The osmium isotope signature of Phanerozoic Large Igneous Provinces

Alexander Dickson, Anthony Cohen, Marc Davies

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The emplacement of Large Igneous Provinces (LIPs) throughout the Phanerozoic Eon introduced vast quantities of mafic rocks to the Earth’s surface, which were subsequently weathered into the oceans. Osmium isotope data can be used to track these LIP-related weathering fluxes, providing a global fingerprint of the timing and magnitude of LIP emplacement, and guiding assessments of the impact of these events on ocean biogeochemistry and the regulation of the global climate system. Sedimentary Os isotope records spanning late Phanerozoic LIP events are reviewed herein and new observations from Eocene hyperthermal event ETM-2 are presented. While Os isotope stratigraphy can provide major constraints on LIP activity in the geological record, it cannot always distinguish whether the extrusive activity was subaerial or submarine. The utility of osmium isotopes as a global tracer of past volcanism may be enhanced when used alongside proxies such as mercury concentrations, which may be more diagnostic of the style of individual episodes of LIP emplacement. Hitherto, only a few high-resolution Os-isotope records across Phanerozoic LIPs have effectively exploited the short oceanic residence time of Os. Future high-resolution studies across suitable, well-preserved stratigraphic records will significantly improve our understanding of the nature, progression and consequences of LIP emplacement.
Original languageEnglish
Title of host publicationEnvironmental change and large igneous provinces: the deadly kiss of LIPs
Publication statusAccepted/In press - 27 Jul 2019

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