Geology,Geochemistry, and Geochronology of the Fenghuangshan Skarn‐type Copper Deposit in the Tongling Ore Cluster,Anhui Province,East China     

QU Hongying  PEI Rongfu  FEI Hongcai  LI Jinwen  WANG Yonglei  WANG Haolin  YAO Lei 《《地质学报》英文版》2012,86(3):700-718

The Fenghuangshan skarn-type Cu deposit, Tongling Ore Cluster, Anhui Province, is an important component in the Middle–Lower Yangtze River ore-forming belt. To better understand magmatism and its relationship to mineralization, we investigated geochemical features, ore-forming fluids, and geochronology of the Xinwuli intrusion and the related Fenghuangshan Cu deposit. Lithogeochemical characteristics show that the Xinwuli quartz monzodiorite is formed by mixing magma derived from upper mantle alkaline basalt that has been contaminated by crust materials. C, H and O isotopes indicate that ore-forming fluids mainly come from the magma, with minor amounts of meteoric fluids involved at the late stage. S and Pb isotopic components indicate that ore-forming materials are derived from the mantle. Molybdenite Re–Os isotopic dating yields Re–Os model ages ranging from 139.1±2.4 Ma to 142.0±2.2 Ma, with an isochronal age of 141.1±1.4 Ma, which is consistent with sensitive, high-resolution ion microprobe (SHRIMP) zircon U–Pb ages of quartz monzodiorite and granodiorite in the mining area. Dating analysis yields ages from 136.0±2.0 Ma to 143.0±2.4 Ma for the quartz monzodiorite (a weighted average of 139.4±1.2 Ma) and ages from 136.7±2.0 Ma to 145.3±2.4 Ma for granodiorite (a weighted average of 141.0±1.1 Ma).  相似文献   

Re–Os and U–Pb Geochronology of the Erlihe Pb–Zn Deposit, Qinling Orogenic Belt, Central China, and Constraints on Its Deposit Genesis     

ZHANG Fan  LIU Shuwen  LI Qiugen  SUN Yali  WANG Zongqi  YAN Quanren  YAN Zhen 《《地质学报》英文版》2011,85(3):673-682

The Erlihe Pb–Zn deposit is an important mine of the Pb–Zn metallogenic zone in the South Qinling Orogen. It has been considered a sedimentary exhalative deposit in previous investigations because the ore body occurs concordantly at the transitional location of an upright fold. Re and Os isotopic analyses for paragenetic pyrites with sphalerite and galena from the ore body have been used to determine the timing of mineralization and to trace the source of metallogenic materials. The Re–Os isotopic data of four pyrite samples construct an isochron, yielding a weighted average age of 226±17 Ma (mean square weighted deviation=1.7), which is considered the main mineralization age. A dioritic porphyrite vein sample, showing weaker mineralization, was also dated using the SHRIMP zircon U–Pb isotopic method to constrain the youngest metallogenic age of the ore deposit, because it distributes along a group of tensional joints cutting not only the upright fold in the deposit field, but also the main ore bodies. The dioritic porphyrite sample yields a weighted mean 206Pb/238U age of 221±3 Ma, which is slightly younger than the Re–Os isotopic isochron age of the pyrites, considered as the upper age limit of the mineralization, namely the ending age of the mineralization. The Os isotopic compositions of sulfide minerals distribute within a range between Os isotopic compositions of the crust and the mantle, indicating that the ore deposit can be derived from magma-related fluid, and the metallogenic materials are most likely derived from the mixing source of the crust and the mantle. The Erlihe Pb–Zn deposit and associated dioritic porphyrite vein, important records of Qinling tectonic–magmatism–mineralization activities, were formed during the Triassic collisional orogeny processes.  相似文献   

Geochronology of the Xihuashan Tungsten Deposit in Southeastern China: Constraints from Re–Os and U–Pb Dating     

Fang‐Yue WANG  Cong‐Ying LI  Ming‐Xing LING  Hong ZHANG  Ya‐Li SUN  Weidong SUN 《Resource Geology》2011,61(4):414-423

Xihuashan tungsten deposit is one of the earliest explored tungsten deposits in southeastern China. It is a vein type deposit genetically associated with the Xihuashan granite pluton. Here we report new dating and zircon geochemistry results. Re–Os isotopic dating for molybdenite intergrowth with wolframite in the oldest generation of the Xihuashan pluton yielded an isochron age of 157.0 ± 2.5 Ma (2σ). Zircon U–Pb laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) dating shows that the pluton crystallized at 155.7 ± 2.2 Ma (2σ). This age is similar to the molybdenite Re–Os age for the ore deposit within error. This, together with published data, suggests that the major W(Mo)‐Sn mineralization occurred between 160–150 Ma in southeastern China. These deposits constitute a major part of the magmatic‐metallogenic belt of eastern Nanlin. The lower Re content in molybdenite of the Xihuashan tungsten deposit shows crustal origin for the ore‐forming material. The limited direct contributions from the subducting slab for the tungsten mineralization in the Nanling region suggest a change of the style of the paleo‐Pacific plate beneath southeastern China.  相似文献   

福建武平十二排钼矿床辉钼矿Re-Os 同位素年龄及其地质意义   总被引：2，自引：0，他引：2  

王少怀 《地质论评》2013,59(5):885-892

福建武平十二排铝矿床是近年来在闽西南地区找到的又一处铝矿床.钼矿化在中细粒黑云母花岗岩岩体与新元古界楼子坝群、晚古生界变质岩接触带内呈浸染状和脉状产出,并且构成透镜状矿体.本次研究过程中,对5件代表性辉钼矿样品进行了Re-Os同位素年龄测定,模式年龄值变化范围为149.7 ～ 152.8Ma,等时线年龄为(151 ±2) Ma,略晚于黑云母花岗岩的成岩年龄,由此认为十二排钼矿床与黑云母花岗岩的形成时间均为晚侏罗世,属燕山早期构造—岩浆活动的产物.结合矿区外围其他钼矿床同位素年龄数据,可以推测闽西南大规模钼矿化发生在印支期台地向活动大陆边缘转变阶段,并伴随燕山早期挤压隆升(约160 ～ 145 Ma)和燕山晚期由挤压向拉张机制转换(约105 ～90 Ma)作用所诱发的岩浆活动是导致钼矿床形成的主导因素.  相似文献   

特提斯洋对流上地幔Os同位素组成估算的新方法及初步运用     

黄启帅  刘德亮  龚小晗  张晓冉  史仁灯 《地质科学》2013,48(2):532-542

对流上地幔Os同位素组成的准确估算是运用Re-Os同位素体系探讨地幔演化的基础。前人研究主要是以地幔橄榄岩为研究对象,由于地幔橄榄岩Os同位素存在明显的不均一性,因而直接影响估算值的准确性。对流上地幔中包含的不同亏损程度的难熔组分在部分熔融过程中难以熔融,对形成的熔体相的Os同位素组成贡献很少或者没有。因此,与对流上地幔具有相同的Os同位素组成初始值的早期分离结晶岩石(如堆晶岩),结合堆晶岩中锆石的准确定年,可以用来估算对流上地幔Os同位素组成。本文根据这一方法测试了那曲地区弧后盆地堆晶岩的Os同位素组成和锆石U-Pb年龄,推测那曲地区新特提斯洋对流上地幔Os同位素组成为碳质球粒陨石型的。根据这一模型,对比了罗布莎和东巧铬铁矿岩、含矿围岩以及不含矿围岩的Os同位素特征,揭示出矿石及围岩均具有古老大陆岩石圈地幔信息,而不含矿围岩(泽当岩体)的Os同位素组成为碳质球粒陨石型的,无古老大陆岩石圈地幔信息。  相似文献   

Ancient Continents among the Accretionary Complexes of the Central Asia Orogenic Belt: in Situ Os Isotope Evidence     

WANG Kuo-Lung  S.Y. O’REILLY  Mikhail I. KUZMIN  Victor KOVACH  Sergey D''RIL  Alexandar VORONTROV  Vladimir YARMOLYUK  W.L. GRIFFIN  N.J. PEARSON 《《地质学报》英文版》2013,87(Z1):317-318

  相似文献   

The age of continental roots   总被引：39，自引：0，他引：39  

D. G. Pearson 《Lithos》1999,48(1-4):171-194

Determination of the age of the mantle part of continental roots is essential to our understanding of the evolution and stability of continents. Dating the rocks that comprise the mantle root beneath the continents has proven difficult because of their high equilibration temperatures and open-system geochemical behaviour. Much progress has been made in the last 20 years that allows us to see how continental roots have evolved in different areas. The first indication of the antiquity of continental roots beneath cratons came from the enriched Nd and Sr isotopic signatures shown by both peridotite xenoliths and inclusions in diamonds, requiring isolation of cratonic roots from the convecting mantle for billions of years. The enriched Nd and Sr isotopic signatures result from mantle metasomatic events post-dating the depletion events that led to the formation and isolation of the peridotite from convecting mantle. These signatures document a history of melt– and fluid–rock interaction within the lithospheric mantle. In some suites of cratonic rocks, such as eclogites, Nd and Pb isotopes have been able to trace probable formation ages. The Re–Os isotope system is well suited to dating lithospheric peridotites because of the compatible nature of Os and its relative immunity to post-crystallisation disturbance compared with highly incompatible element isotope systems. Os isotopic compositions of lithospheric peridotites are overwhelmingly unradiogenic and indicate long-term evolution in low Re/Os environments, probably as melt residues. Peridotite xenoliths from kimberlites can show some disturbed Re/Os systematics but analyses of representative suites show that beneath cratons the oldest Re depletion model ages are Archean and broadly similar to major crust-forming events. Some locations, such as Premier in southern Africa, and Lashaine in Tanzania, indicate more recent addition of lithospheric material to the craton, in the Proterozoic, or later. Of the cratons studies so far (Kaapvaal, Siberia, Wyoming and Tanzania), all indicate Archean formation of their lithospheric mantle roots. Few localities studied show any clear variation of age with depth of derivation, indicating that >150 km of lithosphere may have formed relatively rapidly. In circum-cratonic areas where the crustal basement is Proterozoic in age kimberlite-derived xenoliths give Proterozoic model ages, matching the age of the overlying crust. This behaviour shows how the crust and mantle parts of continental lithospheric roots have remained coupled since formation in these areas, for billions of years, despite continental drift. Orogenic massifs show more systematic behaviour of Re–Os isotopes, where correlations between Os isotopic composition and S or Re content yield initial Os isotopic ratios that define Re depletion model ages for the massifs. Ongoing Sr–Nd–Pb–Hf–Os isotopic studies of massif peridotites and new kimberlite- and basalt-borne xenolith suites from new areas, will soon enable a global understanding of the age of continental roots and their subsequent evolution.  相似文献   

东秦岭地区碳酸岩型钼- 铀多金属矿床成矿时代：来自LA- ICP- MS独居石U- Pb和辉钼矿Re- Os年龄的证据     

王佳营  李志丹  张祺  李超  谢瑜  李光耀  曾威  丁宁 《地质学报》2020,94(10):2946-2964

东秦岭地区碳酸岩型钼- 铀多金属矿床主要包括华阳川铀多金属矿、黄龙铺和黄水庵钼矿等。其中,华阳川矿床为近期取得勘查突破的一例以U、Nb、Pb为主并伴生稀土元素的超大型铀多金属矿床;黄龙铺钼矿为东秦岭钼矿带中成矿类型最为独特的大型钼矿床。为了精确获得东秦岭地区碳酸岩型钼- 铀多金属成矿时代,本研究采用辉钼矿Re- Os法和LA- ICP- MS独居石U- Pb法,分别对黄龙铺大石沟矿床的辉钼矿、秦岭沟矿床和华阳川矿床含矿碳酸岩脉中的独居石进行测定。结果表明,黄龙铺地区大石沟钼矿辉钼矿Re- Os等时线年龄为221. 3±8. 4Ma（MSWD=10. 9);秦岭沟钼矿碳酸岩中独居石LA- ICP- MS Tera- Wasserburg年龄为207±11Ma（MSWD=3. 7, n =38),华阳川铀多金属矿LA- ICP- MS独居石Tera- Wasserburg年龄为222. 5±6. 7Ma（MSWD=1. 8, n =37),表明该地区碳酸岩中的钼矿化和铀多金属矿化均形成于晚三叠世。综合分析认为,东秦岭地区发育于碳酸岩中的黄龙铺钼矿田、华阳川铀多金属矿是同一成矿系列的产物,碳酸岩型钼- 铀多金属的成矿金属可能来源于地幔,这类碳酸岩可能是秦岭地区印支期造山后伸展环境下的产物。  相似文献   

岩石样品中低含量铂族元素和锇同位素比值的高精度测量方法   总被引：9，自引：1，他引：9  

杨竞红  GerharBRUGMANN 《岩石学报》2001,17(2):325-331

铂族元素（Os,Ir,Pt,Ru,Rh,Pd)具有强亲铁性和强亲铜性，为一组地球化学性质相近的相容元素，铂族元素包含两个同位素衰变体系（^190Pt-^186Os和^187Re-^187Os)。近年来，铂族元素和Re-Os同位素在研究各类不同地持作用过程中，尤其是在地幔岩石的研究中，作用独特，效果显著。由于地幔岩石的铂族元素含量较低，因此高精度，高灵敏度的分析测试方法的研究就显得十分重要。以往的分析方法（如常规的ICP－MS和中子活化分析方法），对含10^-9-10^012级低含量铂族元素的产品分析精度一般较差（＞15％－100％）。所采用的分析流程通常也无法同时获得样品的铂族元素含量和Os同位素比值。本文采用新的熔样方法（HAP－S高温高压釜酸溶法），新的化学流程（溶剂萃取和阴离子交换树脂柱）和新的分析仪器（多接收等离子体质谱MC－ICPMS和负离子热电离质谱N－TIMS）。用同位素稀释法对低含量地幔橄榄岩样品同时测定的铂族元素含量和Os同位素比值，获得了高精度的分析结果。对所分析的地橄榄样品中的铂族元素分配曲线和Os同位素组成的地质意义进行了初步探讨。  相似文献   

富Co铁锰结壳铂族元素与铼-锇同位素组成及其意义   总被引：13，自引：0，他引：13  

姚德  张丽洁  初凤友  杜安道  刘心中  杨富贵 《海洋地质与第四纪地质》2002,22(3):53-58

用ICP－MS测定了太平洋富Co铁锰结壳铂族元素和铼－锇同位素组成。富Co铁锰结壳不仅异常富集铂族元素，而且铂族元素及其它亲铁元素的配发与陨石特征非常相似。铁锰结壳的铼－锇同位素组成明显有别于大陆地壳岩石，和K－T界线沉积物相似，接近陨石值。世界大洋范围内的富Co铁锰结壳均产于远离海底构造热液活动区，几乎不可能受到地幔源热液作用的直接影响。因此，富Co铁锰结壳中的铂族元素可能部分来源于地外物质。  相似文献