Basin inversion and magma migration and emplacement: Insights from basins of northern Chile

摘要

During the structural modelling of inverted basins influenced by magmatism is very important understand the geometric and kinematic relationships between inverted structures and intrusive bodies. The northern Chile is a natural laboratory to analyze this situation, since its Cenozoic tectonic evolution was marked by the tectonic inversion of Mesozoic extensional basins, which occurred simultaneously with the emplacement of kin-scale intrusions. In order to provide insights on the interplay between basin inversion and magma emplacement, we completed a comparative analysis based of field data from four inverted Mesozoic basins of northern Chile and a series of previous and new analogue models reproducing the tectonic inversion of half-grabens and magma emplacement. The experiments showed that the magma migration and emplacement is controlled by the initial distribution of normal faults and occur preferentially along the inverted normal faults. High magma injection rate can cause a major reactivation of the normal faults, favoring a comparatively increase in bulk shortening. The most favorable condition for which the magma reaches the surface is under simultaneous high magma injection and shortening rates. The latter allow the magma to be emplaced along the core of inversion related anticlines such as it is recognized in northern Chile.