Ostrácodos y foraminíferos planctónicos de la Loma del Tirabuzón, Santa Rosalía, Baja California Sur, e implicaciones bioestratigráficas y paleoecológicas

Abstract

In the locality· known as Loma del Tirabuzón, in Santa Rosalía. State of Baja California Sur, a micropaleontological study is being carried out, in order to establish the age of the outcropping rocks.

The name of Tirabuzón Formation is proposed to substitute that of Gloria Formation, as the latter was preoccupied.

According to the assemblage of planktonic foraminifera encountered in the Tirabuzón Formation, an early Pliocene-middle

Pliocene age, is proposed for the base and the middle part of the measured section, while its top represents the middle and late Pliocene boundary.

In general, the microfauna constitutes a mixture of warm and cold water faunas that lived in an open sea environment with máximum depths of 200 to 500 m. with marginal debris, which considerably diluted the microfauna.