NEOGENE ONGOING TECTONICS IN THE SOUTHERN ECUADORIAN ANDES - ANALYSISOF THE EVOLUTION OF THE STRESS-FIELD

Microtectonic analysis of infilling deposits in South Ecuadorian Neoge ne basins brings to light a ,compressive stress field with al along a NNE-SSW to NE-SW direction in the early Miocene, changing to an E-W di rection in the Middle and Late Miocene. The syn-sedimentary deformatio ns which affect the deposits of the basins suggest similar stress regi mes due to a compressive ongoing tectonic system in the Miocene, for a t least 15 Ma. There is a good correlation between rapid convergence i n the Neogene and the time period during which the continental South E cuadorian basins were deformed by compression (Quechua period).