TOWARDS A STRATIGRAPHY OF THE MIOCENE/PLIOCENE PISCO FORMATION, PERU

A previous GSA abstract (Brand et al. 2003) introduced a study of the stratigraphy of part of the Miocene/Pliocene Pisco Formation, in Peru. Correlation between prominent outcrops and lateral correlation from the measured section was done by walking out marker beds. Further field work has completed the stratigraphic framework for the section on the west side of the Ica River, from the vicinity of Yesera de Amara to Cerro Blanco and Cerro Ballena, near the village of Ocucaje. Total thickness of the Pisco Formation in this area is 485 m. GPS data for several laterally persistent marker beds confirm the stratigraphic relationships through a series of hills arranged from north to south along this section. This area in the Pisco Formation, with its fairly continuous outcrop and abundant marine vertebrate fauna, has considerable potential for study of faunal changes from Middle Miocene into Pliocene. Other formations above and below the Pisco Formation enhance this potential for study of Tertiary marine faunas.