The Shiyaogou deposit in Luanchuan County, China, is a large concealed porphyry Mo deposit within the East Qinling metallogenic belt (EQMB). Major and trace element analyses reveal that the host granite is defined by high silica (SiO2 = 71.56 to 75.25%) and alkali (Na2O + K2O = 6.91 to 7.88%) contents and has typical I-type characteristics. Zircons derived from the pluton yield U-Pb ages of 133.2 +/- 1.1 Ma, indicating an early Cretaceous magmatic event in the EQMB. The epsilon(Hf) (t) values and TDM2 ages range from - 15.1 to - 11.2 and from 2.1 to 1.9 Ga, respectively, suggesting that the granite mainly originated from the lower crust melting with the involvement of mantle components. The mineralization process can be divided into three stages: (1) quartz + Kfeldspar + pyrite + molybdenite; (2) quartz + pyrite + molybdenite; and (3) quartz + calcite veins. Three different types of fluid inclusions (FIs) are present in quartz veins: NaCl-H-2|O (W-type), CO2-H2O (C-type), and daughter mineral-bearing (S-type). Hematite is recognized as a daughter mineral in 5-type inclusions of stage 1, whereas the daughter sulfide and reducing CH4 gases can be observed in the stage 2 quartz, suggesting that the ore-forming fluids were initially oxidizing and then evolved to more reducing conditions. The FIs in stages 1 mainly display Th above 428 degrees C with salinities up to 57.62 wt% NaCl eqv; in stage 2, the FIs display Th of 132-423 degrees C and salinities of 3.23-50.03 wt% NaCl eqv; in stage 3, the FIs homogenized in the range of 117-247 degrees C with low salinities of 2.74-8.95 wt% NaCl eqv. The coexisting W-, 5- and/or C-type inclusions homogenized at similar temperatures, but contain different salinities during stages 1 and 2, suggesting that the fluids boiled during both stages. Our study reveals that the ore-forming fluids are magmatic in origin. These high-temperature magmatic fluids gradually evolved from high salinities and high CO2 contents to a mixture of magmatic and meteoric water with lower temperature, lower salinity, and lower CO2 content. The precipitation of Mo mainly resulted from the decreasing temperature and salinity. Additionally, the changes in pH and CO2 content due to boiling and the water-rock reaction could have contributed toward the precipitation of Mo.

臼齿构造主要发育于中新元古代地层中,目前所报道的臼齿构造均由纯净的、基本等粒的微晶方解石(或白云石)构成.野外地质考察中,在北京南口长城系高于庄组第3段泥晶灰岩中发现了形态多样的臼齿状构造,野外观察和室内显微镜下分析,发现臼齿状构造与宿主岩石边界多呈圆弧状或港湾状,界线清晰.扫描电镜(SEM)和能谱分析(EDX)表明,"臼齿"成分主要以硅质为主,矿物成分为玉髓和自生石英.从臼齿状构造的形态和充填序列分析,发现南口臼齿状构造形成经历了裂缝形成、裂缝充填和后期破坏再充填等过程.认为臼齿状构造可能是多成因的结果,其中在半固结的条件下由地质事件引起的微裂隙系统可能是臼齿状构造形成的重要因素之一.

塔里木板块西北缘沉积地层的研究,对于恢复南天山洋的演化过程有重要意义.文中利用岩石地球化学的手段,对新疆阿合奇地区志留系砂岩进行物源和构造背景分析.研究表明,阿合奇地区志留系砂岩样品的SiO2含量范围变化较大,为61.97％～93.91％,平均含量为76.76％;稀土元素球粒陨石标准化配分型式为右倾型,(La/Yb)N值较高,δEu值较低,Ce异常不明显.中—顶志留统塔塔埃尔塔格组砂岩的成熟度高于下志留统柯坪塔格组.地球化学物源分析图解和大地构造背景判别表明:研究区沉积物源区逐渐由活动型向稳定型转换,下志留统部分沉积物来自于火成岩物源区,具有主动大陆边缘和大陆岛弧性质;中—顶志留统沉积物全部来自于成熟大陆的石英岩沉积物源区.结合广泛分布的奥陶系—志留系平行不整合,认为晚奥陶世研究区为活动大陆边缘,南天山洋盆向南俯冲到塔里木板块之下;早志留世,向南俯冲结束,研究区大地构造背景开始由活动大陆边缘向稳定的被动大陆边缘转换,来自活动型物源区的沉积物逐渐减少,稳定型物源区的碎屑物质逐渐增多;中—末志留世,研究区构造背景完全转变为被动大陆边缘,碎屑物质全部来自于稳定型物源区.上述成果表明,南天山洋的演化过程中确实存在双向俯冲.

The Shiyaogou granite is a related to the molybdenum mineralization hidden granite,which is found for the first time in the Xionger Mountain at the East Qinling,southern margin of North China landmass.The lithology of the granite is mainly medium-fine biotite monzogranite and porphyritic granite,and the LA-ICP-MS zircon U-Pb dating results indicate that it was formed in the early Cretaceous(140.45±0.75 Ma-136.64±0.55 Ma).The geochemical data show that the granite is character-ized by SiO 2 (70.27%-73.22%),Al2 O 3 (12.71%-14.96%),MgO(0.23%-0.54%),the total alkaline(K2 O+Na2 O)ranging from 6.43% to 1 1.78wt%,which suggests that the granite has high silicon and rich alkali characteristics.The Rittmann Index (δ)ranges from 2.1 1 to 3.02,and AR ranges from 1.48 to 5.73,which shows the granite is calc-alkaline series.The A/CNK value is 0.95-1.01,and shows a Aluminum-peraluminous I-type granite characteristic.The ∑REE of the granite ranges form 147×10 -6 to 322×10 -6 ,the ratio of LREE/HREE ranges from 1 5.2 to 25.2,and the value of LaN/YbN ranges from 1 9.10× 10 -6 to 50.50×10 -6 .The chonrite standardized distribution pattern is characterized by enrichment of LREE in the right-dipping type with medium-weak negative Eu anomalies(δEu=0.53 -0.71,average 0.62).The trace elements are characterized by the value of Sr(133×10 -6 -759×10 -6 ,average 371×10 -6 ),the low value of Y and Yb(Y=10.02×10 -6 -18.80×10 -6 ,average 12.57×10 -6 ;Yb=1.1 6×10 -6 -2.02×10 -6 ,average 1.40×10 -6 ),and the lower ratio of Sr/Y(12.77-61.66,average 30.44). The geochemical characteristics reflect the granite melt experienced feldspar fractional crystallization in the magma.The initial isotopic Sr ratio(I sr =0.707 44-0.713 84),the initial epsilon Sr(εSr (t )= 44.1-134.9)and Nd(εNd (t )=-12.96 to -13.46) disclose the Shiyaogou hidden granite has a magma homology with the Mesozoic Heyu granite.The Nd model ages(t DM2 )of the granites are concentrated in 2.00-2.01 Ga.All the isotopic data suggest the granite formed by the melting of the South Qinling and Yangtze block crystalline basement and with participation of Taihua and Xionger groups.The regional geology and geo-chemical characteristics suggest that the formtion of the Shiyaogou granite experienced two stages:Before Jurassic,the crust of East Qinling thickened with the subduction-collision of South Qinling and Yangtze Block under the North China block;In the Jurassic and Cretaceous,when the extrusion environment changed to the extension condition,with the decompression and war-ming,partial melting of the middle-lower continental crust,finally formed the Shiyaogou granite in the Early Cretaceous.

为探讨石窑沟钼矿床的矿床成因,本文开展了系统的地质及成矿流体特征研究.根据矿脉穿切关系,将热液成矿过程分为早、中、晚3个阶段,其矿物组合分别为石英-钾长石-黄铁矿-辉钼矿、石英-多金属硫化物和石英-方解石±黄铁矿.研究发现,成矿早、中阶段产出的石英中有水溶液包裹体、纯CO2包裹体、H2O-CO2类包裹体和含子晶多相包裹体,而成矿晚阶段产出的石英中仅有水溶液包裹体;对不同阶段包裹体的显微测温和激光拉曼测试结果显示,成矿早阶段成矿流体以高温、高盐度、高氧化性、富CO2为特征;中阶段流体发生沸腾,导致CO2逃逸,还原性增强,成矿物质沉淀;晚阶段流体以低温、低盐度、贫CO2为特征.流体沸腾可能是引起辉钼矿沉淀的重要原因.

Acta Geologica Sinica - English EditionVolume 88, Issue s2 p. 1206-1207 Meeting Abstracts Study on Ore-forming Fluid of Shiyaogou Porphyry Molybdenum Deposit, Henan Province, China Rongzhen ZHANG, Corresponding Author Rongzhen ZHANG School of Geosciences and resources, China University of Geosciences, Beijing 100083 ChinaCorresponding author. E-mail: 763082883@qq.comSearch for more papers by this authorDehui ZHANG, Dehui ZHANG School of Geosciences and resources, China University of Geosciences, Beijing 100083 ChinaSearch for more papers by this authorHongxing HOU, Hongxing HOU No. 6 Gold Geological Party of CAPF, Sanmenxia 472000 ChinaSearch for more papers by this author Rongzhen ZHANG, Corresponding Author Rongzhen ZHANG School of Geosciences and resources, China University of Geosciences, Beijing 100083 ChinaCorresponding author. E-mail: 763082883@qq.comSearch for more papers by this authorDehui ZHANG, Dehui ZHANG School of Geosciences and resources, China University of Geosciences, Beijing 100083 ChinaSearch for more papers by this authorHongxing HOU, Hongxing HOU No. 6 Gold Geological Party of CAPF, Sanmenxia 472000 ChinaSearch for more papers by this author First published: 29 December 2014 https://doi.org/10.1111/1755-6724.12379_70Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume88, Issues2Special Issue: Meeting Abstracts: The 14th Quadrennial International Association on the Genesis of Ore Deposits Symposium. August 19–22, 2014, Kunming, ChinaDecember 2014Pages 1206-1207 RelatedInformation

The fault structure is the Ore-controlling structure in the Zhaishang Gold Deposit,but the formation and the morphology are controlled by fold structure,and it also internally controls the migration and enrichment of oreforming materials.The ore-controlling tectonic system is divided into four levels based on the regional tectonic framework and the vein distribution of the mining area.Through the analysis of the control function of ore body structure(Nana ranch anticline),we obtain the occurrence of vein controlled by the Fold obviously.As the different parts of the Fold have the different lithologic association,and also have the different structural types,the Fold controls the degree of mineralization in mining area.For this understanding,north ore belt in the Fold north have greater potential for exploration,south ore belt in the Fold nuclear have a certain value in the superficial,and the southern fold is not a metallogenic conditions area.