西藏山南地区成矿带S、Pb同位素地球化学研究
|
摘要
西藏山南地区位于冈底斯东段南缘的火山-岩浆构造带,是一条资源潜力巨大的成矿带。本文通过对该成矿带的典型矿床矿石硫化物S、Pb同位素进行系统性分析,并结合区域构造演化,从成矿系统中"源"的角度对其来源特征和成矿规律进行探讨。研究结果显示,各个矿床的岩石铅和矿石铅的206Pb/204Pb、207Pb/204Pb、208Pb/204Pb比值范围分别为18.34～19.03、15.54～15.86、38.31～39.66和18.38～19.58、15.54～15.86、38.25～39.66,均富含放射成因铅,且在Pb同位素构造演化图中表现出良好的相关性,反映了物质来源上的同一性。结合Pb构造图和Δγ-Δβ成因分类图,矿石铅样品均投影于冈底斯岩基区域,表明成矿物质发生壳幔相互作用,显示造山带铅的特征。在时空上矿石铅也显示明显的变化规律,矿床成矿物质从雅鲁藏布江北侧到南侧,地壳来源物质逐渐增多,同时成矿物质由早期偏向于地幔铅向晚期地壳铅演化,指示晚期成矿物质主要为地壳来源,而早期成矿物质来源可能混有较多的幔源物质。S同位素组成具有一致的深源岩浆硫特征,克鲁、双步结热矿床矿石的硫同位素的δ34S平均值明显小于努日、程巴、明则、冲木达等矿床,也表明晚期成矿物质来源中参与了较多的地壳物质。
The Shannan area is in a volcanic-magmatic tectonic belt on the southern margin of the eastern section of the Gangdise belt. It is a metallogenic belt with great mineral resource potential. This paper has presented the sulfur and lead isotopic data of sulfides from ores of typical deposits in the metallogenic belt, and discussed the source characteristics and metallogenic regularity of the Shannan belt from aspect of the sources of ore-forming materials with the combination of the regional tectonic evolution. The results show that the 206Pb/204 Pb, 207Pb/204 Pb and 208Pb/204 Pb ratios of rocks and ores in various deposits vary from 18.34 to 19.03, from 15.54 to 15.86, from 38.31 to 39.66, and from 18.38 to 19.58, from 15.54 to 15.86, from 38.25 to 39.66 respectively, with rich radiogenetic lead and good correlations in the illustration of tectonic environment evolution by lead isotopes, reflecting the consistency of their material sources. Combined with the illustration of tectonic environment evolution by lead isotopes and Δγ-Δβ genetic classification of lead isotopes, data of the ore samples are plotted into a field of the Gangdise granite batholith, indicating that the ore-forming materials were derived from the crust-mantle interaction, with the lead isotope characteristics of the orogenic belt. Lead isotopic compositions of ores show an obviously special and temporal variation regularity as the percentage of crustal materials in the ore-forming materials is gradually increased from the north side to south side of the Yarlung Zangbo River. Meanwhile, the ore-forming materials of early stage have dominant mantle lead while those of late stage have dominant crustal lead, indicating that the ore-forming materials of late hydrothermal stage are mainly derived from crustal sources with minor mantle materials, while the ore-forming sources of early stage may be mainly derived from mantle materials with minor crust materials. The sulfur isotopic compositions have consistent characteristics of the deep magmatic originated sulfur. Moreover, the average δ34S values of ores in the Kelu and Shuangbujiere deposits are obviously lower than those of ores in the Nuri, Chengba, Mingze, and Chongmuda deposits, indicating that the late ore-forming materials of the late stage contain relatively high percentage crustal materials.
The Shannan area is in a volcanic-magmatic tectonic belt on the southern margin of the eastern section of the Gangdise belt. It is a metallogenic belt with great mineral resource potential. This paper has presented the sulfur and lead isotopic data of sulfides from ores of typical deposits in the metallogenic belt, and discussed the source characteristics and metallogenic regularity of the Shannan belt from aspect of the sources of ore-forming materials with the combination of the regional tectonic evolution. The results show that the 206Pb/204 Pb, 207Pb/204 Pb and 208Pb/204 Pb ratios of rocks and ores in various deposits vary from 18.34 to 19.03, from 15.54 to 15.86, from 38.31 to 39.66, and from 18.38 to 19.58, from 15.54 to 15.86, from 38.25 to 39.66 respectively, with rich radiogenetic lead and good correlations in the illustration of tectonic environment evolution by lead isotopes, reflecting the consistency of their material sources. Combined with the illustration of tectonic environment evolution by lead isotopes and Δγ-Δβ genetic classification of lead isotopes, data of the ore samples are plotted into a field of the Gangdise granite batholith, indicating that the ore-forming materials were derived from the crust-mantle interaction, with the lead isotope characteristics of the orogenic belt. Lead isotopic compositions of ores show an obviously special and temporal variation regularity as the percentage of crustal materials in the ore-forming materials is gradually increased from the north side to south side of the Yarlung Zangbo River. Meanwhile, the ore-forming materials of early stage have dominant mantle lead while those of late stage have dominant crustal lead, indicating that the ore-forming materials of late hydrothermal stage are mainly derived from crustal sources with minor mantle materials, while the ore-forming sources of early stage may be mainly derived from mantle materials with minor crust materials. The sulfur isotopic compositions have consistent characteristics of the deep magmatic originated sulfur. Moreover, the average δ34S values of ores in the Kelu and Shuangbujiere deposits are obviously lower than those of ores in the Nuri, Chengba, Mingze, and Chongmuda deposits, indicating that the late ore-forming materials of the late stage contain relatively high percentage crustal materials.
引文
[1]顾雪祥,唐菊兴,王成善,陆彦,王乾.喜马拉雅碰撞造山作用与(超)大型矿集区的形成:科学问题与思考[J].成都理工学院学报,2001,24(4):344-349.
[2]曲晓明,侯增谦,黄卫.冈底斯斑岩铜矿(化)带:西藏第二个“玉龙”铜矿带[J].矿床地质,2001,20(4):355-366.
[3]侯增谦,曲晓明,王淑贤,高永丰,杜安道,黄卫.青藏高原冈底斯斑岩铜矿带辉钼矿Re-Os年龄:成矿年龄时限与动力学背景应用[J].中国科学D辑,2003,33:609-618.
[4]李光明,王高明,高大发,黄志英,姚鹏.西藏冈底斯南缘构造格架与成矿系统[J].沉积与特提斯地质,2002,22(2):1-7.
[5]李光明,芮宗瑶.西藏冈底斯成矿带斑岩铜矿的成岩成矿年龄[J].大地构造与成矿学,2004,28(2):165-170.
[6]高永丰,侯增谦,魏瑞华.冈底斯晚第三纪斑岩的岩石学、地球化学及其地球动力学意义[J].岩石学报,2003,019(3):18-28.
[7]陈雷.冈底斯南缘渐新世努日矽卡岩-斑岩型铜钨钼矿床成矿作用研究[D].北京:中国科学院研究生院,2012:118-154.
[8]曲晓明,侯增谦,国连杰,徐文艺.冈底斯铜矿带埃达克质含矿斑岩的源区组成与地壳混染:Nd、Sr、Pb、O同位素约束[J].地质学报,2004,78(6):813-821.
[9]程文斌,顾雪祥,唐菊兴,等.西藏冈底斯-念靑唐古拉成矿带典型矿床硫化物Pb同位素特征-对成矿元素组合分带性的指示[J].岩石学报,2010,26(11):3350-62.
[10]费光春,多吉,温春齐,等.西藏洞中拉铅锌矿床S、Pb、Sr同位素组成对成矿物质来源的示踪[J].矿物岩石,2011,31(4):52-57.
[11]朱弟成,潘桂堂,王立全,等.西藏冈底斯带中生代岩浆岩的时空分布和相关问题的讨论[J].地质通报,2008,27(9):1535-1550.
[12]Debon F,Le Fort P,Sheppard S M,Sonet J.The four plutonic belts of the Transhimalaya-Himalaya:A chemical mineralogical,isotopic,and chronological synthesis along a Tibet-Nepal section[J].J Petrol,1986,27:219-250.
[13]Harris N B W,Xu R,Lewis C L,Jin C W.Plutonic rocks of the 1985 Tibet Geotraverse,Lhasa to Golmud[J].Phil Trans R Soc Lond,1988,A327:145-168.
[14]莫宣学,赵志丹,邓晋福,董国臣,周肃,郭铁鹰,张双全,王亮亮.印度-亚洲大陆主碰撞过程的火山作用响应[J].地学前缘,2003,10(3):135-147.
[15]沈渭洲.稳定同位素地球化学[M].北京:原子能出版社,1987:78-83.
[16]王立强,唐菊兴,陈伟等.西藏努日、程巴铜-钼-钨矿床硫铅同位素地球化学[J].地球学报,2014,35(1):39-48.
[17]Gariépy C,Allègre C J,Xu R H.The Pb-isotope geo-chemistry of granitoids from the Himalaya-Tibet collision zone implication for crustal evolution[J].Earth and Planetary Science Letters,1985,74:220-234.
[18]朱炳泉,李献华,戴樘谟,等.地球科学中同位素体系理论与应用--兼论中国大陆壳幔演化[M].北京:科学出版社,1998:216-230.
[19]侯增谦,潘桂棠,王安建,等.青藏高原碰撞造山带:II.晚碰撞转换成矿作用[J].矿床地质,2006,25(5):521-543.
[20]侯增谦,杨竹森,徐文艺,等.青藏高原碰撞造山带:I.主碰撞造山成矿作用[J].矿床地质,2006,25(4):337-354.
[21]侯增谦,曲晓明,杨竹森,等.青藏高原碰撞造山带:III.后碰撞伸展成矿作用[J].矿床地质,2006,25(6):629-651.
[22]姜子琦,王强,Wyman D A,等.西藏冈底斯南缘冲木达约30Ma埃达克质侵入岩的成因:向北俯冲的印度陆壳的熔融?[J].地球化学,2011(2):126-146.
[23]Chung S L,Chu M F,Ji J,O'Reilly S Y,Pearson N J,Liu D,Lee T Y,Lo C H.The nature and timing of crustal thickening in Southern Tibet:geochemical and zircon Hf isotopic constraints from postcollisional adakites[J].Tectonophysics,2009,477:36-48.
[24]Hou Z Q,Gao Y F,Qu X M,Rui Z Y,Mo X X.Origin of adakitic in trusives generated during Mid-Miocene east-west extension in southern Tibet[J].Earth and Planetary Science Letter,2004,220:139-155
[25]姚鹏.西藏冈底斯南缘火山-岩浆弧演化与不同类型夕卡岩矿床的研究[D].成都:成都理工大学,2006.
[26]赵珍,胡道功,吴珍汉,等.西藏冈底斯东段南缘桑布加拉辉钼矿Re-Os定年及地质意义[J].地质力学学报,2012,2(18):178-186.
[27]闫学义,黄树峰,杜安道.冈底斯泽当大型钨铜钼矿Re-Os年龄及路远走滑转换成矿作用[J].地质学报,2010,84(3):398-406.
[28]张松,郑远川,黄克贤,等.西藏努日矽卡岩型铜钨钼矿辉钼矿Re-Os定年及其地质意义[J].矿床地质,2012,(2):337-346.
[29]孙祥,郑有业,吴松等.冈底斯明则-程巴斑岩-夕卡岩型Mo-Cu矿床成矿时代与含矿岩石成因[J].岩石学报,2013(4):1392-1406.
[30]李光明,秦克章,丁奎首,等.冈底斯东段南部第三纪夕卡岩型Cu-Au±Mo矿床地质特征、矿物组合及其深部找矿意义[J].地质学报,2006,80(9):1407-1423.
[31]范新,陈雷,秦克章,等.西藏山南地区明则斑岩钼矿床蚀变矿化特征与成矿时代[J].金属矿产,2011,47(1):89-99.
[32]Jiang Z Q,Wang Q,Li Z X,Wyman D A,Tang G J,Jia X H,Yang Y H.Late Cretaceous(ca.90 Ma)adakitic intrusive rocks in the Kule area,Gangdese Belt(southern Tibet):Slab melting and implications for Cu-Au mineralization[J].Journal of Asian Earth Sciences,2012,52:67-68.
[2]曲晓明,侯增谦,黄卫.冈底斯斑岩铜矿(化)带:西藏第二个“玉龙”铜矿带[J].矿床地质,2001,20(4):355-366.
[3]侯增谦,曲晓明,王淑贤,高永丰,杜安道,黄卫.青藏高原冈底斯斑岩铜矿带辉钼矿Re-Os年龄:成矿年龄时限与动力学背景应用[J].中国科学D辑,2003,33:609-618.
[4]李光明,王高明,高大发,黄志英,姚鹏.西藏冈底斯南缘构造格架与成矿系统[J].沉积与特提斯地质,2002,22(2):1-7.
[5]李光明,芮宗瑶.西藏冈底斯成矿带斑岩铜矿的成岩成矿年龄[J].大地构造与成矿学,2004,28(2):165-170.
[6]高永丰,侯增谦,魏瑞华.冈底斯晚第三纪斑岩的岩石学、地球化学及其地球动力学意义[J].岩石学报,2003,019(3):18-28.
[7]陈雷.冈底斯南缘渐新世努日矽卡岩-斑岩型铜钨钼矿床成矿作用研究[D].北京:中国科学院研究生院,2012:118-154.
[8]曲晓明,侯增谦,国连杰,徐文艺.冈底斯铜矿带埃达克质含矿斑岩的源区组成与地壳混染:Nd、Sr、Pb、O同位素约束[J].地质学报,2004,78(6):813-821.
[9]程文斌,顾雪祥,唐菊兴,等.西藏冈底斯-念靑唐古拉成矿带典型矿床硫化物Pb同位素特征-对成矿元素组合分带性的指示[J].岩石学报,2010,26(11):3350-62.
[10]费光春,多吉,温春齐,等.西藏洞中拉铅锌矿床S、Pb、Sr同位素组成对成矿物质来源的示踪[J].矿物岩石,2011,31(4):52-57.
[11]朱弟成,潘桂堂,王立全,等.西藏冈底斯带中生代岩浆岩的时空分布和相关问题的讨论[J].地质通报,2008,27(9):1535-1550.
[12]Debon F,Le Fort P,Sheppard S M,Sonet J.The four plutonic belts of the Transhimalaya-Himalaya:A chemical mineralogical,isotopic,and chronological synthesis along a Tibet-Nepal section[J].J Petrol,1986,27:219-250.
[13]Harris N B W,Xu R,Lewis C L,Jin C W.Plutonic rocks of the 1985 Tibet Geotraverse,Lhasa to Golmud[J].Phil Trans R Soc Lond,1988,A327:145-168.
[14]莫宣学,赵志丹,邓晋福,董国臣,周肃,郭铁鹰,张双全,王亮亮.印度-亚洲大陆主碰撞过程的火山作用响应[J].地学前缘,2003,10(3):135-147.
[15]沈渭洲.稳定同位素地球化学[M].北京:原子能出版社,1987:78-83.
[16]王立强,唐菊兴,陈伟等.西藏努日、程巴铜-钼-钨矿床硫铅同位素地球化学[J].地球学报,2014,35(1):39-48.
[17]Gariépy C,Allègre C J,Xu R H.The Pb-isotope geo-chemistry of granitoids from the Himalaya-Tibet collision zone implication for crustal evolution[J].Earth and Planetary Science Letters,1985,74:220-234.
[18]朱炳泉,李献华,戴樘谟,等.地球科学中同位素体系理论与应用--兼论中国大陆壳幔演化[M].北京:科学出版社,1998:216-230.
[19]侯增谦,潘桂棠,王安建,等.青藏高原碰撞造山带:II.晚碰撞转换成矿作用[J].矿床地质,2006,25(5):521-543.
[20]侯增谦,杨竹森,徐文艺,等.青藏高原碰撞造山带:I.主碰撞造山成矿作用[J].矿床地质,2006,25(4):337-354.
[21]侯增谦,曲晓明,杨竹森,等.青藏高原碰撞造山带:III.后碰撞伸展成矿作用[J].矿床地质,2006,25(6):629-651.
[22]姜子琦,王强,Wyman D A,等.西藏冈底斯南缘冲木达约30Ma埃达克质侵入岩的成因:向北俯冲的印度陆壳的熔融?[J].地球化学,2011(2):126-146.
[23]Chung S L,Chu M F,Ji J,O'Reilly S Y,Pearson N J,Liu D,Lee T Y,Lo C H.The nature and timing of crustal thickening in Southern Tibet:geochemical and zircon Hf isotopic constraints from postcollisional adakites[J].Tectonophysics,2009,477:36-48.
[24]Hou Z Q,Gao Y F,Qu X M,Rui Z Y,Mo X X.Origin of adakitic in trusives generated during Mid-Miocene east-west extension in southern Tibet[J].Earth and Planetary Science Letter,2004,220:139-155
[25]姚鹏.西藏冈底斯南缘火山-岩浆弧演化与不同类型夕卡岩矿床的研究[D].成都:成都理工大学,2006.
[26]赵珍,胡道功,吴珍汉,等.西藏冈底斯东段南缘桑布加拉辉钼矿Re-Os定年及地质意义[J].地质力学学报,2012,2(18):178-186.
[27]闫学义,黄树峰,杜安道.冈底斯泽当大型钨铜钼矿Re-Os年龄及路远走滑转换成矿作用[J].地质学报,2010,84(3):398-406.
[28]张松,郑远川,黄克贤,等.西藏努日矽卡岩型铜钨钼矿辉钼矿Re-Os定年及其地质意义[J].矿床地质,2012,(2):337-346.
[29]孙祥,郑有业,吴松等.冈底斯明则-程巴斑岩-夕卡岩型Mo-Cu矿床成矿时代与含矿岩石成因[J].岩石学报,2013(4):1392-1406.
[30]李光明,秦克章,丁奎首,等.冈底斯东段南部第三纪夕卡岩型Cu-Au±Mo矿床地质特征、矿物组合及其深部找矿意义[J].地质学报,2006,80(9):1407-1423.
[31]范新,陈雷,秦克章,等.西藏山南地区明则斑岩钼矿床蚀变矿化特征与成矿时代[J].金属矿产,2011,47(1):89-99.
[32]Jiang Z Q,Wang Q,Li Z X,Wyman D A,Tang G J,Jia X H,Yang Y H.Late Cretaceous(ca.90 Ma)adakitic intrusive rocks in the Kule area,Gangdese Belt(southern Tibet):Slab melting and implications for Cu-Au mineralization[J].Journal of Asian Earth Sciences,2012,52:67-68.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |