新疆卡拉麦里地区金成矿流体和O、H、S同位素地球化学特征

卡拉麦里金矿带位于准噶尔北缘和阿尔曼太至北塔山以南地区,成矿带划分属卡拉麦里—达尔布特成矿带(Ⅲ级成矿带)的卡拉麦里—莫钦乌拉成矿带(Ⅳ级成矿带),是新疆重要的金多金属成矿带。对双泉、南明水、苏吉泉等金矿床流体包裹体,氢、氧同位素和硫同位素研究表明,主成矿期成矿温度一般在200～230℃,属中低温;盐度(质量分数)一般为3.55%～4.5%,属低盐度;成矿流体为C-O-H-N-S体系。除库布苏金矿床成矿流体主要为岩浆水外,其他金矿床的成矿流体以变质水为主,但也兼具有岩浆水、建造水和/或大气降水的特征。双泉、南明水金矿中的硫主要来自变质的围岩,可能有部分深源岩浆硫的混入;金山沟、柳树泉金矿床的硫同位素组成具有深源硫的特征,成矿可能与火山、次火山活动有关。

Characteristics of ore-forming fluids and O,H,S isotopic geochemistry of the gold deposits in the Kalamaili Area,Xinjiang,China

The Kalamaili gold belt is located at the north margin of the Junggar Basin and includes the area to the south of Armantai-Beitashan. As an important gold and polymetallic ore belt in Xinjiang,it belongs to the Kalamaili-Moqinwula mineralization belt (IV-grade metallogenic belt) of the Kalamaili-Daerbute gold metallogenic belt (III-grade metallogenic belt). The study of fluid inclusions of the Shuangquan,Nanmingshui,Sujiquan and other gold deposits in the Kalamaili belt indicates that the ore-forming fluid during the major stage of mineralization was a C-O-H-N-S system,with medium to low temperature (200-230 ℃) and low salinity (3.55%-4.5%). The study of hydrogen and oxygen isotopes suggests that the ore-forming fluid of the Kubusu gold deposit was mainly derived from magmatic water,while metamorphic water dominated in the other gold deposits of the belt. Sulfur isotopic geochemistry indicates that the sulfur in the Shuangquan and Nanmingshui gold deposits was mainly from metamorphic wall rock,though partial sulfur may have been contributed by magma. In the Jinshangou and Liushuquan gold deposits,the sulfur was mainly derived from magma and the mineralization may have been associated with volcanic to subvolcanic activity.