The deformation sequences, attributes of ore-controlling structures, and structural ore-controlling model in the Huangjindong gold mining area in northeastern Hunan Province

Objective The Wangu−Huangjindong area in northeast Hunan is one of the most important gold producing areas in Hunan Province. This paper aims to identify the structural types in this region from different periods, based on which it reveals the ore−controlling structural types and their formation ages.

Methods Through the observation and analysis of surface outcrop structures, combined with the previous research results of regional tectonic events, this paper determined the tectonic deformation sequences and their settings of Huangjindong gold deposit, discussed the metallogenic age, and determined the types and formation ages of ore−controlling structures in the area. On this basis, the structural genesis of the distribution characteristics of ore veins and bodies was briefly discussed.

Results The study area has experienced seven main deformation events from early to late. The tectonic activation in Late Silurian led to the preliminary enrichment of minerals, and the granitic magmatism of Yanshanian led to the formation of gold deposit. The ore body’s structures are mainly the NWW−trending north−dipping thrust interlayer shear faults formed in Middle Neoproterozoic and the EW−trending thrust faults in Late Silurian; NE−trending thrust faults of late Middle Triassic were the passages of ore fluid; the Paleogene NEE—EW−trending sinistral strike−slip faults, SN—NNE−trending dextral strike−slip faults and NW−trending thrust faults can become ore−breaking structures; the thrust faults and strike−slip faults formed in Silurian, late Middle Triassic and Middle Jurassic may also cut or limit the development of NWW and EW−trending veins; the intersection of NWW and EW trending ore−bearing faults and NE trending faults may control the direction of orebody plunge, and the sinistral displacement between the Jinmei and Jintang mining areas may be related to the thrust of the NE trending Niwan fault.

Conclusions The formation of gold deposits is primarily associated with Yanshanian granitic magmatic activity. The host structures are mainly mid−Neoproterozoic NWW−trending north−dipping thrust interlayer shear faults and Late Silurian EW−trending reverse faults.