The CAP and MATE PROJECTS

Proyecto MATE (pronounced ‘mah-tey’ after the herbal drink) is a 50-staton survey GPS (SGPS) network focused on the active Precordillera fold and thrust belt in west-central Argentina. The project’s goal is to relate the current velocity field in the Precordillera with geologically averaged deformation rates. In order to do this we must first remove understand the regional signal (provided by the CAP network) due to coupling of the Nazca-South America plate boundary. In our analysis, we found it necessary to add an ‘Andes’ microplate to the traditional kinematic description of Nazca-South America plate convergence. The model suggests the oceanic Nazca boundary is fully locked while the contintental backarc boundary creeps continuously at ~4.5 mm/yr except for a shallowly locked frontal portion. Thus, the Precordillera currently accommodates intracontinental subduction only within a narrow deformational zone and permanent deformation is not currently accumulating throughout the backarc contractional wedge. This is consistent with the geologic reconstructions both in the location and rate of the deformation.