柿竹园钨多金属矽卡岩_云英岩与铅锌银矿脉C、H、O、Pb同位素地球化学研究  

C,H,O,Pb isotopic geochemistry of W polymetallic skarn_greisen and Pb_Zn_Ag veins in Shizhuyuan orefield,Hunan Province

作　　者：吴胜华[1,2] 戴盼[1] 王旭东[3] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]中国地质大学地球科学与资源学院,北京100083 [3]东北大学秦皇岛分校,河北秦皇岛066004

出　　处：《矿床地质》2016年第3期633-647,共15页Mineral Deposits

基　　金：国家自然科学基金项目(编号:41303034;41430314);中国地质调查局地质调查工作项目(编号:12120113093600)联合资助

摘　　要：柿竹园W_Sn_Mo_Bi_Pb_Zn_Ag矿田是南岭地区典型多金属矿田,其具有显著的蚀变_成矿分带特征:近接触带矽卡岩-云英岩型W_Sn_Mo_Bi矿床(如柿竹园、金船塘、柴山地区)和远接触带脉状Pb_Zn_Ag矿床(如蛇形坪、横山岭、百步窿、枞树板地区)。通过对远—近接触带中主要蚀变岩石和矿石样品的C、H、O、Pb同位素研究,发现在近接触带块状矽卡岩中方解石的δ^(13)C和δ^(18)O值分别在-6.5‰^-3.6‰和4.8‰~8.4‰之间,远接触带Pb_Zn_Ag矿脉中团块状和脉状方解石的δ^(13)C和δ^(18)O值分别在-3.5‰^-1.5‰和8.1‰~15.8‰之间,表明矽卡岩形成于岩浆热液流体的渗滤交代作用,而远接触带碳酸盐脉的形成与热液流体沿灰岩裂隙充填过程中的水岩反应相关。近接触带块状云英岩中石英的δD_(H_2O)和δ_(18)O_(H_2O)值分别为-77‰和5.1‰,矽卡岩中石榴子石的δD_(H_2O)值为-97‰,δ_(18)O_(H_2O)值范围在9.2‰~9.4‰,网脉状云英岩中石英的δD_(H_2O)和δ_(18)O_(H_2O)值分别为-83‰和-8.2‰,退化蚀变矽卡岩中石英的δD_(H_2O)和δ_(18)O_(H_2O)值分别为-65‰和-4.2‰,远接触带石英脉中石英样品的δD_(H_2O)和δ_(18)O_(H_2O)值分别为-83‰和2.8‰,表明近接触带的块状矽卡岩和云英岩与远接触带石英脉成矿流体具有岩浆水的特征,而网脉状云英岩和退化蚀变矽卡岩成矿流体具有岩浆流体与大气水混合的特征。远—近接触带中方铅矿的206Pb/204Pb值范围18.565~18.622,207Pb/204Pb值范围15.694~15.738,208Pb/204Pb值范围38.819~38.986,表明Pb等金属元素来源于上地壳。The Shizhuyuan W-Sn-Mo-Bi-Pb-Zn-Ag orefield is one of the typical polymetallic orefields in Nanling region and shows significant alteration and mineralization zonation for proximal skarn-greisen W-Sn-Mo-Bi deposits （such as Shizhuyuan, Jinchuantang, and Chaishan） and distal veined Pb-Zn-Ag deposits （such as Shexingping, Hengshanling, Baibulong, and Congshuban）. The authors carried out C-O-H-Pb isotopic analysis of the alter-ation rocks and ores from proximal-distal mineralization areas. The δ^13C and δ^18O values of calcites from the proximal skarns are between - 6.5‰ and - 3.6‰ and between 4.8‰% and 8.4‰, respectively, and those from the distal Pb-Zn-Ag range from -3.5‰ to - 1.5‰ and from 8.1‰ to 15.8‰, respectively, which suggests that skarn was formed by the infiltration metasomatism and distal carbonate veins were derived from water/rock reactions with limestone. The δDH2O and δ^18OH2O values of quartz from proximal greisens are - 77‰ and 5.1‰, respectively, δDH2O values of garnets from proximal skarns are - 97‰, while δ^18OH2O values of them range be- tween 9.2‰and 9.4‰, the ^13H2O and δ^18OH2O values of quartz from stockwork greisens are - 83‰ and - 8.2‰, respectively, the δDH2O andδ^18OH2O values of quartz from retrograde skarns are - 65‰ and - 4.2‰, respectively, and the δDH2O and δ^18OH2O values of quartz from distal quartz veins are -83‰ and 2.8‰. It is thus concluded that the hydrothermal fluids forming proximal skarn-greisen and distal quartz veins were probably magmatic water, while the fluids forming stockwork greisens and retrograde skarns were mixtures of magmatic and meteoric water. The ^206pb/^204pb values of galena from proximal-distal mineralization areas are between 18. 565 and 18. 622, ^207pb/^204apb between 15. 694 and 15. 738, and ^208pb/^204pb between 38. 819 and 38. 986, which confirm that ore-forming elements were mainly derived from the upper crust.

关 键 词：地球化学 W_Sn_Mo_Bi矿床 Pb_Zn_Ag矿床 稳定同位素 柿竹园 

分 类 号：P618.67[天文地球—矿床学]