首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
<正>The Pulang porphyry copper deposit,located in the Gezan tectonic-magmatic arc and south of the Yidun island arc,southwest of Sanjiang metallogenic belt in Yunnan province,is a super-large porphyry copper deposit.During recent decades,the Pulang deposit has attracted wide attention among geologists both at home and abroad.Many previous researches have discussed its  相似文献   

2.
The Nage Cu-Pb polymetallic deposit is located in the transitional zone of the Yangtze craton and cathaysia, that is the southwest of Jiangnan orogenic belt. The mainly strata are Wentong formation of Mesoproterozoic Sibo group and the Jialu formation (Qbj) , Wuye formation (Qbw) , Fanzhao formation (Qbf) and Gongdong formation (Qbg) of the Neoproterozoic Qingbaikou System Xiajiang group.  相似文献   

3.
<正>1 Introduction The Maozu Pb–Zn deposit,located in the Northeast of Yunnan Province,southwest China,is a typical carbonate-hosted deposit in the Northeast of Yunnan Pb–Zn metallogenic province.Fluorite is the main gangue  相似文献   

4.
Gold Headquarter of the CAPF has discovered the Yangshan super large-scale gold deposit in Gansu Province, which is a great breakthrough of gold exploration and prospecting in Western Qinling Mountains of China. The gold resources of this deposit achieved 308 tons with increasing potentials. Preliminary geological investigations indicate that the Yangshan gold deposit is located in the intra-continental collision orogenic belt; and the deposit was formed during the continent-continent collision orogenic processes. The geological characteristics of the deposit are similar to that of the typical Carlin-type gold deposits, while differences still exist. The ore-forming background is notably different from the Carlin gold deposit province in the United States; and the ore-forming fluids are similar with that of the orogenic-type gold deposit. Accordingly, the Yangshan gold deposit is a transitional type between the Carlin-type and the orogenic type gold deposits. At present, the Yangshan gold deposit is the largest Carlin and Carlin-like type gold deposit that is ever discovered in China. Researches on metallogeny, metallogenic model and ore-enrichment regularities of the Yangshan gold deposit are crucial to meet the pressing needs of the current geological investigation and ore exploration of the deposit.  相似文献   

5.
<正>The Suoluogou gold deposit in Muli County of Sichuan Province is located in the southern section of the GanziLitang suture zone(Figs.1a,b),which is the largest gold deposit discovered in this suture zone in recent years.At present,the exploration of the Suoluogou gold deposit is still in progress,and the amount of resource is increasing.  相似文献   

6.
The Maoniuping REE deposit, located about 22 km to the southwest of Mianning, Sichuan Province, is the second largest light REE deposit in China, subsequent to the Bayan Obo Fe-Nb-REE deposit in the Inner Mongolia Autonomous Region. Tectonically, it is located in the transitional zone between the Panxi rift and the Longmenshan-Jinpingshan orogenic zone. It is a carbonatite vein-type deposit hosted in alkaline complex rocks. The bastnaesite-barite, bastnaesite-calcite, and bastnaesite-microcline lodes are the main three types of REE ore lodes. Among these, the first lode is distributed most extensively and its REE mineralization is the strongest. Theδ34Sv-CDT values of the barites in the ore of the deposit vary in a narrow range of +5.0 to +5.1‰in the bastnaesite-calcite lode and +3.3 to +5.9‰in the bastnaesite-barite lode, showing the isotopic characteristics of magma-derived sulfur. Theδ13Cv-PDB values and theδ518OV-SMOW values in the bastnaesite-calcite lode range from -3.9 to -6.9‰and from +7.3 to +9.7‰, respectively, which fall into the range of "primary carbonatites", showing that carbon and oxygen in the ores of the Maoniuping deposit were derived mainly from a deep source. Theδ13Cv-PDB values of fluid inclusions vary from -3.0 to -5.6‰, with -3.0 to -4.0‰in the bastnaesite-calcite lode and -3.0 to -5.6‰in the bastnaesite-barite lode, which show characteristics of mantle-derived carbon. TheδDv-SMOW values of fluid inclusions range from -57 to -88‰, with -63 to -86‰in the bastnaesite-calcite lode and -57 to -88‰in the bastnaesite-barite lode, which show characteristics of mantle-derived hydrogen. Theδ18OH2OV-SMOW values vary from +7.4 to +8.6‰in the bastnaesite calcite lode, and +6.7 to +7.8‰in the bastnaesite-barite lode, almost overlapping the range of +5.5 to +9.5‰for magmatic water. The 4He content, R/Ra ratios are (13.95 to 119.58×10-6 (cm3/g)STP and 0.02 to 0.11, respectively, and 40Ar/36Ar is 313±1 to 437±2. Considering the 4He increase caused by high contents of radioactive elements, a mantle-derived fluid probably exists in the inclusions in the fluorite, calcite and bastnaesite samples. The Maoniuping deposit and its associated carbonatite-alkaline complex were formed in 40.3 to 12.2 Ma according to K-Ar and U-Pb data. All these data suggest that large quantities of mantle fluids were involved in the metallogenic process of the Maoniuping REE deposit through a fault system.  相似文献   

7.
<正>1 Introduction Sareke glutenite-type copper deposit is located in the Sarekebayi basin,a sub-basin of southwest margin of the Tuoyun Mesozoic hinterland basin in the northwestern part of the Tarim Basin.The Tuoyun Mesozoic hinterland  相似文献   

8.
The Tongkuangyu metaporphyry copper deposit formed in the Early Proterozoic is tectonically located in the northern part of the Zhongtiao X -type palaeorift depression, on the southern margin of the North China platform. The genesis of the deposit has long been a hot subject of research of geologists working on mineral deposits. By means of the protolith reconstruction and fluid inclusion and isotope studies of host rocks of the deposits, the authors hold that this deposit is the product of combined exogenic, endogenic and metamorphic processes. Its formation mainly involved the following four stages: (1) the stage of formation of Mg- and Fe-rich tuffaceous variegated cupriferous sand-shale and K-rich biomodal volcanic rocks; (2) the early stage of formation of the metaporphyry copper deposit; (3) the stage of formation of the metaporphyry copper deposit; and (4) the stage of reworking of the metaporphyry copper deposit.  相似文献   

9.
Detailed studies have been conducted on the geology and geochemistry of the deposit and granite in the mining district in the last two decades, and by comparing this deposit with other typical epithermal deposits in the world, it is clear that the Erentaolegai silver deposit is a lower-sulfidation, adularia-sericite-type epithermal silver deposit and the bulk mineralogy of this deposit is consistent with low-sulfidation epithermal mineralization. Determined by the Rb-Sr isochron method, the age of magmatic intrusives in the mining district is 120 Ma. So, it can be concluded that the local areas were marginally subjected to the movement in Late Yanshanian and produced granitic magma, and about 29% mantle material, as is calculated, was involved in magmatism. The magma experienced crystallization-differentiation, resulting in the formation of granite and quartz porphyry; the latter was the product of violent granitic magma crystallization-differentiation, so silver was enriched in later petrogenetic stages and post-petrogenetic ore fluids from which Ag was derived dominantly. Oxygen and hydrogen isotopic characteristics indicate that meteoric waters on the Earth‘ s surface played an important role in the formation of granitic magma and the deposit: ( 1 ) contributing a lot to the fundamental complex partial melting;(2) contributing a lot to magma crystallization-differentiation, and bringing silver into the magma which is eventually responsible for the formation of quartz porphyry; and (3) contributing a lot to the formation of great amounts of ore fluid. The lead isotopic characteristics show that the silver and lead have an affinity for each other.  相似文献   

10.
The formation of the Tongyu gold deposit, controlled by regional polyphase deformation-metamorphism.is closely related to the regional composite antiform-shear slip fracture zone. Late-stage reworking of theTaihua Group accounts for the enrichment of ore substances. It is a typical syntectonic gold deposit. The formation and evolution of the deposit involved four stages: (Ⅰ) the state of preparation of ore sub-stances, in which primary source beds originated: (Ⅱ) the stage of remobilization of ore substances, in whichregional progressive metamorphism and migmatization and thermodynamic-chemical differentiation led toremobilization of gold and its initial local concentration: (Ⅲ) the stage of gold deposit formation, in which re-gional folding produced concordant and cross shear-slip fractures and under the dynamic action gold was sepa-rated and migrated in a certain direction and concentrated to form a gold deposit: (Ⅳ) the stage ofsuperpositon, reworking and exposure of orebodies, in which the block uplifted and the deposit againunderwent reworking through faulting and mechanical differentiation.Thermodynamic mineralization played adominant role in the formation of the deposit.  相似文献   

11.
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.  相似文献   

12.
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提  相似文献   

13.
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.  相似文献   

14.
15.
16.
This paper discusses the result of the detailed investigations carried out on the coal characteristics, including coal petrography and its geochemistry of the Pabedana region. A total of 16 samples were collected from four coal seams d2, d4, d5, and d6 of the Pabedana underground mine which is located in the central part of the Central-East Iranian Microcontinent. These samples were reduced to four samples through composite sampling of each seam and were analyzed for their petrographic, mineralogical, and geochemical compositions. Proximate analysis data of the Pabedana coals indicate no major variations in the moisture, ash, volatile matter, and fixed carbon contents in the coals of different seams. Based on sulfur content, the Pabedana coals may be classified as low-sulfur coals. The low-sulfur contents in the Pabedana coal and relatively low proportion of pyritic sulfur suggest a possible fresh water environment during the deposition of the peat of the Pabedana coal. X-ray diffraction and petrographic analyses indicate the presence of pyrite in coal samples. The Pabedana coals have been classified as a high volatile, bituminous coal in accordance with the vitrinite reflectance values (58.75–74.32 %) and other rank parameters (carbon, calorific value, and volatile matter content). The maceral analysis and reflectance study suggest that the coals in all the four seams are of good quality with low maceral matter association. Mineralogical investigations indicate that the inorganic fraction in the Pabedana coal samples is dominated by carbonates; thus, constituting the major inorganic fraction of the coal samples. Illite, kaolinite, muscovite, quartz, feldspar, apatite, and hematite occur as minor or trace phases. The variation in major elements content is relatively narrow between different coal seams. Elements Sc,, Zr, Ga, Ge, La, As, W, Ce, Sb, Nb, Th, Pb, Se, Tl, Bi, Hg, Re, Li, Zn, Mo, and Ba show varying negative correlation with ash yield. These elements possibly have an organic affinity and may be present as primary biological concentrations either with tissues in living condition and/or through sorption and formation of organometallic compounds.  相似文献   

17.
18.
《Chemical Geology》2007,236(1-2):13-26
We examined the coprecipitation behavior of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides under two different fluoride forming conditions: at < 70 °C in an ultrasonic bath (denoted as the ultrasonic method) and at 245 °C using a Teflon bomb (denoted as the bomb method). In the ultrasonic method, small amounts of Ti, Mo and Sn coprecipitation were observed with 100% Ca and 100% Mg fluorides. No coprecipitation of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides occurred when the sample was decomposed by the bomb method except for 100% Ca fluoride. Based on our coprecipitation observations, we have developed a simultaneous determination method for B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by Q-pole type ICP-MS (ICP-QMS) and sector field type ICP-MS (ICP-SFMS). 9–50 mg of samples with Zr–Mo–Sn–Sb–Hf spikes were decomposed by HF using the bomb method and the ultrasonic method with B spike. The sample was then evaporated and re-dissolved into 0.5 mol l 1 HF, followed by the removal of fluorides by centrifuging. B, Zr, Mo, Sn, Sb and Hf were measured by ID method. Nb and Ta were measured by the ID-internal standardization method, based on Nb/Mo and Ta/Mo ratios using ICP-QMS, for which pseudo-FI was developed and applied. When 100% recovery yields of Zr and Hf are expected, Nb/Zr and Ta/Hf ratios may also be used. Ti was determined by the ID-internal standardization method, based on the Ti/Nb ratio from ICP-SFMS. Only 0.053 ml sample solution was required for measurement of all 9 elements. Dilution factors of ≤ 340 were aspirated without matrix effects. To demonstrate the applicability of our method, 4 carbonaceous chondrites (Ivuna, Orgueil, Cold Bokkeveld and Allende) as well as GSJ and USGS silicate reference materials of basalts, andesites and peridotites were analyzed. Our analytical results are consistent with previous studies, and the mean reproducibility of each element is 1.0–4.6% for basalts and andesites, and 6.7–11% for peridotites except for TiO2.  相似文献   

19.
Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号