豫西熊耳山地区沙沟银铅锌矿床成矿的^(40)Ar-^(39)Ar年龄及其地质意义  

^(40)Ar/ ^(39)Ar dating of fuchsite and sericite from altered rocks close to ore veins in Shagou large-size Ag-Pb-Zn deposit of Xiong'ershan area, western Henan Province, and its significance

作　　者：毛景文[1] 郑榕芬[2] 叶会寿[1] 高建京[2] 陈文[3] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]中国地质科学院地质研究所,北京100037

出　　处：《矿床地质》2006年第4期359-368,共10页Mineral Deposits

基　　金：国家自然科学基金项目(40434011)的资助

摘　　要：豫西沙沟、铁炉坪和蒿坪沟银铅锌矿构成秦岭地区最大的银矿集区,初步探明银金属储量约4000t。在这3个矿区中矿脉群受NE向断裂的控制,单个矿脉仅数厘米到数十厘米厚,但延长达数千米和延深数百米,矿石银品位极高,是一种罕见的工业性矿床。本次研究在沙沟矿区的近矿蚀变岩中选取绢云母和铬云母进行40Ar/39Ar年龄测定,获得坪年龄为(145.0±1.1)Ma和(147.0±1.5)Ma,相应的等时线年龄为(145.2±2.5)Ma和(147.6±2.3)Ma。这些年龄数据与熊耳山地区的三道庄—南泥湖钼钨矿成矿年龄基本相同,鉴于在沙沟矿区银铅锌矿脉于深部钼矿化越来越强以及在邻区可见到围绕中生代花岗岩体发育的斑岩型_矽卡岩型钼钨矿及外围的脉状和破碎带型铅锌银矿的矿化分带之现象,可以认为银铅锌与钼钨矿化属于同一成矿系统。The Tieluping ore district comprising Shagou, Tieluping, and Haopinggou Ag-Pb-Zn deposits is the largest silver area in western Henan Province, with controlled reserves of 4 000 tons of silver metal and extreme high grade. The ore veins extending along a large group of NE-trending fractures are several kilometers long, several hundred meters deep and several to 20 centimeter thick, showing a significant economic value. These deposits are hence a rare type of silver deposits in the world. ^40Ar-^39Ar dating was performed on fuchsite and sericite from the altered rocks close to the ore veins, which yielded a set of age data, i.e., plateau ages of （ 145.0 ± 1.1 ） Ma and （147.0 ± 1.5） Ma, and isoehronal ages of （145.2 ± 2.5） Ma and （ 147.6 ± 2.3） Ma. These age data corre- spond to Re-Os dating data of molybdenite from the ores in the Sandaozhuang, Nannihu, and Shangfanggou porphyry-skarn Mo-W deposits in Xiong＇ ershan area. A group of Pb-Zn-Ag deposits surround the three Mo-W deposits, exhibiting zoning in space. As more and more molybdenum appears downward in the Shagou Ag-Pb-Znmine, it is inferred that there possibly exists a Mo ore body at the depth.

关 键 词：地球化学 银铅锌矿 ^40Ar-^39Ar测年 熊耳山 豫西 

分 类 号：P618.52[天文地球—矿床学] P618.42[天文地球—地质学]