La cuenca cámbrica del Grupo Mesón en el Noroeste Argentino: desarrollo estratigráfico y paleogeográfico

Abstract

The siliciclastic sediments of the Mesón Group represent the Cambrian of the NW Argentine; it is the initial stage of the Paleozoic marine transgressions that had place in the Central Andes . During the Middle-Upper Cambrian, in the northwest Argentine an intracratonic basin developed between the Arequipa-Antofalla craton, to the east, and Terreno Pampeano, to the west, in the present Eastern Cordillera. The Mesón Group is constituted by three formations: Lizoite (lower), Campanario (middle) and Chalhualmayoc (upper). The Mesón Group overlies the Puncoviscana Fo rmation and granitic rocks (Late Proterozoic - Early Cambrian) with a marked unconformity, and the Cambrian is followed, through an discontinuity, by the overlying fossiliferous Lower Ordovician strata or by the Cretaceous Salta Group in some places of the quebrada of Humahuaca area. The facies association reveals a shallow marine depositional environment with strong evidence for tide-influenced sedimentation for the Mesón Group, reflected in the type of bedding structures and palaeocurrent orientation.