Wed 13th February @ noon, Rm 312.222

Abstract:

The reaction calcite + quartz => wollastonite + CO₂ is the archetypal model for metamorphic decarbonation. Silicate-carbonate reactions of this type operate in a wide range of rock types, are ubiquitous during metamorphism in subduction zones and orogenic belts, and have operated for most of geologic time. Metamorphic decarbonation releases CO₂ to the mantle wedge and arc magmas in subduction zones. This flux is augmented by stoichiometric dissolution of carbonate minerals where fluid fluxes are high. In collisional mountain belts, CO₂ is released by a host of metamorphic processes, particularly orogenic thickening and associated self heating. Our recent estimate of the areal orogenic flux (~10¹² mol CO₂ km^-2 Myr^-1; Stewart and Ague, 2018, EPSL) is comparable to that for volcanic arcs and mid-ocean ridges. Progressive CO₂ release during the Devonian Acadian orogeny coincides with warming and sea level rise, and may have helped drive the Taghanic biocrisis. Given the role that CO₂ has played in the development of Earth as a habitable planet, it is unlikely that life as we know it would have evolved without metamorphic decarbonation.

Short bio:

Jay Ague is the Henry Barnard Davis Memorial Professor of Geology and Geophysics and Curator-in-Charge of Mineralogy and Meteoritics at the Yale Peabody Museum of Natural History. He grew up in the Detroit, Michigan, area and earned his B.S. and M.S. degrees from Wayne State University before moving out to California for his Ph.D. work at UC Berkeley. He joined Yale as an Assistant Professor in 1988. He studies the metamorphic and igneous rocks that comprise the deep roots of mountain belts, with a focus on heat and fluid transport through rocks and implications for earthquake hazards, volcanism, economic mineral deposits, and the roles of mountain building and subduction in global carbon and climate cycles. He has led or participated in geological research expeditions to numerous places around the globe including British Columbia, California, Greece, New England, New Zealand, Papua New Guinea, Scotland, Spitzbergen, and Washington State. He was the Chair of the Department of Geology and Geophysics from 2012 to 2018, and the Acting Director of the Peabody Museum in 2008. He has served as a mentor for more than 35 students and postdoctoral associates. He is heavily involved in public outreach through his work at the Yale Peabody Museum of Natural History.