Spatial distribution of faults and structural ore-control regularity in the Daping gold deposit, Yunan Province

Abstract: The Daping gold deposit is a typical orogenic gold deposit in the Ailao Shan-Red River (ASRR) metamorphic belt. Auriferous veins are controlled by ASRR fault, Xiaoxinjie fault and its secondary faults. In this study, the authors analyzed regional structures and distribution of auriferous veins in the ASRR metamorphic belt during several times of changes of structural dynamic mechanism which have had great influence on the mineralization of the Daping gold deposit since 58 Ma. The results achieved by the authors are valuable for theoretical research and gold exploration. There are three grades of northwest structural faults in the ASRR belt which resulted from convergence between India and Eurasia that led to four times of changes of regional structural dynamic mechanism due to the four times of change of the convergence direction since 58 Ma. Intense mineralization in ASRR orogenic belt had close relationship with changes of structural dynamic mechanism, and the metallogenic substance mainly came from the lower crustal layers and the upper mantle. The left- and right-lateral shears were responsible for the formation of gold deposits in the ASRR orogenic belt. The ASRR fault corresponds to the distribution of the ASRR gold belt, whereas the Xiaoxinjie fault and its secondary faults serve as the mineral transfer and mineral deposition structure. It is also demonstrated that extensive part of the secondary fracture in auriferous veins formed by tensile stress indicates the deposition of bonanza. This study plays an important role in the metallogenic mechanism research and the exploration prediction of the Daping gold deposit and is also useful for the study of other orogenic gold deposits along the ASRR orogenic belt.