内蒙古苏尼特左旗地区发现三叠纪金矿化  

Triassic gold mineralization is discovered in Sunitezuoqi, Eastern Inner Mongolia

作　　者：赵利青[1] 孙世华[2] 肖成东[3] 覃功炯[2] 王金龙[4] 

机构地区：[1]武警黄金地质研究所,河北廊坊065000 [2]中国科学院地质与地球物理研究所矿产资源研究重点实验室,北京100029 [3]天津华北地质勘查局,天津300181 [4]武警黄金第二支队,内蒙古呼和浩特010010

出　　处：《黄金地质》2003年第4期1-7,共7页Gold Geology

基　　金：中国科学院资源与生态环境重大项目基金资助(KZ951 A1 401);武警黄金指挥部项目基金资助(HJ99 6)

摘　　要：目前,在苏尼特左旗地区确定了元古宙地层、韧性剪切带,并发现了金矿化。该区总体属含古老地块并经中生代改造的中古生代造山带,金矿化带产于NE与NEE向构造组成的楔形体内,受韧性剪切带控制。金矿围岩为奥陶—志留—泥盆纪英云闪长岩,中新元古界温都尔庙群绢云片岩、绿泥片岩,下二叠统大石寨组安山岩等。金矿石类型包括石英(硫化物)脉型、破碎带蚀变岩型、糜棱岩型。2件含Au石英脉中绢云母的Ar Ar法坪年龄分别为(337 56±0 93)和(236 45±0 53)Ma,根据绢云母的产出特征推断,前者可能代表华力西早期华北板块与蒙古古板块碰撞热事件的时代,并叠加有225 60、247 58Ma的热事件;后者代表金矿成矿时代,与大规模韧性剪切作用主要活动期相同,成矿作用可能与韧性剪切作用有关。Sunitezuoqi locates in the middle Paleozoic Inner Mongolia orogenic belt that contains some Precambrian continental blocks and was reformed by Mesozoic tectonic-magmatic process. The Sunitezuoqi gold mineralization belt was a newly discovered in the Inner Mongolia orogenic belt where little gold deposits have been found so far. The belt locates in the wedge limited by NE and NEE strike structures. The gold ores can be devided into quartz (sulfide) vein type, alteration rock type and mylonite type. Their wall rocks include tonalite of Ordovician-Silurian-Devonian, sericite schist and greenschist of Meso-Proterozoic Wenduermiao Group, andesite of Lower Permian Dashizhai Formation and others. Two perfect ()^(39)Ar-^(40)Ar plateau ages analyzed from two sericites in gold-bearing quartz vein are (337.56±0.93)Ma and (236.45±0.53)Ma. The former one may corresponds to the early Variscan middle Paleozoic collision event between the North China plate and the Mongolia Palaeo-plate and has been overprint by the heat event of 225.60 Ma and 247.58 Ma. The Later one represents Triassic metallogenic age and corresponds to main active period of large-scale ductile shear process. This age has a regional geological significance and implies an important metallogenic event showing a good potential for gold exploration in the region.

关 键 词：金矿化 韧性剪切带 法坪年龄 构造演化 成矿时代 内蒙古 

分 类 号：P618.51[天文地球—矿床学]