Structural context of Ambatovarahina copper deposit, Central Madagascar

Abstract

This study presents a comprehensive structural analysis of a copper skarnoid deposit hosted in dolomitic marble within Itremo subdomain, central part of Madagascar. The deposit exhibits two distinct styles of mineralization: stratabound replacement-type (i) and vein-type (ii), both controlled by structural features. The first type is related to D1 deformation and the second with a transpressional shearing associated with transversal fractures syn to post deformation. Primary ore minerals formed by chalcopyrite, cubanite, and bornite followed hydrothermal fluid circulation. And cataclastic textures within the ore confirm the presence of D2 deformation which promoted the remobilisation and reconcentration of primary copper ore along syn to post fracture to form secondary copper ore appearing as “copper vein type” deposit.

The result of stereonet analysis reveals the presence of D1 deformation with S1 cleavage and its axial planes-oriented Northeast-Southwest, while D2 deformation represented by crenulation cleavage and asymmetric boudinage.