A contribution to the Geology of the Mogna High, to the north of the Tulum depression, Province of San Juan

Abstract

The Mogna structural high, situated in the central part of the province of San Juan, between the Pampean and Eastern Precordillera Ranges, in Central West Argentina, trends from E to W, transverse to the structural orientation of these mountain ranges. It separates two tectonic depressions of regional extension: the Bermejo valley, to the North, and the Tulum depression to the South. In this high crop out Mio-Pliocene continental clastics, mostly reddish or yellowish sandstones and clayey siltstones with abundant gypsum, overlain, in the northern part of the high, by Pliocene and, in the uppermost intervals, perhaps Pleistocene conglomerates. In these outcrops are observed E-W trending faults and folds, but near the western part of the Mogna High, next to the Precordilleran ranges, the structures strike WNW-ESE. The tectonic rise is higher in the west, and gradually diminishes to the east, The tectonic activity that gave origin to the high took place during Pliocene and Quaternary time.