Andes Centrales: modelado gravimétrico integrado en 3D.

CLAUDIA PREZZI; HANS-JÜRGEN GÖTZE; SABINE SCHMIDT

La Plata, Argentina

Congreso; XVI Congreso Geológico Argentino; 2005

Our motivation to study the Central Andes is that this mountain belt is a subduction related cordillera, which accommodates the Earth’s largest plateau formed without continent-continent collision. Moreover, a wealth of geophysical and geological information has been produced during the last years, providing a huge amount of data to constrain our model. We present a forward modelling of the Bouguer anomaly through a 3D model of densities distribution. We used the interactive modeling tool IGMAS. The geometry of our model is constrained by seismic reflection and refraction profiles, receiver function analysis, hypocenter locations, magnetotelluric data, tomographic studies, balanced cross sections, etc. We produced a contour map of the upper surface of the subducting slab below the continental margin. We also compared the modelled Moho with Airy and flexural isostatic Mohos. Residual gravity maps were prepared considering the gravity effect of the subducting slab and of the modelled Moho. The upper and lower limits of the possible amount of partial melting occurring in the Andean Low Velocity Zone were estimated.  In this study we have demonstrated how 3D gravity modelling, integrating geophysical and geological information, can help to reveal the geodynamic processes playing a role in the building of Central Andes.