SGER: Deccan Volcanism Implicated in K-T Mass Extinction

德干火山活动的生物效应及其对K-T大灭绝的潜在影响可能是当今K-T研究中尚未解决的主要问题。最近的研究表明，大部分（80%）的德干圈闭喷发发生在不到80万年的时间里。在磁极性C29 r的跨越古近纪-第三纪（K-T）的边界和最后一次德干火山喷发发生在早期Danian C29 n。这两个德干火山口形成了最长的熔岩流，横跨印度1000公里，一直延伸到孟加拉海。然而，确定在C29 r主要喷发阶段的K-T大规模灭绝发生的地方仍然存在问题，因为圈闭间沉积物通常沉积在河流或河口环境中，这提供了较差的年龄控制。因此，估计德干火山活动的生物和环境后果的模型通常低估了德干气体排放的速率和数量，导致火山活动不可能导致K-T大灭绝的结论。PI对印度东南部Krishna-Godavari盆地浅海序列中的圈闭间沉积物进行的初步调查显示，主要的德干C29 r火山爆发在K-T大灭绝时结束，这表明火山活动和影响可能导致了这场灾难。在本项目中，PI建议调查开始，C29 r德干火山活动主要阶段的持续时间和结束及其在海洋领域的生物后果，以及恐龙灭绝和C29 n火山活动及其与长期延迟的早期Danian生物恢复的关系。具体来说，他们将测试两个假设：（1）德干火山活动在K-T大灭绝中发挥了至关重要的作用，（2）德干火山活动是大灭绝后长期延迟的生物恢复的原因。PI计划通过以下方法来实现这一目标：基于他们最初的发现，即主要的德干火山阶段在K-T大灭绝（拉贾赫蒙德里和梅加拉亚）结束，并通过分析新的岩心，恢复两个最长的德干圈闭熔岩流的圈闭间和圈闭下沉积物。该项目的结果可能会打开有争议的大规模灭绝的辩论，潜在的变革性的研究思路，直接联系大规模灭绝的大火成岩省。

The biotic effects of Deccan volcanism and its potential impact on the K-T mass extinction are perhaps the major unsolved problems in K-T studies today. Recent studies indicate that the bulk (80%) of the Deccan trap eruptions occurred over less than 0.8 m.y. in magnetic polarity C29r spanning the Cretaceous-Tertiary (K-T) boundary and that the last Deccan eruption occurred in the early Danian C29n. These two Deccan Traps form the longest lava flows extending 1000 km across India and out to the Sea of Bengal. However, determining just where within the C29r major eruptive phase the K-T mass extinction occurred has remained problematic because intertrappean sediments were generally deposited in fluvial or estuarine environments, which provide poor age control. As a result, models estimating the biotic and environmental consequences of Deccan volcanism have generally underestimated the rate and quantity of Deccan gas emissions by orders of magnitude leading to conclusions that volcanism could not have caused the K-T mass extinction. PIs preliminary investigations of the intertrappean sediments in shallow marine sequences of the Krishna-Godavari Basin in SE India revealed that the major Deccan C29r volcanic eruptions ended at the K-T mass extinction, which suggests that volcanism and impact(s) may have caused this catastrophe.In this project PIs propose to investigate the onset, duration and end of the main phase of C29r Deccan volcanism and its biotic consequences in the marine realm as well as the dinosaur extinction and C29n volcanism and its relationship to the long delayed early Danian biotic recovery. Specifically, they will test two hypotheses: (1) Deccan volcanism played a crucial role in the K-T mass extinction, and (2) Deccan volcanism is responsible for the long-delayed biotic recovery after the mass extinction. PIs plan to accomplish this by building on their initial discovery that the main Deccan volcanic phase ended at the K-T mass extinction (Rajahmundry and Meghalaya) and by analyzing new drill cores that recover intertrappean and infratrappean sediments of the two longest Deccan Trap lava flows. The results of this project may open the contentious mass extinction debate to potentially transformative research ideas by directly linking mass extinctions to large igneous provinces.This research is jointly funded with NSF's Office of International Science and Engineering.