Geological characters of Baogutu porphyry copper deposit in Xinjiang,NW China.

Abstract

The newly found Baogutu porphyry copper deposit is located at the west margin of Junggar basin and to the south of Dalabute fault,Our study object is the V intrusion,which is the main ore containing body.In this paper,mineralization,alteration zoning and mineral assemblages of the deposit are described.The researching to fluid inclusions shows the temperatures of the main mineralization epoch are between 180℃～450℃ and the formation pressures of the fluid inclusions are between 1～9MPa.So the corresponding emplacement depths of the V intrusion are between 100～600 m.The e~(34)S of chalcopyrite and pyrite are varying between-2.4‰～-0.8%0 and-2.7‰～+0.7‰,respectively,indicate sulfur of the ore came from mantle.According to the preliminary researching,we consider the mineralization process of the ore is that,the V intrusion has experienced two epoch ore- forming fluid activities in addition after the diagenesis of the adakitic magma came from mantle.The early epoch can be divided into four phases and Cu-Fe-Mo-Zn sulfides were formed.In the late epoch,compound minerals of Cu-Te-Bi-Au-Ag were formed.Re-Os age of molybdenite from the early epoch mineralization is 310Ma.