Geological and structural characteristics of the zengjiacun copper deposit in jinggu, southern yunnan: A comprehensive analysis of three-dimensional ore-controlling structures

Abstract

The Zengjiacun copper deposit is situated in the northeastern part of the Minle copper deposit, located in Jinggu County, Yunnan Province. It is one of the typical deposits in southern Yunnan. In this paper, we employ the theory and method of ore field tectonics to elucidate the formation mechanism of ore bodies and their structural controls on hosting spaces. The regional geological structure exerts control over lithofacies paleogeography and magmatic activity within this area, directly influencing the formation and distribution of various endogenetic and exogenetic minerals such as Songjiapo, Nanwenghe, Wengkongba, and Dadutian. Under the combined influence of regional crustal uplift and nearly east-west compression stress during the Yanshanian period, strata within this region underwent folding and interlaminar sliding processes. Notably, due to differences in rigidity between limestone and sand mudstone lithologies, limestone formations became brittle and prone to fracturing. This resulted in the development of interlaminar fracture zones that provided pathways for tectonic hydrothermal fluids to migrate and accumulate, ultimately leading to the formation of a reformed copper deposit. Tectonic stress variations have led to increased complexity within strata and ore bodies present in the northern section where local closed folds have formed. However, the stratum and copper body in the south part are inclined to the East in a gentle wave shape due to relatively small tectonic stress. Overall, understanding these structural controls on mineralization is crucial for guiding exploration efforts both at depth as well as around periphery areas surrounding this deposit.