--> Abstract: The Cura-Mallin Basin: Tectonic and Stratigraphic Analysis of an Intra-arc Basin in the Southern Andes of Argentina and Chile, by W. M. Burns; #90925 (1999)

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BURNS, W. MATTHEW, Cornell University, Dept. of Geological Sciences, Ithaca, NY

Abstract: The Cura-Mallin Basin: Tectonic and Stratigraphic Analysis of an Intra-arc Basin in the Southern Andes of Argentina and Chile

The Oligo-Miocene age Cura-Mallin basin lies between 36-39°S in the Southern Andes, where it has been uplifted and exposed, and in the subsurface of the adjacent Central Valley of Chile. The basin formed in an intra-arc setting and contains primarily alluvial and fluvial volcaniclastic rocks sourced by contemporaneous volcanism. However, significant thicknesses of lacustrine limestones and shales have been identified locally within the basin fill. Similar, approximately coeval basins create a nearly continuous swath extending from 33-45°S between 70-72°W, but the tectonic and depositional histories of the basins are unclear. The synchroneity and geologic similarity of the basins suggest a common tectonic mechanism and similar mode of development, and the goal of the current study is to develop an understanding of the Cura-Mallin basin that can serve as a model for its associated basins.

Analysis of the Cura-Mallin basin involves detailed geologic mapping with emphasis on structure and facies relationships, radiometric dating focusing on the timing of deposition and deformation, geochemical studies of volcanic rocks related to the basin which will be used in definition of the tectonic setting, and apatite fission-track thermal history studies which will further define the depositional and deformational history of the basin as well as provide information on the thermal evolution of the basin fill. The integration of these datasets will allow for the production of tectonic and depositional models of the Cura-Mallin basin and will also provide guidelines for understanding the extensive chain of basins of which it is a part. 

AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid