Wangu Au deposit, Dawan gold mining district, Pingjiang Co., Yueyang, Hunan, Chinai

Regional Level Types
Wangu Au deposit	Deposit
Dawan gold mining district	Mining District
Pingjiang Co.	County
Yueyang	Prefecture-level City
Hunan	Province
China	Country

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Medium-scale gold deposit, hosted in a sequence of Mesoproterozoic siltstone, greywacke and slate metamorphosed to sub-greenschist facies. Gold mineralization developed along EW-trending shear and fracture zones, which link to the Tancheng-Lujiang (Tanlu) regional deep fault zone. Gold mainly occurs in quartz veins, but also in fractured slate and tectonic breccias.

Several gold deposits with varying scales are developed in the gold field, mainly controlled by the NNE-trending Changsha-Pingjiang and Xinning-Huitang faults, and the nearly EW-trending Jiuling-Qingshui ductile shear zone. The Wangu gold deposit is the largest gold deposit in the gold field, with a proven gold resource reserve of about 85 t. The strata of the mining area are mainly composed of Quaternary sediments covering the upper layer of the Cretaceous siltstone, and the Pingyuan Formation of the Neoproterozoic Lengjiaxi Group. The orebodies mainly occur in the Neoproterozoic sandy slate and banded silty slate, and the veins V1, V2, V4 and V8 are relatively developed. Other orebodies, such as V3, V10, and V13 veins, occur in sandy-silty slate and metamorphic sandstone. No magmatic rocks have been detected in the Wangu gold deposit. Twelve NW- to near EW-trending orebodies, including V1, V2, V3, V8, and V10, are developed in the Wangu gold deposit. These are controlled by NWW-trending fault dipping to NE with dip angles of 34 ∼ 83°. The length of V2 orebody is 800 m, with a thickness of 0.48 ∼ 14.11 m (avg: 1.76 m), and the gold grade of 7.88 g/t. The V8 orebody has a total length of 720 m, a thickness of 0.5 ∼ 4.64 m (avg: 2.18 m), and gold grade of 6.20 g/t. The V10 orebody has length of 1000 m, thickness of 0.3 ∼ 2.0 m, and the gold grade of 3.97 g/t. The hydrothermal mineralization process has been divided into five stages. The pre-gold barren quartz Stage I and barren quartz- sericite- scheelite Stage II, syn-gold smoky gray quartz- sericite- arsenopyrite (Apy-1)- pyrite (Py-1)- gold Stage III and smoky gray quartz- sericite- pyrite (Py-2)- arsenopyrite (Apy-2)- gold- polymetallic sulfide Stage IV, and post-gold quartz- calcite Stage V.

The Pingyuan Formation is a suite of low-grade metamorphic clastic rocks and it can be divided into three lithologic sections from bottom to top based on sedimentary cycles and lithological assemblages. The first section is dominated by siltstone slate, sandstone slate, and metamorphic conglomerate. The second section mainly consists of siltstone slate, with local occurrence of striated bedding and banding structures. The third section is primarily composed of siltstone slate and metamorphic fine sandstone. The Cretaceous Daijiaping Formation mainly consists of sandstones, and conglomerates. The ore types of the Wangu deposit are present as quartz veins and altered slate, as well as minor structural breccia. Among them, the quartz vein-type ores are mainly hosted in fault fracture zones and exhibit banded and stockwork structures. Altered rock-type ores are mainly developed on both sides of gold-bearing quartz veins.

Tungsten mineralization in the Wangu gold deposit is mainly concentrated in Stage II of the pre‑gold hydrothermal event, and scheelite shows clear textural variations in CL images. Based on textural features and cross-cutting relationships, tungsten mineralization can be divided into two episodes, namely main-stage scheelite and late-stage scheelite. Main-stage scheelite can be further subdivided into two generations, Sch-1a and Sch-1b, whereas late-stage scheelite also comprises two generations, Sch-2a and Sch-2b.
Main-stage scheelite is the most abundant scheelite type in the deposit and generally occurs as irregular anhedral grains or aggregates with comparatively few pores and fractures. Sch-1a formed earlier and is characterized by darker luminescence and well-developed banded to striped internal structures in CL images. It is the most widely distributed and represents the dominant scheelite generation of the main-stage. Sch-1b formed slightly later, displays relatively brighter CL luminescence, is less abundant, and commonly occurs adjacent to or in association with Sch-1a.
Late-stage scheelite is generally weakly developed and texturally more complex. It mainly occurs as thin veinlets filling fractures in main-stage scheelite, or as rims enclosing main-stage scheelite. Sch-2a is characterized by dark CL luminescence and commonly occurs along fractures, grain boundaries, or brecciated parts of Sch-1a. In several grains, Sch-2a preserves discontinuous relict banded or oscillatory internal structures similar to those of Sch-1a, but these inherited structures are partly obscured by later fluid-related modification. Sch-2b is lighter in CL images, better crystallized, and commonly encloses or replaces Sch-2a.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

16 valid minerals.

Rock Types Recorded