Abstract

The Cenozoic magmatism in the Habo - Ô Quý Hồ (HOQ) Belt, southeastem part of the Ailao Shan - Red River Shear Zone, formed high-K alkaline magmatic rocks and a typical epithermal-porphyric Cu-Mo-Au mineralization system. The magmatic rock are characterized by enrichment of incompatible elements (Rb, Sr, Ba, K), depleted in high field strength elements (Nb, Ta, Ti and P), low initial ^l43Nd/^l44Nd values of 0.512336- 0.512450 and moderate (⁸⁷Sr/⁸⁶Sr)i values of 0.706585-0.707521. The high-K alkaline magatism and Cu-Mo-Au mineralization formation took placed at about 42-32 million years ago, coeval with those in the eastem part of Tibet region. This indicated that the magmatism and Cu-Mo-Au mineralization formation in the HOQ Belt occurred prior to the onset of the left-lateral movement along the Ailao Shan-Red River Shear Zone. The magmatic rocks with geochemical and Rb-Sr isotopic characteristics above were perhaps generated from enriched mantle source region (EMI) or affected by subducted Paleotethys plate - derived fluids