Electrical Conductivity Beneath the Andean Back-arc in Argentina Near 36.5°S: Creation of Minimum Structure 2D Model Across EW Transect Based on Significantly 3D Data

S. Mendoza Province, south of the Nazca flat slab, has widespread recent basaltic volcanism, but no historic activity. Over the last 1 MY, the basalt has evolved from having a slab signature to OIB. In early 2005, we collected 18 MT sites from 67 to 70°W along 36.7°S, near the large caldera Payún Matrú. Significantly 3D data cause difficulty identifying regional strike and performing minimum structure 2D inversions. Use of phase tensors and induction vectors allow identification of possible regional strikes. Various starting models for the minimum structure inversion allow comparison of effect of different regional strikes on the resulting electrical conductivity models. Preliminary analysis of a piecewise-2D region at the center of the profile suggests the west end of the profile to contain lower crustal to upper mantle conductivity which decreases and deepens to the east.