Determination of mono- and multielement anomalies through geochemical analyses at La Equis project (Chocó - Colombia)

Cerrón-Sarcco J.F. · Boletin de Geologia (2025) · DOI: 10.18273/revbol.v47n3-2025005

Resumen

The La Equis project is located in the Chocó, department of Colombia, and lies within the Paleocene–Eocene Mandé-Acandí Batholith Metallogenic Belt, recognized for hosting porphyry-type (Cu±Mo) and epithermal-type (Au±Ag±Pb±Zn±Cu) mineral deposits. This study aimed to identify mono- and multielement geochemical anomalies to delineate areas of interest for mineral exploration. A total of 253 rock samples from surface and underground were analyzed using ICP-MS and fire assay techniques. The geochemical data were processed using univariate, bivariate (Spearman correlation), and multivariate (Principal Component Analysis, PCA) statistical methods, as well as ordinary kriging for geostatistical interpolation to determine the spatial distribution of economically significant elements (Au, Cu, Mo, Zn, Pb), pathfinder elements (As, Sb, Tl, Bi, Te, Se, among others), and the first three PCA components (65.2% of the total variance). These results were integrated into a geochemical cross-section (profile AA’), which identified the following anomalous sectors of interested for mineral exploration within the project area: 1) The Progreso and Capotero mining sectors in the southwest, historically classified as intermediate-sulfidation epithermal systems, characterized by the multielement association Pb-Au-Ag-Cd-Zn-Hg-As-Sb-Mo-Tl-(Rb, Cu) and partial Mn or Te anomalies; 2) Anomalous sector 1, located in the central area, defined by the associations Se-Te-Bi-S-(Mo) and Cr-Ni-Cu-Co-S-(Te, Bi, Se, Fe), surrounded by Mn and As anomalies, indicating the relationship of pathfinder elements suggesting potential for exploration of a porphyry Cu±Mo event; and 3) Anomalous sector 2 in the northeast, exhibiting a similar multielement signature to the Progreso-Capotero sector, indicating the possibility of a second epithermal event.

Instituciones: Universidad Nacional Mayor de San Marcos