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DeepDust - A Proposed Drilling Project to Probe Continental Climate of the Late Paleozoic Icehouse-Greenhouse Transition

Abstract : The climatic, biotic, and tectonic events of the Permian are amongst the most profound in Earth history. Global orogeny leading to Pangaean assembly culminated by middle Permian time, and included multiple orogenic belts in the equatorial Central Pangaean Mountains, from the Variscan-Hercynian system (east) to the Ancestral Rocky Mountains (west). Earth’s penultimate global icehouse peaked in early Permian time, transitioning to full greenhouse conditions by late Permian time, thus archiving the only example of icehouse collapse on a fully vegetated Earth. The Late Paleozoic Icehouse was the longest and most intense glaciation of the Phanerozoic, with hypothesized low-elevation glaciation posited for both eastern and western tropical Pangaea during early Permian time. Reconstructions of atmospheric composition record the lowest CO2 and highest O2 levels of the Phanerozoic, with average CO2 levels comparable to the Quaternary, rapidly warming climate. Fundamental shifts occurred in atmospheric circulation: a global megamonsoon developed and the tropics became anomalously arid with time. Extreme environments are well documented in the form of voluminous dust deposits, acid-saline lakes and groundwaters, extreme continental temperatures and aridity, and major extinctions/extirpations, ultimately culminating at the Permo-Triassic boundary with the largest extinction of Earth history. We seek to elucidate paleoclimatic conditions and forcings through the Permian at temporal scales ranging from the millennial to the Milankovitch and beyond by acquiring continuous core in continental lowlands known to harbor stratigraphically complete records dominated by loess and lacustrine strata. We have identified sites in the western U.S. and Europe as the key sites globally to achieve our objectives, as these represent the western and eastern limits, respectively of the Pangaean tropics. Identified sites harbor arguably the most complete continental Permian sections in the paleoequatorial region, with adjacent paleo-uplands hypothesized to have hosted glaciation. We will also address the nature and character of the modern and fossil microbial biosphere, Mars-analog conditions, and exhumation histories of source regions.
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https://hal-insu.archives-ouvertes.fr/insu-02539479
Contributor : Isabelle Dubigeon <>
Submitted on : Friday, April 10, 2020 - 10:27:33 AM
Last modification on : Friday, May 15, 2020 - 10:24:02 AM

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Gerilyn Soreghan, Laurent Beccaletto, Kathleen Benison, Sylvie Bourquin, Natsuko Hamamura, et al.. DeepDust - A Proposed Drilling Project to Probe Continental Climate of the Late Paleozoic Icehouse-Greenhouse Transition. European Geosciences Union General Assembly, Apr 2020, online, Austria. pp.EGU2020-11830. ⟨insu-02539479⟩

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