胶东地区金矿床流体包裹体的He、Ar同位素组成及成矿流体来源示踪

关于胶东地区金矿床成因，多年来一直存在较大的争议。代表性金矿床中黄铁矿流体包裹体的He-Ar组成表明，胶东金床黄铁矿流体包裹体的^3He/^4He比值为0．43－2．36R／Ra。该值可分为两组：一组如蓬家夼金矿和发云夼金矿^3He/^4He比值＜1．0R／Ra；另一组如邓格庄和焦家金矿^3He/^4He比值＞1．0R／Ra。蓬家夼－发云夼金矿成矿流体的^40Ar/^36Ar比值为393－310，比较接近于大气氩的同位素组成（^40Ar/^36Ar=295.5），而焦家金矿成矿流体的^40Ar/^36Ar比值为500－1148。He-Ar同位素系统显示了蓬家夼－发云夼金矿成矿流体来源以大气降水为主，邓格庄、焦家金矿成矿流体来源以地幔流体为主。进一步研究表明，胶东金矿成矿流体H－O和He-Ar同位素系统对流体来源的示踪具有一致性。     

The Isotopic Composition of Noble Gases in Gold Deposits and the Source of Ore- Forming Materials in the Region of North Hebei, China

1IntroductionOnthenorthernmarginoftheNorthChinaplatformislocatedoneofthemostimportantAu Ag polymetallicore concentratedzones,wherethereareavarietyoforetypes .Soithasbeenat tractingeverincreasingattentionofmanygeologists (PeiRongfuetal.,1 998;ShenBaofengetal.,1 994 ;LuSongnianetal.,1 997;HuShouxietal.,1 994 ;ChenYuchuan ,1 999;ZhaiYushengetal.,1 999) .Manyscholarspresentedtheirresearchresultsinvariousaspects.How ever ,thesourceofore formingmaterialshaslongbeenafocusofdiscussion .Studieso…     

江西相山铀矿田深部多金属矿化成矿流体来源:流体包裹体He-Ar同位素证据

江西相山铀矿田西部地区实施的铀矿科学深钻3号孔在深部–700 m发现大量铅锌银多金属矿化脉,垂向上呈"上铀下多金属"的分布特征。本文对深部多金属矿化主成矿阶段的黄铁矿、闪锌矿、方铅矿进行了流体包裹体He和Ar同位素组成测定,结果表明,相山深部多金属矿化主成矿阶段的黄铁矿、闪锌矿和方铅矿具有较一致的He、Ar同位素组成,矿物内流体包裹体的~3He含量范围为4.55×10^–14～1560×10^–14 cm^3·STP/g,~4He含量范围为1.05×10^–7～525×10^–7 cm^3·STP/g,~3 He/~4He为2.98×10^–7～4.96×10^–7,即0.21～0.35 Ra,介于地壳(0.01～0.05 Ra)和饱和大气水(1 Ra)之间,明显低于地幔的~3 He/~4He值(6～9 Ra),⁴⁰Ar浓度为0.969×10^–7～157×10^–7 cm^3·STP/g,⁴⁰Ar/³⁶Ar值为303.7～573.9,略高于饱和大气水的Ar同位素组成,结合矿石和蚀变岩石中Li元素富集特征,本文认为相山西部地区深部多金属成矿流体以地壳流体和大气降水为主,成矿流体富Li元素是He同位素明显高于地壳的原因,可能存在少量幔源流体的加入。另外,通过对比前人研究的该地区铀矿化矿石中黄铁矿He-Ar同位素组成,并结合前人对该地区幔源组分明显参与铀成矿的认识,本文认为多金属矿化和铀矿化成矿流体可能并非同一来源。     

粤北诸广南部铀矿田流体包裹体的氦氩同位素组成及成矿流体来源示踪

粤北诸广南部铀矿田是我国重要的花岗岩型铀矿产地之一,有关诸广南部花岗岩型铀矿田的成因,多年来一直存在较大的争议。本文以诸广南部铀矿田典型铀矿床成矿期萤石、方解石和黄铁矿中流体包裹体为测试对象,研究了成矿流体的He、Ar同位素地球化学。研究表明,萤石流体包裹体的~3He/~4He比值为0. 021～0. 186Ra,~(40) Ar/~(36)比值为298. 4～2515. 7;方解石流体包裹体的3He/4He比值为0. 027～0. 209Ra,~(40) Ar/~(36)比值为295. 9～327. 2;黄铁矿流体包裹体的3He/4He比值为0. 021～1. 543Ra,~(40) Ar/~(36)比值为326. 9～1735. 1; He-Ar同位素系统显示成矿流体的3He/4He比值略高于地壳氦同位素特征值(0. 01～0. 05Ra),但低于幔源氦同位素特征值(6～9Ra),~(40) Ar/~(36)比值接近或高于大气氩的同位素组成(~(40) Ar/~(36)=295. 5),成矿流体为壳-幔混合来源。结合H-O、He-Ar、C和Sr等多元同位素证据表明,成矿流体由两个端元组成:一是含有一定放射性成因Ar的大气降水的地壳流体,二是含幔源He的地幔流体。进一步研究表明,受NNW向断裂控制的棉花坑、书楼丘、长排等铀矿床受地幔流体影响比较大,而受NE向断裂控制的蕉坪、东坑、烟筒岭铀矿床受大气降水影响比较大。     

幔源挥发性组分参与302铀矿床成矿作用的氦同位素证据

对取自302铀矿床井下与沥青铀矿矿石共生的9件紫黑色萤石、肉红色方解石样品进行了流体包裹体的He同位素测定,3He／4He测定值为0．03～0．57Ra（绝大部分在0．11～0．25Ra之间）,位于地幔与地壳的氦同位素值范围之间,显示成矿流体中的氦同位素具有壳、幔两个端元混合的特点,表明有大量幔源挥发性组分参与铀成矿作用。该矿床碳同位素值与流体包裹体证据均表明,地幔挥发性组分确实大规模参与了铀成矿作用。研究显示,几乎华南所有的热液铀矿床都形成于白垩纪-古近纪,且这些矿床的碳同位素组成均显示成矿流体中的矿化剂CO2来自地幔．暗示它们成矿时具有相似的成矿动力学背景：可能均与华南中,新生代岩石圈伸展作用所控制的幔源挥发性组分具有密切的关系。     

云南金顶和白秧坪矿床He,Ar同位素组成及其意义

对金顸铅锌矿床和白秧坪Cu-Co-Ag矿床成矿阶段形成的热液矿物中原生流体包裹体的He，Ar同位素研究结果表明：金顸铅锌矿床的成矿流体的。He／^4He值为0．19～1．02Ra，^40Ar／^36Ar值为274～305，白秧坪Cu-Co-Ag矿床0．71～4．60Ra，^40Ar／^36Ar值为290～334，表明成矿流体中可能含有地幔He。这些新资料的获得为研究该区成矿作用和深部的关系提供了同位素地球化学依据。     

川滇黔地区天宝山、会泽铅锌矿床成矿流体来源初探:来自流体包裹体及氦氩同位素的证据

为限定川滇黔地区大型铅锌矿床成矿流体来源,选择天宝山大型铅锌矿床和会泽超大型铅锌矿床中热液矿物进行流体包裹体及氦氩同位素研究.结果显示:（1）天宝山矿床为中低温、中等盐度流体成矿,成矿流体主要来源于盆地卤水;会泽矿床为中高温、中等盐度流体成矿,成矿流体也主要来源于盆地卤水,但具有不同性质流体混合特征;（2）两矿床硫化物3He/4He值范围介于0.02~0.32 Ra,证明成矿流体以地壳流体为主,但混有少量（< 5.3%）地幔成分,40Ar/36Ar值（345.0~1 698.8）表明成矿流体以饱和大气水为主;（3）综合两个矿床地质特征、流体包裹体及氦氩同位素研究认为天宝山矿床和会泽矿床的形成与右江盆地演化及峨眉山大火成岩省的岩浆活动有关.      

Helium and Argon Isotopic Composition of Cenozoic Alkali Basalts and Mantle-Derived Xenoliths from Kuandian, Liaoning Province, China

The noble gas isotopic composition and content data of 2 alkali basalts, 3 Iherzolite xenoliths and one clinopyroxene megacryst from the Kuandian region have confirmed the occurrence of a fractionation of noble gases during magmatism. Light noble gases such as He and Ne are high in mobility and appear to be incompatible as compared with heavy ones ( such as Kr and Xe). Therefore, light noble gases are abundant in volcanics, especially in the volcanics with bubbles; lherzolite xenoliths have relatively high heavy noble gases. The clinopyroxene megacryst has the lowest abundance of noble gases, probably due to its high P-T origin. Noble gas isotopic composition of the clinopyroxene megacryst reveals that the mantle source beneath the Kuandian area has an MORB-like reservoir with^3 He/^4He ratio of—10 Ra(Ra: atmospheric^3 He/^4He ratio) and^40 Ar/^36 Ar ratio of 345.6. The Iherzolite xenoliths possess moderate^3 He/^4He ratios of 2.59 -4.53 Ra, reflecting the loss of primary helium during rock deformation or metasomatism caused by enriched mantle fluids during the up-lifting. The alkali volcanics have very low^3 He/^4 He ratios(0.47—0.61 Ra),indicating a contribution of radiogenic^4 He, probably having resulted from crust contamination. Most of the samples have excess^21 Ne and^22 Ne as compared with atmospheric neon, but Kr and Xe isotopic compositions are indistinguishable from atmospheric values within uncertainties with only individual samples having excess^129Xe,^134Xeand^136 Xe.     

贵州晴隆锑矿床成矿流体He-Ar同位素地球化学

晴隆锑矿床是华南中生代低温成矿域右江盆地Au-Sb-As-Hg矿集区内的大型锑矿床,成矿时代约150Ma。本文以该矿床矿石矿物辉锑矿中的流体包裹体为测试对象,研究了成矿流体的He和Ar同位素地球化学。研究表明,成矿流体的~3He/~4He为0.13~0.46Ra(Ra为空气的3He/4He值,1.4×10~(-6)),~(40)Ar/~(36)Ar为305~327,He、Ar同位素组成具有一定程度的正相关;成矿流体由两个端元组成:一是含地壳He的低温饱和空气的雨水,二是含地幔He的高温流体。含地幔He的高温流体可能来自右江盆地下部的侏罗纪壳幔混合成因花岗岩浆,这种岩浆的形成机制与华夏地块侏罗纪与钨锡成矿有关的花岗岩具有相似性。晴隆锑矿床以大气降水为主的成矿流体的加热、循环并浸取矿床围岩"大厂层"下伏地层中的成矿元素而成矿,受深部壳幔混合成因花岗岩浆释放出的含幔源He和岩浆S的热流所驱动。     

内蒙古哈达门沟金矿成矿流体来源的氦、氩同位素示踪

内蒙古包头市哈达门沟金矿床是华北陆块北缘乌拉山-大青山地区的大型金矿床,矿床赋存于新太古界乌拉山群黑云角闪斜长片麻岩、角闪黑云二长片麻岩和含石榴石黑云斜长片麻岩中,成矿流体性质不明。文章对哈达门沟金矿主要载金矿物黄铁矿开展了流体包裹体中的He、Ar同位素组成研究。研究表明,赋存于黄铁矿流体包裹体中的4He含量为(83.92~606.46)×10-8cm3STP/g,n(3He)/n(4He)值为0.19~0.91Ra,幔源He的含量为2.62%~13.73%,平均为9.95%,表明成矿流体中的He主要来源于地壳,大约10%来源于地幔。~(40)Ar含量为(71.22~308.22)×10~(-8)cm~3STP/g,~(40)Ar/~(36)Ar比值变化于2793.6~7253.5之间,在n(~(40)Ar)/n(~(36)Ar)与R/Ra图解和n(~(40)Ar*)/n(4He)与R/Ra图解中,显示地壳氩和地幔氩的混合来源特征。结合已有的氢、氧、硫同位素研究,认为哈达门沟金矿成矿流体主体为地壳来源,但幔源流体的加入清晰可辨,乌拉特前旗-呼和浩特山前断裂很可能为富钾质壳幔混合流体的运移提供了通道和动力。     

新疆望峰金矿成矿流体的He、Ar同位素示踪

本文采用稀有气体同位素质谱方法,通过分析望峰金矿石中载金黄铁矿流体包裹体He、Ar同位素组成,对成矿流体进行示踪研究。结果显示,黄铁矿流体包裹体3He/4He比值为0.00473～0.01079Ra,40Ar/36Ar比值为301～413,具地壳放射性成因氦同位素组成和大气降水成因氩同位素组成,总体显示由大气降水改造而成的地壳流体特征。望峰金矿成矿流体中He同位素组成异常,是成矿前大气降水与高U、Th含量古老容矿围岩作用遭受放射性成因4He稀释、成矿时发生流体减压沸腾综合作用的结果,Ar同位素组成异常是成矿前大气降水下渗获取容矿围岩放射性成因40Ar的结果,成矿流体是大气降水深循环的产物。     

江西省横迳温泉区地热气体地球化学

从赣南横迳温泉区采集10个水样并分析了温泉及冷泉的水化学成分,认为热水起源于大气降水补给。在此基础上,还在温泉区采集了4个气样,测定了气体组分的含量及氦同位素．以及CO₂和CH₄的碳同位素。研究结果表明：横迳地区温泉气中CO₂的含量很高(>96％),δC_CO2较重(-4.43‰～-5.50‰),属幔源CO₂;He同位素特征值(R/Ra)变化于1.36～2.11之问．均大于1,有幔源He的加入;本区温泉气的的组合类型为二氧化碳幔源温泉气,从整体上来说属于幔源无机成因气,是地幔脱气的产物。     

Geochemical Characteristics of Gases from the Wudalianchi Volcanic Area,Northeastern China

The origins of gases in springs, pools and wells from the Wudalianchi (WDLC) volcanic area are discussed based upon molecular and isotope compositions of the gases. Nine gas and water samples were collected from bubbles and water of the springs and pools in the WDLC volcanic area, Northeastern China, in August 1997. The molecular components were measured with a MAT-271 mass spectrometer (MS), helium isotope ratios with a VG-5400 MS, and (13C with a MAT-251 MS in the Lanzhou Institute of Geology. The gases are enriched in CO2 , and most of the CO2 concentrations are over 80% (V). The helium and methane concentrations have relatively wide ranges of 0.7 to 380×10-6 and 4 to 180×10-6, respectively. The 3He/4He ratios are between 1.05 Ra and 3.1 Ra (Ra = 1.4×10-6); the 4He/20Ne values are between 0.45 and 1011, larger than the atmospheric value (0.32). The (13C (PDB) values of carbon dioxide range from (9.6 to (4.2‰. These geochemical data demonstrate that the spring water is from aquifers at different depths, and that helium and carbon dioxide are derived from the mantle, and are contaminated by crust gases during deep fluid migration. Also, there are larger fluxes of deep-earth matter and energy in the WDLC volcanic area.     

湖南瑶岗仙钨矿床成矿流体的氦、氩同位素组成及其意义

瑶岗仙钨矿床是南岭地区最典型的石英脉型钨矿床之一。本文对该矿床黄铜矿和黑钨矿中流体包裹体的氦、氩同位素进行了较系统地测定。研究表明,黄铜矿和黑钨矿流体包裹体中3He／4He分别为0．37—0．43Ra和0．05～0．49Ra,明显高于地壳值;黄铜矿和黑钨矿流体包裹体中的氩同位素分别为673～886和325～903,均明显高于饱和大气雨水的40Ar／36Ar值。这些氦、氩同位素组成揭示该矿床的成矿流体具有壳、幔两端元混合的特点。结合区域地质构造演化和成矿年代学的研究成果,本文认为瑶岗仙钨矿床的成矿流体是由瑶岗仙S型花岗岩浆分异出的含有地幔He的岩浆流体与大气成因地下水的二端元混合产物,S型花岗岩的形成也是壳幔相互作用的结果。     

Heterogeneous lithospheric mantle metasomatism in the eastern North China Craton: He–Ar isotopes in peridotite xenoliths from Cenozoic basalts

The abundances and isotopic compositions of Helium and Argon have been analyzed in a suite of fresh spinel peridotite xenoliths in Cenozoic basalts from the eastern North China Craton (NCC) by step-wise heating experiments, to investigate the nature of noble gas reservoirs in the subcontinental lithospheric mantle beneath this region. The xenoliths include one harzburgite collected from Hebi in the interior of the NCC, two lherzolites from Hannuoba at the northern margin of the craton, and three lherzolites from Shanwang and Nushan on the eastern margin. ³He/⁴He ratios in most of the xenoliths are similar to those of mid-ocean ridge basalts (MORB) or slightly lower (2–10.5 Ra, where Ra is the ³He/⁴He ratio of the atmosphere), suggesting mixing of MORB-like and radiogenic components. One olivine separate from Nushan has a helium value of 25.3 Ra, probably suggesting cosmogenic ³He addition. The ⁴⁰Ar/³⁶Ar ratios vary from atmospheric value (296) to 1625, significantly lower than the MORB value. Available data of the peridotite xenoliths indicate the He and Ar isotopic systematics of the mantle reservoirs beneath the NCC can be interpreted as mixtures of at least three end-members including MORB-like, radiogenic and atmospheric components. We suggest that the MORB-like noble gases were derived from the underlying asthenosphere during mantle upwelling, whereas the radiogenic and recycled components probably were incorporated into the lithospheric mantle during circum-craton subduction of oceanic crust. Available data suggest that the MORB-like fluids are better preserved in the interior of the NCC, whereas the radiogenic ones are more prevalent at the margins. The Paleo-Asian ocean subduction system probably was responsible for the enriched and recycled noble gas signatures on the northern margin of the craton, while the Pacific subduction system could account for the observed He–Ar isotopic signatures beneath the eastern part. Therefore, integration of helium and argon isotopes reflects heterogeneous metasomatism in the lithospheric mantle and demonstrates the critical importance of lithospheric mantle modification related to both circum-craton subduction of oceanic crust and asthenospheric upwelling beneath the eastern NCC.     

Mantle-derived noble gases in ore-forming fluids of the granite-related Yaogangxian tungsten deposit,Southeastern China

More than 90% of the tungsten resources of China are in the Nanling region of South China, and the Yaogangxian vein deposit is the largest tungsten deposit in this region. The tungsten deposits have ages of 150–160 Ma, and are spatially, temporally and genetically related to granites which were previously believed to be produced by crustal anatexis. This paper provides He and Ar isotope data of fluid inclusions in pyrite and arsenopyrite from the Yaogangxian W veins. ³He/⁴He ratios range from 0.41 to 3.03 Ra (where Ra is the ³He/⁴He ratio of air?=?1.39?×?10^?6), and ⁴⁰Ar/³⁶Ar ratios from 328 to 1,191. Moreover, there are excellent correlations between He and Ar isotopic compositions. The results suggest that the ore-forming fluids are a mixture between a crustal fluid containing atmospheric Ar and crustal ⁴He and a fluid containing mantle components. It is likely that the former is a low temperature meteoric fluid, and the later is a fluid exsolved from the W-associated granitic magma, which formed by crustal melting induced by intrusion of a mantle-derived magma.     

金川Cu-Ni-PGE硫化物矿床成矿过程稀有气体同位素组成示踪

稀有气体同位素在示踪成矿作用流体来源方面具有独特优势。本文应用熔融质谱法测定了金川Cu-Ni-PGE硫化物矿床23个硅酸盐矿物和金属硫化物单矿物的He、Ne和Ar丰度和同位素组成。结果表明,硅酸盐矿物的3He/4He比值(0.239Ra)略低于硫化物(平均0.456Ra),且从橄榄石(平均0.291Ra)、斜方辉石(0.215Ra)到单斜辉石(0.174Ra)逐渐降低,20Ne/22Ne-21Ne/22Ne分布于MORB与大陆地壳演化线之间,扣除放射性成因4He*和40Ar*后橄榄石和辉石中3He/4He和40Ar/36Ar接近岩石圈地幔组成。He、Ne和Ar同位素组成示踪表明成矿岩浆中存在岩石圈地幔(SCLM)、地壳(CC)和大气饱和流体(ASW)三种端元成分,硫化物熔体的分离发生在岩浆结晶分异的早期。岩石圈地幔部分熔融形成的成矿初始岩浆经历了两阶段的演化。在深部岩浆房高温成矿岩浆同化围岩引入地壳混染组分,促使硫饱和及硫化物熔体的熔离,同时形成具有壳幔混合特征的混合岩浆组分(MC),上升至上部岩浆房后混入较高比例的大气饱和流体,进一步促使硫饱和及浸染状硫化物就地熔离堆积。     

Multiple isotope composition (S, Pb, H, O, He, and Ar) and genetic implications for gold deposits in the Jiapigou gold belt, Northeast China

The Jiapigou gold belt (>150 t Au), one of the most important gold-producing districts in China, is located at the northeastern margin of the North China Craton. It is composed of 17 gold deposits with an average grade around 10 g/t Au. The deposits are hosted in Archean gneiss and TTG rocks, and are all in shear zones or fractures of varying orientations and magnitudes. The δ³⁴S values of sulfide from ores are mainly between 2.7?‰ and 10?‰. The Pb isotope characteristics of ore sulfides are different from those of the Archean metamorphic rocks and Mesozoic granites and dikes, and indicate that they have different lead sources. The sulfur and lead isotope compositions imply that the ore-forming materials might originate from multiple, mainly deep sources. Fluid inclusions in pyrite have ³He/⁴He ratios of 0.6 to 2.5 Ra, whereas their ⁴⁰Ar/³⁶Ar ratios range from 1,444 to 9,805, indicating a dominantly mantle fluid with a negligible crustal component. δ¹⁸O values calculated from hydrothermal quartz are between ?0.2?‰ and +5.9?‰, and δD values of the fluids in the fluid inclusions in quartz are from ?70?‰ to ?96?‰. These ranges suggest dominantly magmatic water with a minor meteoric component. The noble gas isotopic data, along with the stable isotopic data, suggest that the ore-forming fluids have a dominantly mantle source with minor crustal addition.     

胶东夏甸金矿成矿流体及成矿物质来源：H-O、He-Ar、Sr-Nd-Pb同位素证据

夏甸金矿是胶东金矿集区中一处大型焦家式矿床。文章在详尽的岩相学和矿相学研究基础上，对该矿床进一步开展 了H-O同位素并首次开展了He-Ar和Sr-Nd-Pb同位素示踪研究，为该矿床成矿流体及成矿物质来源提供了新的制约。石 英中流体包裹体的H-O同位素（δDV-SMOW=-102.3‰~-93.9‰，δ18OH2O=-0.2‰~1.6‰） 揭示出成矿流体主要为富集地幔流体， 并有少许大气降水加入；黄铁矿中He-Ar同位素[3He/4/He=0.58×10− 6~1.90×10− 6 （0.42~1.36 Ra），40Ar/36Ar=724.7~1358.4]同样 表明成矿流体以富集地幔流体为主导；矿石及蚀变岩的Nd-Pb同位素既不同于围岩花岗岩，也不同于基底变质岩，与胶东 地区中生代软流圈地幔起源的玄武岩也相差甚远，而与胶东地区中生代富集岩石圈地幔起源的煌斑岩相一致，但它们的初 始87Sr/86Sr比值明显高于煌斑岩，甚至高于围岩花岗岩。Sr-Nd-Pb同位素特征表明成矿流体及成矿物质来源于富集岩石圈地 幔，并在其上升过程中与基底变质岩发生了相互作用。     

胶东夏甸金矿成矿流体及成矿物质来源:H-O、He-Ar、Sr-Nd-Pb同位素证据

夏甸金矿是胶东金矿集区中一处大型焦家式矿床。文章在详尽的岩相学和矿相学研究基础上,对该矿床进一步开展 了H-O同位素并首次开展了He-Ar和Sr-Nd-Pb同位素示踪研究,为该矿床成矿流体及成矿物质来源提供了新的制约。石 英中流体包裹体的H-O同位素（δDV-SMOW=-102.3‰~-93.9‰,δ18OH2O=-0.2‰~1.6‰） 揭示出成矿流体主要为富集地幔流体, 并有少许大气降水加入;黄铁矿中He-Ar同位素[3He/4/He=0.58×10− 6~1.90×10− 6 （0.42~1.36 Ra）,40Ar/36Ar=724.7~1358.4]同样 表明成矿流体以富集地幔流体为主导;矿石及蚀变岩的Nd-Pb同位素既不同于围岩花岗岩,也不同于基底变质岩,与胶东 地区中生代软流圈地幔起源的玄武岩也相差甚远,而与胶东地区中生代富集岩石圈地幔起源的煌斑岩相一致,但它们的初 始87Sr/86Sr比值明显高于煌斑岩,甚至高于围岩花岗岩。Sr-Nd-Pb同位素特征表明成矿流体及成矿物质来源于富集岩石圈地 幔,并在其上升过程中与基底变质岩发生了相互作用。