Definición matemática de “Microfacies” bentónicas en el noreste de Cuenca Pescadero, Golfo de California

http://dx.doi.org/10.18268/BSGM1987v48n2a1

Gabriela Diego Casimiro*, Adolfo Molina Cruz**

* Dirección de Investigaciones Oceanográficas de la Sría. De Marina.
** Instituto de Ciencias del Mar y Limnología, UNAM.

Abstract

In an area approximately 3090 km², northeast from Pescadero Basin, Gula of California are established five “microfacies”. This is consequence of the swell influence, of the longshore current, of the fluvial input and of the temperature (depth) and substrate combination. These “microfacies” are characterized by the occurrence of benthonic foraminifera assemblages which have been revealed through “Q” and “R” mode Factor Analysis. One of two “microfacies” established along the littoral, is influenced by the Rio Sinaloa input and Buliminella elegantissima and Reophax manus occur in very fine sand. In the continental shelf, the medium grain sand distribution corresponds with the presence of Crancis auriculus, Gavelinopsis campanulata and Hanzawaia nitidula; while the distribution of a foraminifera assemblage, characterized by Brizalina acuminata, Brizalina mexicana and Cassidulina braziliensis, depicts the shelf edge. The Bathyal Superior Environment, defined by Bolivina plicata and Bolivina seminuda var. Humilis, is found at a depth of 160 m. Comparing assemblages of live foraminifera and dead foraminifera, is suggested that the faunistic composition of the “microfacies” varies temporarily, in small proportion.