Abstract:

Located in Qimantage area of southwest Qaidam basin,Kaerqueka copper polymetallic deposit is a characteristic hydrothermal vein-skarn ore deposit controlled by the fractured and altered zone. Two kinds of wall-rock alterations can be recognized in the ore deposit, i.e., skarn and phyllic alteration. The former was formed by intrusion of Indosinian porphyaceous biotite adamellite. Copper polymetallic skarn lenticular bodies are commonly seen in the contact zone of the intrusion, different lithologic interfaces and faulted structural zones of the surrounding rocks. There are some typical calcium skarn minerals, such as diopside, hedenbergite, andradite, hessonite, idocrase, wollastonite, epidote, scapolite and actinolite. The latter forms many parallel NWW-striking chacopyritized hydrothermal alteration zones in porphyaceous biotite adamellite in the northwest part of the ore district, belonging to hydrothermal vein type mineralization controlled by faulted fractured zones. It is concluded that Kaerqueka copper polymetallic deposit is related to Indosinian hypabyssal and high emplacement porphyaceous biotite adamellite. The ages of rocks and ores in the copper polymetallic skarn deposit and the veinlet-disseminated hydrothermal veinlike copper deposit are the same, and the backgrounds of tectono-magmatic activities are identical; nevertheless, they are products of different ore-forming processes that occurred at different stages, different depths and different parts. This ore deposit is a compound one, with the skarn copper polymetallic mineralization as the main body, accompanied by the hydrothermal vein type copper mineralization in well-developed faults of the parent rock.

Key words: mineralization and alteration types, altered zonation, skarn mineralogy, Kaerqueka, Qimantage, Qinghai Province, eastern Kunlun, ore deposit