岩石学报
巖石學報
암석학보
ACTA PETROLOGICA SINICA
2009年
11期
2823-2832
,共10页
倪智勇%李诺%张辉%薛良伟
倪智勇%李諾%張輝%薛良偉
예지용%리낙%장휘%설량위
Sr-Nb-Pb同位素%成矿物质来源%大湖金钼矿床%小秦岭金矿田%A型俯冲
Sr-Nb-Pb同位素%成礦物質來源%大湖金鉬礦床%小秦嶺金礦田%A型俯遲
Sr-Nb-Pb동위소%성광물질래원%대호금목광상%소진령금광전%A형부충
Sr-Nd-Pb isotope systematics%Ore-forming element source%Dahu Au-Mo deposit%Xiaoqinling gold field%A-typesubduction
河南灵宝大湖金钼矿床位于小秦岭金矿田北缘,属典型的断控脉状矿床.前人较好研究了矿床流体包裹体和成矿年代,但对成矿物质来源研究薄弱.本文对16件矿石硫化物及5件赋矿围岩样品进行了Sr-Nd-Pb同位素分析,金属硫化物I_(Sr)=0.70470～0.71312,平均0.70854;(~(143)Nd/~(144)Nd)_i=0.51143-0.51215,平均0.51162;(~(206)Pb/~(204)Pb)_i=17.033～17.285,(~(207)Pb/~(204)Pb)_i=15.358～15.438,(~(208)Pb/~(204)Pb)_i=37.307-37.582,平均值分别是17.162,15.405,37.440.5件太华超群样品I_(Sr)=0.70947～0.73201,平均0.72294;(~(143)Nd/~(144)Nd)_i=0.51076～0.51133,平均0.51107;(~(206)Pb/~(204)Pb)_i=17.127～18.392,(~(207P)b/~(204)Pb)_i=15.416～15.604,(~(208)Pb/~(204)Pb)_i=37.498～37.814,平均值分别是17.547,15.470,37.616.Sr-Nd-Pb同位素特征表明成矿物质来源具壳幔混合特征,初始成矿流体可能来源于亏损的残余洋壳,并通过成矿过程的水岩相互作用与太华超群混合;据此认为,在218Ma年左右,秦岭地区的陆陆碰撞造山作用并没有结束,而仍在进行之中.
河南靈寶大湖金鉬礦床位于小秦嶺金礦田北緣,屬典型的斷控脈狀礦床.前人較好研究瞭礦床流體包裹體和成礦年代,但對成礦物質來源研究薄弱.本文對16件礦石硫化物及5件賦礦圍巖樣品進行瞭Sr-Nd-Pb同位素分析,金屬硫化物I_(Sr)=0.70470～0.71312,平均0.70854;(~(143)Nd/~(144)Nd)_i=0.51143-0.51215,平均0.51162;(~(206)Pb/~(204)Pb)_i=17.033～17.285,(~(207)Pb/~(204)Pb)_i=15.358～15.438,(~(208)Pb/~(204)Pb)_i=37.307-37.582,平均值分彆是17.162,15.405,37.440.5件太華超群樣品I_(Sr)=0.70947～0.73201,平均0.72294;(~(143)Nd/~(144)Nd)_i=0.51076～0.51133,平均0.51107;(~(206)Pb/~(204)Pb)_i=17.127～18.392,(~(207P)b/~(204)Pb)_i=15.416～15.604,(~(208)Pb/~(204)Pb)_i=37.498～37.814,平均值分彆是17.547,15.470,37.616.Sr-Nd-Pb同位素特徵錶明成礦物質來源具殼幔混閤特徵,初始成礦流體可能來源于虧損的殘餘洋殼,併通過成礦過程的水巖相互作用與太華超群混閤;據此認為,在218Ma年左右,秦嶺地區的陸陸踫撞造山作用併沒有結束,而仍在進行之中.
하남령보대호금목광상위우소진령금광전북연,속전형적단공맥상광상.전인교호연구료광상류체포과체화성광년대,단대성광물질래원연구박약.본문대16건광석류화물급5건부광위암양품진행료Sr-Nd-Pb동위소분석,금속류화물I_(Sr)=0.70470～0.71312,평균0.70854;(~(143)Nd/~(144)Nd)_i=0.51143-0.51215,평균0.51162;(~(206)Pb/~(204)Pb)_i=17.033～17.285,(~(207)Pb/~(204)Pb)_i=15.358～15.438,(~(208)Pb/~(204)Pb)_i=37.307-37.582,평균치분별시17.162,15.405,37.440.5건태화초군양품I_(Sr)=0.70947～0.73201,평균0.72294;(~(143)Nd/~(144)Nd)_i=0.51076～0.51133,평균0.51107;(~(206)Pb/~(204)Pb)_i=17.127～18.392,(~(207P)b/~(204)Pb)_i=15.416～15.604,(~(208)Pb/~(204)Pb)_i=37.498～37.814,평균치분별시17.547,15.470,37.616.Sr-Nd-Pb동위소특정표명성광물질래원구각만혼합특정,초시성광류체가능래원우우손적잔여양각,병통과성광과정적수암상호작용여태화초군혼합;거차인위,재218Ma년좌우,진령지구적륙륙팽당조산작용병몰유결속,이잉재진행지중.
The Dahu Au-Mo deposit,Lingbao County,Henan Province is a typical fault-controlled lode deposit occurring in the northern Xiaoqinling gold field.The fluid inclusions and mineralization age have been well documented,but the ore-forming metal source has not been discussed in previous studies.This paper reports analytical results of Sr-Nd-Pb isotope systematics for 16 sulfide samples(7 pyrite,4 molybdenite,3 galena and 2 chalcopyrite)and 5 ore-hosting rocks of Taihua Supergroup gneisses.The sulfides yield I_(Sr) of 0.70470～0.71312,with a mean value of 0.70854,(~(143) Nd/~(144) Nd)_i of 0.51143～0.51215(average 0.51162),and (~(206)Pb/~(204)Pb)_i,(~(207) Pb/~(204)Pb)_i and(~(208) pb/~(204)pb)_i of 17.033～17.285,15.358～15.438 and 37.307～37.582,with a mean value of 17.162,15.405 and 37.440,respectively.Whilst the gneisses of Taihua Supergroup yield I_(Sr) of 0.70947～0.73201 with an average of 0.72294,(~(143) Nd/144Nd)_i of 0.51076～0.51133 with an average of 0.51107,(~(206) Pb/~(204) Pb)_i of 17.127～18.392,averaging 17.547,(~(207)pb/~(204)pb)_i of 15.416～15.604,averaging 15.470 and(~(208)Pb/~(204)Pb)_i of 37.498～37.814,averaging 37.616,respectively.The Sr-Nd-Pb isotope systematics shows a source of mixing crust and mantle.Therefore,it is concluded that the oreforming materials or fluids originated initially from a residual depleted ocean crust,which had subducted and accumulated beneath the interested area,and then mixed the Taihua Supergroup during fluid-rock interaction;and that time the continental collision between Yangtze and North China were not ended yet,instead,it just widely began at about 218 Ma.
