MODELLING EXTENSION, INVERSION TECTONICS AND SYNTECTONIC SEDIMENTARY INFILL
THE TRANSECTS 23º S, 32º S AND 41º S (ARGENTINE ANDES)
The Andean Cordillera is one of the best examples of a mountain chain resulting from subduction. The relatively recent and unfinished orogeny has produced significant historical seismic and volcanic activity and has controlled the distribution of sedimentary basins within the cordillera.
In current interpretations there are many uncertainties in the sedimentary and tectonic processes involved in the initial episodes of development of the Andean Cordillera. Moreover, a number of doubts exist concerning the timing of initiation and migration of the orogenic processes, the existence of wrench faults controlled by the supposed oblique subduction, and the spatial and temporal coexistence of contractional and extensional episodes. Furthermore, there are a number of uncertainties concerning the relationships between the magmatism and tectonics, and the control exerted by previous Mesozoic extension on the contractional structures.
The research project proposed consists of a multi-disciplinary study to gain insight into the evolution of the Andean Ranges during the Andean orogenic cycle, which accounts for the present-day framework of this mountain belt. This research project will be carried out within the three segments in to which the Andean Ranges are usually divided. From north to south they are (Gutscher et al., 2000): the "central volcanic segment", the "flat slab segment" or "Pampean segment", and the "south volcanic segment". These segments are located north of parallel 27°S, between parallels 27°S and 33°S, and south of parallel 33°S respectively. One representative transect across each of these segments has been selected; they run along parallels 23°S, 32°S and 41°S. Reliable previous geological data are currently available along these transects. A deep geological cross-section along each of these transects will be constructed, integrating both surface and subsurface data. The inversion tectonics regime, the structural control exerted by previous extensional features, and the growth strata deposited during the Andean orogeny will be studied in detail and modelled. Moreover, the pre-and syn-orogenic magmatism will be investigated in order to understand the geodynamic environment responsible for its origin. The crustal sections constructed across the three segments of the Andean Ranges, together with the data collected in previous studies, will allow us to propose an evolutionary model for the Argentine Andes.
|Funded by the Spanish Ministry for Science and Technology|
|Partially supported by Paradigm Geophysical|
20 de Noviembre de 2003