现代地质
現代地質
현대지질
GEOSCIENCE-JOURNAL OF GRADUATE SCHOOL CHINA UNIVERSITY OF GEOSCIENCES
2014年
1期
51-60
,共10页
段士刚%薛春纪%石海岗%李野%贾志业
段士剛%薛春紀%石海崗%李野%賈誌業
단사강%설춘기%석해강%리야%가지업
矿床地质%C%O%S%Pb同位素%喇嘛萨依铜矿%西天山%新疆
礦床地質%C%O%S%Pb同位素%喇嘛薩依銅礦%西天山%新疆
광상지질%C%O%S%Pb동위소%나마살의동광%서천산%신강
ore geology%C,O,S and Pb isotopes%Lamasayi copper deposit%Western Tianshan%Xinjiang
喇嘛萨依铜矿是新疆西天山赛里木微地块内的一处典型铜矿床,关于其成因类型尚存争议。总结了该铜矿床的地质特征,测试围岩、脉石碳酸盐的C、O同位素和硫化物的S、Pb同位素组成,探讨其成因类型。研究表明,喇嘛萨依铜矿床具有后生矿床特征,发育矽卡岩化蚀变,脉石方解石的δ13 C值变化范围为-1.04‰~-0.87‰,低于围岩灰岩的δ13C值(变化范围为3.51‰~5.47‰),δ18O值变化范围为9.33‰~9.61‰,明显低于正常的海相碳酸盐岩的O同位素(δ18 O=20‰~26‰),C、O同位素组成反映喇嘛萨依铜矿成矿晚阶段流体来自岩浆水和地下水的混合水;硫化物的δ34 S值主要变化范围为3.75‰~8.64‰,与区域上海西期斑岩的硫同位素组成(如达巴特斑岩铜钼矿床硫化物的δ34 S变化范围为4.9‰~7.9‰)接近,反映硫来源于斑岩;黄铜矿的铅同位素为206 Pb/204 Pb=18.264~19.544,207 Pb/204 Pb=15.575~15.656,208Pb/204Pb=38.103~38.705,具有富含放射成因铅、两阶段异常铅特征,与区域上海西期斑岩(达巴特流纹斑岩)的铅同位素组成特征相似,反映成矿金属物质部分来源于斑岩。通过综合分析认为,喇嘛萨依铜矿是与斑岩有关的矽卡岩型矿床。
喇嘛薩依銅礦是新疆西天山賽裏木微地塊內的一處典型銅礦床,關于其成因類型尚存爭議。總結瞭該銅礦床的地質特徵,測試圍巖、脈石碳痠鹽的C、O同位素和硫化物的S、Pb同位素組成,探討其成因類型。研究錶明,喇嘛薩依銅礦床具有後生礦床特徵,髮育矽卡巖化蝕變,脈石方解石的δ13 C值變化範圍為-1.04‰~-0.87‰,低于圍巖灰巖的δ13C值(變化範圍為3.51‰~5.47‰),δ18O值變化範圍為9.33‰~9.61‰,明顯低于正常的海相碳痠鹽巖的O同位素(δ18 O=20‰~26‰),C、O同位素組成反映喇嘛薩依銅礦成礦晚階段流體來自巖漿水和地下水的混閤水;硫化物的δ34 S值主要變化範圍為3.75‰~8.64‰,與區域上海西期斑巖的硫同位素組成(如達巴特斑巖銅鉬礦床硫化物的δ34 S變化範圍為4.9‰~7.9‰)接近,反映硫來源于斑巖;黃銅礦的鉛同位素為206 Pb/204 Pb=18.264~19.544,207 Pb/204 Pb=15.575~15.656,208Pb/204Pb=38.103~38.705,具有富含放射成因鉛、兩階段異常鉛特徵,與區域上海西期斑巖(達巴特流紋斑巖)的鉛同位素組成特徵相似,反映成礦金屬物質部分來源于斑巖。通過綜閤分析認為,喇嘛薩依銅礦是與斑巖有關的矽卡巖型礦床。
나마살의동광시신강서천산새리목미지괴내적일처전형동광상,관우기성인류형상존쟁의。총결료해동광상적지질특정,측시위암、맥석탄산염적C、O동위소화류화물적S、Pb동위소조성,탐토기성인류형。연구표명,나마살의동광상구유후생광상특정,발육석잡암화식변,맥석방해석적δ13 C치변화범위위-1.04‰~-0.87‰,저우위암회암적δ13C치(변화범위위3.51‰~5.47‰),δ18O치변화범위위9.33‰~9.61‰,명현저우정상적해상탄산염암적O동위소(δ18 O=20‰~26‰),C、O동위소조성반영나마살의동광성광만계단류체래자암장수화지하수적혼합수;류화물적δ34 S치주요변화범위위3.75‰~8.64‰,여구역상해서기반암적류동위소조성(여체파특반암동목광상류화물적δ34 S변화범위위4.9‰~7.9‰)접근,반영류래원우반암;황동광적연동위소위206 Pb/204 Pb=18.264~19.544,207 Pb/204 Pb=15.575~15.656,208Pb/204Pb=38.103~38.705,구유부함방사성인연、량계단이상연특정,여구역상해서기반암(체파특류문반암)적연동위소조성특정상사,반영성광금속물질부분래원우반암。통과종합분석인위,나마살의동광시여반암유관적석잡암형광상。
The Lamasayi copper deposit is a representative copper deposit in the Sailimu massif in Western Tianshan,Xinjiang,China.However,the genesis of this ore deposit is controversial.This study tries to discuss the problem through tracing the origin of ore forming material using stable isotopes of C,O,S and Pb and inves-tigating the geological characteristics of the Lamasayi copper deposit.The δ1 3 C values of gangue calcite vary be-tween -1.04‰and -0.87‰which are lower than those of wall-rock limestone (δ13C =3.51‰-5.47‰);the δ1 8 O values of gangue calcite are from 9.33‰ to 9.61‰ and are quite lower than those of normal marine carbonate (δ1 8 O =20‰-26‰).The C and O isotopic compositions reflect that the ore-forming fluid may be a mixture of magmatic water and ground water.The δ34 S values of sulfides mainly vary from 3.75‰ to 8.64‰ which is close to the sulfur isotope composition of the Hercynian porphyries (for example,theδ34 S values of sul-fides from the Dabate porphyry copper-molybdenum deposit are from 4.9‰to 7.9‰)and which reflects that the sulfur may be originated mainly from porphyry.The Pb isotope compositions of chalcopyrite are from 1 8.264 to 1 9.544 for 206 Pb/204 Pb,from 1 5.575 to 1 5.656 for 207 Pb/204 Pb,and from 38.1 03 to 38.705 for 208 Pb/204 Pb, respectively,which shows characteristic of two-stage abnormal lead and being rich in radiogenic lead,similar to the Pb isotope composition of the Hercynian porphyries (for example,the Dabate rhyolitic porphyry)and which also indicates that the ore-forming metal may be derived from the porphyry.In summary,the Lamasayi copper deposit may be skarn type deposit related to porphyry.