Six sections along a SW-NE profile in the southern part of the Pucará basin have been studied: Tingocancha, Malpaso, Tarmatambo, Shalipayco, San Vicente and Vilcapoma. The study deals with lithology, facies, diagenesis, paleogeometry and sequence analysis. The Chambará Formation (Norian - Rhaetian) is mainly dolomitic and predominantly composed of supra/intertidal, lagoonal, and subtidal shallow marine barrier facies; however, open sea shelf facies are also present (in part crinoidal banks). The Aramachay Formation (Hettangian - Sinemurian) consists in the westernmost studied profiles (Tingocancha and Malpaso) of strongly recrystallized argillaceous and siliceous fine-grained sediments with variable amounts of calcite and intercalations of tuffaceous layers. Chert is abundant. In general, the Aramachay Formation consists of bituminous calcareous shales with lower chert content. The sedimentary facies mainly correspond to a relatively deep basin. In the Condorsinga Formation (Pliensbachian - Toarcian) limestones predominate over dolomites. This formation comprises lagoonal and subtidal shallow marine barrier facies with thin intercalations of supra/intertidal sediments. In the western part (Tingocancha/Yauli Dome} a set of «within-plate" basaltic flows is present at the base of the Condorsinga Formation. The Pucará Group is significantly thicker to the east than to the west in the studied profile, indicating asymmetrical subsidence in a half-graben. The facies evolution in the occidental part (Tingocancha and Malpaso) can be explained by a second order transgressive/regressive sequence that reaches its maximum flooding during the deposition of the deep-basin facies ot the Aramachay Formatlon. The transgression progressed in a N-S direction and the regression in a S-N direction.