Stratigraphy of the Santa Catalina region (Jujuy province, Argentina)

Abstract

The area is in the northwest of the province of Jujuy, on the border with Bolivia. It comprises the northern part of the Sierra de la Rinconada, and the valleys of the Santa Catalina and Grande de San Juan rivers. The basement consists of siltstones, shales and shaly sandstones, very poorly fossiliferous, forming the bulk of the Rinconada range. They have been named the Acoite Formation and assigned to the Ordovician. These older rocks are overlain with an angular unconformity by continental sediments, the red sandstones of the Pirgua Formation (Cretaceous), which indicate the tectonic lines in the Santa Catalina valley, The next Formation is the Peña Blanca (medium to fine grained sandstones, with intercalations of clayey horizons). Lastly there are alluvial deposits of the Quaternary, differentiated in three units, which fill the broad depressions.