Secuencias depositacionales del Grupo Malargüe (límite Cretácico-Paleógeno), sur de la provincia de Mendoza, Argentina

PARRAS, ANA; CASADIO, SILVIO; PIRES, MÓNICA

Paleógeno de América del Sur y de la Península Antártica

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 1998; p. 61 - 70

The sequence stratigraphic analysis of the Malargüe Group in the south of Mendoza Province, allows the recognition of five depositional sequences. The first sequence is attributed to a river dominated delta and lake setting and the second one to a river dominated delta transitional to a tide dominated delta (continental to marginal-marine facies), both assigned to Loncoche Formation. The third sequence was deposited in a subtidal to intertidal environment, contains Maastrichtian fossils and is referred to Roca Formation. The fourth sequence is attributed to lacustrine and fluvial environments, and the fifth indicates fluvial conditions, both assigned to Pircala Formation. The paleontological evidences and two 40K-40Ar radiometric ages indicate that, in this area of the basin, the Cretaceous-Paleogene boundary lies in the continental deposits of Pircala Formation (depositional sequence IV), concluding that at the beginning of the Danian, the northern boundary of the ?Rocanense Sea? was found at south of 36º S.