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Naturally occurring granular uranium particles are typically fine and are often found as accessory minerals. However, reports of megacrystalline uraninite are rare. The discovery of megacrystalline uraninite is a significant achievement in uranium prospecting and mineralogy in the Kangdian region and China. Our team's research and review of previous studies have led to a systematic summary of the formation age, genetic types, relationship with migmatization, and metallogenic dynamic background of megacrystalline uraninite in the Kangdian region. The key findings are as follows: (1) the formation age of megacrystalline uraninite is Neoproterozoic (790–770 Ma); (2) migmatization preceded uranium mineralization; (3) the formation of megacrystalline uraninite is linked to high-temperature, low-pressure metamorphism caused by partial melting; (4) and the formation of megacrystalline uraninite may be associated with the Rodinia rifting event. This review aims to enhance our understanding of uranium mineralization during the Neoproterozoic in China and worldwide. [ABSTRACT FROM AUTHOR]

To promote the widespread use of mobile robots in diverse fields, the performance of trajectory tracking must be ensured. To address the constraints and nonlinear features associated with mobile robot systems, nonlinear model predictive control (MPC) is applied to realize trajectory tracking of mobile robots. Specifically, to alleviate the online computational complexity of nonlinear MPC, this paper devises a lattice piecewise affine (PWA) approximation method that can approximate both the nonlinear system and control law of explicit nonlinear MPC. The kinematic model of the mobile robot is successively linearized along the trajectory to obtain a linear time‐varying description of the system, which is then expressed using a lattice PWA model. Subsequently, the nonlinear MPC problem can be transformed into a series of linear MPC problems. Furthermore, to reduce the complexity of online calculation of multiple linear MPC problems, the optimal solution of the linear MPCs is approximated by using the lattice PWA models. That is, for different sampling states, the optimal control inputs are obtained offline, and lattice PWA approximations are constructed for the state control pairs. Simulations are performed to evaluate the performance of the method in comparison with the state‐of‐the‐art methods, and the results show that the method has a higher online computing speed and can decrease the offline computing time without significantly increasing the tracking error. [ABSTRACT FROM AUTHOR]

Dajing area is one of the key exploration areas in Junggar basin. In this paper, based on scientific exploration and exploitation, the geochemical characteristics of the carboniferous crude oil and potential source rocks were analyzed using gas chromatograph-mass method. The correlation of biomarkers showed that the parent materials of the carboniferous crude oil formed in freshwater-mildly brackish water environment and were sourced from low grade aquatic organisms and terrigenous higher plants. Oil-source correlation results showed that the carboniferous crude oil in Dajing area was derived from the source rocks of Songkaersu. [ABSTRACT FROM AUTHOR]

Megacrystalline uraninite (up to one centimeter in size) represents one of the most important discoveries in uranium mineralogy in the western margin of the Yangtze Block and even in China in recent years. However, the genesis of megacrystalline uraninite remains controversial. In this study, the megacrystalline uraninite found in the felsic and quartz veins in the Haita area is examined for the first time. The study examined the geochemical characteristics of uraninite in the two veins and resulted in two primary findings. (1) The genesis of the uraninite was likely intrusive and was closely related to partial melting. (2) The quartz vein and feldspar vein are cogenetic and have a simple differentiation evolution relationship. Therefore, the partial melting of felsic materials during migmatization may be the most important mechanism of uranium mineralization in the study area. Furthermore, further simple fractional crystallization may be another important mechanism for the formation of megacrystalline uraninite. This study enriches the REE database of uraninite in uranium deposits worldwide, which is meaningful for studying the genesis of megacrystalline uraninite. [ABSTRACT FROM AUTHOR]

The Xifanping deposit is a distinct Cenozoic porphyry Cu (Au) deposit located in the Sanjing porphyry metallogenic belt 100–150 km east of the JinshajFiang fault in the western Yangtze craton. We present new zircon U–Pb–Lu–Hf isotopic studies and geochemical data of the ore-bearing quartz monzonite porphyry from the Xifanping deposit to determine their petrogenesis and geodynamic mechanisms. LA–ICP–MS zircon U–Pb dating yielded precise emplacement ages of 31.87 ± 0.41 Ma (MSWD = 0.86) and 32.24 ± 0.61 Ma (MSWD = 1.8) for quartz monzonite porphyry intrusions, and 254.9 ± 5.1 Ma (MSWD = 1.7) for inherited zircons of the monzonite porphyry. The ore-bearing monzonite porphyry is characterized by high-K calc–alkaline to shoshonite and peraluminous series, relatively enriched in light over heavy REEs, with no distinct Eu anomalies, as well as enrichment in LILEs and depletion of HFSEs, with adakitic affinities. The zircon Lu–Hf isotope data ranged from εHf(t) values of −2.94 to +3.68 (average −0.47) with crustal model (TDM2) ages ranging from 0.88 to 1.30 Ga, whereas the inherited zircons displayed positive εHf(t) values ranging from +1.83 to +7.98 (average +5.82), with crustal model (TDM2) ages ranging from 0.77 to 1.17 Ga. Results suggest that the Xifanping porphyry Cu (Au) deposit is related to two periods of magmatic activities. Early magmas were generated from the Paleo-Tethys oceanic subduction during the Late Permian. The subsequent porphyry magma was likely formed by the remelting of previously subduction-modified arc lithosphere, triggered by the continental collision between the Indian and Asian plates in the Cenozoic. The deep magmas and late hydrothermal fluids took advantage of the early magma transport channels along tectonically weak zones during the transition from an extrusive to an extensional–tensional tectonic environment. Early dikes from remelted and assimilated crust contributed to the two age ranges observed in the porphyry intrusions from the Xifanping deposit. The juvenile lower crust materials of the early magmatic arc were potential sources of the Cenozoic porphyry magmas, which has significant implications for mineral exploration and the geological understanding of porphyry Cu deposits in this region. [ABSTRACT FROM AUTHOR]

The article presents a study which provides analysis on uranium mineralization potential of Late Yanshanian granites in Sichuan of Sanjiang Area, China. Topics discussed include uranium geochemical anomalies and granite distribution, comparison of geochemical characteristics, granite intrusion activities, and distribution of uranium anomalies.

The article presents a study which discusses metallogenic regularity of hydrothermal uranium deposits in the migmatite of the Kangdian Axis. It mentions that the uranium mineralization is found in the iron oxide copper gold deposit. It also reveals that spatial distribution of uranium mineralization is controlled by migmatite that related to ductile shear zones.

The article presents a study which discusses geochemical characteristics and uranium mineralization potential of Yanshanian Granite in West of Yunnan Province in China. It mentions that Sanjiang metallogenic belt is an important nonferrous metal metallogenic belt in China. It also reveals comparison of rock mass geology and geochemical characteristics of the related rock mass with characteristics of uranium granite.

The article presents a study which discusses geological and geochemical evolution of forming of kalium-rich brine in Sichuan Basin in China. Topics discussed include effects of numerous distinct tectonic events on salt brine reservoir in Sichuan Basin, varied ion concentration of sea water due to sea water evaporation, occurrence of small amount of evaporites, and occurrence of celestite precipitate.

The article presents a study which examines the characteristics of rare earth elements (REE) in Chahe copper (Cu) deposit in Yunnan Sheng, China. Topics geological survey of the deposit which reveals morphology of ore bodies, ore minerals and gangue minerals found in the deposit, activation of REE in hydrothermal alteration at high water to rock ratios and analysis of the REE samples which shows negative anomaly of Europium, right sloping and belonging to the Light REE (LREE)-rich type.

The article focuses on a research paper discussing the geochemical characteristics of major elements in rocks surrounding the Yi Nachang iron-copper-rare earth element (Fe-Cu-REE) deposit in Wuding in Yunnan, China. It mentions that the surrounding rocks of the upper and lower plate of ore are garnet biotite schist and quartz cloud schist. The methods to recover the protolith of Yi Nachang suggests that the protoliths are volcanic and sedimentary rocks.

The article focuses on a research paper discussing the geochemical characteristics of rare earth elements (REE) in quartz of Chahe copper deposit in Yuanjiang in Yunnan, China. It mentions that REE patterns of quartz in the deposit is characterized by enrichment in light REE. It also suggests that mineralization occurs in an oxidized environment and ore-forming fluids are from mixed sources.

The article focuses on research related to formation of diabase dykes and its relation with Sanqisan uranium deposits in South China. Topics discussed include relation of diabase dykes with metallogeny of uranium depots, formation of dolerite from altered minerals including kaolinite, serpentine and chlorite, conduction of uranium lead dating analysis by multiple collector - inductively coupled plasma - mass spectrometer and diabase dykes as the ore forming material source.

The article focuses on a geochemical study related to characteristics of calcite and its significance in formation of Sanqisan uranium deposits in South China. Topics discussed include Sanqisan deposits are carbonate siliceous- pelitic rock type uranium deposit, association of uranium with chromium and zirconium which is a high field strength elements reflects as ore forming fluids of calcite, and water rock reaction of fluid and wall rock as the main mechanism of calcite precipitation.

The article presents a study focusing on the composition of Carbon and Oxygen Isotope of the Calcites and source of mineralization fluid in Chahe Copper Deposit in Yuanjiang, Yunnan, China. It discusses the Silicification process to be the main part of the hydrothermal mineralization and states several other processes through which the country rocks undergo including chloritization, carbonatation and micacization. It highlights the impact of contamination of sedimentary rock on mineralization.

The article offers information on the research "The Relationship between Basic Intrusive Dykes and Uranium Mineralization and Deposit Examples" by Zhao Jing and colleagues. Topics discussed include the intrusion of magma from the mantle lithosphere in ore genesis, the relationship between basic rock and uranium mineralization, and improving the solubility of uranium in the granite.

[Display omitted] • Au and As in pyrite are positively correlated, with higher Au content in pyrite from granite dykes. • Co/Ni ratios in pyrite indicate the dominance of magmatic hydrothermal action in the early stage and metamorphic fluid action in the main stage of ore formation. • The mixing of ore-forming fluids may be the key factor controlling gold mineralization. The Devonian Sanhekou Group phyllite in the Yangshan gold belt includes multiple stages of pyrite development, and Au is mainly distributed within the pyrite. Bodies within the Gaoloushan ore section of the gold belt are located in the broken and altered carbonaceous phyllite and granitic rock dykes, where quartz vein-type gold ores are more common as compared to other ore sections (Anba, Getiaowan). Studying the trace element distribution characteristics of gold-bearing and non-gold-bearing pyrite can constrain the evolution of ore-forming fluids and the types of ore deposit genesis. Based on detailed fieldwork and microscopic identification, 48 pyrite samples from the 69th exploration line of the Gaoloushan ore section were analyzed in situ by LA-ICP-MS. The following conclusions were drawn: (1) The gold-bearing pyrite formed during the ore-forming stage while the non-gold-bearing pyrite formed during the sedimentary and metamorphic period. The morphology of the pyrites differs, with gold-bearing pyrite mainly characterized by medium-fine grains, impregnation, fine veins, and reticulate structure, with crystal morphology mainly pentagonal dodecahedra or pentagonal octahedra, whereas non-gold-bearing pyrite is mainly characterized by a medium or medium-coarse grains, with stellate, strawberry, or cluster structures, and crystal morphology mainly in the form of cubes or pentagonal octahedra; (2) The As and Te content of the sedimentary pyrite is low, locally below the detection limit, and the Co and Ni contents and ratios vary greatly, with a distribution of 117–945 ppm and ratio distribution of 0.11–1.92. Pyrite from the ore-forming stage is primarily characterized by high As, Pb, Co, Ni, Cu, Sb, Zn, and Se concentrations, with Bi, Au, and trace amounts of Tl, Te, and Sn observed in later formations; (3) Au and As are positively correlated. The average Au content of 60.53 ppm in pyrite from granite dykes is higher than the average Au 15.97 ppm in carbonaceous phyllite. Pyrite particles with Au contents below the detection limit are sourced in carbonaceous phyllite. In addition, the higher As enrichment is observed in pyrite from granite dykes, averaging 35 770.60 ppm with a maximum value of 72 930.19 ppm. In comparison, the average As content in carbonaceous phyllite is 8974.66 ppm, with a maximum of 69 800.50 ppm, and the Au-As diagram indicates that gold in the Gaoloushan ore section is mainly in the form of solid solution gold within the pyrite lattice; (4) Statistical analysis of the Co/Ni ratio variation in the different lithologies and pyrite stages reveals an initial increase followed by a decrease. The median Co/Ni ratio variations during the mineralization stages of Py1s (0.51–0.7), Py1m (1.35–2.25), Py2 (1.43–1.87), Py1-2 m (1.53), Py2a (1.59), Py2b (1.4), Py2s (1.2), Py2m (1.63), and Py3 (0.19–1.40) suggest that magmatic-hydrothermal fluids dominated during the early stage of mineralization in the gold belt and metamorphic fluids during the main mineralization stage, with deep-seated metamorphic fluids playing a significant role in the late mineralization stage. The varying proportions of ore-forming fluids are likely to have been crucial in controlling gold mineralization in the Yangshan gold belt. [ABSTRACT FROM AUTHOR]

The Neoproterozoic tectonics of the Yangtze Block is crucial for understanding its evolution history over the assembly and disintegration of the supercontinent Rodinia. Herein, we integrate all the published geochemical and geological data for igneous rocks of 1.0–0.6 Ga from the northern margin of the Yangtze Block to investigate the secular tectonic evolution of the Yangtze Block. The results show that the early Neoproterozoic intra-oceanic subduction could have initiated at ca. 1.0 Ga, which was followed by the flare-up of continental arc magmatism since ∼0.9 Ga along the northern margin of the Yangtze Block. Crustal reworking was enhanced during episodes of subduction compression at ca. 0.86 Ga and 0.83 Ga, respectively, revealed by the striking decrease in zircon ε Hf (t) and whole-rock ε Nd (t) values. The gradual progression to depleted mantle-like isotopic signatures during 850–840 Ma and 820–810 Ma reflects the diminishing subduction-induced enrichment in the mantle source as the tectonic setting altered to the extensional back-arc modes shortly after the compressional phases. The secular isotope pattern during the continental arc stage (0.9-0.8 Ga) implies alternative regimes of compressive and extensional tectonics, which were accompanied with synchronous changes in crust thickness. After ∼0.8 Ga, the northern margin of the Yangtze Block evolved into distinct tectonics in different regions. The 0.8–0.73 Ga magmatism in the northeastern domains displays both within-plate and arc-like geochemical affinities, as well as exclusively low δ18O signatures, suggesting a predominantly continental rift setting. However, the widespread calc-alkaline I-type granitoids and contemporaneous arc-like mafic rocks in the northwestern domains demonstrate that the tectonic regime were still controlled by a continuous subduction process until the end of arc magmatism at ca. 0.73 Ga. Subsequently, the entire northern margin of the Yangtze Block gradually evolved into a volcanic rifted margin during 0.72-0.62 Ga as revealed by the deposition of massive syn-rift volcanic-sedimentary sequences and the emplacement of the contemporaneous mafic-ultramafic equivalents, probably as a response to the far-field effect of supercontinent breakup. Collectively, the prolonged (∼1.0–0.73 Ga) supra-subduction magmatism along the northwestern of the Yangtze Block, together with the 0.97–0.82 Ga accretionary belt along the southeastern margin, likely indicates an external position of the South China Block in Rodinia. • Amalgamation of South China into Rodinia through subduction accretionary orogeny. • Advancing-retreating subduction dynamics control the crustal thickness. • Rifts accompanied with Rodinia breakup superimposed on juvenile continental crust. • The South Qinling was a part of the northern Yangtze Block during Neoproterozoic. • The South China Block was peripheral in Rodinia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-existing pyrite and calcite with uranium minerals play a significant role in ISL of uranium. • Gypsum produced by pyrite and calcite in CO 2 + O 2 environment disadvantages the leaching of uranium. • Secondary hexavalent uranium minerals will be produced in the ore layer of a neutral environment. Oxidative weathering of pyrite, a widespread iron sulfide mineral, is crucial for the uranium mineralization in sandstone-hosted uranium deposits and the ore utilization leaching under manual intervention. To understand the behavior of pyrite under CO 2 + O 2 leaching conditions in sandstone-hosted uranium deposits, samples of uranium ore from the mineralized zone of the Qianjiadian IV uranium deposit located in the lower section of the Yaojia Formation were collected for this study. The stirring leaching experiment was carried out through the processes of the pyrite-bearing uranium ore samples thinned before and after the reaction, followed by an optical microscopic study and the TESCAN Integrated Mineral Analyzer analysis, and finally, the thermodynamic simulation by making use of PHREEQC3.0. The results revealed the following: (1) The dissolution particles of pyrite become smaller, which may increase the porosity of the ore layer and the exposure ratio of uranium minerals. And more soluble pyrite with a high free surface will be more competitive with uranium minerals for the consumption of O 2. (2) The ion (Fe2+) produced by the dissolution of pyrite will be oxidized to Fe3+ by excess O 2 (4 mol), which provides an oxidant for the oxidation of uranium minerals, and the generated SO 4 2- will combine with the Ca2+ released from calcite to form a permanent precipitate of gypsum, which may block pores and cover the uranium ore. (3) Pyrite and calcite will consume O 2 and CO 2 in the injection system, thus jointly inhibiting the leaching of uranium minerals. After the injection of excessive CO 2 and O 2 , the concentration of Ca2+, SO 4 2-, Fe3+, UO 2 2+, and HCO 3 – in the system will continue to accumulate, resulting in the secondary precipitation of calcite, co-precipitation of gypsum, iron minerals, colloids, and hexavalent uranium minerals, resulting in plugging pores and seriously affecting the effective leaching of uranium. This study contributes to the understanding of the behavior of pyrite during uranium recovery through CO 2 + O 2 leaching. It also contributes to the understanding of quantitative uranium mineralization in sandstone-hosted uranium deposits and process parameters in in-situ leaching (ISL) of uranium. [ABSTRACT FROM AUTHOR]

In this work, we demonstrated a facile strategy to fabricate paintbrush-like Co Doped Cu 3 P architecture grown on porous copper foam (Co-Cu 3 P/CF), which was obtained from cation exchange reaction followed by a pyrolysis assisted phosphorization step. Co-Cu 3 P/CF showed outstanding electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 1 M NaOH solution, affording low overpotential of 270 mV to reach the current density of 50 mA cm−2 for OER. As for HER, a low overpotential of 200 mV is required to obtain the same catalytic current density. The overall water electrolyzer by using Co-Cu 3 P/CF as both anode and cathode showed a low cell voltage of 1.55 V to deliver 10 mA cm−2. The excellent electrocatalytic performance of Co-Cu 3 P/CF could be ascribed to its paintbrush-like hierarchical architecture, offering plentiful of active sites and accelerating electrolyte penetration, the presence of Co dopant also could rationally modify its electronic properties, and thus lead to the synergetic effects. • Co-Cu 3 P architectures in-situ grown on copper foam was prepared via a facile method. • The paintbrush-like morphology of Co-Cu 3 P is beneficial for exposing plentiful of catalytic active sites. • The overall water splitting cell showed a low cell voltage of 1.55 V to deliver 10 mA cm−2. • Co dopants play a vital role in enhancing the catalytic performance of Co-Cu 3 P. [ABSTRACT FROM AUTHOR]

Abstract Greed is ubiquitous in human existence. However, empirical research on greed is surprisingly rare, in part due to a lack of sound scales to measure it. This article reports on 3 studies that test the Chinese version of the Dispositional Greed Scale (DGSC) using 4 samples with a total of 1048 participants. Study 1 and study 2 provide evidence for the factorial validity, internal consistency, convergent validity and criterion-related validity of the DGSC. Study 2 and study 3 present evidence for the concurrent validity of the DGSC from three aspects: a) the DGSC was positively correlated with Belief in a Zero-Sum Game and subjective socio-economic insecurity; b) the DGSC was negatively correlated with all facets of core self-evaluations (i.e., self-esteem, generalized self-efficacy, locus of control, neuroticism) except neuroticism, with which the DGSC was positively correlated; and c) the DGSC was negatively correlated with all facets of external core evaluations (i.e., trust in people, belief in a just world, belief in a benevolent world). These findings provide new insight into the nomological net of greed and shed light on the beliefs and behaviors of greedy people in economic transactions and their fundamental attitudes toward the self, others and the external environment. [ABSTRACT FROM AUTHOR]

Potassium‐rich brine in the Sichuan Basin has been much studied in recent years, but few studies have focused on the distribution and migration of salt basin and the differences of potassium formation mechanisms. This work examined the salt‐gathering and potassium formation of potassium‐rich brine during the Triassic in the Sichuan Basin using lithofacies palaeogeographic depiction and geochemical analyses. (1) The favorable sedimentary facies controlling the formation of potassium‐rich brine during the Triassic in the Sichuan Basin are evaporation platform and restricted platform, whereas the salt basin is one of the main factors controlling the poly‐salt center. (2) The distribution and migration of this salt basin were affected by certain factors. The salt basin of the Jialingjiang Formation was mainly distributed in the east and central Sichuan Basin, whereas that of the Leikoupo Formation was mainly distributed in the central and west Sichuan Basin. The sedimentary centers have gradually moved westward and become smaller. (3) Three main formation mechanisms were identified for the potassium‐rich brine during the Triassic in the Sichuan Basin, i.e., evaporation and concentration of seawater, surface fresh water leaching, and deep water‐rock reaction. Fresh water leaching was characterized by low anomaly δ18O and δ13C values. Water‐rock reaction was mainly related to temperature, and high temperature environment (caused by burial depth, overthrust and deep hydrothermal fluids) was beneficial to water‐rock reaction. The characteristics of water‐rock reaction do not correspond to the increase ratio of K•103/Cl and Br•103/Cl in brine, and the Rb+ content of the brine was high. (4) The formation mechanisms of potassium‐rich brine differed between different areas of the Sichuan Basin. In east Sichuan, the evaporation and concentration of seawater, together with meteoric fresh water leaching, was the main formation factor, whereas the evaporation and concentration of seawater and water–rock reaction predominated in west Sichuan. This study of the sedimentary environment and formation mechanisms is of significance to the exploration and exploitation of potassium‐rich brine in the Sichuan Basin. [ABSTRACT FROM AUTHOR]

The article discusses a study that focuses on the results of Tibetan Mineral Resources Potential Assessment Project based on the analysis and research of multi-source information data of Nixiong and Jiangla skarn iron ore forecast in Gangdese magmatic arc in Tibet, China. Topics discussed include analysis of iron mineralization law; processing of geological, geophysicalCgeochemical data; and application of Prediction Auxiliary System of Geologic Volume Method in resource reserve estimation.

Accurately constraining the age and source of primary U mineralization is commonly difficult as diverse U minerals are affected by α-recoils and subjected to overprints of multi-stage fluids. Titanite has a good potential in revealing rock-forming and metallogenic information, and widely occurs in magmatic, metamorphic, and hydrothermal U deposits. However, the textural and chemical characteristics of titanite from these U deposits are poorly documented and little is known about the relationship between titanite and U mineralization. At the western margin of the Yangtze Block, a series of U occurrences and uraninite-predominant ores are hosted in the leucocratic dykes, ranging from fine-grained (albitised) monzogranite to pegmatitic quartz vein. The genesis of U mineralization remains unclear largely because of the uncertainties as to the timing of mineralization and the origin of metals. Here, we present comprehensive U Pb and Sm Nd isotopic data, and major and trace element compositions for metamorphic (Ttn-I) and magmatic/hydrothermal (Ttn-II) titanites from the leucocratic dykes and/or amphibolitic wall rocks. Ttn-I is in direct contact with metamorphic hornblende and plagioclase or occurs as xenoliths hosted in the leucocratic dykes, and is thus inferred to result from amphibolite facies metamorphism. Chemically, Ttn-I is characterized by low Fe/Al ratios, LREE-depleted patterns and weakly negative to positive Eu anomalies. By contrast, magmatic/hydrothermal Ttn-II crystals intergrown with uraninite in the leucocratic dykes generally display flatter REE patterns, more negative Eu anomalies, higher Fe/Al ratios, and U, Nb, REE and Y contents, which could be applied as an indicator for U exploration. LA-ICP-MS U Pb dating on Ttn-I yielded ages of ∼860 Ma for amphibolite facies metamorphism. Instead, U Pb dating on syn -ore Ttn-II yielded ages of ∼786–779 Ma for U mineralization, which is coeval with the emplacement of leucocratic dykes. Uraninite and intergrown Ttn-II have uniform, negative εNd(t) values (−5.7 to −15.5), indicating the initial melts were predominantly sourced from the old crustal materials (T DM2 = ∼1.9–2.7 Ga). Considering the occurrences as dykes, feldspar-quartz-dominant lithologies, and wide textural and compositional variations of leucocratic dykes, we infer that low-degree partial melting of U-rich protolith is the main factor controlling U concentration in the melt. Variable REE patterns and ThO 2 contents in different uraninite types seem to imply there have been multi-stage U mineralization. • Dyke-hosted U mineralization at the western margin of the Yangtze Block formed at ∼786–779 Ma. • The uraniferous leucogranitic magma was derived from old crust with a T DM2 of ∼1.9–2.7 Ga. • Low-degree partial melting process may be the main factor controlling U concentration. • Titanite with high REE, Y, Nb, and U contents could be applied as an indicator for U exploration. [ABSTRACT FROM AUTHOR]

The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained: 64.08±0.59 Ma for the granite-prophyry and ∼200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ∼90 Ma and ∼60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5-200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories: the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous (about 90 Ma), while the latter, closely related to the granite porphyry, formed at early Paleogene (about 60 Ma). And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc. [ABSTRACT FROM AUTHOR]

Abstract: The effect of cooling rate on hot-crack behavior of duplex stainless steel (DSS) is investigated using a type ZQS-2000 hot cracking and linear contraction apparatus, in which the hot-crack susceptibility is also evaluated. With the cooling rate decreasing from 6 to 1°C/s, the ferrite/austenite ratio in DSS decreases from 2.3 to 1.25, while its linear contraction rate increases from 1.59% to 1.9%. The results demonstrate that the cooling rate influences both the ferrite/austenite ratio of DSS and its hot-crack susceptibility. When the cooling rate decreases to 1°C/s, the hot crack appears firstly on the pitch circle of hot-crack samples. The decreasing cooling rate encourages the hot-crack susceptibility of DSS. [Copyright &y& Elsevier]

• Pyrite hosting visible gold is low in Au and As. • Gold-bearing pyrite was subject to brittle rather than ductile deformation. • Visible gold in pyrite did not result from remobilization of lattice gold. • Visible gold in pyrite was introduced by evolved ore fluids after host pyrite. Pyrite (FeS 2) is one of the most common hosts for gold (Au) in different types of gold deposits, including visible and invisible gold. For visible gold in pyrite, it remains unclear whether it resulted from remobilization of invisible gold in the gold-hosting pyrite or from external input. This paper reports a case study from the Zhaoxian gold deposit, which is the deep extension of the well-known Jiaojia gold deposit, in the Jiaodong gold province. The texture and composition of Au-bearing pyrite from the Zhaoxian deposit were studied with petrographic, Electron Back-Scattered Diffraction (EBSD) mapping, and Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA-ICP-MS) methods. Four types of pyrite (Py-1 to Py-4), corresponding to four generations of veins, i.e., the pre-ore V1, syn -ore V2 and V3, and post-ore V4, were distinguished. Py-2 is volumetrically the most abundant among the four, and is the main host of visible gold. LA-ICP-MS analyses of pyrite indicate that gold contents in most analysis points are below the detection limit, with measured Au contents ranging from 0.02 to 0.17 ppm (median 0.09 ppm) in Py-1, and 0.03 to 2.45 ppm (median 0.07 ppm) in Py-2. EBSD analyses indicate that pyrite (Py-2) display brittle deformation features including microstructures, lattice dislocation, and grain boundary displacement. Visible gold in Py-2 occurs in micro-fractures, cavities, and grain boundaries. The generally low contents of Au in pyrite, including Py-2, and the brittle deformation features, suggest that the visible gold grains did not result from remobilization of invisible gold from pyrite. Rather, the majority of gold was introduced by fluids after the formation of the gold-hosting pyrite. These fluids were derived from the same sources as those precipitating the gold-hosting pyrite, but were more evolved and enriched in Au. Circulation of these auriferous ore-forming fluids in microfractures of pyrite and interstitial space resulted in precipitation of visible gold. [ABSTRACT FROM AUTHOR]

Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, water body and stream sediment. An environmental geochemical investigation was carried out in and around the Panzhihua mining and smelting area to determine the extent of chemical contamination in soil and sediment. The main objective of this study was to investigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil and sediment and to assess the degree of pollution in the study are. The data of heavy metal concentrations reveal that soils and sediments in the area have been slightly contaminated. Geochemical maps of I[subgeo] of each heavy metal show that the contaminated sites are located in V-Ti-magnetite sloping and smelting, gangues dam. The pollution sources of the selected elements come mainly from dusts resultant from mining activities and other three-waste-effluents. The are needs to be monitored regularly for trace metal, especially heavy metal enrichment. [ABSTRACT FROM AUTHOR]

• Elevated U concentrations (up to 266 ppm) were found in the Lala IOCG ores. • Uraninite, uranothorite, polycrase and coffinite were recognized. • Uranium was initially enriched with Cu, Mo, Th and REE at ca. 1086 to 1053 Ma. • U and Mo were remobilized and re-enriched together at ca. 888 to 828 Ma. Elevated uranium concentrations have been reported in many IOCG deposits, but detailed information about the occurrences of uranium minerals and their relationships with other minerals remains scarce, which hinders understanding of the mineralization mechanisms and the nature of the association of these metals. This paper reports a new case of uranium enrichment in an IOCG system, the Lala Cu-Fe deposit in the Kangdian region, SW China. Whole-rock analyses of ores and barren rocks yielded highly variable U concentrations ranging from 0.76 to 266 ppm. Uranium shows a strong positive correlation with Mo, broadly positive correlations with Cu and ΣREE, and a vague, negative correlation with Th. Four uranium minerals, uraninite [UO 2 , uranothorite [(Th,U)SiO 4 , polycrase [(Y,Ca,Ce,U,Th)(Ti,Nb,Ta) 2 O 6 , and coffinite [U(SiO 4) 1-x (OH) 4x , were identified. The uraninite is divided into two phases: phase 1 (Ur1) characterized by corroded or irregular crystal shapes, and phase 2 (Ur2) showing well-developed, subhedral to euhedral crystal shapes. Ur1 is interpreted to be formed in the primary Cu – Fe – Mo – REE – U mineralization, together with the bulk of Cu and other metal sulfides, as well as other U and REE minerals, including uranothorite, polycrase, bastnäsite and xenotime, and accompanied by K-alteration (K-feldspar and biotite). Ur2 is interpreted to be formed in a secondary hydrothermal event characterized by introduction of fluorite and carbonates, in which U and Mo, and to lesser extent Cu and REE, were remobilized, while Th remained relatively stable. The primary mineralization is inferred to have taken place in a period from ca. 1086 to 1053 Ma based on previous Re-Os geochronology, and the secondary mineralization (remobilization) likely took place from ca. 888 to 828 Ma, as suggested by uraninite chemical ages obtained in this study and other published geochronological data. These ages correspond to tectonomagmatic events taking place in generally extensional environments, in the western margin of the Yangtze Block during the Meso- to Neoproterozoic time. The Lala Cu-Fe deposit represents a new case of IOCG deposits with U (and REE) enrichment, the economic potential of which warrants further examination. [ABSTRACT FROM AUTHOR]

The article discusses the research study conducted to examine the geologic history of the iron oxide copper gold (IOCG) deposits in Southwestern China that was associated with polymetallic mineralization. It reveals the age of magmatic rocks and metallogenic epoch and the coupling relationship between polymetallic elements. It also reveals the ore-forming process including the volcanic sedimentation, grenville orogenic event, and superimposed mineralization.