Curie surface of the alkaline provinces of Goias (GAP) and Alto Paranaiba (APAP), central Brazil

摘要

The study area includes the most important carbonatite and kimberlite complexes in Brazil, located in the Brazilian states of Goias and Minas Gerais. The central portion of this area involves the Azimuth 125 degrees lineament (Az 125 degrees) that consists of an extensive set of faults (oriented in the NW-SE direction) that served as a conduit for magma ascent. This lineament is the main structural feature associated with these complexes. The Goias (GAP) and Alto Paranaiba (APAP) Alkaline Provinces occur along the Az 125 degrees and include highly economically valuable mineralizations. In this study, we aim to map the depth to the curie isotherm (or Curie Point Depths: CPD) of the study area (mainly the Gap and APAP regions) based on spectral analysis of aeromagnetic data. The CPD estimations were achieved from a spectral approach known as the centroid method, providing the relationship between the spectra of magnetic anomalies and the depths of the magnetic source of a 2-D magnetic data. The CPD estimates from approximately 500 overlapping blocks vary from 7 km to 40 km deep.