Imaging Yellowstone magmatic system by the joint Gramian inversion of gravity and magnetotelluric data

Abstract

Gravity and long-period magnetotelluric data are combined in a joint Gramian inversion to obtain structurally-similar 3D density and electrical resistivity models of the Yellowstone magmatic feeding system. Structural constraints are enforced through a correlation of the model gradients. Gravity data are sensitive to upper-crustal structure, whereas long-period magnetotelluric data are more sensitive to deeper structure. By combining these complementary data, the jointly inverted models provide a consistent image of the partially molten structure underlying the Yellowstone Caldera from the surface to the Moho. Discrete zones of inferred partial melt in the upper and lower crust are fed by a southwest trending plume, and satisfy expectations from modern mantle plume models.