Study of the Claromecó Basin from gravity, magnetic and geoid undulation charts

In this work we analyze crustal characteristics of Claromeco intermontane basin using gravity and magnetic anomalies, and local geoid undulations. They are: i) isostatic compensation (based on Airy hypothesis), related to stretching; ii) old sediments filling the basin, covering more than 12 km, with a density contrast value of -100 kg m (super -3) , resulting to be well balanced by an antiroot filled with upper mantle materials. A crustal model is proposed justifying both observed Bouguer anomalies and local geoid undulations. A chart of isobath contours is built using a quadratic equation involving sediments' thickness and local geoid undulation. Magnetic basement depth Z T and Curie point depth Z B are obtained using spectral analysis on a total field magnetic anomaly chart. Results show that Z T reaches a maximum value of 12 km, whereas Z B attains a minimum value below the Claromeco basin. The basin puts aside two different depth domains of the Curie isothermal surface: at the southwestern zone of the Ventania ranges Z B is about 25 km, while northeast of these mountains Z B is about 30 km.