The Qiandong-Xiangxi-Guibei (Big Riverside, Xiangqian-style) mining area is located on the southwestern edge of the Yangtze platform, and the junction of Hunan and Guizhou to the north of Guizhou is a belt with a north-south trend. The main types of deposits in the area are sedimentary types. Known deposits include the barite deposits such as Guizhou Tianzhu Dahe River, Hunan Xinhuang Gongxi, and Guangxi Sanjiang Banbi.

1. Regional geological background

From the Sinian period to the early Cambrian, intense tension activity occurred in the southern continental plate, which led to the disintegration of the Middle Proterozoic continent, resulting in the Yangtze block and the South China block, separated by the deep ocean. Due to the intra-continental tension rifting, a geomorphic trough-shaped deep-water basin was formed in the shallow waters along the Yangtze block, and the extension activity continued until the late Sinian period with alkaline volcanic eruption.

During the early Cambrian, the sea level rose throughout the south, and black shales were deposited, with deep-sea condensate deposits such as phosphorus-containing nodules and siliceous radiolarians. According to the research of the barite ore data, the barite is built in the combination layer of phosphorus-containing nodules, siliceous rocks, and black shale near the Sinian-Cambrian boundary.

The exposed strata in the Guizhou Barite Mine Concentration Area include the Proterozoic Yuxiajiang Group and the Sinian, Cambrian, Ordovician and Silurian. The Cambrian is widely exposed, and the Sinian, Ordovician and Silurian are relatively limited in distribution. The Cambrian is the main ore-forming stratum of the barite deposit, and the Ordovician is the secondary ore-forming stratum of the barite deposit.

2. Metallogenic characteristics of ore clusters

The barite deposits in the ore gathering area are all marine sedimentary, mainly produced in the siliceous rock series of the Lower Cambrian Niutitang Formation, Qingxi Formation, Upper Devonian Xiangshuidong Formation, and Liujiang Formation. The ore body is produced in layered, layer-like, lenticular single or multiple layers. The scale of the barite deposits in the area is mainly large-to-large sized deposits, followed by medium-sized deposits.

Typical deposits in the area include Guizhou Zhenning Leji Barite Mine, Guizhou Dahebian Barite Mine, Hunan Xinhuang Gongxi Barite Mine.

3.Typical deposit

Guizhou Tianzhu Dahebian sedimentary barite deposit is located in Tianzhu County, Guizhou Province. The mining area is more than 30 km long and about 10 km wide. It is an ultra-large sedimentary barite deposit.

(1) Regional geological background: The deposit is located at the southern edge of the Yangtze platform fold belt on the Yangtze quasi-platform.

(2) Metallogenic environment: The deposit is located at the bottom of the Lower Cambrian Niutitang Formation, and the lithological changes of the Niutitang Formation are siliceous rock-phospholite-barite ore layer-carbonaceous from bottom to top. Shale-argillaceous limestone.

(3) Ore body distribution and occurrence: The main barite ore layer is exposed on the two wings of the Pingdi (Gongxi) syncline. It is large in scale and simple in form. It is layered in contact with surrounding rocks. The ore body is in contact with the surrounding rocks. Consistent, synchronized folds, generally heading 45 ° northeast; tending to be southeast east on the westward flank and northwest on the east wing; inclination angle 16 ° to 84 °, generally 20 to 40 °; shallow shallows, gradually deeper Slow down. The thickness of the ore layer is extremely stable. The thickness of the main ore layer is generally 3 ~ 5m, smaller by 0.5m and larger by 10.17m. The average thickness of the entire deposit is 3.49m. The thickness of the ore layer is gradually increasing. In the inclined direction, the thickness of the ore layer is also slightly increasing.

(4) Ore types and mineral combinations: block ores, banded ores, piebald ores, dissolved pore ores, nodular ores, etc. Barite ore is light gray-ash, accompanied by dolomite, calcite, carbonaceous, organic matter, a small amount of authigenic feldspar, clay minerals, pyrite, etc., and its content varies with the type of ore.

(5) Ore structure and structure: Barite ore is mostly shaped-semi-automorphic, and the main structure is powder crystal fine crystal structure, unequal grain crystal structure, granitic crystal structure, and the secondary structure has a centripetal radial shape. Unequal grain change crystal structure, metabolized dissolution structure, strip-like structure, etc. The ore structures are blocky, variegated, pore-like, striped, and nodular. There are three types of structures: blocky, variegated, and striped.

(6) Physical and chemical conditions of mineralization: The mineralization temperature of this deposit is 100 ～ 200 ℃, the mineralization pressure is several Pascals to 20 × 105Pa, the Eh value (mV) of the mineralization is 357, the pH value is 6.5, and it is weak acid- Generated in a weakly alkaline oxidizing environment.