Lithospheric study of the Argentine Continental Margin: isostatic behavior, and tectonic implications

Abstract

This work is a study of the continental and oceanic lithosphere in the Argentine Continental Margin. These investigations are based on existing geophysical data in the area corresponding to the platform, slope, emersion and abyssal plain of Argentina, between 50° to 66° west longitude and 36° to 50° south latitude. It consists of obtaining a model of isostatic compensation of the area and its correlation with existing models. With the dual objective of evaluating the isostatic behavior of the region and searching for mechanisms to explain its development, models of local compensation (Airy mechanism) and regional compensation (flexural mechanism) are considered. In this study we use the models of a) Sedimentary Thickness and Basement Depth, b) Depth of the upper crust-mantle discontinuity and c) Curie Point Depth (CPD) in order to analyse the isostatic state of the offshore basin zone, crustal thinning and asthenospheric levels, among other things.

The correlation of these elements allows to determine the degree of isostatic compensation in this zone, geometry of the offshore basins in relation to crustal thinning and asthenospheric ascent, locate the sectors where the upper mantle would be magnetized, model the listric asymmetry of the Colorado basin, determine for the first time the limits and geometry of the structural highs of Belén and San Javier and discuss the causes that give rise to the great depth of the basement in the Argentine Basin, among others like serpentinization zones and Belen transform zone. In the same way, questions arise that require new analyses and studies, such as those related to the CPD in the Valdés basins, sectorize the modelled area to seek a better density adjustment, deepen the causes of the great bathymetry of the Argentine Basin, among others.