GEOLOGICAL AND GEOCHEMICAL PROSPECTING OF ZAMORA TOPOGRAPHIC SHEET (1: 50 000), ECUADOR

This study presents the results of analysis and interpretation of geological and geochemical prospection in the area that covers the Zamora topographic sheet, scale 1: 50 000, Southeastern of Ecuador to determine mineral occurrences.

Useful field observations, with laboratory assays for rock samples: thin section, whole-rock geochemical analysis (major elements XRF, minor elements ICP-OES and rare earth elements REE) and fire assay, were necessary to discriminate the alkaline (Triassic?) and calc-alkaline (Jurassic) volcanism, and to define the economic geology (<40 ppb Au; <67,30 ppm Ag; <43 375 ppm Cu; <1 165 ppm Pb; <1 165 ppm As; 47,32 ppm Sb; <3 772 ppm Zn). In addition, sampling of stream sediments, preparation and chemical analysis (ICP-OES) for subsequent exploratory analysis of spatial data and geostatistical treatment, were developed to determine anomalies of 11 elements (Hg, Au, Ag, As, Cu, Sb, Zn, Co, Mo, Ni and Pb), by using the analytical-graphical method of Lepeltier (modified) and the ordinary kriging interpolation method.

Two zones with possible mineral potential (Tzunantza and Nanguipa), were defined from the correlation profiles of geochemical anomalies (As-Sb-Hg-Ag-Zn-Pb-Co and Au-Hg±As±Sb-Cu±Mo-Zn-Co, respectively) with geology (phreatomagmatic breccias and skarns, both related to porphyry). This study recommends to follow up these two areas. A detailed study is suggested with geochemical soils and geophysical surveys to delimit the areas of mining interest.