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JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, vol.375, pp.1-17, 2019 (SCI-Expanded)
Spectral analysis of NAMAG magnetic data enabled us to estimate depths to the Curie isotherm along the Pacific-North America plate boundary. The estimated depths for the Gulf of California, and southern Baja California peninsula, correlate quite well with the depths to the Moho available from previous studies based on receiver function, and seismic refraction. In northernmost Baja California, and southwestern USA no correlation is observed between depths to the Curie isotherm and depths to the mantle obtained from receiver function analysis. Depths to the Curie isotherm are shallower. Along the coastal plains of Sonora and Sinaloa, differences between receiver function based Mantle depths and Curie depths are equally large. However, there is more consistency with depths established by seismic refraction studies. Four zones with shallow Curie isotherm are identified in southern Gulf of California (GS1, GS2, GS3, and GS4). GS1 is located at the Gulf of California mouth. The Alarcon rise is located between GS1 and GS2. Pescaderos Basin is located northwest of GS2. GS3 stretches from the Carmen Basin to the Farallon Basin. GS4 extends from Tiburon Island up to northern Guaymas Basin. Northernmost shallow Curie depth zone (GN1) comprises Upper and Lower Delfin Basins, as well as the Consag and Wagner Basins. A northern prolongation also covers Pinacate Volcanic center. The southern shallow Curie isotherm zones are associated with lithospheric-asthenospheric material upwelling zones. GN1 also includes a convective component related to the younger magmatism of the Pinacate Volcanic Field.