Metalogénesis en depósitos tipo placer asociados genéticamente con áreas ígneo-metamórficas en el Bajo Cauca : caso de estudio Mina Lucky (Antioquia – Colombia)

Abstract

Historically, mineral extraction in Colombia has taken place on a small scale and in an artisanal manner, serving as a means of livelihood for some communities in the country. Gold has been considered an economic driver in the development of the northeastern Antioquia region, particularly in the Mining District of Bajo Cauca-Nechí, renowned for gold exploitation in Quaternary age placer deposits associated with terraces and alluvial formations, generated by the fluvial dynamics of the Cauca and Nechí rivers.

However, over time, petrographic analysis has not been conducted to identify the mineralogical composition of the exposed lithological units in the area. Petrographic/metallographic characterization enables the establishment of transport conditions and deposition mechanisms for gold particles. This approach will provide detailed information on the compositional and textural features of mineralization present in the alluvial deposit of the study area.

The mineralogy of the analyzed deposit in its concentrates of black sands is composed of oxides such as Magnetite (Mt), Ilmenite (Ilm), and Hematite (Hm), accompanied by laminarly arranged fractions of gold. From a petrographic perspective, the mineralogical relationship was analyzed, revealing a significant presence of Magnetite with small inclusions of sulfides like Pyrite (Py) and the existence of silicate group minerals such as Zircons (Zir), Garnet (Gnt), and Epidote (Ep).

This study focused on analyzing the mineralogical composition and textural features of the paleoplacer-type deposit in Bajo Cauca. This allowed the establishment of information regarding the geological conditions during the formation of the observed mineralogy in the deposit. The information will serve as a foundation to establish specific aspects of the genetic model of the deposit, which is crucial in the exploration and exploitation of mineral deposits, facilitating an understanding of the conditions in their source areas that favored their formation.