Stratigraphic study of Giron W of the Santander Massif (Eastern Cordillera, Colombia)

Abstract

This is a detailed study of the Girón Formation, in the section of the Lebrija River, between Bocas and Conchal on the Bucaramanga-Puerto Wilches railroad. The Girón Formation has a thickness of 2.600 m. and clearly have been distinguished the following levels: a lower lutitic level with alternated sandstones in his upper section (550 m.); alternating with sandstones (850 m.); an upper arkosic level (700 m.) and a level of red lutites (230 m.) These levels broadly are distributed W of the Suárez fault and at the same time in its E side only appeared the lowest levels. The Girón basement is not consistent, in Bocas it is found apparently concordant with the Carboniferus, S of Piedecuesta is resting over the Metamorphic and there is a basal conglomerate of igneous pebbles mainly porphirics which is not in Bocas in spite that the Iutitic basal level is present in both parts. The top is determined by the discordance Girón-Cretacic.