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Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Resources is the property of Geology & Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dinan Uplift in the Junggar Basin has good oil and gas display and exploration potential. Taking the Lower Carboniferous Songkalsu Formation intrusive rocks in the Dixi 185 Well Area as the research object, using core observation, microscopic identitication, and conventional physical property analysis, combining with drilling and seismic data, the lithology and distribution characteristics of intrusive rocks, and the main controlling factors for reservoir development are analyzed. The results indicate that the intrusive rocks of the Lower Carboniferous Songkalsu Formation in the study area are mainly granite porphyry and dorite porphyry. Dorite porphyry is distributed on the hanging wall of the Dixi 181 Well South Fault, and its thickness decreases with the increase of intrusion distance. The distribution of granite porphyry is not controlled by the Dixi 181 Well South Fault. The storage space of granite porphyry is mainly composed of secondary dissolution pores and microcracks, while the storage space of dorite porphyry is mainly composed of secondary dissolution micropores. The development of favorable reservoir diorite porphyry and granite porphyry intrusions is controlled by multiple factors such as intrusive facies zones, mineral components, dissolution, invasion time, and magmatic properties. Oil and gas often tend to accumulate and form reservoirs near the upper edge subfaces zone of the intrusion or the contact zone with the surrounding rock. Granite porphyry has a significantly lower content of dark minerals compared to dorite porphyry, and has a strong ability to form fractures. However, the content of feldspar porphyry crystals and matrix is significantly higher than diorite porphyry, and the proportion of secondary dissolution pore faces is large. Various secondary pore combinations and structural microfractures communicate to form favorable reservoir. The intrusion of magma in the later stage causes fluids such as gas-water solutions and hydrothermal fluids to penetrate along the early primary pores and secondary pores, resulting in dissolution and hydrothermal filling, dissolution, can increase the porosity and permeability of intrusive rock reservoir, and improve the quality of early intrusive rock reservoir. The hydrothermal filling effect, to some extent reduces the primary porosity and reduces the quality of early intrusive rock reservoir. The nature of magma directly affects the distance of magma intrusion into surrounding rocks along faults and secondary fault systems, thereby constraining the scale of reservoir development. The research results provide reference for the study of the genesis and exploration and development of oil and gas reservoirs in similar intrusive rock areas. [ABSTRACT FROM AUTHOR]

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Shibaogou deposit located in the Luanchuan ore concentration area, is a large scale porphyry skarn Mo(W) deposit discovered in recent years. However, the dating of ore forming pluton is still controversial. Meanwhile, the studying of magmatic oxygen fugacity, the important physical and chemical parameters of porphyry deposit, is also not very satisfactory. In order to constrain the age of the Shibaogou pluton and the metallogenic significance of the magmatic oxygen fugacity, the zircon U Pb dating and trace element composition were detected via LA ICP MS method, and the oxygen fugacity and temperature were also calculated. The results show that the ages of porphyritic biotite monzonitic granite, medium fine grained biotite monzonitic granite, and quartz porphyry in the mine were (147.4 + 0.8) Ma, (147.0 ± 1.0) Ma and (146.9 + 1.1) Ma, respectively. The temperatures were 692 °C, 718 °C and 737 °C. The oxygen fugacity(log (O2) wexe - 16.16, - 14.40, and - 12.77, with the relative oxygen fugacity (AFMQ) of 1.25, 3.35, and 3.56, respectively. These indicated that Shibaogou pluton had the characteristics of high temperature and oxygen fugacity, conducive to the formation of porphyry Mo deposits. With evolution of magma, the temperature and oxygen fugacity increased, thus quartz porphyry intruded in the late stage may be an important criteria in ore prospecting. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The impurity content in the molybdenum concentrate produced from the flotation process of a porphyry molybdenum ore is high. To solve the problem, experimental research on the flotation process is carried out and investigates the influencing factors such as reagent regime and grinding fineness. The results show that when the process of the bulk flotation of copper and molybdenum — flotation to separate copper and molybdenum is adopted, and the optimal reagent regime and regrinding fineness are applied, the molybdenum concentrate obtained has a grade of 57.13 %, the copper and lead indexes are greatly reduced, the copper content decreases from 0.2 % —0.5 % to 0.037 %, the lead content decreases from 0.2 % —0.83 % to 0.014 %, the molybdenum recovery rate increases from about 87 % to 91.02 %. The research provides a technical basis to optimize the ore-dressing process. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study uses the method of Audio-frequency magnetotelluric sounding (EH4) to detect and analyze the deep geological structure in the Donglifang mining area. The underground spatial electricity and structural characteristics were effectively determined. We built an EH4-based indicator system for localizing ore bodies and summarized the relationship between the apparent resistivity anomalies and the ore bodies in the EH4 profile. The shallow veined or columnar low-resistance bodies may correspond to the low-medium temperature hydrothermal gold, lead, and zinc polymetallic ore bodies; the columnar medium-resistance or medium -low resistance bodies correspond to the silica or porphyry copper-molybdenum polymetallic ore bodies; the medium-resistance bodies correspond to the medium acidic magmatic rocks (porphyrites and porphyries). We identified eleven concealed ore bodies in the deep of the mine area, five of which are consistent with the drill holes, and the remaining six have an excellent prospect of finding ore bodies. It is further inferred that larger-scale porphyry copper-molybdenum ore bodies are formed in the deep rock body. This study proves that the EH4 is an effective geophysical method for finding concealed rock (ore) bodies in the Dongxuofang copper-molybdenum polymetallic mine or this type of deposit. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Resources is the property of Geology & Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Resources is the property of Geology & Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Central Orogenic Belt of New Guinea is the youngest orogenic belt in the world and the most important porphyry-type copper-gold mineralization belt in the world. A set of high-magnesium diorite mass developments has been found in the Nabire region of Indonesia, located in the central-northwestern part of the Central Orogenic Belt of New Guinea, providing a good record for detailed study of magmatic processes and mineralization environments associated with ocean subduction. Through field observations and studies of petrology and geochemical characteristics, it was found that the high magnesium diorite was dominated by fine-grained hornblende and plagiobolite, and no olivine traps or trap crystals were found; Rocks have high MgO content (mass fraction, the same below) (4.51%~10.88%), Yb content ((1.16~2.69)×10) and Y content ((11.68~25.09)×10), high Mg value (50.07~72.50), enrichment of large ionite elements, loss of high field strength elements, relatively low Sr/Y and La/Yb values; Combined with the more consistent Nb/La, U/Nb, Th/La and U/Th values, it is suggested that it may have evolved from the interaction of subduction sediment melt with the overlying mantle peridotite and undergoing separation crystallization, which is accompanied by the release of a large number of HO and fluids, increasing oxygen escape; The formation environment of high magnesium andes/diorites is similar to that of porphyry copper-gold deposits, and has a close affinity with porphyry copper-gold deposits, which is a prospecting marker for large porphyry deposits, while the high-magnesium diorites in the Nabire area have been found to have the development of copper-gold mineralization, indicating that the area has the potential to find large copper-gold deposits [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Early Cretaceous dosemic rhyolite porphyry in Shuangsheng area of Chifeng, Inner Mongolia, is characterized by vesicular structure and multi-porphyritic texture, with 70% of phenocryst content, including sanidine (30%), quartz (35%) and plagioclase (5%). The sanidine phenocryst shows subhedral wide tabular structure with comb-like reaction rim, which is composed of Na-orthoclase and contains needle-columnar mineral crystallite. The edge or interior of the quartz phenocryst is strongly corroded, where porphyroclastic texture is developed, with the characteristics of cracked or dispersed but not separated. Matrix components are filled in between the quartz porphyroclasts. The rock contains vesicles, showing the dual structure of lava and porphyroclastic lava. The structure characteristics of the rock reflect a rapid uplift process with adiabatic-decompression of magma, probably indicating the beginning of regional extensional tectonic setting in diagenetic period. [ABSTRACT FROM AUTHOR]

Huangmeijian composite pluton is a uranium-bearing A-type granite in Middle-lower Yangtze River valley metallogenic belt. Huangmeijian composite pluton can be divided into four emplacement stages from earliest to latest, including stage Ⅰ biotite quartz syenite, stage Ⅱ syenite porphyry, stage Ⅲ quartz syenite and stage Ⅳ alkali feldspar granite. The vein-type uranium mineralization predominantly occurs along the contacts between the stage Ⅰ biotite quartz syenite and the clastic rocks. The study on the micro-textures, REE characteristics and U-Pb dating of zircons in Huangmeijian composite pluton was carried out. The results show that the zircons of biotite quartz syenite, syenite porphyry and quartz syenite are of magmatic genesis, and yield zircon U-Pb ages of(131.8±1.1),(129.7±1.6),(124.7±1.6)Ma, respectively. The cores of zircons in alkali feldspar granite are of magmatic genesis and undergo metamictization, while the rims of zircons in alkali feldspar granite are altered by hydrothermal fluid, and probably undergo recrystallization. The zircon U-Pb dating of alkali feldspar granite yields the crystallization age of(111.5±1.3)Ma and the hydrothermal activity age of(107.6±2.1)Ma. Based on the previous geochronological studies, the A-type granites in Middle-lower Yangtze River valley metallogenic belt can be divided into three periods. The early period is represented by biotite quartz syenite and syenite porphyry with crystallization age of 132-129 Ma; the main period is represented by quartz syenite and syenogranite with crystallization age of 128-124 Ma; the late period is represented by alkali feldspar granite with crystallization age of 115-110 Ma. The crystallization ages of alkali feldspar granite and hydrothermal activity time are close to the uranium mineralization ages; combining with the stable isotope studies, it probably indicates that stage Ⅳ alkali feldspar granite of Huangmeijian composite pluton has provided the ore-forming fluid and heat for the uranium mineralization. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mining Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the fluid inclusion study on the Jiangjiatun and Lanjiagou Mo deposits, two distinctive ore-forming fluids were identified. Fluid inclusions in the Jiangjiatun Mo deposit are characterized by type I two-phase aqueous inclusions, with homogenization temperatures from 163 to 234°C and salinity values from 3. 06% to 6. 01 % . It indicates that ore-forming fluids are moderate-low homogenization temperature and salinity. Fluid inclusions in the Lanjiagou Mo deposit are featured by type II CO2-bearing fluid inclusions, indicating a deep formation environment. Microthermometric data in the Lanjiagou Mo deposit show homogenization temperatures from 200 to 283°C for type I inclusions and from 281 to 346°C for type II inclusions, and salinities from 2. 74% to 7. 3 1 % for type I inclusions and from 3.52% to 4.80% for type II inclusions. In view of the above research results, it is believed that the discovered ore bodies in the Jiangjiatun deposit were formed in a much shallower environment with lower homogenization temperature and salinity than the Lanjiagou Mo deposit. It indicates that it is possible to find Mo orebodies at depth beneath the exposed ore bodies. [ABSTRACT FROM AUTHOR]

The Central Asian metallogenic domain (CAMD) is located between the Siberian craton to the north, the North China-Tarim craton to the south, and the East Europe craton to the west. It's considered as one of the three major metallogenic domains in the world along with the Circum-Pacific and the Tethyan metallogenic domains. There exists a series of porphyry Cu-Au, Cu(Au, Mo) and Cu-Mo deposits, and the two representative deposits from them, namely Erdenet porphyry Cu-Mo and Oyu Tolgoi porphyry Cu-Au deposit, were chosen to make comprehensive comparisons in terms of geological characteristics and ore-related rocks geochemical features. Mineralizing porphyrys of Erdenet porphyry Cu-Mo deposit are mainly granites and granodiorites, and the volcanic rocks developing in the same period are primarily andesite, daci te and r hyoli te, all of which show calc-alkaline to high-K calc-alkaline series rocks. Mineralizing porphyrys of Oyu Tolgoi porphyry Cu-Au deposit are mainly quartz monzodiorites, and the same period's volcanic rocks primarily consist of dacite-basaltic rocks, belonging to high K calc-alkaline series. The trace and rare earth elements of the ore-related rocks from the above two deposits show typical features of arc magmatic rocks. However, compared with Oyu Tolgoi porphyry Cu-Au deposit, Erdenet porphyry Cu-Mo deposit shows high Sr/ Y and La/Yb ratios, low contents of compatible elements (Cr, Ni) and relatively enriched Sr-Nd-Hf isotopic compositions. Combined with the regional geological background of the study area, it is believed that the mineralizing porphyrys of Erdenet porphyry Cu-Mo deposit originate from the partial melting of the thickened young lower crustal material, and are formed in a continental arc tectonic setting during the end of the Mongol-Okhotsk ocean evolution, while Oyu Tolgoi porphyry CuAu deposit' s mineralizing porphyrys generate from fractional crystallization of depleted mantle materials, and form in an island arc tectonic setting. Therefore, it can be concluded that Er den et porphyry Cu-Mo and Oyu Tolgoi porphyry Cu-Au deposits develop different mineral resources, matching themselves' tectonic setting where they formed. The above conclusions may help us better understand the relationship between the metallogenic tectonic environment and the types of porphyry deposits in the CAMD, and then have significant influence for the exploration of porphyry mineral resources under different tectonic environments. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is a certain deviation between the on-site analysis results of hand-held XRF and the laboratory analysis results due to the unique technical difficulties in field X-ray fluorescence measurement such as roughness effect, uneven effect and humidity effect of samples. OBJECTIVES: To seek economic, rapid and practical porphyry copper ore in practical work. test conditions of hand-held XRF for rapid exploration of METHODS: Influence of test conditions, such as analytical time, sample content, test distance, sample dry humidity and sample particle size on the analytical results of Niton XL31 GOLDD+ hand held XRF was quantitatively studied. RESULTS: The results showed that, under the best test time of 90s, the determination limits of Cu, Mo, Pb, and Zn were 57 μg/g. 14μg/g, 24ug/g, and 38μg/g, respectively, and the calculation formula for the determination limit was given. The field analysis test distance should be less than 5mm and the sample surface should be kept dry. The test method for bulk sample was the simplest but the test results varied the most. When sample was crushed to a particle size of 80 mesh or above, the stability and accuracy of the results were best. Considering that it took a long time to crush sample into 80 mesh, the mixed state of the sample after crushing was better strategy for field testing. CONCLUSIONS: The practical application of core scanning in Qulong porphyry copper deposit in Tibet shows that the handheld XRF analyzer is suitable for in-situ analysis and can meet the requirements of rapid exploration and evaluation such as delineation of copper ore bodies in field, which can greatly improve work efficiency and reduce exploration cost. [ABSTRACT FROM AUTHOR]

The metallogenic belt is a geological unit for possessing potential of ore resources. The metallogenic system mainly focuses on the overall characteristics of mineralization from the aspects of metallogenic elements and processes, including deposit assembly, metallogenic series and their original link. The metallogenic system is an important evidence for dividing metallogenic belt and summarizing metallogenic regularity. East Tianshan orogenic belt, which is sandwiched between Tuha Basin and Tarim block, may be divided into four metallogenic belts in terms of spatial distribution, including Dananhu-Tousuquan Cu-Au-polymetallic metallogenic belt, Kanggurtag-Huangshan Au-Cu-Ni metallogenic belt, Aqishan-Yamansu Fe-Cu-polymetallic metallogenic belt and Caixiashan-Jiyuan Pb-Zn-Ag-polymetallic metallogenic belt. The temporal evolution of East Tianshan orogenic belt is distinctly characterized by multi-stage and multiple metallogenic system, including ① Middle-Late Proterozoic extension continental margin, where there occurs a metallogenic system of sedimentation Pb-Zn-Ag deposits; ② Ordovician-Carboniferous active continental margin, where there occurs a metallogenic system of VMS Cu-Zn deposits and porphyry Cu deposits; ③ Carboniferous island arc, where there occurs a metallogenic system of volcanic Fe-Cu deposits; ④ Late Carboniferous-Early Permian post-collision orogeny and superimposition of mantle plume, where there occurs a metallogenic system of magmatic Cu-Ni deposits and a metallogenic system of Au deposits related to ductile shear processes. [ABSTRACT FROM AUTHOR]

Boguorize area is located in the central part of Bangonghu-Nujiang suture zone, the northern margin of Gangdese belt, Tibet. At present, the closure time of Bangonghu-Nujiang ocean basin is controversial. The A-type granite outcropped in Boguorize area intrudes into the first member of Woronggou Formation in the form of rock stocks, and its lithology is mid-fine-grained biotite granite porphyry. The rock is characterized by high SiO2(the contents are 70. 61 %-74.94%), K2 (4. 96%-7. 48%), lean Al2O3 ( 11. 90%13. 79%), high ratio of FeOT/MgO (7. 47-25. 88), and low TiO2(0. 16%-0. 25%), which belongs to weak aluminum-quasi-aluminum alkaline series (A/CNK is 0. 90-1. 12, A/NK is 1. 10-1. 34). The total contents of REE are (179. 80-370. 29) X 10 h, (La/Yb)N is 5. 36-8. 70, and Eu anomaly is 0. 28-0. 61. The chondrite-normalized REE pattern is right-leaning seagull type, which belongs to typical aluminous A-type granite. On the primitive mantle-normalized trace element spider diagram, the large ion lithophile elements and high field strength elements (Rb, Th, U, K, Zr and Hf) are obviously enriched.while Ba, Sr, Nb, Ta and Ti are obviously depleted. The higher contents of Zr, Nb, Ce and Y, and the higher ratios of Y/Nb, Yb/Ta and Ce/Nb indicate that the A-type granite is A2type. The combination research of petrography, geochemistry and regional geological data shows that the A-type granite in Boguorize area forms in the extension of the lithosphere after the collision. It is the product of the lower crust displacing, which causes the asthenosphere material upwelling and heats the metamorphic mudstone in the upper crust, and make the metamorphic mudstone occur partially melt and undergo a certain degree of separation crystallization. The LA-ICP-MS zircon U-Pb age of A-type granite is (110. 8 + 1. 3)Ma, indicating that it is formed in late Early Cretaceous. It is estimated that Bangonghu-Nujiang ocean basin is closed at least in late Early Cretaceous. [ABSTRACT FROM AUTHOR]

Xuemisitan metallogenic belt in West Junggar is an important Chinese uranium polymet metallogenic belt with the massively distributed Paleozoic intermediate-acid intrusive plutons. These plutons provide an important basis for the exploration of Paleozoic magmatism and tectonic evolution of Xuemisitan metallogenic belt. The petrography, zircon U-Pb geochronology, petrogeochemistry and Sr-Nd-Hf isotopes of Bayinbulake granite porphyry in the southeastern margin of Xuemisitan metallogenic belt were studied systematically. The results show that the granite porphyry is formed in (393. 7+ 1. 7)Ma (MSWD is 1. 3), belonging to Early Devonian, and invades into Silurian Xuemisitan Formation; the granite porphyry is characterized by high Si, poor EDO, high Al, rich alkali (especially K), low Mg and Fe, belonging to metaluminous-peraluminous series A2 sub-type granite; the granite porphyry is enriched in Rb, Th, U, etc. , and depleted in Sr, P, Ti, etc. , chondrite-normalized REE pattern is a right-leaning type with relative rich FREE, and the granite porphyry has the characteristics of obvious FREE and FIREE fractionation, higher contents of total REE, and apparent Eu negative anomaly; the variation range of Nd isotopic composition is small, εNd is 4. 3-6. 7 with the two-stage Nd model age of 591-788 Ma, indicating that the magma is relatively homogeneous, and εHf is 3. 98-9. 35 with the two-stage Hf model age of 794-1 130 Ma, indicating that the diagenetic material maybe come from Neoproterozoic depleted mantle. In general, Bayinbulake pluton is formed in subduction setting, which causes partial melting of the mantle, and is mixed with a small amount of ancient crustal material during the rising along the subduction zone. Compared with Yangzhuang pluton, Bayinbulake pluton has the prospect of forming industrial uranium deposits. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Tengchong block in western Yunnan is an important component of East Tethys tectonic belt, and the Mesozoic and Cenozoic magmatism is widely distributed. The zircon U-Pb ages of Menglian granites and their dark enclaves in the southeastern Tengchong block indicate that they are formed in (127±2)Ma and (125±2)Ma, respectively. The main rock types of Menglian granites are quartz monzonite, granodiorite and biotite monzogranite, and the geochemical characteristics show that they are high K calc-alkalinity I-type granites with the aluminum saturation index point to S-type granites. Although the dark enclaves and granites show similar zircon U-Pb ages, the dark enclaves display smaller grain size, higher REE contents ((305.2-322.8)×10-6), higher w(Nb)/w(Ta) (18.2-19.5), lower Pb isotope compositions and depleted εNd(t), indicating that the dark enclaves should be heterogenous, and may be quenched by the mafic and felsic magma mingling or mixing process. The constant Sr-Nd isotope compositions with varying SiO2 contents suggest the crustal contamination is negligible. The Ba-Sr diagram implies the crystallization of plagioclase and K-feldspar for Menglian granites. The two-stage Nd model ages (1.37-1.58 Ga) and similar upper crust Pb isotope compositions indicate that the main material source of Menglian granites should be Mesoproterozoic Gaoligongshan Group. But in contrast to Gaoligongshan granites, the more depleted εNd(t) indicates that some mantle-derived materials should be involved. As a whole, the initial N(87Sr)/N(86Sr) (0.710 020-0.712 001) and εNd(t) (-4.6-2.1) of Menglian granites are similar to the granites in the northern magmatic belt of Lhasa block, suggesting the same formation environment. Combining with the island arc tectonic environment and the heterogenous dark enclaves with high w(Nb)/w(Ta), the Menglian granites and their dark enclaves may be formed by the subduction-collision-closure processes of the middle Tethys ocean. [ABSTRACT FROM AUTHOR]