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Origin Of Primitive Ocean Island Basalts By Crustal Gabbro Assimilation And Multiple Recharge Of Plume-Derived Melts, Anastassia Y. Borisova, Wendy A. Bohrson, Michel Grégoire

All Faculty Scholarship for the College of the Sciences

Chemical Geodynamics relies on a paradigm that the isotopic composition of ocean island basalt (OIB) represents equilibrium with its primary mantle sources. However, the discovery of huge isotopic heterogeneity within olivine‐hosted melt inclusions in primitive basalts from Kerguelen, Iceland, Hawaii and South Pacific Polynesia islands implies open‐system behavior of OIBs, where during magma residence and transport, basaltic melts are contaminated by surrounding lithosphere. To constrain the processes of crustal assimilation by OIBs, we employed the Magma Chamber Simulator (MCS), an energy‐constrained thermodynamic model of recharge, assimilation and fractional crystallization. For a case study of the 21–19 Ma basaltic series, the …