Análisis estratigráfico, procedencia y caracterización de facies correspondientes a los depósitos sedimentarios de la formación san mateo de la cuenca de Manabí: análisis de procedencia, estratigrafía y distribución de la fm. san mateo.

Abstract

The present geological work was carried out in the Province of Manabi and the northwestern part of the Province of Santa Elena, specifically in the westernmost part of the coast. The study was focused on the analysis of provenance by means of heavy minerals and the survey of stratigraphic columns with the objective of elaborating a geological map at a scale of 1:500000. Stratigraphically where the field work was carried out, it conforms the basement of the Ecuadorian coast called Piñon Formation of igneous composition with Cretaceous age, overlain by volcanoclastic turbidites of the Cayo Formation of late Cretaceous age that laterally passes to volcanoclastic turbidites, basaltic flows, ash beds of the San Lorenzo Formation extending into the early Paleocene, the latter two formations were deposited before or during the accretion of the oceanic terrains (Hernández et al. , 2020). While land accretion was taking place, the sedimentation of southwestern Ecuador was marked by thick Paleocene conglomerates and turbidites of the Azucar Formation, the post-accretion period includes early Eocene sediments represented by the calcareous sequences of the San Eduardo Formation, Ostiones and Santiago Formations, which unconformably overlie the older Formations, this sedimentation was followed by the regional clastic sequence deposited during the early and middle Eocene represented by the Ancon Group, the Zapallo and the San Mateo Formation which are laterally equivalent to each other (Benítez, 1995). Sedimentation began with the deposition of the Zapotal, Playa Rica and Pambill formations, after a hiatus at the Oligocene-Miocene boundary sedimentation continued during the early Miocene with pelitic deposition of the Tosagua Group (Dos Bocas, Viche and Villingota formations), Viche and Villingota Formations) followed by a hiatus in the upper part of the same, the marine sandstones of the Angostura Formation were deposited during the middle Miocene to finally in the late Miocene the pelitic sequence of the Ónzole Formation overlapped the Angostura Formation in transitional contact (Reyes, 2013).