Noble gas studies along the ultraslow spreading Southwest Indian Ridge: Constraining magmatic degassing processes and the origin and lengthscale of mantle hetereogenities

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The inert nature of the noble gases makes them ideally suited to trace the evolution of the Earth's atmosphere. In particular, the Iodine-Xenon and Plutonium-Uranium-Xenon radioactive decay systems provide constraints on the timing and rates of degassing from Earth's mantle during the first few hundred million years of earth history. This research involves measuring the abundance of the noble gases and CO2 in a suite of basalt glasses from the ultraslow mid-ocean ridge spreading center, the Southwest Indian Ridge. Isotopic measurements of He, Ne, Ar, Kr, Xe will also be carried out. This research is important for understanding the compositions of the major gases in the early atmosphere. It will also address first order questions relating to the evolution of volatiles in Earth's mantle including how tectonic control, mid ocean ridge spreading rates, and mantle temperature influence planetary degassing. Data from the study will allow evaluation of the volatile budget of the Earth and provide fundamental constraints on the early (first 100 million years) outgassing of the mantle and the origin of the atmosphere. Broader impacts are student training and support of an early career scientist.