Collaborative Research: EAR Climate: Earth-System Responses to the Penultimate Icehouse-Greenhouse Transition

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About 300 million years ago, large glaciers and ice sheets at high latitudes waxed and waned as Earth’s climate alternated between glacial and interglacial states, continuing a pattern that had persisted for several millions of years. Shortly thereafter, however, the glaciers collapsed entirely, and the Earth system lurched beyond an ice-free state into an increasingly severe “hothouse” climate, powered in large part by a massive and sustained release of greenhouse gases into the atmosphere, ultimately culminating in the largest extinction of life known in Earth history. This project will examine a complete record of this dramatic transition by recovering and studying a 2000 m-long rock core from what was, at that time, the equatorial region of the planet, which is now the US midcontinent (Oklahoma). The principal goal is to uncover the driving forces for these extreme environmental changes, shedding light on the fundamental workings of the Earth system (geosphere-atmosphere-biosphere connections) during an interval of unprecedented upheaval. This project involves many students and early-career researchers across twelve US research institutions, in addition to international collaborators, and additionally will engage Native American youth, educators, scientists, artists and poets in Oklahoma and beyond.This project seeks to elucidate paleoenvironments, biogeochemical cycling, and responses of the terrestrial biosphere to climate forcing during the Permian Period, a critical time in the evolution of Earth and life. A drill core will be taken in the Anadarko Basin (Oklahoma), which is a deep continental basin that preserves a globally unique and stratigraphically complete archive of the continental Permian in equatorial Pangaea. A well-preserved paralic-to-continental transition is overlain by a succession of red-bed, paleo-loess/dust, lacustrine, and evaporite deposits that collectively record the demise of the Late Paleozoic Ice Age and an intensifying greenhouse climate, culminating in the most severe mass extinction in Earth history. The project will establish a high-resolution chronostratigraphic framework by integrating U-Pb geochronology, astrochronology, magnetostratigraphy, and biostratigraphy. The resulting framework will serve as the scaffolding for subsequent research designed to test hypotheses focused on the interrelationships among climatic, orogenic, and biotic changes during an interval characterized by pronounced Earth-system upheavals. This research addresses major questions relevant to both Earth’s past and its future, as it will elucidate various mechanistic linkages, e.g. among atmospheric dust, climate, mountains, and the biosphere on an Earth experiencing a cold-to-hot climate transition. Owing to the known importance but great uncertainty of the role of dust in the Earth system, exploration of these links will measurably expand the knowledge of Earth system behavior across the Phanerozoic.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.