Thermal evolution of upper crustal magmatic systems from the Sierra de Velasco, NW Argentina

Autor: Virginia Valeria Reinoso Carbonell, Gimena Mariel Uran, Marcos Simón Macchioli Grande, Pablo H. Alasino, Mariano A. Larrovere, Sebastián Rocher, Gabriel G. Moreno
Rok vydání: 2019
Předmět:
Zdroj: Journal of Structural Geology. 118:1-20
ISSN: 0191-8141
DOI: 10.1016/j.jsg.2018.10.006
Popis: Detailed mapping of the Huaco intrusive Complex in NW Argentina documents a shift in the emplacement style of successive magma additions in an upper crustal environment as the system evolves thermally. The units of the Huaco intrusive complex exhibit a change from a tabular to funnel-shaped subhorizontal body (Huaco unit) with stoping and brittle fracturing as main emplacement mechanisms, to a cylindrical body (Sanagasta unit), emplaced in a heated host rock which shows local ductile behaviour. As the system cools, the youngest intrusion (La Chinchilla unit) emplaces again as a subhorizontal tabular to funnel-shaped body. Furthermore, magmatic fabrics recorded a regional strain field that changed from a SW-NE to WSW-ENE shortening, as well as boundary strain increments and stress reorientation. Our results demonstrate that the evolution of magma chambers involves the emplacement of magma batches in a stiff crust, changing its thermal conditions and maturing the system for following intrusions. The latter ascend as visco-elastic elongated bodies using the same magmatic plumbing system, leading to a shift in the emplacement style. The described evolution is similar to that reported for the contemporaneous San Blas intrusive Complex located in the same range. This allows us to affirm that these processes are recurrent in the upper crustal section, and that the thermal and rheological conditions of the crust are locally modified by the formation and evolution of long-lived magma reservoirs. Fil: Macchioli Grande, Marcos Simón. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica La Rioja (CRILAR) - Provincia de La Rioja - UNLaR - SEGEMAR - UNCa - CONICET; Argentina Fil: Alasino, Pablo Horacio. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica La Rioja (CRILAR) - Provincia de La Rioja - UNLaR - SEGEMAR - UNCa - CONICET; Argentina Fil: Rocher, Sebastian. Universidad Nacional de La Rioja; Argentina Fil: Larrovere, Mariano Alexis. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica La Rioja (CRILAR) - Provincia de La Rioja - UNLaR - SEGEMAR - UNCa - CONICET; Argentina Fil: URAN, GIMENA MARIEL. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica La Rioja (CRILAR) - Provincia de La Rioja - UNLaR - SEGEMAR - UNCa - CONICET; Argentina Fil: Reinoso Carbonell, Virginia Valeria. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica La Rioja (CRILAR) - Provincia de La Rioja - UNLaR - SEGEMAR - UNCa - CONICET; Argentina Fil: Moreno Guzmán, G.. Gobierno de La Rioja, Dirección General de Minería ; Argentina
Databáze: OpenAIRE
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