Procesos sedimentarios y controles metalogénicos a lo largo del tiempo geológico.

LÓPEZ DE AZAREVICH, V.

Salta

Simposio; Controles modernos y antiguos en sistemas sedimentarios; 2017

INSUGEO-CEGA-CONICET

Sedimentary process and metallogenic controls along the geological time. A mineral deposit is a natural, locally restricted anomalous concentration of a useful mineral substance in the earth´s crust. An ore deposit is an economically exploitable mineral deposit. The concept of Metallogenesis, strictly speaking, represents the study of the processes of formation of metalliferous mineral deposits, with emphasis on their spatial and temporal relations with regional petrology and the tectonic characteristics of the earth´s crust. Metallogenesis studies the laws governing the distribution of mineralization of economic interest in connection with the geological history of the individual structural elements of the earth´s crust.The metallogenic study of any deposit involves the knowledge of its intrinsic characteristics of space and time of formation. Space refers to the form (concordance or non-concordance) and to the place of formation in the lithosphere, if they are in contact with: i) Hydrosphere-atmosphere (hypergenic, hypogenic); ii) With meteoric alteration limit (supergenic- hypogenic), iii) According to the depth of crystallization (plutonic-subvolcanic-volcanic). Time classifies the deposits in syngeneic, epigenic, diagenetic.Some authors point out that metallogeny during tectonic evolution would be better understood considering the relation of metalliferous deposits with: i) Deposition events, ii) Regional metamorphic events, iii) Plutonic events, iv) Deformational events expressed by regional folds and fracture systems. Some or all of these processes can take part in the metal ore genesis.The metallogenic processes vary according to the evolution stage of the basins:? Opening (rifting): linkage with endogenous tholeitic (oceanic), alkaline (intracontinental) or bimodal (intra-arc) magmatic processes; hydrothermalism (VMS-SEDEX-BIF).? Development and filling: linkage with exogenous processes (residuals, placers, brines, chemical precipitation).? Diagenesis/deformation: linkage with diagenetic processes (dissolution, recrystallization), deformation and fluid circulation in the crust (Stratabound, Cu, Pb-Zn, U-V-Th).The metallic ore deposits associated with the evolution of sedimentary basins are of economic importance because they record a metallic concentrate by natural processes, which can be magnified by diagenetic or hydrothermal processes linked to post-depositional tectonics. In this sense, the stratigraphic, compositional, permeability and structural controls are determinant characteristics in the accumulation or location of the metallic ore.