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Mechanism of inversion metallogeny of quartz vein type gold deposits in the Xiaoqinling region
Liangwei Xue,Quanzeng Shi,Xiangdong Yu,Yadong Zheng,Jinjiang Zhang
Chinese Science Bulletin , 1998, DOI: 10.1007/BF03182752
Abstract: There are a lot of important gold-bearing quartz veins in the Xiaoqinling metamorphic core complex. The quartz veins are strictly controlled by shear zones. Stress analysis indicates that the metallizing process of the Xiaoqinling gold deposits of quartz vein type can be divided into two stages. At the first stage, the shear zones were formed in an extensional environment, and the temperature was higher and thr buried depth was greater; at the second stage, the brittle thrusts were superimposed in ductile shear zones after the tectonic stress field turnrd form the extension to compression. The ore-bearing fluids were concentrated in these weak positions, and the gold deposits of quartz vein type were developed.
Mechanism of inversion metallogeny of quartz vein type gold deposits in the Xiaoqinling region

科学通报(英文版) , 1998,
Abstract: There are a lot of important gold_bearing quartz veins in the Xiaoqinling metamorphic core complex. The quartz veins are strictly controlled by shear zones. Stress analysis indicates that the metallizing process of the Xiaoqinling gold deposits of quartz vein type can be divided into two stages. At the first stage, the shear zones were formed in an extensional environment, and the temperature was higher and the buried depth was greater; at the second stage, the brittle thrusts were superimposed in ductile shear zones after the tectonic stress field turned from the extension to compression. The ore_bearing fluids were concentrated in these weak positions, and the gold deposits of quartz vein type were developed.
The thermal decrepitation feature mapping method of quartz in prognostication and evaluation of deeper level perspective of quartz vein type gold deposits.
脉金矿床深部成矿远景预测评价的石英热爆裂特征填图法

Feng Benzhi,Wang Keyong,Sun Fengyue Changchun University of Science,Technology,Changchun,China,
冯本智
,王可勇

岩石学报 , 2000,
Abstract: The study showed that the barren quartz, poor goldbearing quartz and quartz from ore bodies possess obviously different thermal decrepitation features on beginning decrepitation temperature, decrepitation temperature region, shape of decrepitation curve as well as main decrepitation peak value etc.aspects, so they are important marks in evaluation of goldbearing features of quartz veins. According to the thermal decrepitation parameters of quartz, mapping of the given parts of vein No.505 and No.530 was carried out, the distribution of quartz with different thermal decrepitation characteristics was enclosed and their mineralization perspective of deeper level parts was evaluated. So the result of this study has great methodological significance for prognostic and evaluation work of the same type of gold deposits.
40Ar-39Ar dating and geological implication of auriferous altered rocks from the middle-deep section of Q875 gold-quartz vein in Xiaoqinling area, Henan, China
Yitian Wang,Jingwen Mao,Xinxiang Lu,Anwang Ye
Chinese Science Bulletin , 2002, DOI: 10.1007/BF03183322
Abstract: The40Ar-39Ar age method is employed in this work to analyze the auriferous altered rocks from the middle-deep section of the Q875 gold-quartz vein in the Xiaoqinling area, and the results show that the main gold deposition of the Q875 occurred in ca. 128–126 Ma. As a typical gold-bearing quartz vein in this gold-rich area, the age data obtained from the Q875 also constrain on the metallogenic time of the lode gold deposits developed in the same geological settings. This geochronological study supplies new evidence for further understanding the timing of gold mineralization, the genesis of gold deposits and the geodynamic settings in Xiaoqinling area.
Fluid inclusion characteristics and ore genesis of the Wenyu gold deposit, Xiaoqinling gold belt
小秦岭文峪金矿床流体包裹体研究及矿床成因

ZHOU ZhenJu,JIANG ShaoYong,QIN Yan,ZHAO HaiXiang,HU ChunJie,
周振菊
,蒋少涌,秦艳,赵海香,胡春杰

岩石学报 , 2011,
Abstract: The Wenyu gold deposit, Henan Province, is located in the southern part of the Xiaoqinling gold belt. It is controlled by a brittle-ductile shear zone and hosted in the Taihua Group metamorphic complex. The crosscutting relationships and mineral assemblages suggest that the ore forming process includes the early, middle and late stages. Three types of fluid inclusions (FIs) in the quartz of Wenyu gold deposit are identified as CO2-H2O, pure CO2, and H2O-solution. The early-stage quartz contains primary pure...
Tectonic Environment of Hydrothermal Gold Deposits and Physico_chemistry of Ore_forming Fluid
热液金矿床控矿断裂性质与成矿流体的物理化学

XU Jiu-hu,XIE Yu-ling,SHEN Shi-liang,
徐九华
,谢玉玲,申世亮

地球学报 , 1998,
Abstract: Metallogenic physico_chemical conditions of hydrothermal gold deposits are greatly associated with ore_controlling fault environment .A comparison of physico_chemical parameters of fluid inclusions from different tectonic environments(including Xiaoqinling,Jiaojia,Linglong and Taibei gold deposits)has been studied .The result shows that the pressures of ore_forming fluids of gold deposits in ductile shear zones are higher,so the values of CO 2/H 2O of fluid inclusions are high.K +/Na + and F -/Cl - of fluid inclusions varies in different tectonic environments,which is not only related to chemistry of host rocks,but also related to tectonic stress.Because ore_forming fluid pressures vary,other parameters of physico_chemistry change sysmaticly,very useful for gold prospecting.
FLUID INCLUSION IN XIAOQINLING GOLD FIELD AND ITS SIGNIFICANCE TO GOLD MINERALIZATION
小秦岭金矿流体包裹体挥发组分与金的矿化

Wang Yinglan,Xie Yihan,Fan Hongrui,
王英兰
,谢奕汉

岩石学报 , 1994,
Abstract: Gas chromatographic analysis of the fluid inclusion volatile in vein quartz from several gold deposits in Xiaoqinling gold field reveals that H,O and CO, are main components of volatile in the ore-forming fluid, and CH4, CO2, H2 and H2 S are minor ones. The gold-bearing fluid is significantly enriched in CO2. Variation of CO2 content bears close relationshipwith distribution of high grade ores.CO2 content of fluid inclusions in gold-rich ores(commonly more than 30 mole percent and CO2/H2O>0. 4)is higher than that in gold-poor ores. CO,content is typically less than 20 mole percent and CO2 /H2 is less than 0.2 in gold-poor ores. In addition,fluid inclusion volatile in gold-rich ores have a much higher concentration of redox gases (i. e.,CH4,CO and H2, etc.) CO2 content and CO2/H2O ration of fluid inclusion volatile may be a good exploration guide in deeper prediction of gold mineralization, and this method has achieved great successes in Xiaoqinling gold field.
Sr-isotope constraint on the origin of the Xiaoqinling gold field.
小秦岭金矿田成因的锶同位素约束

QI JinPing,LAI Yong,REN KangXu,TANG GuoJun,
祁进平
,赖勇,任康绪,唐国军

岩石学报 , 2006,
Abstract: This paper discusses the Sr isotope data obtained from previous studies on the ore-host rocks (Taihua Group),the Wenvu granite and the fluid inclusions of gold-bearing quartz veins in the Xiaoqinling gold field as well as new Sr isotope data recently obtained by the authors for the Neo-Mesoproterozoic strata (Guandaokou and Luanchuan Groups).All the ~(87)Sr/~(86) Sr ratios are calculated into initial ~(87)Sr/~(86)Sr ratios at 130 Ma,i.e.I_(Sr-130),considering that both the Wenyu granite and the gold deposits were formed at about 130 Ma.Eight I_(Sr-130) ratios of the Wenyu granite range from 0.7077 to 0.7084 with an average of 0.7082;twelve I_(Sr-130) ratios of the Taihua Group range from 0.7073 to 0.8090 with an average of 0.7557;fifteen I_(Sr-130) ratios of the Neo-Mesoproterozoic strata range from 0.7119 to 0.8373 with an average of 0.7623;twenty-two I_(Sr-130) ratios of the Taihua Group-hosted quartz veins range from 0.7334to 0.75 I9 with an average of 0.7440;and seven I_(Sr-130) ratios of the Wenyu granite-hosted quartz veins range from 0.7135 to 0.7185 with an average of 0.7162.Obviously,the I_(Sr-130) ratios of the Taihua Group-hosted quartz veins are far higher than those of the Wenyu granite,but accord with the I_(Sr-130) range of the Taihua Group and/or the Neo-Mesoproterozoie strata,suggesting that the ore fluids might be sourced from the metamorphic devolatilization of the Taihua Group and/or the Neo-Mesoproterozoic strata,instead of derivation from the Wenyu granite magma.The Wenyu granite-hosted quartz veins,whose I_(Sr-130) values are lower than those of the Taihua Group,Neo-Mesoproterozoie strata and the Taihua Group-hosted quartz veins,and higher than those of the Wenyu granite, should be the resuhs of interaction between the high I_(Sr-130) fluids and the low I_(Sr-130) Wenyu granite.Hence a tectonic model that combines eollisional orogeny,metallogeny and hydrothermal fluid flow is proposed to interpret the origin of the Xiaoqinling gold field.During the Mesozoie collision between the Yangtze and North China plates,a crustal slab containing the Neo-Mesoproterozoie strata and the Taihua Group was intracontineutally (A-type) subducted northwards beneath the Xiaoqinling gold field along the Xiaohe fault.Metamorphic devolatilization of the underthrust slab provided the ore fluids to develop the Xiaoqinlin gold field.Fluid-wallrock interaction resuhed in the significant differences in I_(Sr-130)value between the Wenyu granite- and Taihu Group-hosted quartz veins.
Jiaodong and Xiaoqinling: two orogenic gold provinces formed in different tectonic settings
胶东和小秦岭:两类不同构造环境中的造山型金矿省

JIANG ShaoYong,DAI BaoZhang,JIANG YaoHui,ZHAO HaiXiang,HOU MingLan,
蒋少涌
,戴宝章,姜耀辉,赵海香,侯明兰

岩石学报 , 2009,
Abstract: Jiaodong and Xiaoqinling areas are two largest gold metallogenic provinces in China.On the basis of field observation and compilation and evaluation of available research progresses and data in these two areas,we argued that gold deposits in both Jiaodong and Xiaoqinling are orogenic gold deposits,but formed in different geological settings.The Jiaodong gold deposits formed in an accretionary orogeic setting while the Xiaoqinling was in a collisional orogeic setting.The Jiaodong gold deposits are likely formed in an active continental margin related to subduction of the Pacific plate in early Cretaceous(ca.130~120Ma).They are mainly hosted in Mesozoic granitoids and controlled by NNE-trend or NE-trend fault zones.The ore-forming fluids have low salinity and high CO_2 contents,and the He-Ar isotopic systematics in fluid inclusion show fingerprint of mantle-derived fluid input.As the consequence of roll-back of the Pacific slab and increase in density of lower crust when changed into eclogite after thickened by compression,part of the lithospheric mantle and lower crust were delaminated,which led to intensive crust-mantle interaction and extensive magmatism with formation of gold deposits in Jiaodong.In contrast,in the Xiaoqinling area gold deposits are mainly controlled by brittle-ductile shear zones(mainly EW-trend)in metamorphic basement rocks of Taihua Group,and show no close connection with Mesozoic granites.Geological features of these deposits(e.g.,hydrothermal fluid with low salinity and high CO_2 contents,and originated mainly from metamorphic water)are consistent with those of orogenic gold deposits worldwide.Some vein-type Au-Mo deposits have been dated at 215~256Ma through method of molybdenite Re-Os geochronology,which support the idea that the gold deposits in the Xiaoqinling area mainly formed in Indosinian period,when collision between North China Craton and Yangtze Block took place.
Acoustic decrepitation as a means of rapidly determining CO2 (and other gas) contents in fluid inclusions and its use in exploration, with examples from gold mines in the Shandong and Hebei provinces, China
爆裂法作为快速测定流体包裹体中二氧化碳(和其它气体)含量的手段及其在勘探中的使用:以中国山东和河北省金矿为例

Kingsley Burlinson,
Kingsley
,Burlinson

中国科技期刊研究 , 2007,
Abstract: The acoustic decrepitation method heats a small monomineralic sample and counts pressure impulses as the inclusions burst when they develop high internal pressures. For aqueous fluids, the decrepitation temperature is correlated with the homogenisation temperature, but gas rich fluids give a distinct and characteristic low temperature decrepitation peak which can be used to recognize gas rich fluid inclusions. This information is useful in exploration for Au deposits, which are frequently associated with CO2 rich and sometimes CH4 rich fluids. This distinctive decrepitation occurs because the CO2 rich inclusion fluids expand according to the gas law and develop internal pressures high enough to burst the host mineral grain at temperatures well below their homogenisation temperatures. In contrast, aqueous fluids condense to a liquid and vapour phase during post-entrapment cooling. Upon subsequent heating their internal pressures do not increase significantly until after homogenisation to a single phase occurs and hence they do not decrepitate "prematurely" as gas rich inclusions do. This behaviour is usually regarded as an annoyance in conventional microthermometric homogenisation studies, but can readily be used as an exploration aid to find mineralisation deposited from such gas rich fluids. Decrepitation results on samples from Cowra Ck, NSW, Australia, which have also been microthermometrically measured for CO2 content, show that amounts of less than 5 mole % CO2 are easily distinguished by decrepitation and amounts as low as 1 mole % CO2 may be determinable. Examples of the use of acoustic decrepitation in the study of 6 gold mines in the Shandong and Hebei provinces of China are discussed.
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