Oligocene deposition and Cenozoic sequence boundaries in the Pisco Basin (Peru)

A newly identified early Oligocene marine transgression across the Pisco Basin of southern Peru resulted in the deposition of at least 150 m of fossiliferous sandstones and siltstones, informally designated the Otuma formation. Basal sandstones can usually be recognized in the field by the presence of the gastropod, Turritella woodsi Lisson 1925. New stratigraphic data demonstrate that Cenozoic marine sediments were deposited in the Pisco Basin between about 41-34 Ma, 31-28 Ma, 25-16 Ma, 15-11 Ma, 10-5 Ma, and 4-2 Ma. Most sequence boundaries in the Pisco Basin coincide with compressional tectonic events and/or eustatic low stands of sea level.