北山中南带海西印支期岩浆活动与金的成矿作用  

Hercynian-Indosinian Magmatic Activities and Gold Metallogeny in Central and Southern Beishan Region, Northwest China

作　　者：聂凤军[1] 江思宏[1] 白大明[1] 张义[1] 赵月明 王新亮 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]内蒙古地质调查院,内蒙古呼和浩特010020

出　　处：《地球学报》2003年第5期415-422,共8页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目 ( 4 0 0 73 0 15 );地质调查项目 (K1.3 .3 2 )部分研究成果。

摘　　要：北山中南带地处哈萨克斯坦和塔里木板块交汇处 ,区内深大断裂纵横交错 ,各类海西期 印支期岩浆岩发育 ,金矿床(点 )星罗棋布 ,是中国西北地区最重要的金成矿带之一。该区金矿床 (点 )大体可划分为 :①火山岩型 ;②侵入岩型 ;③夕卡岩型 ;④变质岩型 ;⑤沉积岩型。尽管各类金矿床 (点 )的容矿围岩不同 ,但均与海西期或印支期火成岩具密切的时空分布关系。受海西期和印支期各板块空间分布位置、运动机制和构造应力变化的影响 ,强烈的构造 岩浆活动不仅可形成大面积分布的高钾钙 碱性火成岩 ,而且导致贵重金属元素“爆发式”堆积。研究结果表明 ,各金矿床 (点 )成矿流体大都是深源岩浆流体与大气降水相混合的产物 ,属混源型中温热液金矿床 (点 )。The central and southern Beishan region,located at the convergence area of the Kazakhstan and Tarim plates,is one of the most important gold metallogenic provinces in northwest China.Gold deposits and spots are widely distributed in this area.Up till now,about 38 deposits and ore spots have been identified. Among them, the most important ones include Xiaoxigong, Xiaowannanshan, Xin Lao Jinchang, Shijinpo, Jinwozi, No. 210, Huaniushan, Huaxishan and Nanquan. These gold deposits and spots can be classified into 5 groups according to their host rocks. They are ① hosted by volcanic and volcaniclastic rocks, ② hosted by or related to granitoid intrusions,③ of skarn type, ④ hosted by Precambrain schists and ⑤ hosted by sedimentary rocks, respectively. Moreover, three mineralization concentration camps have been outlined:① Xiaoxigong Xiaowannanshan camp,② Xin Jinchang Huaniushan Jinchanggou camp and ③ Jinwozi 210 camp.Among the three camps, the first one occurs within the ancient Mazongshan uplift,whereas the other two are located along the active margin of the ancient continent.Systematic geological investigations indicate that the wall rocks of these gold deposits vary from place to place, but most of them show an intimate relation with the granitoid intrusions or Paleozoic felsic volcanic rocks. The forming processes of the gold deposits and spots are genetically related to Hercynian or Indosinian magmatic activities.The tectonic movement and the emplacement or eruption of the granitoid magma may result in the ascent and unloading of the deep seated ore fluids.The combined sulfur,oxygen,hydrogen and lead isotope data and petrological observations indicate that most of the gold deposits were formed by the mixing of magmatic fluids with heated meteoric water. These deposits are, therefore, believed to be products of Hercynian or Indosinian magmatism related to collision of the Kazakhstan and Tarim plates.

关 键 词：岩浆活动 成矿作用 金矿床 海西-印支期 

分 类 号：P588.115[天文地球—岩石学] P618.51[天文地球—地质学]