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

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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.