新疆阿勒泰乌拉斯沟铅锌铜矿床的富CO_2流体及其地质意义
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摘要
乌拉斯沟铅锌铜矿床位于新疆阿尔泰南缘克兰火山–沉积盆地。本矿床分为铜、铅–锌两个矿化带,矿体赋存在下泥盆统康布铁堡组上亚组,容矿岩石为大理岩、绿泥石英片岩等。矿床内角砾状铅锌矿石反映了早期海相沉积成矿作用,矿床变形变质特征明显,其矿化石英脉可分为两个阶段:早阶段顺层石英脉和晚阶段切层硫化物石英脉。石英脉中流体包裹体分为富CO_2包裹体、碳质流体包裹体和部分水溶液包裹体,含子晶包裹体。显微测温结果显示,早阶段石英脉中富CO_2包裹体,CO_2相的三相点温度(Tm,CO_2)范围在–62.3~–58.5℃,CO_2笼合物熔化温度(Tm,clath)为0.5~7.5℃,部分均一温度(Th,CO_2)集中在5.0~21.0℃,均一温度(Th,total)集中在285~378℃,所计算的盐度变化于4.9%~15.1%Na Cleqv之间,密度为0.84~0.97 g/cm~3,最低捕获压力为260~360 MPa。晚阶段石英脉中,富CO_2包裹体的CO_2三相点的温度(Tm,CO_2)为–61.9~–56.9℃,T_(m,clath)为0.4~9.5℃,Th,CO_2为9.0~28.0℃,Th,total范围为242~389℃,盐度分布于1.0%~15.5%Na Cleqv之间,密度为0.55~0.98 g/cm~3,最低捕获压力范围为180~370 MPa。激光拉曼探针测试显示包裹体除含CO_2外,还含有不定量的CH4和N2。铜矿化石英脉的流体以富CO_2为特征,为中高温、低盐度、中低密度的H_2O-NaCl-CO_2±CH_4±N_2变质流体,与造山–变质成因有关。
The Wulasigou Cu-Pb-Zn deposit is one of the Cu-Pb-Zn polymetal deposits in the Devonian kelan volcanicsedimentary basin of Southern Altaids. The origin of the deposits in the basin is still controversial yet. They were considered as volcano-sedimentary-related in many early literatures. Recently, metamorphic fluids were recognized by some authors. The Wulasigou Cu-Pb-Zn deposit occurs in the Lower Devonian Kangbutiebao Formation, which is composed of metamorphosed rhyolite, quartz schist, and metamorphic crystal tuff. There are two stages of vein-type Cu mineralization, the lentoid or streaked early quartz veins(QI) and the later sulfide-quartz veins(QII). Microthermometric studies show that solid CO2 melting temperatures(Tm,CO~2) of LH_2O-LCO_2 inclusions in(QI) are mostly in the range of –62.3~ –58.5 ℃, clathrate melting temperatures(Tm,clath) are in the range of 0.5~7.5 ℃, partial homogenization temperatures(Th,CO_2) vary from 5.0-21.0℃, and the total homogenization temperatures(Th,total) are in the range of 285~378 ℃, with the salinities and densities of 4.9%~15.1% Na Cleqv and 0.84~0.97 g/cm~3 respectively. The later quartz veins(QII) have –61.9~ –56.9 ℃ of Tm,CO2, 0.4~9.5 ℃ of Tm,clath, 9.0~28.0 ℃ of Th,CO_2, and 242~388 ℃ of Th,total, with the salinities of 1.0%~15.5%Na Cleqv and densities of 0.55~0.98 g/cm~3. The lowest trapping pressures of fluid inclusions in QI are 180~370 Mpa and 260~360 MPa in QII. Laser Raman spectroscopy revealed that the CO_2-rich fluid inclusion contains major contents of CO_2 and a little variable component of CH_4 and/or N_2 in CO_2 phases. The fluids of Cu-bearing veins from the Wulasigou deposit are characterized by CO_2-rich, medium-high temperatures, low salinities, medium-low densities, and can be considered as H_2O-CO_2-NaCl±CH_4±N_2 system. The ore-forming fluids should be related to orogenic and metamorphic hydrothermal fluids.
The Wulasigou Cu-Pb-Zn deposit is one of the Cu-Pb-Zn polymetal deposits in the Devonian kelan volcanicsedimentary basin of Southern Altaids. The origin of the deposits in the basin is still controversial yet. They were considered as volcano-sedimentary-related in many early literatures. Recently, metamorphic fluids were recognized by some authors. The Wulasigou Cu-Pb-Zn deposit occurs in the Lower Devonian Kangbutiebao Formation, which is composed of metamorphosed rhyolite, quartz schist, and metamorphic crystal tuff. There are two stages of vein-type Cu mineralization, the lentoid or streaked early quartz veins(QI) and the later sulfide-quartz veins(QII). Microthermometric studies show that solid CO2 melting temperatures(Tm,CO~2) of LH_2O-LCO_2 inclusions in(QI) are mostly in the range of –62.3~ –58.5 ℃, clathrate melting temperatures(Tm,clath) are in the range of 0.5~7.5 ℃, partial homogenization temperatures(Th,CO_2) vary from 5.0-21.0℃, and the total homogenization temperatures(Th,total) are in the range of 285~378 ℃, with the salinities and densities of 4.9%~15.1% Na Cleqv and 0.84~0.97 g/cm~3 respectively. The later quartz veins(QII) have –61.9~ –56.9 ℃ of Tm,CO2, 0.4~9.5 ℃ of Tm,clath, 9.0~28.0 ℃ of Th,CO_2, and 242~388 ℃ of Th,total, with the salinities of 1.0%~15.5%Na Cleqv and densities of 0.55~0.98 g/cm~3. The lowest trapping pressures of fluid inclusions in QI are 180~370 Mpa and 260~360 MPa in QII. Laser Raman spectroscopy revealed that the CO_2-rich fluid inclusion contains major contents of CO_2 and a little variable component of CH_4 and/or N_2 in CO_2 phases. The fluids of Cu-bearing veins from the Wulasigou deposit are characterized by CO_2-rich, medium-high temperatures, low salinities, medium-low densities, and can be considered as H_2O-CO_2-NaCl±CH_4±N_2 system. The ore-forming fluids should be related to orogenic and metamorphic hydrothermal fluids.
引文
柴凤梅,毛景文,董连慧,杨富全,刘峰,耿新霞,张志欣,黄承科,2009.阿尔泰南缘克朗盆地康布铁堡组变质火山岩年龄及岩石成因.岩石学报,25(6):1403-1415.
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焦学军,马忠美,郭旭吉,张连昌.2005.阿尔泰山南缘克朗盆地泥盆纪火山沉积与矿产.西北地质,38(3):21-28.
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万博,张连昌.2006.新疆阿尔泰南缘泥盆纪多金属成矿带Sr-Nd-Pb同位素地球化学与构造背景探讨.岩石学报,22(1):145-152.
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徐九华,肖星,迟好刚,王琳琳,林龙华,褚海霞,龚运辉.2011.阿尔泰南缘克兰盆地的脉状金-铜矿化及其流体演化.岩石学报,27(5):1299-1310.
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郑常青,徐学纯,Masaki Enami,Takenori Kato.2005.新疆阿勒泰红柱石-矽线石型递增变质带特征及其P-T条件研究.矿物岩石,25(4):45-51.
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Andersen T,Whitehouse M J and Burke E A J.1997.Fluid inclusions in Scourian granulites from the Lewiaian complex of NW Scotland:Evidence for CO2-rich fluid in Late Archaean high-grade metamorphism.Lithos,40:93-104.
Brown P E and Lamb W M,1989.P-V-T properties of fluid in the system CO2±H2O±Nacl:New graphical presentations and implications for fluid inclusions studies.Geochimica et Cosmochimica Acta,53(6):1209-1221.
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Bodnar R J.2003.Introduction to fluid inclusions//Samson I,Anderson A and Marshall D.Fluid Inclusions:Analysis and Interpretation.Mineralogical Association of Canada,Short Course,32:1-8.
Ertan I E and Leeman W P.1999.Fluid inclusions in mantle and lower crustal xenoliths from the Simcoe volcanic field,Washington.Chemical Geology,154:83-95.
Goldstein R H and Reynolds T J.1994.Systematics of Fluid Inclusion in Diagenetic Minerals.Society of Sedimentary Geology:1-199.
Hall D L,Sterner S M and Bodnar R J.1988.Freezing point depression of Na Cl-KCl-H2O solutions.Economic Geology,83:197-202.
Lowenstern J B.2001.Carbon dioxide in magmas and implications for hydrothermal systems.Mineralium Deposita,36:490-500.
Marshall B and Gilligan L B.1987.An introduction to remobilization:In-formation from ore-body geometry and experimental considerations.Ore Geology Review,2(1-3):87-131.
Marshall B,Vokes F and Laroucque A.2000.Regional metamorphic menobilization upgrading and formation of ore deposits//Spy P,Marshall B and Vokes F.Metamorphosed and Metamorphogenic Ore Deposits.Reviews in Economic Geology,11:19-38.
Philips G and Powell R.1993.Link between gold provinces.Economic Geology,88(5):1084-1098.
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Stanton R L.1972.Ore Petrology.New York:Mc Graw-Hill Book Company:1-713.
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陈衍景,倪培,范宏瑞,Pirajno F,赖勇,苏文超,张辉.2007.不同类型热液金矿系统的流体包裹体特征.岩石学报,23(4):2085-2108.
池国祥,卢焕章.2008.流体包裹体组合对测温数据有效性的制约及数据表达方法.岩石学报,24(9):1945-1953.
褚海霞,徐九华,林龙华,卫晓峰,王琳琳,陈栋梁.2010.阿尔泰大东沟铅锌矿的碳质流体及其成因.岩石矿物学杂志,29(2):175-188.
傅斌,肖益林,郑永飞,Touret J L R,Van den Kerkhof AM,Hoefs J.2000.大别山双河和碧溪岭超高压变质岩流体包裹体研究.岩石学报,16(1):119-126.
耿新霞,杨富全,杨建民,黄承科,刘峰,柴凤梅,张志欣.2010.新疆阿尔泰铁木尔特铅锌矿床流体包裹体研究及地质意义.岩石学报,26(3):695-706.
顾连兴,汤晓茜,郑远川,吴昌志,田泽满,陆建军,肖新建,倪培.2004.辽宁红透山铜锌块状硫化物矿床的变质变形和成矿组分再活化.岩石学报,20(4):923-934.
焦学军,马忠美,郭旭吉,张连昌.2005.阿尔泰山南缘克朗盆地泥盆纪火山沉积与矿产.西北地质,38(3):21-28.
李思强,马忠美,郭旭吉.2006.阿勒泰复向斜的成矿环境及其矿产.矿床与地质,20(2):116-121.
马忠美,仇银江,郭旭吉.2001.萨热阔布-铁米尔特矿区金铅锌成矿系列.地质与勘探.37(4):23-26.
倪培,田京辉,朱筱婷,凌洪飞,蒋少涌,顾连兴.2005.江西永平铜矿下盘网脉状矿化的流体包裹体研究.岩石学报,21(5):1339-1346.
秦克章.2000.新疆北部中亚型造山与成矿作用.北京:中国科学院地质与地球物理研究所博士后出站报告:1-207.
秦雅静,张莉,郑义,刘春发,迟好刚.2012.新疆萨热阔布金矿床流体包裹体研究及矿床成因.大地构造与成矿学,36(2):227-239.
沈晓明,张海祥,马林.2013.阿尔泰南缘晚石炭世淡色花岗岩的发现及其构造意义.大地构造与成矿学,37(4):721-729.
万博,张连昌.2006.新疆阿尔泰南缘泥盆纪多金属成矿带Sr-Nd-Pb同位素地球化学与构造背景探讨.岩石学报,22(1):145-152.
王京彬,秦克章,吴志亮,胡剑辉,邓吉年,张进红,边亚光,李思强.1998.阿尔泰山南缘火山喷流沉积型铅锌矿床.北京:地质出版社:1-210.
王琳琳,徐九华,孙丰月,林龙华,褚海霞.2012.新疆阿尔泰萨热阔布-铁木尔特地区两类矿化及成因.世界地质,31(1):100-112.
徐九华,林龙华,王琳琳,褚海霞,卫晓峰,陈栋梁.2009.阿尔泰克兰盆地VMS矿床的变形变质与碳质流体特征.矿床地质,28(5):585-598.
徐九华,肖星,迟好刚,王琳琳,林龙华,褚海霞,龚运辉.2011.阿尔泰南缘克兰盆地的脉状金-铜矿化及其流体演化.岩石学报,27(5):1299-1310.
杨蕊,徐九华,林龙华,郭旭吉,肖星,陈栋梁.2013.阿勒泰恰夏铜矿床的富CO2流体与矿床成因.矿床地质,32(2):323-336.
尹意求,杨有明,李嘉兴,郭正林,郭旭吉.2005.新疆阿尔泰山南缘克兰盆地沉积构造演化与铅锌成矿.大地构造与成矿学,29(4):53-59.
袁万明,保增宽,董金泉,安银昌.2007.新疆阿尔泰克朗盆地热液成矿时代的裂变径迹分析.世界科技研究与发展,29(2):8-14.
郑常青,徐学纯,Masaki Enami,Takenori Kato.2005.新疆阿勒泰红柱石-矽线石型递增变质带特征及其P-T条件研究.矿物岩石,25(4):45-51.
Andersen T,Austrheim H and Burke E A L.1993.N2 and CO2 in deep crustal fluids:Evidence from the Caledonides of Norway.Chemical Geology,108:113-132.
Andersen T,Whitehouse M J and Burke E A J.1997.Fluid inclusions in Scourian granulites from the Lewiaian complex of NW Scotland:Evidence for CO2-rich fluid in Late Archaean high-grade metamorphism.Lithos,40:93-104.
Brown P E and Lamb W M,1989.P-V-T properties of fluid in the system CO2±H2O±Nacl:New graphical presentations and implications for fluid inclusions studies.Geochimica et Cosmochimica Acta,53(6):1209-1221.
Bodnar R J.1983.A method of calculateing fluid inclusion volumes based on vapor bubble diameters and PTVXproperties of inclusion fluids.Economic Geology,78:535-542.
Bodnar R J.2003.Introduction to fluid inclusions//Samson I,Anderson A and Marshall D.Fluid Inclusions:Analysis and Interpretation.Mineralogical Association of Canada,Short Course,32:1-8.
Ertan I E and Leeman W P.1999.Fluid inclusions in mantle and lower crustal xenoliths from the Simcoe volcanic field,Washington.Chemical Geology,154:83-95.
Goldstein R H and Reynolds T J.1994.Systematics of Fluid Inclusion in Diagenetic Minerals.Society of Sedimentary Geology:1-199.
Hall D L,Sterner S M and Bodnar R J.1988.Freezing point depression of Na Cl-KCl-H2O solutions.Economic Geology,83:197-202.
Lowenstern J B.2001.Carbon dioxide in magmas and implications for hydrothermal systems.Mineralium Deposita,36:490-500.
Marshall B and Gilligan L B.1987.An introduction to remobilization:In-formation from ore-body geometry and experimental considerations.Ore Geology Review,2(1-3):87-131.
Marshall B,Vokes F and Laroucque A.2000.Regional metamorphic menobilization upgrading and formation of ore deposits//Spy P,Marshall B and Vokes F.Metamorphosed and Metamorphogenic Ore Deposits.Reviews in Economic Geology,11:19-38.
Philips G and Powell R.1993.Link between gold provinces.Economic Geology,88(5):1084-1098.
Roedder E.1984.Fluid Inclusions:Reviews in mineralogy12.Washington:Mineral Society of America:1-644.
Stanton R L.1972.Ore Petrology.New York:Mc Graw-Hill Book Company:1-713.
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