检索结果-南通市图书馆

Gold mineralization age of the Anjiayingzi gold deposit in Chifeng County, Inner Mongolia and implications for Mesozoic metallogenic explosion in North China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第2期47卷 115-121页

作者： LI Yonggang ZHAI Mingguo YANG Jinhui MIAO Laicheng GUAN Hong Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The Anjiayingzi gold deposit in Chifeng County, Inner Mongolia is located in the central part of the gold mineralization belt of the northern margin of the North China Craton (NCC), and is adjacent to the Paleozoic Inner Mongolia-Da Hinggan Mountains orogenic belt in the north. The Chifeng-Kaiyuan fault, which separates the NCC from this orogenic belt, is considered to be a regional ore-controlling structure. The Anjiayingzi gold deposit is a mediate-size quartz lode-gold deposit and is hosted by the Anjiayingzi quartz monzonite that was emplaced into the basement composed of early Precambrian gneisses. Rhyolitic and porphyritic dikes are generally associated with the gold mineralization. Zircon U-Pb analyses suggest that the Anjia- yingzi granite was emplaced from 132 Ma to 138 Ma, while the rhyolitic dikes that occupy the same fracture system as the gold-bearing quartz veins and locally crosscut the gold lodes crystallized from 125 Ma to 127 Ma. These results constrain the mineralization age between 126 Ma and 132 Ma, early Cretaceous time for the Anjiayingzi gold deposit. This mineralization age is consistent with that of the gold deposits in other major gold-bearing areas of the NCC, such as the Jiaodong Peninsula and the Xiaoqinling Mountain, and specially is roughly coeval with the geodynamic reversion of the NCC in Mesozoic. This coincidence probably indicates that the gold deposits in the NCC, including the Anjiayingzi deposit, formed in a similar geodynamic setting characterized by large-scale thinning of the lithosphere underlying the NCC.

关键词： Anjiayingzi, gold deposit, granite, zircon, geochronology, explosive metallogeny.

Discovery of double-peaking potassic volcanic rocks in Langshan Group of the Tanyaokou hydrothermal- sedimentary deposit, Inner Mongolia, and its indicating significance

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第6期48卷 822-833页

作者： PENG Runmin1, ZHAI Yusheng1, WANG Zhigang2 & HAN Xuefeng2 1. Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology, Ministry of Education, China University of Geosciences, Beijing 100083, China 2. Inner Mongolia Geological Prospecting Institute, Ministry of Chemical Industry, Hohhot 010074, China Correspondences should be addressed to Peng Runmin Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology Ministry of Education China University of Geosciences Beijing China Inner Mongolia Geological Prospecting Institute Ministry of Chemical Industry Hohhot China

It is revealed that the protolith of gray-light brown potash-feldspar-leucogranulites and granulites in the 2nd formation of the LG in Tanyaokou deposit are quartz kerotophyre of synsedimentary eruption based on the following facts and features: (1) The rocks look compact and homogeneous without obvious crystals with naked eyes; (2) they contain blastoporphyritic or glomeroporphyritic and blasto-crystalloclastic crystals consisting of quartz with wavy extinction and albite with obvious alteration and deformation; (3) they also contain radiated and fibrous blasto-microspherulitic texture and swallow-tailed bifurcate and blasto-hollow-skeleton crystal texture, representing the rapid cooling characteristic of the magma during submarine volcanic eruption; (4) the major chemical compositions of the rocks are: SiO2 = 70.80%―76.00%, K2O (4.83%―6.22%)>Na2O(2.78%―3.80%), and K2O+Na2O = 8.63%―9.00%; and (5) their petro-chemical diagrams indicate that they are volcanic rocks. Together with the characteristic that they occur in the same sequence with potassic spilite (SiO2 = 46.12%―50.68%, K2O = 4.23%―5.93%>Na2O = 2.15%―3.14%, K2O+Na2O = 6.51%―8.08%), it can be confirmed that the vol-canics occurring in the 2nd Formation of the LG in Tanyaokou district are double-peaking potas-sic volcanic rocks. The discovery, together with the tuffs with ore minerals and the distribution of lead isotopic as well as the value of Co/Ni of pyrites >1 showing the obvious endogenic metali-zation, can prove that the Tanyaokou deposit is an untypical SEDEX-type deposit formed in the extension fault basin in the Mesoproterozonic aulacogen of the northern margin of the North China Platform, and its metallogenesis is related to the synsedimentary volcanic activities and the hydrothermal exhalation, and both the ore-forming material source and volcanics came from mantle or lower crust. These facts mentioned above, together with the meta-volcanic rocks (double-peaking) found in the Dongshengmiao and Huogeqi districts and the host stratigraphic sequenc

关键词： extensional rift basin, double-peaking potassic volcanic rocks, Mesoproterozoic, the 2nd formation of LG, Tanyaokou deposit, Inner Mongolia.

Continental hydrothermal sedimentary siliceous rock andgenesis of superlarge germanium(Ge)deposit hosted incoal:A study from the Lincang Ge deposit,Yunnan,China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第11期47卷 973-984页

作者： QI Huawen1,2,HU Ruizhong1,SU Wenchao1,QI Liang1 & FENG Jiayi1 1.Key Laboratory of Ore deposit Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China 2.Department of Earth Sciences,Nanjing University,Nanjing 210093,China Correspondence should be addressed to Qi Huawen(email: qihuawen@***) Key Laboratory of Ore deposit Geochemistry Chinese Academy of Sciences Guiyang China Department of Earth Sciences Nanjing University Nanjing China

There are abundant hydrothermal sedimentary structures and plant fragment fossils in the siliceous rocks from the Lincang Ge deposit. The major element compositions of these siliceous rocks are characterized by high content SiO2, low TiO2 and Al2O3concentrations, and low Al/(Al+Fe+Mn) ratios (0.010 on average). The siliceous rocks are distinctly enriched in Ge, Sb, As, W, and secondly enriched in Cs, U, Mo and Tl. Their total REE content are generally less than 1μg/g, LREE relatively concentrated, and the values of Eu anomaly and Ce anomaly vary from 0.452 to 5.141 and 0.997 to 1.174, respectively. Their NAS-normalized REE patterns are plain or left-inclined. The Oxygen isotope compositions of these siliceous rocks are similar to those of the hydrothermal siliceous sinter. The above characteristics, as well as the geological setting of the deposit, indicate these siliceous rocks formed in continental hydrothermal envi- ronment. As the interlayer or cliff of the Ge-rich coal seams, siliceous rocks tightly contacted with ore-body, and the contents of Ge in siliceous rocks vary from 5.6 to 360 μg/g (78 μg/g on aver- age). The Ge content increased in coal which close to the siliceous rocks. With the increase of Ge content, the typical trace element ratios (i.e., Ge/Ga, Nb/Ta and U/Th) and REE patterns of Ge-rich coal are more close to those of the siliceous rocks. The Ge concentrated in coal seams of the Lincang Ge deposit might be transported by the hydrothermal water, which demonstrated by the siliceous rocks, during the coal-forming processes.

关键词： siliceous rock, continental hydrothermal sedimentation, superlarge Ge deposit, Lincang.

Characteristics of chlorine isotope distribution and analysis on sylvinite deposit formation based on ancient salt rock in the western Tarim Basin

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第11期48卷 1913-1920页

作者： TAN Hongbing1,2, MA Haizhou1, XIAO Yingkai1, WEI Haizhen1,2, ZHANG Xiying1 & MA Wandong1 1. Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Institute of Salt Lakes Chinese Academy of Sciences Xining China Graduate School of the Chinese Academy of Sciences Beijing China

During formation of the Tarim Basin, there repetitively happened seawater invasion for it was ever connected with wide Paleo-mediterranean Sea. At the same time, for the applica-tion of tectonic and paleoenvironmental condition, the basin deposits many sequences of thick strata of evaporites, especially in its two largest subbasins of Kuqa in the north and Shaqa in the southwest. Therefore, the western Tarim Basin has been considered to be a favorable location to prospect ancient sylvinite deposit. But it is unfortunate that the Br×103/Cl ratio, as a common geochemical index to uncover clues of sylvinite deposit, is almost invalid to indicate the stage of ancient brine condensation for very low content of bromine in salt rock samples (less than 10?6 commonly) in the western Tarim Basin evaporites. Fortunately, we noticed recently that the val-ues of chlorine isotope (δ 37Cl value) for salt rock samples follow some clear laws from place to place, which in the Shaqa subbasin, all δ 37Cl values of salt rock samples behaved negatively and on the contrary, they all surprisingly showed positive values in the Kuqa subbasin. Based on conclusions of previous research and referring to the ratios of Br×103/Cl for salt rock or brine samples, we proved that the chlorine isotope (δ 37Cl) could be used as an effective index to find ancient sylvinite deposit in those evaporites rock basin with low content of Br element back-ground, such as the Tarim Basin. Thus according to the new index of chlorine isotope, we con-clude that the concentration of ancient brines formed ancient salt rocks is much more concen-trated in the Shaqa subbasin than that in the Kuqa subbasin. Particularly, the δ 37Cl value of salt rock in Kashi depression of the western Shaqa subbasin is greatly negative (deposit or even the later stage of sylvinite deposit. Then it is possible to find sylvinite-bearing deposits around the western region (periphery of

关键词： the Tarim Basin, chlorine isotope, ancient salt rock, ancient sylvinite deposit, deposit stage

Study on Mineralization Age of Xiaoban Gold deposit, Fujian Province

在线全文

学校读者我要写书评

暂无评论

Journal of China University of Geosciences 2002年第3期13卷 225-233页

作者： Chen Bailin Institute of Geomechanics, CAGS, Beijing 100081 Wu Ganguo Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083 Zhang Da Institute of Geomechanics, CAGS, Beijing 100081 Huang Rensheng West Fujian Geological Party of FBGMRE, Sanming 365000 Wu Jianshe Fujian Bureau of Geological and Mineral Resources Exploration, Fuzhou 350003 Institute of Geomechanics CAGS Beijing 100081 Faculty of Earth Sciences and Mineral Resources China University of Geosciences Beijing 100083 West Fujian Geological Party of FBGMRE Sanming 365000 Fujian Bureau of Geological and Mineral Resources Exploration Fuzhou 350003

The Xiaoban gold deposit is a large size deposit recently found in middle area of Fujian Province. It belongs to magmatic hydrothermal type occurred in Mayuan Group metamorphic rocks of Middle Proterozoic and is controlled by low angle fault (detachment) structures. The contents of Au in Mayuan Group metamorphic rocks, Caledonian Indosinian deformed granite and early Yanshanian granite are higher with Au enrichment coefficient of 2.06-5.68, 5.11 and 6.67 than those in other geological bodies. And the higher enrichment coefficients (>2) of Ag, S, Sn and Te are similar to those of gold ore. Meanwhile, the distribution of Au in Mayuan Group metamorphic rocks and early Yanshanian granite with a low D value (0.58 and 0.67) is favorable to gold mineralization. REE characteristics of gold ore, ratios of (LREE/HREE), (La/Sm) n, (Yb/Lu) n, (La/Tb) n and (Sm/Nd) n are similar to Mayuan Group metamorphic rocks, only non or little normal Eu abnormal of ore is dissimilar to metamorphic rocks. The δ ( 34 S) of the gold ore, with a high homogenization, is (-4.7×10 -3 )-(-2.7×10 -3 ). The study of inclusion indicates 180-249 ℃ of mineralization temperature, 3.69 %-11.81 % of salinities and 0.869-0.991 g/cm 3 of densities of mineralization fluid. Based on hydrogen and oxygen isotope ( δ ( 18 O)=11.0×10 -3 -11.7×10 -3 , δ (D)=(-48×10 -3 )-(-62×10 -3 )) and initial w ( 87 Sr)/ w ( 86 Sr) =0.715,combining to the analysis of geological history, regional metamorphism and magamtic activity, the authors confirm that the source for the ore fluid was mainly from magmatic, partly from metamorphic water, and with a little influence of meteoric water. Isotopic dating made on Rb Sr isochron age of 182 Ma, by using alteration minerals of gold ores from the deposit, indicates that the mineralization occurs in early Yanshanian epoch. This is close to the age of 187 Ma of the Anchun magmatite with a similar alteration and gold mineralization to the Xiaoban gold deposit. The age of early Yanshanian epoch of the Xiaoban gold is indentical with the

关键词： mineralization age, early Yanshanian epoch, Xiaoban gold deposit, Fujian.

Sources of ore-forming fluids and metalik materials in the Jinwozi lode gold deposit, eastern Tianshan Mountains of China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2003年第Z1期46卷 135-153页

作者：刘伟李新俊邓军 Key Laboratory of Research for Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100101 China School of the Earth and Land Resources China University of Geosciences (Beijing) Beijing 100083 China

This paper presents gas compositions and H-, O-isotope compositions of sulfide- and quartz-hosted fluid inclusions, and S-, Pb-isotope compositions of sulfide separates collected from the principal Stage 2 ores in Veins 3 and 210 of the Jinwozi lode gold deposit, eastern Tianshan Mountains of China. Fluid inclusions trapped in quartz and sphalerite are dominantly primary. H- and O-isotopic compositions of pyrite-hosted fluid inclusions indicate two major contributions to the ore-forming fluid that include the degassed magma and the meteoric-derived but rock 18O-buffered groundwater. However, H- and O-isotopic compositions of quartz-hosted fluid inclusions essentially suggest the presence of groundwater. Sulfide-hosted fluid inclusions show considerably higher abundances of gaseous species CO2, N2, H2S, etc. Than quartz-hosted ones. The linear trends among inclusion gaseous species reflect the mixing tendency between the gas-rich magmatic fluid and the groundwater. The relative enrichment of gaseous species in sulfide-hosted fluid inclusions, coupled with the banded ore structure indicating alternate precipitation of quartz with sulfide minerals, suggests that the magmatic fluid has been inputted to the ore-forming fluid in pulsation. Sulfur and lead isotope compositions of pyrite and galena separates indicate an essential magma derivation for sulfur but the multiple sources for metallic materials from the mantle to the bulk crust.

关键词： sulfide-hosted fluid inclusion, H- and O-isotopes, gas composition, lode gold deposit, eastern Tianshan Mts.

Pb Isotope Compositions of Shibaqinghao Gold deposit in Central Inner Mongolia,China

在线全文

学校读者我要写书评

暂无评论

Global Geology 2002年第1期7卷 54-61页

作者： ZHANG Hongying(Jilin University, Changchun 130026, P. R. China)LIANG Yibo(Hailun Normal School, Hailun 152300, P. R. China) Jilin University Changchun130026 P. R. China Hailun Normal School Hailun152300 P. R. China

There are two types of gold ore in Shibaqinghao gold deposit, a mylonite ore and a quartz - vein ore. Pb isotope compositions for mylonite ore are characterized by lower Pb isotope ratios ranging from 16.63 to 17.45 (206Pb/204Pb), 15.31 to15.48 (207Pb/204pb), 36.52 to 38.85 (208Pb/204Pb). They are scattered very close to a model curve of the mantle evolution. These ratios suggest that gold in the mylonite ore might be derived from the country rocks, which originated directly in the upper mantle. Pb isotope compositions for quartz - vein ore are characterized by higher Pb isotope ratios ranging from 18.23 to 19.74 (206Pb/204Pb), 15.69 to 15.89 (207Pb/204Pb), 38.64 to 40. 13 (208Pb/204Pb). They are scattered very close to a model curve of the upper crustal evolution. These facts indicate that the gold in the quartz - vein ore might be related to some granitic magma generated in the crust.

关键词： Pb isotope, Shibaqinghao gold ore deposit, Mylonite ore, Quartz vein ore

Sulphur Isotope Compositions of Shibaqinghao Gold deposit in Central Inner Mongolia, China

在线全文

学校读者我要写书评

暂无评论

Global Geology 2001年第1期6卷 90-96页

作者： Zhang Hongying and Liu Xiang (Faculty of Earth Science.Jilin University, ChangChun 130026,P. R. China) Faculty of Earth Science Jilin University Changchun 130026 P. R. China

Shibaqinghao gold deposit is situated in the western part of the northern margin of the North China Craton. It is controlled by an E-W trending tectonic zone that is located in the middle unit of Dongwufenzi group which consists of a se- quence of greenschist-facies metamorphic rocks in an Archean greenstone belt. In Shibaqinghao gold deposit there are two types of gold ore, a mylonite ore and a quartz vein ore. Mylonite ore bodies were formed during ductile shearing stage in the Early Proterozoic, whereas quartz vein ore bedies might have been fOrmed in the Mesozoic time. Pyrite accompanied with native gold in the mylonite ore has sulpfur of which ■S values range from-5. 8 to + 0. 8 per mil,similar to the values of mantle-derived sulphur. These data suggest that gold in the mylonite ore be derived from the country rocks which originated directly in the upper mantle. Pyrite in quartz vein ore has the of ■S values between + 3. 0 and + 11. 0 per mil, similar to the values of some granitic rocks. These facts indicate that the gold in the quartz vein ore is related to some granitic magma generated in the crust. This study revealed that two different mineralization occurred at different geological times and in different environments but in the same place, resuling in the Shibaqinghao gold deposit.

关键词： Shibaqinghao gold ore deposit, mylonite ore, quartz vein ore, sulphur isotope

Basical characteristics of fluid geologic process of interlayer oxidation zone sandstone-typeuranium deposit

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2007年第Z2期50卷 185-194页

作者： WU BoLin LIU ChiYang WANG JianQiang State Key Laboratory of Continental Dynamics(Northwest University) Xi'an 710069 China State Key Laboratory of Continental Dynamics(Northwest University) Xi'an 710069 China State Key Laboratory of Continental Dynamics(Northwest University) Xi'an 710069 China

This paper reveals the physicochemical properties such as component, formulation, genesis, tem- perature, pH, Eh, salinity and pressure of all main alteration fluid of interlayer oxidation zone sand- stone-type uranium deposits after studying the geologic process and geochemistry of internal typical sandstone-type uranium deposits such as Shihongtan deposit in the Turpan-Hami basin, 512 deposit in the Yili basin, Dongsheng deposit in the Ordos basin. The composition of fluid can be divided into two parts based on the analysis of inclusion: one can be affirmed as atmospheric water with ordinary temperature epigenesist according to the character of hydrogen and oxygen isotope of inclusion, the other is natural gas containing gaseous hydrocarbon like CH4, and CO2 as well as a little H2S, CO, H2, N2 and so on, it always contains a small quantity of hydrocarbon liquid in petroliferous basins. The fluid property of oxidation alteration zone is always oxidation alkaline, and neutrality or weak acid-weak alkaline and reducibility during the metallizing process, but at secondary reduction or deoxidization zone it becomes strong reduction alkaline. Oxygenic groundwater in the fluid is the activate and mig- ratory medium of uranium element, but the gaseous hydrocarbon like CH4 as well as H2, H2S, CO from natural gas is the important sedimentary reducer of uranium mineral; the transformation of pH,Eh in fluid environment is the main reason for the formation of uranium metallization.

关键词： fluid, interlayer oxidation zone, uranium deposit, inclusion, isotope