundary in Pb and other heavy metal trace elements, compared to the depth function for these elements in paleosols above and below the boundary that are otherwise similar petrographically, chemically and in burial history. Should this research prove to indicate acid rain, then full scale search of other sequences of paleosols across the Cretaceous-Tertiary boundary would be warranted. Should this research be unsuccessful indicating acid rain, it may nevertheless add paleoenvironmental information for reconstructing events at this place and time in Earth history.

这份提案是为探索性研究提供一笔小额赠款（SGER）：对掩埋土壤进行试验性研究，重痕量金属的移动、脱钙和灰化作用本应伴随着硝酸雨一些外星人撞击的情景预测，第三系界线。适当完整的序列已经找到了跨越这一地质边界的埋藏土壤，在蒙大拿州东部的布格溪采样分析选定的用AA（常量和微量元素）对古土壤进行分析，同位素稀释质谱法（Pb）和Walkley-Black（有机碳）技术。岩石学研究也将是为了完成地下的记录，粘土（Bt）层和其他古环境意义古土壤的特征。硝酸雨的指示是边界古土壤强烈亏损，重金属微量元素，相比之下，这些元素在边界之上和之下的古土壤中在岩石学、化学和埋藏学上相似历史如果这项研究证明是酸雨，全面搜索其他序列的古土壤第三纪-第三纪界线是有根据的。如果这种研究表明酸雨是不成功的，然而，添加古环境信息以重建事件. 地球历史上的这个时间和地点。