The exposed strata in the mining area are mainly the Middle-Lower Ordovician Qiaganbulake Formation, which is mainly composed of basalt, andesite, volcanic breccia, and tuff. The predominant lithologies visible at the surface of the mining area are mafic–ultramafic rocks and granite. The granites are primarily composed of moyite and monzonitic granite, with the latter being more extensively exposed in the southern part of the mining area. The mafic–ultramafic rocks distributed in the central part of the mining area are mainly composed of gabbro, olivine gabbro, and pyroxene-peridotite, which intruded into a suite of volcanic rocks within the Ordovician Qiaganbulake Formation. The primary ore-bearing lithology in the mining area is pyroxene-peridotite, which is exposed in the western section of the mafic–ultramafic rocks. The Baixintan Ni-Cu deposit is divided into two ore belts from west to east. The western ore body is notably larger, with drill holes revealing an average thickness of 19.56 m and average grades of 0.83 % Cu and 0.57 % Ni. In contrast, the eastern ore body averages 11.23 m in thickness, with grades of 0.72 % Cu and 0.69 % Ni.

The Baixintan Cu-Ni deposit, hosted in a Permian mafic–ultramafic intrusion, is a typical magmatic Cu-Ni sulfide deposit. It is situated at the junction of the Tarim ancient continental margin block and the southern Junggar active belt.

Intrusive rocks at Baixintan include a Permian mafic–ultramafic complex in the north and Devonian monzogranite and syenogranite in the south. The Permian mafic–ultramafic complex is the main ore host that extends NE for 2800 m (width: 250–760 m). In cross-section, the intrusion dips gently (dip angle: 30°) to the northwest. The mafic–ultramafic complex is composed of (from the margin to the core) gabbro, olivine gabbro, hornblende olivine gabbro (HOG), and hornblende olivine websterite (HOW), of which the latter two are mineralized.
The Baixintan Ni–Cu orebodies are lensoidal and hosted in the HOW and HOG. Among the 12 orebodies, the largest and thickest one (No. I2) is hosted in the deeper level. It is ~1100 m long, 167 m wide, and 1.73 to 49.25 m thick (mean 17.10 m), and has on average 0.75% Cu and 0.59% Ni. The ores are disseminated, net-textured, or massive to semi-massive. The sulfides can be divided into two generations based on their inclusions and paragenetic relationships. The early generation mainly comprises pyrrhotite and pentlandite. The late generation is characterized by chalcopyrite occurrence on the margin of the early generation sulfide inclusions.

Other Regions, Features and Areas containing this locality

References