3-D crustal-scale gravity model of the San Rafael Block and Payenia volcanic province in Mendoza, Argentina

Abstract

The San Rafael Block (SRB) is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza, Argentina. This block is located in the Andean foothills between the orogenic front and foreland basement uplifts of late Miocene age. In order to analyze the geochronological evolution of the Quaternary volcanism in the region, several geologic and geophysical studies have been conducted. Nevertheless, the crust, where the SRB is located, has not been well characterized yet. Based on gravimetric and magnetic data, together with isostatic and elastic thickness analyses, we modeled the crustal structure of the area. Information obtained has allowed us to understand the crust where the SRB and the Payenia volcanic province are located. Bouguer anomalies indicate that the SRB presents higher densities to the North of Cerro Nevado and Moho calculations suggest depths for this block between 40 and 50 km. Determinations of elastic thickness would indicate that the crust supporting the San Rafael Block presents values of approximately 10 km, being enough to support the block loading. However, in the Payenia region, elastic thickness values are close to zero due to the regional temperature increase.