新疆红山糜棱岩-超糜棱岩金矿带矿床地质特征与成矿条件

红山糜棱岩-超糜棱岩金矿带大地构造背景属天山地槽北天山地向斜褶皱带,位于康古尔与苦水断裂之间狭长的含金韧性剪切带东段北缘;其出露地层为中下石炭统;华力西中晚期的多期次岩浆活动、韧性剪切作用和构造活动叠加形成了一系列金及多金属矿床,已成为新疆东部主要的产金基地;通过对糜棱岩-超糜棱岩带金矿带赋存的金矿床矿床地质特征的研究,并从宏观及微观尺度进行成矿条件分析,发现金的富集与多金属硫化物,尤其是与方铅矿关系密切;主要特征是贫黄铁矿,多金属硫化物少,局部富含方铅矿,金的分布极不均匀;金具有多源性,主要来自岩浆,少量来自围岩;剪切作用多次叠加及强烈糜棱岩化,使金矿物与多金属硫化物多沿糜棱面理及显微裂隙分布,最终导致工业矿体侵位,沿该带形成一系列糜棱岩-超糜棱岩型金矿床.

GEOLOGICAL FEATURES AND METALLOGENETIC CONDITIONS OF ORE DEPOSITS ASSOCIATED WITH THE MYLONITE- AND ULTRAMYLONITE-TYPE GOLD ORE ZONES AT HONGSHAN, XINJIANG

The geotectonic background of the gold field of Hongshan belongs to the syncline fold zone of the Tianshan's geosyncline in northern Tianshan mountains,and is located at the north edge of the eastern section of the long and narrow ductile shear zone that contains gold between the Kanguer and Kushui faults.The strata exposed are Middle-Lower Carboniferous in age.Many times of magmatism,ductile shearing and tectonic activities in the middle-late period of Variscan led to the formation of a series of gold deposits,thus creating a main base of gold production in eastern Xinjiang.The geological features of the gold deposits at Hongshan were studied,and the metallogenetic conditions were analyzed.It is shown that the enrichment of gold is related closely to polymetallic sulfide,especially galena.The main features are: poor pyrite,minor polymetallic sulfide but abundant galena and uneven distribution of gold.The gold has a variety of sources,mainly from magma,some from country rocks.Multi-time superimposition of shearing and strong mylonitization made the gold minerals and polymetallic sulfide distribute along the micro-fissures and mylonitic foliation.So the ore deposits of industrial scale were emplaced at last,forming the mylonite-or ultramylonite-type gold deposits.