Abstract:

Hongqiling magmatic Cu-Ni sulfide deposit is located in the southeastern margin of the Central Asian orogenic belt (CAOB). In this paper, the multi-degree vertical derivative and 2.5-D interactive inversion technique are used to predict the mineralization of the hidden orebodies in the deep (500-1 000 m) Cu-Ni deposit, and to study the ore-bearing properties of the mafic-ultramafic rocks (such as #1, #3 and new #3 plutons). The results show that the high-precision gravity anomaly can effectively determine the spatial distribution of deep hidden orebodies by carrying out data processing on the upper edge of different heights and the vertical first-order derivative, and the 2.5-D interactive inversion technique can be used to detect the weak anomaly caused by deep orebodies. It is speculated that there are 5 blind vein-shaped orebodies in the #3 pluton in the study area with a burial depth of 700-1 100 m. After drilling verification, 32 259 t of Ni ore was successfully discovered (the average grade of ore is 0.36%), of which No. 2 ore body is the thickest ore body, the ore penetration depth is 700-1 100 m, the average Ni ore grade is 0.39%, and the reserves are up to 27 433 t.

Key words: Central Asian orogenic belt, Hongqiling Cu-Ni deposit; deep exploration, geophysics, 2.5-D interactive inversion technique