Collaborative research: Multi-disciplinary investigation of the links between volcanism, marine redox, and mass extinction during the Late Triassic and Early Jurassic

三叠纪末的大灭绝发生在大约2.1亿年前，是地球历史上最大的灭绝之一。了解导致这一事件和类似事件的环境压力的时间轴，为理解当前和未来的全球变化提供了重要的背景。我们目前的理解是有限的，主要是因为数据的地理覆盖范围有限，而且大多数验证研究都狭隘地关注大灭绝本身的时间间隔。这项研究将通过调查阿拉斯加兰格尔山脉沉积岩化石和化学成分中记录的环境和生物变化记录来解决这些空白。这一独特的岩石序列代表了海洋沉积物，这些沉积物沉积在地球上一个未被充分研究的部分-古太平洋或泛海底。此外，该项目将为研究生和本科生提供指导和科学培训，并将涉及一些公共宣传活动，突出地球科学研究的跨学科性质，用于解决大规模灭绝的原因等重大科学问题。博物馆和巡回展览将被开发，项目团队将参与访问高中科学教室和公共科学开放日。这项研究将使用多学科的方法来开发一个更全面的了解海洋多样性和海洋内的氧化还原条件的地理和时间记录之前，期间和之后的三叠纪末大规模灭绝从一个研究不足的泛海底海洋网站。这将通过研究阿拉斯加兰格尔山脉麦卡锡组中记录的从晚三叠世到早侏罗世的长期时间间隔来实现。将收集四个主要分类群（菊石、双壳类、牙形石、珊瑚）的古生物学数据;地球化学数据（碳、硫和铊同位素;铁的形态;对氧化还原敏感的微量金属丰度）;以及火山灰层的铀铅年代。通过对古生物学、地球化学和年代学结果的仔细整合，拟议的研究将为理解生物、海洋氧化还原和碳循环变化之间的关系提供一个框架。拟议研究的结果将用于直接评估和在时间上限制以下方面的时间：（1）海洋多样性的丧失和恢复，（2）地方和全球环境变化，以及（3）该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的学术价值和更广泛的影响审查标准。

The end-Triassic mass extinction that occurred ~210 million years ago was one of the largest in Earth’s history. Understanding the timeline of environmental stresses that led to this event and similar events, provide important context for understanding current and future global change. Our current understanding is limited, mostly because of the limited geographic coverage of data and most of exisiting studies narrowly focus on the time interval of the mass extinction itself. This study will address these gaps by investigating a record of environmental and biologic change that is recorded in the fossils and chemistry of sedimentary rocks now located in the Wrangell Mountains of Alaska. This unique sequence of rocks represent marine sediments that were deposited in an understudied part of the planet — the Paleo-Pacific or Panthalassic Ocean. Additionally, this project will enable the mentorship and scientific training of graduate and undergraduate students and will involve a number of public outreach activities that highlight the interdisciplinary nature of geoscience research used to tackle big scientific problems like the causes of mass extinctions. Museum and traveling exhibits will be developed and the project team will engage in visits to high school science classrooms and public science open houses.This study will use a multi-disciplinary approach to develop a more holistic understanding of the geographic and temporal record of marine diversity and redox conditions within the oceans before, during, and after the end-Triassic mass extinction from an understudied Panthalassic Ocean site. This will be accomplished by studying the long-term Late Triassic through Early Jurassic time interval recorded in the McCarthy Formation in the Wrangell Mountains of Alaska. Paleontological data will be collected for four major taxonomic groups (ammonoids, bivalves, conodonts, corals); geochemical data (carbon, sulfur, and thallium isotopes; iron speciation; redox-sensitive trace metal abundances); and uranium-lead dates from ash beds. Through the careful integration of the paleontological, geochemical, and geochronological results, the proposed study will provide a framework for understanding the relationship between the biotic, marine redox, and carbon cycle changes. Results of the proposed study will be used to directly assess and temporally constrain the timing of (1) marine diversity losses and recovery, (2) local and global environmental changes, and (3) the potential factors that led to mass extinction and allowed for faunal recovery during the Late Triassic to Early Jurassic.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.