IBIGEO   22622
INSTITUTO DE BIO Y GEOCIENCIAS DEL NOA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Petrology of the Luingo caldera: a key area to understand the Middle Miocene arc-back arc configuration in the Southern Puna plateau
Autor/es:
GUZMÁN, SILVINA; PETRINOVIC, IVÁN ALEJANDRO; BROD, JOSÉ AFFONSO; HONGN, FERNANDO DANIEL; SEGGIARO, RAÚL; MONTERO, CAROLINA; CARNIEL, ROBERTO; SUDO, MASAFUMI
Lugar:
Heidelberg
Reunión:
Conferencia; LAK, Latinamerikan Kollokium.; 2011
Resumen:
In the present contribution we present geochemical and mineral chemistry data of rocks from the middle Miocene Luingo caldera and of some spatially close group of upper Miocene lavas. Luingo caldera (Guzmán and Petrinovic, 2010) is located in the south-eastern portion of the Central Volcanic Zone (CVZ) of the Andes, becoming the oldest caldera (ca. 13-12 Ma: Guzmán and Petrinovic, 2010) of the Southern CVZ (SCVZ: 25-27ºS). We modelled the petrogenesis of the Luingo caldera rocks as a mixture of ca. 20% crustal magmas and 80% of mantle magmas by AFC with recharge processes. We compare the Luingo caldera with the close by and younger Cerro Galán caldera (upper Miocene to Pliocene: e.g. Sparks et al. 1985) and with other westward volcanic centres of the Southern CVZ. Luingo caldera’s location makes this a key area for assessing geochemical variations over the time and also to constrain differences across the main volcanic axis of the Andes. A comparison of Luingo geochemical data with the composition of Miocene-Pliocene volcanic rocks from the broad area, points to major thickening events during the middle Miocene for the western portion and during the upper Miocene for the eastern portion of the Southern CVZ. The main objective of this research is assessing the conditions of the SCVZ during middle Miocene on the basis of geochemical data but also based on the areal distribution of the volcanic products. The combination of these two tools allows to visualize a broad arc, which was structurally controlled at the proto-Puna/Puna margins and whose geochemical differences are related with variations in crustal thicknesses and heterogeneous mantle sources from west to east.