Collaborative Research: Flood volcanism and environmental impacts -- A multidisciplinary investigation of the Deccan Traps and events at the Cretaceous-Paleogene boundary

合作研究：洪水火山活动和环境影响——对德干地盾和白垩纪-古近纪边界事件的多学科调查

• 批准号: 1615203
• 负责人: Michael Manga
• 金额: $ 97.61万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1615203&HistoricalAwards=false
• 关键词: Collaborative; Research; Flood; volcanism; environmental

Increasing evidence suggests that the four most recent mass extinction events: end-Guadalupian; end-Permian; Triassic-Jurassic boundary; Cretaceous-Paleogene boundary (KPB)- are closely associated in time with continental flood basalt (CFB) volcanism. Paradoxically, the KPB is associated with both the Deccan Traps CFB and the Chicxulub impact in Yucatan, Mexico, engendering an intense three-decades-old debate over causal relationships. Deccan volcanism began well before and continued well after KPB/Chicxulub time, but the largest Deccan eruptions (Wai Sub-group) appear to have been initiated within ~50,000 years of both the KPB and the Chicxulub impact, suggesting that this subset of eruptions may have been triggered by the impact. It remains unclear whether large Deccan flood basalt eruptions or the Chicxulub impact (or both) were the cause of the KPB extinction, because both may have injected massive amounts of volatiles, aerosols, and particulates into the atmosphere. This project's research will improve our understanding of the genesis, timing, and environmental effects of Deccan Traps volcanism by considering Earth systems interactions from mantle plume convection to crustal magmatism to eruption and to atmosphere/biosphere effects. The research will include studies of: (1) The genesis and geodynamic context of Deccan magmatism based on physical volcanology and geochemical signatures, coupled with analysis of volatile contents; (2) Radioisotopic geochronology of the Deccan Traps to tightly constrain their eruptive tempo and relation to other KPB events; (3) Geophysical modeling of mantle and crustal magmatic processes, launching of volatiles and aerosols by the Deccan eruptions, and mechanisms of volcanic triggering by dynamic (seismic) stresses due to earthquakes and impacts; (4) Analysis of geophysical exploration data from offshore western India that has not previously been integrated into the main on-land Deccan stratigraphy. Results of these studies will be compared with other Phanerozoic CFB events, some of which are and, importantly, some of which are not associated with mass extinction.

越来越多的证据表明，四个最近的大规模灭绝事件：结束瓜达卢佩;结束二叠纪;三叠纪-侏罗纪边界;白垩纪-古近纪边界（KPB）-在时间上与大陆溢流玄武岩（CFB）火山活动密切相关。巧合的是，KPB与德干圈闭CFB和墨西哥尤卡坦半岛的希克苏鲁布撞击有关，引发了长达30年的关于因果关系的激烈争论。德干火山活动在KPB/希克苏鲁布撞击之前就开始了，并在之后持续了很长时间，但最大的德干火山喷发（阿威亚群）似乎是在KPB和希克苏鲁布撞击后约50，000年内开始的，这表明这部分喷发可能是由撞击引发的。目前尚不清楚是否是德干玄武岩大规模喷发或希克苏鲁布撞击（或两者）是KPB灭绝的原因，因为两者都可能向大气中注入大量的挥发物，气溶胶和微粒。该项目的研究将通过考虑从地幔柱对流到地壳岩浆活动到火山爆发和大气/生物圈影响的地球系统相互作用，提高我们对德干陷阱火山活动的成因，时间和环境影响的理解。研究将包括：（1）根据物理火山学和地球化学特征，结合挥发物含量分析，研究德干岩浆活动的成因和地球动力学背景;（2）德干圈闭的放射性同位素地质年代学，以严格限制其喷发克里思及其与其他KPB事件的关系;（3）地幔和地壳岩浆过程的地球物理建模，德干火山喷发发射挥发物和气溶胶，地震和撞击造成的动态（地震）应力触发火山的机制;（4）分析印度西部近海的地球物理勘探数据，这些数据以前没有纳入主要的陆上德干地层。这些研究的结果将与其他中生代CFB事件进行比较，其中一些是，重要的是，其中一些与大规模灭绝无关。