Banca de QUALIFICAÇÃO: Leonardo Santacruz Reyes

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Leonardo Santacruz Reyes
DATE: 16/12/2024
TIME: 14:00
LOCAL: Sala de Videoconferência e Plataforma Teams
TITLE:

THE GOLD DISTRICTS OF MARMATO AND SEGOVIA, COLOMBIA: AN APPROACH FROM THE MINERAL SYSTEM CONCEPT

 

KEY WORDS:

key-words: mineral system, gold, Marmato, Segovia

PAGES: 94
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

This research focuses on the Marmato and Segovia gold deposits in Colombia, interpreted through the Mineral System Concept, which underscores its utility in deciphering complex ore systems. Our synthesis demonstrates that the genesis of Marmato comprises a complex mineral system, primarily initiated by the oblique collision of the Choco block in the northern Andes and the formation of pull-apart basins.This collision triggered magmatic activity that led to the emplacement of tholeiitic, calc-alkaline, and shoshonitic magmas.Their interaction with carbon-rich rocks resulted in the formation of Au-fertile Marmato intrusions and hydrothermal fluids, which followed an evolutionary trend close to the rock-buffer, bismuth-bismuthinite, and pyrite-pyrrhotite buffers. From approximately 6.05±0.02 Ma to 5.96±0.02 Ma, this activity created a mineralization profile extending over 1.4 km vertically. Changes from the lower to the upper zone included: 1) a structural transition from a narrow network of veinlets to a broader zone of veins, 2) fluid temperatures decreasing from 360°C to 180°C, 3) mineralogy transitioning from bismuth-telluride, chalcopyrite, and pyrrhotite to pyrite, marmatite, galena, arsenopyrite, and sulfosalts, and 4) a shift from native to predominantly electrum gold. These complex interactions and evolving physico-chemical conditions suggest that the deposits hosts lower-zone porphyry-type mineralization with reduced characteristics, conducive to the liquid bismuth collector model, followed by an upper zone with typical low to intermediate epithermal features. This comprehensive approach demonstrates how multi-scale geological observations refine deposit models and enhance exploration strategies, providing insights into the broader applicability of the Marmato and Segovia Mineral Systems in analogous settings across the Colombian and Northern Andes.

COMMITTEE MEMBERS:
Interna - 1555904 - CATARINA LABOURE BEMFICA TOLEDO
Interno - 418965 - CLAUDINEI GOUVEIA DE OLIVEIRA
Interna - 2697315 - MARIA EMILIA SCHUTESKY
Presidente - 6404885 - NILSON FRANCISQUINI BOTELHO
Interno - 1057547 - VALMIR DA SILVA SOUZA