Large-scale potassium metasomatite (Kuranakh type), hosted in rocks of the middle and upper Archean Wulashan Group, mainly garnet gneiss, granulite, magnetite quartzite, and cordierite-, sillimanite-, garnet and graphite-biotite schist, quartzite, and marble. The veins occur in clusters and swarms in large groups or plates. Three types of veins are observed: (1) quartz veins with gold, quartz, pyrite, chalcopyrite, galena, and sphalerite; (2) K-feldspar and quartz-K-feldspar veins with gold, K-feldspar, quartz, pyrite, sericite, chlorite, and specularite; and (3) potassic and silica-altered rock with gold, quartz, K-feldspar, albite, sericite, chlorite, calcite, and pyrite, and minor biotite, magnetite, muscovite, and garnet. Alterations include K-feldspar, silica, sericite, and carbonate alterations. Temperature of formation of the deposit varies from early high temperatures of about 400 to 450°C to later, lower temperatures of about 172°C. The deposit is interpreted as having formed during magmatic-related hydrothermal alteration related to the Dahuabei granite.

The largest gold deposit in Inner Mongolia. More than 100 gold veins have been found in the mining area, and the ore bodies are mainly distributed in the approximate east–west direction in a parallel and equidistant manner.

Liubagou Segment Vein Nos. 313, 314; Wulanburlangou Segment Vein No. 113 (incl. No. 14/8);
Hulusitaigou Segment Vein No. 59; Vein Nos. 51–55;
Dabagou Segment Vein No. 100; Vein No. 99; Vein No. 98
Dabagou North Segment Vein No. 268 1.08; Vein No. 25; Vein No. 28
Baishitougou Segment Vein No. 20; Vein No. 24
Baishugou Segment Vein No. 13
Huluntu Segment Vein No. 32
Hadamengou West Segment Vein No. 1; Vein No. 2; Vein No. 2-1; Vein No. 3; Vein No. 207
In 2024, the Hohhot Institute of Geological Survey submitted newly identified gold resources totaling 41 t from the No. 100, No. 99, and No. 98 lodes, increasing the filed and approved resources of the Hadamengou mining area to 150.38 t Au. Within the Hadamengou segment of the Wulashan gold belt, auriferous lodes are distributed from west to east, including vein groups 313–314, 113 (incl. 14/8), 59, 51–55, 100, 99, 98, 268, 25, 28, 20, 24, 13, 32, 1, 2, 2-1, 3, and 207. In addition to the filed resources, 45.4 t of resources have been identified through preliminary exploration, and 76 t of potential resources are inferred from ongoing exploration efforts. Altogether, the Hadamengou district demonstrates a substantial resource potential approaching 272 t Au.

Over 40 years of exploration has delineated more than 100 gold-mineralized veins in the Hadamengou gold deposit. The majority of these veins strike subparallel to the EW and dip southward, with rare exceptions exhibiting NW- or SN-trending orientations. The No. 55 ore vein is characterized by a northerly dip. Among these, the No. 13, No. 113, No. 100, No. 313, and No. 32 ore veins collectively account for over 85% of the demonstrated reserves within the mining district. The main textures displayed by the ore minerals include euhedral, subhedral, and anhedral granular textures, poikilitic texture, metasomatic dissolution texture, metasomatic residual texture and cataclastic texture. Mineralization styles include veins, disseminations, and stockworks. In addition, massive, banded, honeycomb, drusy, geodal, and brecciated structures can also be observed in the deposit. These hydrothermal alterations can be divided into the following two distinct zonation patterns from the ore bodies to wall rocks: (1) the inner potassium feldspathization-silicification zone consisting of potassium feldspar and quartz, reddish in color with a width ranging from 0.3 to 10 m, and (2) the outer sericitization-chloritization zone containing sericite, epidote, chlorite, and quartz, which is gray–green in color and 1.5–10 m in width. Carbonatization occurs in both zones as cross-cutting veins and veinlets. The contact between these two alteration zones is gradational. Four hydrothermal stages have been identified on the basis of the paragenetic sequences of minerals and crosscutting relationships among ore veins observed in the field and in thin sections. The hydrothermal ore-forming process comprised an early pyrite–potassium feldspar–quartz stage (Stage I), a quartz–gold–pyrite–molybdenite stage (Stage II), a quartz–gold–polymetallic sulfide stage (Stage III), and a late quartz–carbonate stage (Stage IV).


Note: "Hadamenggou" is a mis-nomer.

Other Regions, Features and Areas containing this locality

References