EAGER: Do Mass Extinctions Have Diagenetic Consequences? Investigating Unique Early Diagenesis at the Triassic-Jurassic Boundary

EAGER：大规模灭绝会产生成岩作用吗？

• 批准号: 1017536
• 负责人: David Bottjer
• 金额: $ 3.28万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1017536&HistoricalAwards=false
• 关键词: EAGER; Do; Mass; Extinctions; Diagenetic

Do Mass Extinctions Have Diagenetic Consequences? Investigating Unique Early Diagenesis at the Triassic-Jurassic BoundaryPI: David J. BottjerCo-PI: Frank A. CorsettiEAR-1017536ABSTRACT The geological process of diagenesis occurs when soft sediments are turned into hard rocks. Diagenetic features are commonly considered ?secondary features? because they occur after the sediments are buried, mostly isolated from surface conditions. As secondary features, they are usually overlooked when investigating ancient environments. In contrast, PIs recent discoveries suggest that diagenetic processes operating at or just below the seafloor during the time of a mass extinction may indeed hold previously unnoticed clues to the causes of mass extinctions. PIs have discovered unique diagenetic features?calcium carbonate fan layers?associated with the Triassic-Jurassic (T-J) boundary, one of the ?Big 5? mass extinctions, in eastern British Columbia. Textural and geochemical evidence suggests that the calcium carbonate layers grew immediately below the seafloor, likely influenced by ocean chemistry at the time of the mass extinction. Carbon isotopic analysis coupled with mass balance calculations suggest dissolution of preexisting carbonate likely provided the source of calcium carbonate for the early diagenetic layers, potentially indicating ocean acidification in their formation and as a potential extinction mechanism.Here, PIs propose the novel concept that mass extinction mechanisms could affect the diagenetic realm and that studying long-ignored diagenetic features might elucidate the extinction mechanisms in ways not previously exploited. Intriguingly, a literature search turned up unusual carbonate diagenetic features at other T-J boundary sites from around the world, but their nature and occurrence with respect to the extinction is unclear. To determine whether the features are relevant to the extinction, PIs propose a pilot study to investigate unusual diagenetic phases found elsewhere (e.g., St. Audrie?s Bay, England; Lavernock Point, Wales; and Larne, Northern Ireland) within their emerging framework of extinction-related diagenetic effects. The discovery that the carbonate diagenetic features from multiple localities are indeed relevant to the extinction will provide the impetus for a subsequent full-scale study of numerous other T-J sites to exploit a new window?the early diagenetic realm?in the study of mass extinctions.

大规模灭绝有成岩作用的后果吗？三叠-侏罗纪界线独特的早期成岩作用研究PI：大卫J. BottjerCo-PI：Frank A.成岩作用的地质过程发生在软沉积物变成硬岩石的过程中。 成岩特征通常被认为是？次要特征？因为它们发生在沉积物被掩埋之后，大多与地表条件隔绝。 作为次要特征，它们在研究古代环境时通常被忽视。相比之下，PI最近的发现表明，在大规模灭绝期间，在海底或海底以下的成岩过程可能确实存在以前未被注意到的大规模灭绝原因的线索。 PI发现了独特的成岩特征？碳酸钙扇层？与三叠纪侏罗纪（T-J）边界，一个？大五？在不列颠哥伦比亚省的东部，纹理和地球化学证据表明，碳酸钙层生长在海底以下，可能受到大灭绝时海洋化学的影响。 碳同位素分析结合质量平衡计算表明，先前存在的碳酸盐的溶解可能为早期成岩层提供了碳酸钙的来源，这可能表明海洋酸化在其形成过程中并作为潜在的灭绝机制。PI提出了一个新的概念，即大灭绝机制可能会影响成岩领域，研究长期的被忽视的成岩作用特征可能会以以前未被利用的方式阐明灭绝机制。 有趣的是，文献检索在世界各地的其他T-J边界地点发现了不寻常的碳酸盐成岩特征，但它们的性质和发生与灭绝的关系尚不清楚。 为了确定这些特征是否与灭绝有关，PI提出了一项试点研究，以调查在其他地方发现的不寻常的成岩阶段（例如，圣奥德里？s湾，英格兰; Lavernock点，威尔士;和拉恩，北方爱尔兰）在其新兴的框架内的沉积相关的成岩作用。 从多个地方的碳酸盐岩成岩功能的发现确实是相关的灭绝将提供动力，随后的全面研究的许多其他T-J网站，以利用一个新的窗口？早期成岩作用领域在研究大规模自杀事件时。