Geometry of Middle to Late Triassic extensional deformation pattern in the cordillera del Viento (Southern Central Andes): A combined field and geophysical study

SAGRIPANTI, L; FOLGUERA, A; GIMÉNEZ, M; ROJAS VERA, E; FABIANO, J; MOLNAR, N; FENNELL, L; RAMOS, V

JOURNAL OF IBERIAN GEOLOGY

SERVICIO PUBLICACIONES

Lugar: Madrid; Año: 2013 p. 1 - 20

1698-6180

Combined field and gravimetric-magnetic data reveal a complex pattern of extensional structures superimposed to the Gondwanic orogen at the inner sectors of the Southern Central Andes fold and thrust belt in the cordillera del Viento area. W-NW, NW basement structures of regional significance, segmented by minor NE structures are bounding Late Triassic depocenters and structural highs corresponding to the cordillera del Viento Formation rifting, an equivalent to the Precuyo unit. A pattern of roughly N- structures recognized in the field associated with Andean thrusts does not show evident previous structural control as magnetic anomalies are cut by these. Field observations show that W-NW and NW and NE structures are controlling changes in Late Triassic sedimentary thicknesses and are associated with synextensional geometries. Our model indicates that Late Triassic rifting in the area would have had a regional W-NW to NW trend and that it would have been segmented by minor NE structures. Both sets show reactivation during Andean times as transfer zones between decoupled contractional panels and frontal contractional structures respectively. N- contarctional structures did not respect rifting architecture cutting through the depocenters and eventually exhuming synextensional geometries.