Depositional palaeoenvironment of the Salicas Formation: miocene evolution in the SE of the Pipananco Basin, La Rioja Province, central-western Argentina

Abstract

From a facies analysis of the Salicas Formation, it is interpreted as a fluvial distributary system that includes dune deposits and eolian mantles. This system shows paleosols, bioturbations, rhizoconcretions and carbonatic concretions, suggesting calcium carbonate-rich sandy sediments subjected to repeated wetting and drying cycles. These characteristics indicate a seasonal climatic regime. These sedimentary deposits together with the identification of clay minerals such as illite and kaolinite are associated with a semi-arid climate. The development of this depositional system manifests a quasi-plain palaeorelief with a remote input area, during the period of deposition of these Late Miocene strata and with the development of a progressive unconformity at least in the strata of the lower section of the Formation.