Spatial Variation Regularity and Ore Potential of S-type and I-type Granites in the Beishan Mountain
北山花岗岩S型/I型空间变化规律及含矿性

Granites are well developed in Beishan area, with the outcrop making up nearly 30% of the total area. Over 80% of the granites were formed in the Variscan epoch. According to petrochemical discrimination, the ratio of S-type to I-type granites is 0.33 in the north belt, 0.54 in the middle belt and 0.59 in the south belt respectively. From north to south, the I-type granite gradually decreases whereas the S-type granite increases. The granites in this area constitute important ore-bearing rocks. The typical porphyry Cu deposits are related to the I-type granitic porphyry, and the Cu-Pb combination has to do with the S-type granitic porphyry. The Mo deposits are associated with the I-type granite, which grades off into the S-type granite when the W-Mo combination appears. The W-Sn deposits are mainly linked with the S-type granite. The granites related to gold deposits are S-type and I-type ones, with indistinct specialization.