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This study uses landslide inventory of a single typhoon event and Weight of Evidence (WOE) analysis to establish landslide susceptibility map of the Laonung River in southern Taiwan. Eight factors including lithology, elevation, slope, slope aspect, landform, Normalized Difference Vegetation Index (NDVI), distance to geological structure, and distance to stream are used to evaluate the susceptibility of landslide. Effect analysis and the assessment of grouped factors showed that lithology, slope, elevation, and NDVI are the dominant factors of landslides in the study area. Landslide susceptibility analysis with these four factors achieves over 90%of the AUC (area under curve) of the success rate curve of all eight factors. Four landslide susceptibility models for four typhoons from 2007 to 2009 are established, and each model is cross validated. Results indicate that the best model should be constructed by using landslide inventory close to the landslide occurrence threshold and should reflect the most common spatial rainfall pattern in the study region for ideal simulation and validation results. The prediction accuracy of the best model in this study reached 90.2%. The two highest susceptibility categories (very high and high levels) cover around 80% of the total landslides in the study area. [ABSTRACT FROM AUTHOR]

Post‐collisional magmatism contains important clues for understanding the reworking and growth of continental crust, as well as lithospheric delamination and orogenic collapse. Early Devonian magmatism has been identified in the North Qilian Orogenic Belt (NQOB). This paper reports an integrated study of petrology, whole‐rock geochemistry, Sm‐Nd isotope and zircon U‐Pb dating, as well as Lu‐Hf isotopic data, for two Early Devonian intrusive plutons. The Yongchang and Chijin granites yield zircon U‐Pb ages of 394–407 Ma and 414 Ma, respectively. Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium‐rich minerals, LREE‐enriched patterns with negative Eu anomalies and a negative correlation between P2O5 and SiO2 contents, consistent with geochemical features of I‐type granitoids. Zircons from the studied granites display negative to weak positive εHf(t) values (–5.7 to 2.1), which agree well with those of negative εNd(t) values (−6.4 to −2.9) for the whole‐rock samples, indicating that they were derived from the partial melting of Mesoproterozoic crust. Furthermore, low Sr/Y ratios (1.13–21.28) and high zircon saturation temperatures (745°C to 839°C, with the majority being >800°C) demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source. Taken together, the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle‐derived magmas at high‐temperature and low‐pressure conditions during post‐collisional extensional collapse. The data obtained in this study, when viewed in conjunction with previous studies, provides more information about the tectonic processes that followed the closure of the North Qilian Ocean. The tectonic transition from continental collision to post‐collisional delamination could be constrained to ∼430 Ma, which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon εHf(t) values for granitoids. A two‐stage tectonic evolution model from continental collision to post‐collisional extensional collapse for the NQOB includes (a) continental collision and crustal thickening during ca. 455–430 Ma, characterized by granulite‐facies metamorphism and widespread low‐Mg adakitic magmatism; (b) post‐collisional delamination of thickened continental crust and extensional collapse of orogen during ca. 430–390 Ma, provided by coeval high‐Mg adakitic magmatism, A‐type granites and I‐type granitoids with low Sr‐Y ratios. [ABSTRACT FROM AUTHOR]

Based on the analysis of lithology, lithofacies combinations, sedimentary structures, and fossil types in five geological sections measured through fieldwork, this paper comprehensively elucidates the sedimentary evolution characteristics of the Jurassic period in the South Qiangtang area. The South Qiangtang Basin is renowned for preserving the most complete Jurassic marine sedimentary strata in China, and it primarily consists of a mixed platform environment of carbonate and clastic rocks. The Jurassic strata in the South Qiangtang Basin range from the Quse Formation at the base to the Suowa Formation at the summit, with sedimentary facies evolving from the outer shelf to the subtidal zone, and seawater depth gradually becoming shallower. This trend may be associated with the division and expansion of the Bangong–Nujiang suture zone during the Late Triassic, subduction in the Middle Jurassic, and the suture and splicing of the Qiangtang–Lhasa plate during the Late Jurassic tectonic movements. In conclusion, this research presents a comprehensive analysis of the sedimentary evolution of the Jurassic period in the South Qiangtang Basin for the first time. The findings offer significant contributions to the understanding of the region's geological history and serve as a valuable foundation for future investigations. [ABSTRACT FROM AUTHOR]

In the process of diagenesis and burial of sedimentary basins, basin fluid activities participate in the process of hydrocarbon accumulation and metal mineralization. Understanding the evolution of basin fluid is of great significance in revealing the related hydrocarbon accumulation and mineralization. Paleo-reservoirs are closely associated with Carlin-type gold deposits in the Nanpanjiang-Youjiang Basin, South China. Calcite, the fluid activity product, is closely related to bitumen and gold-bearing pyrite. By integrating petrographic, cathode luminescence, and fluid inclusion analysis, as well as the relevant chronological results of predecessors, this paper attempts to establish the relationship between fluid evolution, hydrocarbon accumulation, and gold mineralization. Two types of calcite (black/gray and white) developed in the Banqi-Yata-Laizishan area, the Nanpanjiang-Youjiang Basin. Black/gray calcite is symbiotic with bitumen and features dark red colors in cathode luminescence. Many hydrocarbon inclusions developed along with fluid inclusion analysis at low homogenization temperatures (65.7~173.1 °C). Combining the previously reported U-Pb ages (~250–230 Ma) of this kind of calcite with some geochemistry data on the associated reservoir and gold deposit, this calcite records the consecutive hydrocarbon accumulation and Carlin-type gold mineralization from the Late Permian to the Late Triassic periods controlled by Indosinian tectonic movement. The white calcite featuring bright red in cathodoluminescence is symbiotic with gold-bearing pyrite and realgar, and the associated fluid inclusions have high homogenization temperatures (128.2~299.9 °C). Combined with regional tectonic background and isotopic chronology (~140–106 Ma), it seems to record the early Cretaceous Carlin-type gold mineralization controlled by the subduction of the paleo-Pacific plate in the late Yanshanian period. [ABSTRACT FROM AUTHOR]

Multi-source remote sensing data can provide abundant Earth observation information for lithology classification and identification, especially in some areas with complex geological conditions where the field geological survey is difficult to carry out. Compared with mountainous areas with large outcrops of rock, the lithology information obtained based on traditional field measurement and single optical remote sensing data in semi-arid areas is greatly limited due to the uneven vegetation coverage. While the combination of microwave and optical remote sensing technologies can effectively improve the integrality and reliability of the obtained lithology information in semi-arid areas. This paper selected Duolun County of Inner Mongolia Autonomous Region as the study area, added vegetation suppression for microwave and optical images into the conventional lithology classification process, and integrated Sentinel-1A and Landsat-8 images of the study area to carry out the experiment. The improved water-cloud model with the parameter of vegetation coverage and the method of feature-oriented principal component analysis based on multiple vegetation indices were used to realize the vegetation suppression in Synthetic Aperture Radar (SAR) backscattering images in two polarization modes and multispectral images. The processed SAR backscattering, SAR texture and spectral feature images were used to form seven feature combinations for lithology classification by the maximum likelihood method. The results showed that the proposed lithology classification scheme cannot achieve high-precision classification of all lithologic types, but it was effective in identifying the major lithologies dominated in the Quaternary deposits of the study area. In all feature combinations, the combination of all the three types of features reached the highest classification accuracy, with the overall classification accuracy of 88.60% and the kappa coefficient of 0.75 for five major lithologies. The experimental results fully demonstrated the advantages of integrating microwave and optical remote sensing data in lithology classification in a semiarid area. [ABSTRACT FROM AUTHOR]

Red slipped and painted wares (RSW and RPW) were manufactured to cook, serve, or store foods and liquids in the middle Yangtze River valley (MYRV) of China some 8500 and 7800 years ago, respectively. Their primary use narrowed down to serving and drinking in the Upper Qujialing (5300–4500 cal BP) and Shijiahe (4500–4200 cal BP) periods when initial states (bang guo) took shape and developed in the region. The increasing social complexity in MYRV correlated with the formation of community and neighborhood identity through rituals and socio-economic ties involving the widespread use of RSW and RPW. How the two wares were produced and used helps us understand the relationships among productive activities, identity, and social inequality in MYRV. This paper presents the first overview of RSW and RPW in the Neolithic MRYV. It introduces a multi-analytical study of the two wares—mostly dating to the Shijiahe period—unearthed from the site of Fenghuangzui in Xianyang City of Hubei Province, China. Optical microscopic examination revealed that the paint of RPW—50 μm thick on average—was applied using a brush while the slip of RSW is thinner and finer and possibly formed by self-slipping. Handheld X-ray fluorescence (hhXRF) and benchtop micro-XRF analyses ascribed the red paint or slip to iron and iron oxide. Raman and X-ray absorption fine structure analyses confirmed that iron was present in the paint or slip in the form of hematite with a poorly developed crystalline structure. Furthermore, thin-section petrography implied that different pastes were used to produce RPW and RSW, and hhXRF data indicated that the Upper Qujialing and Shijiahe pottery differ in the concentrations of five elements (Zr, Fe, Mn, Ti, and Ba), which might be helpful in future provenance studies of RSW and RPW. Our study discloses the complexity of the manufacture of RSW and RPW at Fenghuangzui. More details of RSW and RPW production and use from our ongoing project shall reveal the role of the two wares in the social dynamics of the Late Neolithic MYRV. [ABSTRACT FROM AUTHOR]

The Jiamusi‐Khanka Massif is an important tectonic unit of the Central Asian Orogenic Belt in North‐east China. Its Late Palaeozoic tectonic properties and the timing of assembly have restricted the understanding of the tectonic evolution process at the eastern segment of the Central Asian Orogenic Belt for a long time. Based on the study of clastic rock petrology and zircon U–Pb chronology of the Early Permian Erlongshan Formation in Mishan, it is clear that the zircon age of the Early Permian Erlongshan Formation in Mishan is mainly Late Palaeozoic, with a major age peak at 300 ± 3 Ma and secondary age peaks at 356 ± 7 Ma and 475 ± 10 Ma. The provenance mainly comes from the magmatic arc source area, and Early Palaeozoic (500–420 Ma) detrital zircons mainly come from the south‐east margin of Jiamusi Massif, Late Palaeozoic (400–270 Ma) detrital zircons mainly come from the eastern margin of Jiamusi Massif and the northern margin of Khanka Massif. Among them, detrital zircons of a special age group 330–310 Ma come from the north of Khanka Massif, while 490–470 Ma detrital zircons which are common in the Early‐Middle Permian strata of Khanka Massif come from Jiamusi Massif. Combined with the evidence of petrology and palaeontology, this paper believes that the Early Permian Jiamusi Massif and Khanka Massif should be a unified Massif, that is, Jiamusi‐Khanka Massif. [ABSTRACT FROM AUTHOR]

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The Qilian orogen marks the northern boundary of the Proto-Tethys Ocean and consists of the North Qilian belt, the Central Qilian block and the South Qilian belt. The metamorphic P–T–t path of the Central Qilian block and the tectonothermal processes that affected it are crucial to understanding the closure of the ocean. This paper presents a systematic investigation of the metamorphic P–T–t path of amphibolites from the Precambrian Huangyuan Group and Maxianshan Group in the Central Qilian block. An amphibole 40Ar/39Ar age of 456.7 ± 5.2 Ma from a garnet amphibolite and a 427.8 ± 3.8 Ma muscovite 40Ar/39Ar age from an orthogneiss in the Huangyuan Group, and amphibole and biotite 40Ar/39Ar ages of 408.7 ± 2.2 Ma and 349.9 ± 2.0 Ma from an amphibolite and a 361.4 ± 2.0 Ma biotite 40Ar/39Ar age from an orthogneiss in the Maxianshan Group record cooling stages after peak metamorphism. Phase equilibrium modeling of all amphibolite samples indicates clockwise P–T paths. A garnet amphibolite from the sillimanite zone in the Huangyuan Group recorded peak metamorphic conditions of 5.6–6.6 kbar and 730–770°C, reflecting granulite-facies metamorphism. Peak P–T conditions for a garnet amphibolite from the garnet zone are constrained to 580–600°C and 6–7 kbar. The amphibolite sample from the Maxianshan Group indicates peak P–T conditions of ~5.2 kbar and ~630°C. The Central Qilian block was affected by both southward subduction of the North Qilian Ocean and northward subduction of the South Qilian Ocean, which resulted in paired metamorphic belts along the northern margin of the Central Qilian block and accretion of the Hualong block to its southern margin. The subducted North Qilian oceanic slab detached and the remainder was exhumed at 453–445 Ma, accompanied by the extension and retrograde metamorphism of the overlying crust of Huangyuan Group at 457–428 Ma. Subsequent cooling of the Maxianshan Group indicates that the thermal regime relaxed during post-collisional extension at c. 409–350 Ma between the Hualong block and the Central Qilian block. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical behaviors of different lithological rocks of coal measure strata from Shanxi Formation in the eastern margin of the Ordos Basin, China, were investigated through uniaxial compression tests, and the deformation characteristics and failure modes of different lithological rocks were investigated. On this basis, the energy evolution of different lithology rocks was also discussed. The results show that there are obvious differences in the mechanical properties of different lithology rocks in coal measure strata, resulting in different wellbore instability prevention measures and fracturing measures in different lithology strata. Under the uniaxial compression condition, the peak strain of different lithological rocks is obviously different, and the denaturation characteristics are also obviously different, and the failure modes of rocks are mainly the tensile fracture mode, suggesting that the rock samples have strong brittle characteristics. With the increase of the strain, the total energy of different lithological rocks of the coal measure strata increases, and the elastic energy first increases and then decreases rapidly, whereas the dissipated energy first increases slowly and then increases rapidly. Each energy at the peak point is different, and the average total energy of shale, silty shale, siltstone, fine sandstone, and coal is 0.022 J/cm3, 0.045 J/cm3, 0.052 J/cm3, 0.042 J/cm3, and 0.003 J/cm3, respectively, indicating that there are obvious differences in the energy evolution laws of the different lithological rocks. [ABSTRACT FROM AUTHOR]

This study is the first systematic assessment of the Lower Ordovician microbial carbonates in Songzi, Hubei Province, China. This paper divides the microbial carbonates into two types according to growth patterns, namely nongranular and granular. The nongranular types include stromatolites, thrombolites, dendrolites, leiolites and laminites; the granular types are mainly oncolites and may include a small amount of microbiogenic oolite. According to their geometric features, the stromatolites can be divided into four types: stratiform, wavy, columnar and domal. Additionally, dipyramidal columnar stromatolites are identified for the first time and represent a new type of columnar stromatolite. The thrombolites are divided into three types: speckled, reticulated and banded. The grazing gastropod Ecculiomphalus and traces of bioturbation are observed in the speckled and reticulated thrombolites. This paper considers these two kinds of thrombolites to represent bioturbated thrombolites. These findings not only fill gaps in the field of domestic Ordovician bioturbated thrombolites but also provide new information for the study of thrombolites. Based on the analysis of the sedimentary characteristics of microbialites, the depositional environments of the various types of microbialites are described, and the distribution patterns of their depositional environments are summarized. The relationship between the development of microbialites and the evolution and radiation of metazoans during the Early to Middle Ordovician is discussed. Consistent with the correspondence between the stepwise and rapid radiation of metazoans and the abrupt reduction in the number of microbialites between the late Early Ordovician and the early Middle Ordovician, fossils of benthonic grazing gastropods (Ecculiomphalus) were found in the stromatolites and thrombolite of the study area. It is believed that the gradual reduction in microbialites was related to the rapid increase in the abundance of metazoans. Grazers not only grazed on the microorganisms that formed stromatolites, resulting in a continuous reduction in the number of stromatolites, but also disrupted the growth state of the stromatolites, resulting in the formation of unique bioturbated thrombolites in the study area. Hydrocarbon potential analysis shows that the microbialites in the Nanjinguan Formation represent better source rocks than those in the other formations. [ABSTRACT FROM AUTHOR]

In recent years, petroleum exploration in the Carboniferous volcanic rock reservoirs in the Junggar Basin has been the focus of important petroleum energy development in western China. The lithologic identification of volcanic rock reservoirs seriously restricts the accuracy of reservoir prediction and affects the success rate of oil exploration. Different types of volcanic rocks have different petrological characteristics and mineral assemblages, especially affected by the depositional environment. The volcanic rocks in different regions have their own uniqueness. This paper takes the Carboniferous volcanic reservoirs in Xiquan block, Beisantai Oilfield, Junggar Basin as the research target. Through a large number of core observations, casting slices, scanning electron microscopy, and X-ray diffraction methods, the Carboniferous volcanic rocks are analyzed. The petrology, pore characteristics, physical properties, and diagenetic evolution history of the reservoir are analyzed. The study shows that the volcanic facies in the Xiquan block can be divided into explosive facies, overflow facies, and volcanic sedimentary facies, among which the explosive facies is subdivided into empty subfacies (volcanic breccia-breccia tuff combination) and thermal base wave subfacies (tuff). The lithology of the reservoir is pyroclastic rock and volcanic lava, belonging to medium-porous and ultralow permeability reservoirs, and the storage space can be divided into three types: primary pores, secondary pores, and fractures. The lithology of key exploration is breccia tuff, followed by breccia tuff and volcanic breccia. [ABSTRACT FROM AUTHOR]

To characterize the polyphase palaeokarst development of Wumishan formation in Jizhong depression, the data of outcrops, cores, thin sections, SEM, core plugs, drilling relief and leakage, and carbon isotope have been analyzed in this paper. The results reveal that the polyphase palaeokarst was petrography controlled of microbial dolostone and grain dolostone, and was identified as three phases: (1) poly-period eogenetic karst during Wumishan depositional environment, (2) two-period telogenetic karst in Triassic and Cretaceous, and (3) hydrothermal karst in Paleogene. The eogenetic karst was related to high frequent sea level fluctuations with development of vugs and selective dissolution porosities which distributed at the top of microbial dolostone and grain dolostone layers. The origin of the telogenetic karst was related to Indosinian and Yanshan orogeny which formed widespread fold belts and thrust faults, and provided the endokinetic force and a strong topography difference. Each period's telogenetic karst was characteristic of one-period fracture-cave system, and the Cretaceous telogenetic karst was stronger than the Triassic telogenetic karst in karst intensity. Moreover, the karst intensity increased downward in superimposed telogenetic karst zones. Hydrothermal karst was related to volcanic activities and provided the hydrothermal environment for its formation. It was featured by solution-enlarged porosities and new forming porosities. The microbial dolostone and grain dolostone layers with three-phase palaeokarst were the best exploration targets for high-quality reservoirs. This paper rebuilds a suitable karst model to show the palaeokarst evolution process. [ABSTRACT FROM AUTHOR]

The oldest extant musical instruments in the world are stone chimes. This music was created by the 'eight tones' that could be produced by these 'stone' voices. Although many of these stone chimes have been unearthed from sites predating the Spring and Autumn Period and the Warring States Period in China, their discussion in archaeological reports is usually not very thorough. In this paper, the ancient and modern samples are analysed from the point of view of lithology. The aim is to explore how the ancients chose to make these stones, and to check that the type of stone from which these ancient Chinese stone chimes are made is actually those recorded in previous studies. The results show that most of the ancient stone chimes in China are made of limestone. These chimes required a material with a single, homogeneous and compact mineral composition. Lingbi chimes (a kind of 'lithophone' produced in Lingbi county, China, are pure in composition and have a fine microcrystalline structure, which is the best choice for making stone chimes. This paper makes a systematic study of the lithology of Chinese stone chimes. The results supplement a significant lacuna in the study of 'lithophone' and ancient stone instruments both in China and on a more global scale. [ABSTRACT FROM AUTHOR]

Identifying lithology from well logs is an important step in deep prospecting and resource estimation. Various machine learning algorithms have been adopted to identify lithology in oil and gas fields. Such algorithms, however, are rarely used for mineral deposits because of their complex geological conditions. In this paper, we propose an application framework using the gradient boosting decision tree (GBDT) algorithm to identify lithology from well logs in a mineral deposit. The GBDT classifier was built via the procedure of grid search and cross-validation to optimize the hyperparameters. In the Zhaoxian gold deposit, as the study area, an optimized GBDT classifier was built to fit the association between a set of well logs and ten lithological classes. The results demonstrate that the GBDT classifier has good classification performance in lithology identification, with a precision of 93.55%, a recall of 93.49% and an F1-score of 93.27%. The GBDT classification results also indicate that the major features contributing to the lithology classification are resistivity, followed by spontaneous potential and natural gamma according to the model interpretation of feature importance and partial dependence plots. The study demonstrates that the GBDT model can enhance our understanding of lithology identification from well logs in mineral deposits, which provides significant implications for further exploration targeting the deep-seated parts of mineral deposits. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu 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.)

Landslides are occurring more frequently in China under the conditions of extreme rainfall and changing climate, according to News reports. Landslide hazard assessment remains an international focus on disaster prevention and mitigation, and it is an important step for compiling and quantitatively characterizing landslide damages. This paper collected and analyzed the historical landslide events data of the past 60 years in China. Validated by the frequencies and distributions of landslides, nine key factors (lithology, convexity, slope gradient, slope aspect, elevation, soil property, vegetation coverage, flow, and fracture) are selected to construct landslide susceptibility (LS) empirical models by back-propagation artificial neural network method. By integrating landslide empirical models with surface multi-source geospatial and remote sensing data, this paper further performs a large-scale LS assessment throughout China. The resulting landslide hazard assessment map of China clearly illustrates the hot spots of the high landslide potential areas, mostly concentrated in the southwest. The study implements a complete framework of multi-source data collecting, processing, modeling, and synthesizing that fulfills the assessment of LS and provides a theoretical basis and practical guide for predicting and mitigating landslide disasters potentially throughout China. [ABSTRACT FROM AUTHOR]

The generation, formation, and development of debris flow are closely related to the vertical climate, vegetation, soil, lithology and topography of the mountain area. Taking in the upper reaches of Min River (the Upper Min River) as the study area, combined with GIS and RS technology, the Geo-detector (GEO) method was used to quantitatively analyze the respective influence of 9 factors on debris flow occurrence. We identify from a list of 5 variables that explain 53.92%% of the total variance. Maximum daily rainfall and slope are recognized as the primary driver (39.56%) of the spatiotemporal variability of debris flow activity. Interaction detector indicates that the interaction between the vertical differentiation factors of the mountainous areas in the study area is nonlinear enhancement. Risk detector shows that the debris flow accumulation area and propagation area in the Upper Min River are mainly distributed in the arid valleys of subtropical and warm temperate zones. The study results of this paper will enrich the scientific basis of prevention and reduction of debris flow hazards. [ABSTRACT FROM AUTHOR]

This paper presents detrital modes, clay and carbonate cements and major and trace element contents of the sandstones from the lower Xiaganchaigou formation deposited during the Eocene/Oligocene transition in the Lenghu tectonic belt on the northern margin of the Qaidam Basin, NW Qinghai–Tibetan plateau. Our results show that the sandstones are mainly lithic feldspathic, with clay content varying from 4.1 to 42.5 vol. % (average 13.7 vol. %). These sandstones have low contents of Na2O, MgO, Al2O3, K2O, CaO and TiO2, with the average contents of 2.14 wt%, 0.78 wt%, 7.96 wt%, 2.11 wt%, 6.14 wt% and 0.15 wt%, respectively. The total content of major elements is < 30 wt%, indicating that the pore water was in an alkaline environment with high pressure, so that the decarboxylation reaction of the organic matter took place to generate a large amount of carbon dioxide with a loss of 13C. Consequently, the δ13C of the carbonate cement is negatively biased to − 6.4‰; the deep high temperature environment and the external fresh water leaching make the δ18O value of the carbonate cement gradually lose, reaching − 13.19‰, according to its precipitation temperature (78–108 °C) and pore water salinity (104–110), it is judged that carbonate cement is mainly formed in the middle diagenetic stage and early diagenetic stage. The rare earth elements are mainly authigenic by the results of ∑REE and Y/Ho, and the deposition characteristics of trace elements such as Zn, Th, U, Ni, Co, Cr, Sr/Cu, Ceanom, Ce/La, ∑REE, Eu/Eu*, La/Yb, V/(V + Ni) and the transformation of later diagenesis, combining the characteristic of the global climate and the influence of uplifting of the Qinghai–Tibetan Plateau, indicate that the lower Xiaganchaigou formation was in a dry, cold and anoxic reducing environment. [ABSTRACT FROM AUTHOR]

The c.a. 259–260 Ma Emeishan mantle plume caused extensive flood basalts and associated peralkaline rocks; petrogenesis of these peralkaline rocks can provide detailed information about the melting process in the mantle. In this paper, we present detailed petrology, chronology, major and trace element geochemistry, Sr-Nd isotope and in situ zircon Hf isotope for an amphibole syenite from Panxi area, inner zone of the Emeishan large Igneous province (ELIP). The amphibole syenite has a zircon U-Pb ages of 260 ± 2 Ma (MSWD = 1.2, n = 22), which is synchronous with Emeishan mantle plume. It displays moderate SiO2 (64.89–65.67 wt.%), high Na2O (7.35–7.71 wt.%) and K2O (4.78–4.96 wt.%) contents, with A/CNK values of 0.86 to 0.90, with high Rittman index of 6.6 to 7.1, showing peralkaline affinity. It displays significantly negative Sr anomalies (133 to 200 ppm) and slightly negative Eu anomalies (Eu/Eu* = 0.78–1.04). The rock displays high εNd(t) values of +2.4 to +2.5. Zircons from the amphibole syenite display positive εHf(t) values from +8.9 to +11.0, with single-stage Hf model ages ranging from 0.47 to 0.55 Ga, combined with the well-developed correlation of TFe2O3, CaO/Al2O3, TiO2, Ni and Cr with MgO, suggesting the amphibole syenite was derived from the mantle source, and the fractional crystallization played a significant role in the generation of the magma. The MELTS model results show that Houzishan amphibole syenite can be formed by the high degree (~80%) fractional crystallization of ~24% clinopyroxene, ~4% orthopyroxene, ~35% plagioclase and ~5% oxide from parental magma resembling high-Ti basalts. These results indicate that Houzishan amphibole syenite represents the juvenile mantle-derived peralkaline melts addition to the continental lower crust in the inner zone of the ELIP and assimilating with minor crust material. [ABSTRACT FROM AUTHOR]

The standards applied to reclassify landslide-conditioning factors differ among studies and may change the accuracy of identifying landslide-prone areas. Therefore, we identified two standards per factor (elevation, aspect, slope, proximity to roads and proximity to streams) from the existing literature and set them as predisposing criteria in this paper. In addition to the five factors, lithology represented by types and a landslide inventory map produced from field surveys were also used in mapping. Thirty-two landslide susceptibility maps were generated based on weights-of-evidence and evaluated using the relative operative characteristic method. The results show that the subdivision criteria of factors change the accuracy, with the success rate varying from 84.34% to 87.51%. The map with the highest value captures more landslides in relatively higher susceptibility classes and is therefore considered the optimal one. Ultimately, a simplified mode of combining subdivision criteria is proposed to simplify comparison. [ABSTRACT FROM AUTHOR]

Carboniferous volcanic rocks are widely distributed in the Junggar Basin and may provide a unique insight into the tectonic history of this basin. In this paper, we focus on the tectonic evolution of the northern Junggar Basin (NJB) using geochronological and geochemical data to establish the diachronous closure model for the Keramaili oceanic basin. The Lower Carboniferous strata in the eastern part (well WC‐1) and the Upper Carboniferous strata in the western part (well Y‐2) of the NJB are composed of a mix of compositional and rock‐type forms. These volcanic rocks are mostly high‐K assemblages characterized by high K (1.73–6.48%), high alkali (Na2O + K2O = 5.04–7.45%), and low TiO2 (0.57–1.06%). They also exhibit various REE concentrations (68.44–168.19 ppm), an enrichment of LREE (LaN/YbN = 4.54–8.09), and small negative Eu anomalies (δEu = 0.74–0.90). The depletion of HFSE and relevant tectonic setting discrimination diagrams demonstrate that these two volcanic associations were formed in a subduction‐related environment. The data also indicate that the high‐K volcanic rocks are derived from a mix of melted subducted sediments and mantle metasomatized by silica‐rich fluids. Although these two sets of volcanic rocks formed in Early and Late Carboniferous, the similar petrographic and geochemical natures suggest similar magma source and tectonic setting. Along with different regional tectonic settings in the NJB during the Carboniferous, we propose an asynchronous subduction of Keramaili oceanic basin, resulting in the inconsistent temporal and spatial distribution of Upper Carboniferous volcanic rocks in the NJB. [ABSTRACT FROM AUTHOR]

Paleoproterozoic granitoids are an important constituent of the Jiao–Liao–Ji Belt (JLJB). The spatial‐temporal distribution and types of Paleoproterozoic granitoids are closely related to the evolution of the JLJB. In this paper, we review the field occurrence, petrography, geochronology, and geochemistry of Paleoproterozoic granitoids on Liaodong Peninsula, northeast China. The Paleoproterozoic granitoids can be divided into pre‐tectonic (∼2.15 Ga; peak age=2.18 Ga) and post‐tectonic (∼1.85 Ga) granitoids. The pre‐tectonic granitoids are magnetite and hornblende–biotite monzogranites and granodiorites. Pre‐tectonic monzogranites are widespread in the JLJB and have A2‐type affinities. In contrast, pre‐tectonic granodiorites are only present in the Simenzi area and have adakitic affinities. The post‐tectonic granitoids consist of porphyritic monzogranite, syenite, diorite, granodiorite, quartz monzonite, monzogranite, and granitic pegmatite, which are adakitic rocks and I‐, S‐, and A2‐type granitoids. The assemblage of pre‐tectonic A2‐type granitoids and adakitic rocks indicates the initial tectonic setting of the JLJB was a continental back‐arc basin. The assemblage of post‐tectonic adakitic rocks and I‐, S‐, and A2‐type granitoids indicates a post‐collisional setting. The 2.20–2.15 Ga A2‐type granitoids and adakitic rocks were associated with the initial stage of back‐arc extension, and the peak of back‐arc extension is inferred from the subsequent (2.15–2.10 Ga) mafic intrusive activity. The ∼1.90 Ga adakitic rocks mark the beginning of the post‐collisional stage, which was followed by the intrusion of low‐temperature S‐ and I‐type granitoids. High‐ to low‐pressure granitoids (S‐type) were generated during the peak of post‐collisional lithospheric delamination and asthenospheric upwelling. The emplacement of later granitic pegmatites occurred during the waning of the orogeny. [ABSTRACT FROM AUTHOR]

• The 2.2 Ga monzogranite identified in the western part of the North Qinling Orogen (NQO) was originally formed in the southwestern North China Craton (NCC). • The monzogranite was involved into the NQO by continental collision between the NQO and the NCC during the early Paleozoic. • The early Precambrian rocks at the southwestern margin of the Ordos Blocks recorded similar tectono-thermal events of 2.5–1.75 Ga with the basement of the central-southern Ordos Block. Precambrian continent remnants in Phanerozoic orogenic belts contain vital information about not only the Precambrian evolution history of continent remnants but also the relationship between orogenic belts and adjacent blocks. This paper presents an integrated study of petrology, geochemistry and accessory mineral chronology on a monzogranite, its wall rocks biotite-quartz schist and an amphibolite interlayer in the schist in the Kuanping Group, from the western part of the North Qinling Orogen (NQO), adjacent to the southwestern margin of the Ordos Block (OB). The results reveal that the crystallization age of the monzogranite is 2200 ± 12 Ma and the protolith of the biotite-quartz schist deposited during 526–447 Ma, and they experienced similar multistage metamorphism during 450–400 Ma. The 2.2 Ga formation age of the monzogranite is significantly older than the protolith deposition age of the biotite-quartz schist, and there is almost no ca. 2.2 Ga detrital zircon age in the schist, indicating that the monzogranite is neither an intrusive body in the Kuanping Group, nor its provenance. Considering the ca. 2.2 Ga magmatism is widely distributed in North China Craton but never found in the NQO, and the monzogranite and host schist recorded similar metamorphic ages, we proposed that the monzogranite initially formed at the southwestern margin of the North China Craton and involved into the NQO during the closure of the Kuanping sedimentary basin at early Paleozoic. Combined with existing studies, three Paleoproterozoic magmatic events of ca. 2.5 Ga, 2.2–2.0 Ga and 1.8–1.75 Ga, and one ca. 1.9–1.85 Ga metamorphic event occurred at the southwestern margin of OB. These tectono-thermal events as well as their geological setting are very similar to the basement rocks of the central-southern part of the OB. Therefore, the early Precambrian rocks at the southwestern margin of the OB should belong to the basement of the central-southern part of OB, and the late tectonic events placed them at their present position. [ABSTRACT FROM AUTHOR]

The Paleogene Shahejie Formation in the KL16 oilfield, Bohai bay, is characterized by a thinly interbedded mixed sedimentary system, with complex sedimentary facies, lithologic types and distributions. It is hard for conventional logging methods to identify the lithology therein. In order to solve the difficulty in lithologic identification of mixed sedimentary system, analyses based on graph data base using elemental capture energy spectrum log have been proposed. Due to the different composition for the various minerals, we innovatively established the molar numbers of silicon, calcium, magnesium, and aluminum as characteristic parameters for sandstone, limestone, dolomite, and mudstone, and a graph clustering analysis method was applied to identify lithology. Considering the seismic waveforms corresponding to lithologic impedance of reservoir, three seismic phases were identified by neural network clustering analysis of seismic waveform, and the seismic attributes with high sensitivity to reservoir thickness were then selected to realize the fine description of the mixed carbonate-siliciclastic reservoir. Drilling results confirmed that the sedimentary facies were accurately identified, with reservoir prediction accuracy reaching up to 80%. Under the guidance of reservoir research, the oil-in-place discovered in the oilfield were estimated to be more than 5 million tonnes. This technology provides reference for the exploration and development of oilfields of mixed sedimentary system. [ABSTRACT FROM AUTHOR]

The Dongpu depression, like other depressions in the Bohai Bay Basin, is characterized by overpressure, however, the published studies have not clearly given the overpressure formation mechanism and paleo-pressure evolution history in the Dongpu depression. In addition, the current researches are mainly focused on the northern Dongpu depression, while rare investigation has been conducted in the southern part. In this context, it is urgent to explore the comprehensive overpressure evolution and formation mechanism in the Dongpu depression in academic and industrial fields. This paper provided a systematic analysis of fluid inclusions, including fluid inclusion petrography, microthermometry, vapor phase filling degree measurement and PVT-x modeling. By using homogenization temperature-burial history projection, the trapping time of the oil inclusions are determined. Four pressure evolution stages are identified in both the northern and the southern Dongpu depression. The results indicate that the pressure accumulation stage is derived by disequilibrium compaction and hydrocarbon generation in the northern part because of the salt rock distribution, while the stage is only derived by hydrocarbon generation in the southern part because of no salt rock distribution. The pressure release stages are mainly caused by the tectonic uplifting movements at the end of Dongying and Minghuazhen Formation. The overpressure in most areas in the northern part has been preserved till now, which is considered as a result of the good plasticity and sealing ability of salt rock that prevent the pressure leakage by smearing on the fault. Areas without salt rock distribution show normal pressure, which means the salt rock is an important factor that contributes to the overpressure preservation. However, there are exceptions that in Baimiao and Qiaokou, the overpressure still exists even without salt rock distribution, which is due to fault closure. [ABSTRACT FROM AUTHOR]

Hydraulic connections between aquifers is usually studied through hydrochemical analysis or by pumping tests. However, hydrochemical analyses are usually conducted in areas of variable lithology. In addition, the hydrogeological data obtained by drilling and pumping tests are typically insufficient to get 3D distributions of hydraulic head. In this paper, the time-lapse transient electromagnetic method (TEM) is used to image groundwater migration between aquifers in Inner Mongolia, China. First, 1D geophysical models of aquifers are generalized according to the hydrogeological conditions of the region, and the feasibility of detecting the multiple aquifers by TEM is analyzed and discussed. Then, the 2D models of aquifers pre- and post- pumping test are established based on the distribution of groundwater in the aquifers, and the variation law of induced electromotive force measured on the surface is analyzed. The simulation results show that significant time-lapse electromagnetic anomalies can be observed between pre- and post- pumping test and the variation in the induced electromotive force reaches a distinguishable level between 0.7 ms and 100 ms due to the vertical change in the aquifer properties. Furthermore, the electromagnetic variation generated by hydraulic connection between aquifers is greater than 30% within the range of 3/4 of the transmitting loop. Finally, a successful case history to map hydraulic connections between aquifers is conducted using a timelapse TEM pre- and post- a pumping experiment. This simulation and field experiment shows that time-lapse TEM could characterize and monitor the groundwater migration more effectively than pump tests or hydrogeochemical methods alone. [ABSTRACT FROM AUTHOR]

In this paper, the data of thin section, organic petrology, geochemistry, lithology and porosity were used to investigate enrichment conditions of Hetaoyuan Formation shale oil in the Biyang Depression. The results show the shale oil is a kind of low-maturity oil with medium density and low viscosity, and main factors controlling shale oil enrichment include total organic content (TOC), formation pressure, lithofacies and effective reservoirs. Shales in the fifth organic-rich interval are developed widely with large thickness (reach up to 150 m), high TOC content (2.0–4.68%), better organic matter types (type I and II1) and appropriate thermal maturity (usually larger than 0.5%), which are beneficial to generate much hydrocarbon, and volume expansion causes overpressure in source rock, especially in sections with low hydrocarbon expulsion efficiency due to less fractures. Free hydrocarbons S1 values increase with TOC contents, and significant overpressure correlates with the larger OSI (S1/TOC × 100) values and porosity. Well-developed calcareous shales and argillaceous shales with silty shale interlayers have better porosity, and effective pores (throat diameters greater than 10 nm) contribute to 47.5% of the total volume. [ABSTRACT FROM AUTHOR]

This paper reports on the petrography, geochemistry, and geochronology of late Mesozoic volcanic rocks in the Wenkutu area of the northern Great Xing'an Range, North‐east China, and discusses the formation age, petrogenesis, and tectonic environment of the Manketouebo, Manitu, Baiyingaolao, and Meiletu formations. Results of Zircon U–Pb dating show that the volcanic rocks in the Wenkutu area were formed during the Early Cretaceous (Manketouebo Formation at 145 ± 1 Ma, Manitu Formation at 141.3 ± 1.7 Ma, Baiyingaolao Formation at 128.7 ± 1.1 Ma, and Meiletu Formation at 129 ± 1 Ma). The Manketouebo, Manitu, and Baiyingaolao formations are dominated by intermediate to acid volcanic rocks that belong to the high‐K calc‐alkaline series, with Eu/Eu* values of 0.38–0.84.They are enriched in light rare earth elements (LREE) and depleted in heavy rare earth elements (HREE). The Meiletu Formation is dominated by intermediate to basic volcanic rocks, belongs to the high‐K calc‐alkaline series, has Eu/Eu* values of 0.89–0.97, and is enriched in Ba, K, Th, U, La, Ce, Sr, Nd, and Hf but relatively depleted in Nb, Ta, Zr, P, and Ti, with no obvious fractionation of LREE and HREE. Results indicate that the magma of the Manketouebo, Manitu, and Baiyingaolao formations had a crustal origin, whereas the Meiletu Formation was sourced from the mantle and subsequently contaminated by crustal materials. The late Mesozoic volcanic rocks in the study area were formed during an orogenic stage, and the compressional environment was caused by subduction of the paleo‐Pacific Plate below the Asian continental plate. [ABSTRACT FROM AUTHOR]

Santanghu Coalfield is the largest integrated coalfield exploration area in China. The major coal seams developing in Xishanyao Formation (Middle Jurassic) are the high-quality steam coals characterized by large thickness, favorable horizontal continuity and high coal quality. In this paper, twenty-two samples were collected from the three typical boreholes in Hanshuiquan district, representing the 11 coal seam sequences (7#, 8#, 9#, 13#, 14#, 15#, 17#, 18#, 19#, 20#, 22#), respectively. The petrographic characteristics of the coal-bearing sequence in Xishanyao Formation were firstly summarized systematicly, and then the coal-forming swamp characteristics and succession mechanism of the coal seam in Xishanyao Formation were defined by analyzing the samples. The maceral composition, structure, geochemical and geophysical characteristics of coal are included in original genetic criteria of coal-forming swamp analysis. And the composition of coal petrography, maceral and microlithotype are the most frequently used parameters. Coal is composed of microscopic constituents and inorganic substances. The Xishanyao Formation maceral mainly consists of vitrinite (65.74%-97.01%), inertinite (1.93%-34%), and the exinite shows the mode of regular change. The coal-forming swamp in Xishanyao Formation possesses the characteristics of mainly marsh, wet forest swamp facies, and shallow water covered forest swamp facies, and a few of coal seams distribute in the deep water covered forest swamp facies. In addition, the sporopollens in Xishanyao Formation are mainly Pinaceae evergreen broad leaf and needle-leaved plants, Osmundaceae, Cyatheaceae and Lygodiaceae, indicating that the warm and humid tropic-subtropical climate conductive to the persistent growth of coal-forming plants in the Middle Jurassic. The coal-forming swamp shows the characteristics of vertically upward fluctuation through the periodic transition. It indicates a shallow-deep-shallow change process of the water covered depth in the swamp. This is the principal factor for the formation of the high-quality and continuous coal seam in Hanshuiquan district, Santanghu Coalfield. [ABSTRACT FROM AUTHOR]

Basaltic magmas can provide important information about mantle source nature, tectonic settings and tectonic evolution for a given terrain. This paper reports geology, petrography and geochemistry of whole-rock major and trace elements and Nd−Sr isotopes for a suite of garnet amphibolites from southeastern Wulan (Ulan), Quanji Massif, northwestern China. The garnet amphibolites were likely generated from basaltic lavas, associated with both paragneisses and orthogneisses of the lower Delingha Group. The basaltic protolith of these amphibolites can be broadly constrained to be formed at ∼2.33 Ga in an extensional setting post-collision. The geochemistry of amphibolites shows subalkaline and highly evolved characteristics. They display high-Fe low-Ti characteristics, with TFeO of 13.1 wt.%–17.9 wt.% and TiO2 of 1.42 wt.%–3.09 wt.% (in most samples TiO2 ⩽2.5 wt.%). The chondrite-normalized REE patterns show enrichment of LREE and LILE and the primitive-mantle-normalized incompatible element patterns display negative P, Ti, Nb−Ta and Zr−Hf anomalies. The (87Sr/86Sr), values of 0.697 8–0.712 3 and εNd(t) values of −2.81–5.08 respond to depleted mantle model ages (TDM) of 2.33–3.30 Ga. These suggest that the precursor magmas of the protolith of the garnet amphibolites were probably derived from the Early Paleoproterozoic depleted sub-continental lithospheric mantle that had been metasomatized by subduction-induced fluids and melts. The precursor basaltic magmas were contaminated by the older crustal components during magma ascending. This post-collisional basaltic magmatic event at ∼2.33 Ga in Quanji Massif thus enhanced the subduction shutdown or slowdown tectonic regime both in NW China and coevally with those plate tectonics in some important domains worldwide during the Early Paleoproterozoic. [ABSTRACT FROM AUTHOR]

In this paper, we propose a methodology for landslide susceptibility assessment at a regional scale in Yunnan, southwestern province of China. A landslide inventory map including 3,242 landslide points was prepared for the study area. Five factors recognized as correlated to landslide (namely, lithology, relative relief, tectonic fault density, rainfall, and road density) were analyzed and mapped in geographic information system. An index expressing the correlation between each factor and landslides [called class landslide susceptibility index (CLSI)] was proposed in the study. While analyzing landslide distribution in a large area, point aggregation might be expected. To quantify the uncertainty caused by aggregation, class landslide aggregation index was proposed. To account for the importance of each of the factors in the landslide susceptibility assessment, some weights were calculated by means of analytic hierarchy process. We propose a weighted class landslide susceptibility model (WCLSM), obtained by the combination of CLSI values of each factor with the correspondent weight. WCLSM performance in the study area was evaluated comparing the results obtained by first modeling all landslides and then by performing a time partition. The model was run including only landslides that occurred before 2009 and then validated with respect to landslides that occurred after 2009. The prediction-rate curve shows that the WCLSM model provides a good prediction for the study area. Of the study area, 21.4 % shows very high and high susceptibility and includes the 87.7 % of the number of landslides that occurred after 2009. [ABSTRACT FROM AUTHOR]

Due to the importance of the wide occurrence of thick coal seams for Chinese coal resources, the origins of these seams have received considerable attention. Using the Early Cretaceous No. 5 coal seam with a thickness of 16.8 m in Inner Mongolia as a case study, this paper presents a systematic investigation of the coal petrology, geochemistry, and palynology of 19 coal samples to explain the origin and evolution of peat accumulation. The results indicate that the No. 5 coal seam is generally characterized by low rank (lignite), dominant huminite (average = 82.3%), intermediate ash yield (average = 16.03%), and sulfur content (average = 1.12%). The proportion of spores generally increases from the bottom to the top of the coal seam, whereas the proportion of pollen decreases. The vegetation in the coal seam is dominated by gymnosperms at the bottom and by ferns at the top. The paleographic precursor peat was most likely accumulated in the lakeshore where herbaceous and bushy helophytes were dominant. The total sulfur content was positively related to the huminite content. The sulfur content was possibly derived from bacterial action with sulfur brought in via marine incursions. Three overall declining-increasing values of carbon isotopes within the No. 5 coal seam possibly indicated three general cooling trends during peat accumulation. The environment of peat accumulation included three cycles, including one drying-wetting-drying in the bottom part and two drying-upwards cycles in the upper part. These cycles of the peat-accumulation environment could likely be ascribed to climate change because of their good agreement with humidity signals from plant types at that stage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluid overpressure plays a key important role in the formation of skarn iron deposit. Skarn iron deposits are important resources for iron-rich ores and their genesis has been a topic of debate. The Nanminghe iron deposit is a typical skarn iron deposit in Wu'an, Hebei Province, China which provides a good example to investigate the metallogenic mechanism. In this paper, we present a detailed study of the geology, petrography, and geochemical characteristics of magnetite in the Nanminghe iron deposit. Two types of magnetite can be identified in the massive ores: Mag1 is euhedral with radial cracks developed in the margin. It is a low-Si magnetite, with SiO 2 content ranging from 0.07% to 0.92%, with an average value of 0.49%. The SiO 2 content of Mag2 is from 0.90% to 3.29%, and an average value of 2.03%. The Mag2 is associated with quartz, goethite, and apatite. Geochemical characteristics of Mag1, together with the ore textures suggest its crystallization from an iron magma. There are significant differences in the geochemical characteristics between Mag1 and Mag2. Mag2 is rich in Nb, Ta, high field strength elements, large ion lithophile elements and has higher silica content. The Nb/Ta of Mag2 is higher than that of the original mantle. These characteristics as well as La/Ta vs Th/La, Th/U vs Sm/Nd and Nb/Ta vs Nb features show that Mag2 is formed in the environment of supercritical fluids. The δ56Fe of Mag1 is 0.157‰-0.172‰, with an average value of 0.166‰, and the δ56Fe of Mag2 is 0.119‰-0.160‰, with an average value of 0.139‰. The Fe isotope of Mag2 is lighter than Mag1. There is a negative correlation between δ56Fe and SiO 2 of Mag1 and Mag2, suggesting that the lighter δ56Fe of Mag2 was caused by injection of Si-rich fluids. We propose a genetic model where we envisage that the iron-rich melt formed in the deep magma chamber by reaction of dioritic rocks and carbonates. Mag1 formed by cooling of the iron-rich magma, following which Si-rich supercritical fluid were injected into the deep chamber resulting in fluid overpressure. The iron-bearing melt-fluid migrated upward along the magmatic conduit, when Mag2 formed. Our study provides insights into the formation mechanism of skarn iron deposits. [ABSTRACT FROM AUTHOR]

The Chinese Continental Scientific Drilling (CCSD) main hole is located in the Sulu ultrahigh-pressure metamorphic (UHPM) belt, providing significant opportunities for studying the metamorphic strata structure, kinetics process and tectonic evolution. Lithology identification is the primary and crucial stage for above geoscientific researches. To release the burden of log analyst and improve the efficiency of lithology interpretation, many algorithms have been developed to automate the process of lithology prediction. While traditional statistical techniques, such as discriminant analysis and K-nearest neighbors classifier, are incompetent in extracting nonlinear features of metamorphic rocks from complex geophysical log data; artificial intelligence algorithms are capable of solving nonlinear problems, but most of the algorithms suffer from tuning parameters to be global optimum to establish model rather than local optimum, and also encounter challenges in making the balance between training accuracy and generalization ability. Optimization methods have been applied extensively in the inversion of reservoir parameters of sedimentary formations using well logs. However, it is difficult to obtain accurate solution from the logging response equations of optimization method because of the strong overlapping of nonstationary log signals when applied in metamorphic formations. As oxide contents of each kinds of metamorphic rocks are relatively less overlapping, this study explores an approach, set in a metamorphic formation model and using the Broyden Fletcher Goldfarb Shanno (BFGS) optimization algorithm to identify lithology from oxide data. We first incorporate 11 geophysical logs and lab-collected geochemical data of 47 core samples to construct oxide profile of CCSD main hole by using backwards stepwise multiple regression method, which eliminates irrelevant input logs step by step for higher statistical significance and accuracy. Then we establish oxide response equations in accordance with the metamorphic formation model and employ BFGS algorithm to minimize the objective function. Finally, we identify lithology according to the composition content which accounts for the largest proportion. The results show that lithology identified by the method of this paper is consistent with core description. Moreover, this method demonstrates the benefits of using oxide content as an adhesive to connect logging data with lithology, can make the metamorphic formation model more understandable and accurate, and avoid selecting complex formation model and building nonlinear logging response equations. [ABSTRACT FROM AUTHOR]

The world-class Jinding deposit in SW China has ~15 Mt of Zn and Pb metals combined, in an evaporite dome containing amounts of gypsum/anhydrite. These gypsum and anhydrite are mainly located in limestone breccias (Member I), gypsum-bearing complexes (Member III), and red mélange, with some occurring as veins in clast-free sandstone (Member IV) and as fractures/vugs of host rock. The gypsum/anhydrite and dome genesis remain equivocal. The gypsum in limestone breccias and in red mélange with flow texture contains numerous Late Triassic Sanhedong limestone fragments. The δ34S (14.1%–17%), δ18O (9.7%–14.6%), and 87Sr/86Sr ratios (0.706913–0.708711) of these gypsum are close to the S-O-Sr isotopes of the Upper Triassic Sanhedong Formation anhydrite in the Lanping Basin (δ34S = 15.2%–15.9%, δ18O = 10.9%–13.1%, 87Sr/86Sr = 0.707541–0.707967), and are inconsistent with the Paleocene Yunlong Formation gypsum in the Lanping Basin (87Sr/86Sr = 0.709406–0.709845), indicating that these gypsum were derived from the Upper Triassic Sanhedong Formation evaporite but not from the Paleocene Yunlong Formation, and formed as a result of evaporite diapirism. The δ34S (14.3%–14.5%), δ18O (10.1%–10.3%), and 87Sr/86Sr ratios (0.709503–0.709725) of gypsum as gypsum–sand mixtures in gypsum-bearing complexes are similar to the 87Sr/86Sr ratios of gypsum in the Yunlong Formation of the Lanping Basin and Cenozoic basins in the northern part of the Himalayan–Tibetan orogen, suggesting that the material source of this gypsum was derived from the Yunlong Formation, and formed as a result of gypsum–sand diapirism. The gypsum veins in clast-free pillow-shaped mineralized sandstone and the gypsum in host rock fractures and vugs formed after the supergene minerals such as smithsonite. The δ34S (−16.3%~−12.7%) and δ18O (−9.8%~−4.7%) of this gypsum indicate that the gypsum is of supergene origin with sulfate derived from the reoxidation of reduced sulfur. We confirmed that the Jinding dome is genetically related to diapir of the Late-Triassic Sanhedong Formation evaporite. Clast-free sandstone and gypsum-bearing complexes in the dome were produced by diapir of the Paleocene Yunlong Formation unconsolidated gypsum–sand mixtures. [ABSTRACT FROM AUTHOR]

Magnetic susceptibility is widely applied in geology, but its use in the study of metamorphic rocks has been limited due to the complex nature of metamorphism. In this study, analyzing a partially retrogressed mafic enclave within Archean TTG gneiss from the Jiaobei Terrane, North China craton, we incorporate magnetic susceptibility with conventional metamorphic (petrographic and major element) proxies in order to investigate profiles of metamorphic retrogression. The magnetic susceptibility results show more complete retrogression in the direction parallel to the tectonic fabric and partial retrogression perpendicular to it. This geophysical observation, which is broadly consistent with the petrological observations and P--T estimates, suggests that the availability of fluids and perhaps even non-lithostatic pressure play roles in the preservation of such differential retrogression. This study thus introduces magnetic susceptibility as a novel proxy in this context, revealing its utility in rapidly and quantitatively identifying variable retrogression gradients consistent with, but with more precision than, measured metamorphic pressures. [ABSTRACT FROM AUTHOR]

Owing to the increasing challenges associated with coal mine exploration and development, extremely precise surveys with high-resolution images are required to support production. Conventional inversion methods cannot provide sufficiently precise images of the complex lithologies in coal measure strata. Accordingly, this study performed research in Qiyuan mining area, Shanxi Province, China, and predicted the complex lithology on the basis of facies control using waveform indication inversion and waveform indication simulation. Horizontal changes in seismic waveforms were used to reflect lithologic assemblage characteristics for facies-controlled constraints, and the vertical mapping the connection between seismic waveform and logging curves was shown. Moreover, high-resolution inversions of wave impedance and natural gamma parameters were conducted. Combined with lithologic shielding and accurate time–depth conversion, the inversions enabled the precise characterization of the lithological assemblage distribution in the study area. Our results showed that waveform indication inversion could distinguish between coal seams and limestone, whereas waveform indication simulation based on natural gamma could effectively distinguish between sandstone and mudstone. Furthermore, the horizontal resolution was improved and the vertical resolution extended to a thickness of 2–3 m. In addition, the inversion results were highly consistent with drilling results, with an error <0.1 m. Therefore, waveform indication inversion and simulation could be applied to coal mines for safe and efficient production. [ABSTRACT FROM AUTHOR]

On the basis of research and analysis of the landslide system of the Three Gorges Reservoir area, this paper systematically analyzes and studies the temporal–spatial distribution law of landslides of this reservoir area and their impacts on environment of this area. The paper puts forward that the temporal–spatial distribution of this area's landslides is mainly controlled by lithologic characters of strata, geological structure, valley landscape, and types of bank slope structure; landslide deformation and failure have such characteristics as simultaneity, laggardness, cyclical instability, and stage. Besides, the paper systematically analyzes and studies the main impacts of landslide on environment and points out that landslides and collapses will bring about relatively serious impacts on relocation and layout of cities and towns along the banks. These impacts mainly include the increase of relocation investment, number of migrants, and compensation for losses. Much attention and evaluation should be paid to the impacts of Xintan Landslide and Lianziya Landslide—large landslides near the Dam—on the construction and safety of the Three Gorges Project. However, landslides have relatively small impacts on shipping and reservoir capacity. The above-mentioned research is of great guiding significance for the construction of the Three Georges Project, planning and construction of cities and towns along the banks, and protection of geological environment. [ABSTRACT FROM AUTHOR]

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[Display omitted] • Middle Permian adakite, arc granitoids and high fractionated granite in the northern Qaidam Block have been identified. • Various magma sources contributed to the occurrence of these granitoids in the northern Qaidam Block. • The northern Qaidam Block was an active continental arc during the Middle Permian. • A five-stage model of subduction slab roll-back and subduction zone retreat for late Late Paleozoic to Early Mesozoic tectonic evolution of the northern Qaidam Block. Origin and tectonic setting of late Late Paleozoic to Early Mesozoic igneous rocks in the northern Qaidam Block (NQ) have long been a matter of debate. In this paper, we report new zircon U-Pb ages and Hf isotopic compositions and bulk rock major and trace elemental compositions for granitoids of the Yanchangbeishan area in the NQ. The granodiorite, tonalite, granodiorite, and syenogranite yielded zircon U-Pb ages of 271.9 Ma, 262.0 Ma, 272.4 Ma and 261.3 Ma, respectively, corresponding to ε Hf (t) values are 13.04–14.32, 8.14–10.77, 8.66–11.88, and 8.22–10.43, respectively. These granitoids are compositionally I-type granites and exhibit varying degrees of enrichment in Rb, Th, U, and K, and depletion in Nb, Ta, and Ti. According to field relationships, petrology, geochronology, and geochemistry, the granitoid types can be divided into three groups: (1) ca. 272 Ma granodiorites, which are formed through partial melting of metagreywackes and amphibolites derived from depleted mantle; (2) ca. 262 Ma tonalite, which represents a typical high-silica adakite derived from partial melting of subducted oceanic crust during the evolution of depleted mantle; and (3) ca. 261 Ma syenogranite, which is formed by the partial melting and high-degree fractional crystallization of mixed crustal materials. Considering our findings and the regional geological background, we propose a five-stage tectonic evolution model of subduction slab roll-back and subduction zone retreat for the late Late Paleozoic to Early Mesozoic of NQ. [ABSTRACT FROM AUTHOR]

Scheelite, one kind of common REE-rich and U-bearing hydrothermal mineral, is extensively developed in various types of gold deposits, which can be used to record nature and timing of metallogenesis. The Zhaishang Carlin-like gold deposit in the Qinling Orogen is a giant Au deposit, hosting 127t of Au @ 2.67 g/t with economic concentrations of tungsten and antimony. The study reports two types of scheelite based on the characteristics of petrography and geochemistry. Sch A shows significant oscillatory zoning with dark gray cathodoluminescence (CL) response, whereas Sch B displays patchy textures with brighter CL response. Systematic LA-ICP-MS U–Pb dating of Sch A and Sch B yields ages of 227.1 ± 3.2 Ma and 226.2 ± 6.9 Ma, respectively. The new dates, constraining the Zhaishang Au–W mineralization to ~ 227Ma, coincide well with the western Qinling magmatism, metallogenic and tectonic events. There are significant variations in concentration, the Sch A has low REE content (mean = 41.3 ppm), negative Eu-anomaly with slightly positive Ce-anomaly, whereas Sch B, with small negative or positive Eu-anomaly, has higher REE content (mean = 247 ppm) and higher positive Ce-anomaly. The positive correlation of EuN and EuN* records oxidizing condition during the whole W mineralization event. Additionally, Sch B intergrown with selenides with an increase in the Ce-anomaly supports that the latter has higher oxygen fugacity environment. The Sr isotope signature for scheelite supports that ore-forming metals mostly inherited the host rock component, while the proportion of magma-derived Sr increased in the Sch B. Fluid–rock interactions co-precipitated Au and W caused by the release of Fe and Ca cations and the increase of pH. The study highlights that scheelite as a recorder can help in deciphering the nature and timing of metallogenesis of the studied Au–Sb–W deposit, and thus other similar Au–W deposits. [ABSTRACT FROM AUTHOR]

The Pulang super-large porphyry Cu polymetallic deposit, located in the Sanjiang area of Yunnan Province, is one of the largest Cu deposits in China. This deposit hosts Cu resources of ~5 × 106 t and other ore-forming elements, such as Mo, Au, Ag, Pb, Zn, Pt and Pd. Recently, obvious hydrothermal vein-type Pb–Zn mineralization, with a Pb + Zn resource of ~0.4 × 106 t, has been detected in the North Ore Section of the deposit. However, the genesis of these Pb–Zn ore bodies, especially their relationship to the major Cu ore bodies in the South Ore Section, remains controversial. We conducted geologic description, fluid inclusion petrography and microthermometry, and C, H, O and S isotope studies to uncover the genesis of Pb–Zn vein-type mineralization in North Pulang. As a result, three types of Pb–Zn veins were identified: a quartz–pyrrhotite–chalcopyrite–sphalerite–galena vein, a quartz–pyrrhotite–sphalerite–galena vein, and a calcite–quartz–pyrrhotite–galena vein. All fluid inclusions in the quartz from different veins are liquid-rich inclusions, with homogenization temperatures in the range of 184 °C–235 °C and salinities between 10.4 wt.% and 17.8 wt.% NaCl eq., indicating that the Pb–Zn ore-forming fluid was a single-phase fluid with a low temperature and low-to-medium salinity. Hydrothermal quartz in different stages displays δDwater values ranging from −46.9‰ to −120.0‰ (V-SMOW), and the calculated δ18Owater values range from 2.4‰ to 4.3‰ (V-SMOW), implying that the mineralization fluids likely originated from magma, with a minor involvement of meteoric water. The δ13CCal values (−2.3‰ to −7.9‰ V-PDB) of calcite indicate that C likely originated from a deep-seated source. The δ34S values of chalcopyrite, pyrite, pyrrhotite and sphalerite reveal that S was possibly derived from magmatic rocks. Based on the above data, it is suggested that the Pb–Zn mineralization in North Pulang was the result of the northward migration of ore-forming fluids that originated from South Pulang along the NE-trending structural fractures. A strong water–rock interaction occurred during the migration process. However, the involvement of meteoric water and accompanied cooling of fluids were most likely responsible for the precipitation of galena and sphalerite. [ABSTRACT FROM AUTHOR]

Thirteen ichnogenera and seventeen ichnospecies were recognised in carbonate rocks from the Lower Permian Taiyuan Formation in North China Basin. Based on the composition, occurrence and diversity of ichnofossils, intensity of bioturbation, lithologic characteristics, especially on the variation of individual size and the filling colour diversities of theZoophycosburrows, four types of ichnofabrics were recognised, that is (1) epigenic tiering ichnofabric – mainly appeared on or near the bedding plane and formed in restricted bay or lagoon sedimentary environments; (2) shallow tiering ichnofabric – developed less than 15 cm under the bedding plane and occurred in the upper shallow-marine environment; (3) medium tiering ichnofabric – mainly distributed from 15 to 20 cm under the bedding plane and generated in the mid-upper shallow sea (restricted–open platform); (4) deep tiering ichnofabric – distributed from 25 to 30 cm under the bedding plane and occurred in lower shallow sea (open platform) far from shore. Based on ichnological and sedimentological analyses above four types of ichnofabrics, the sedimentary environment model of the ichnofabrics in carbonate rocks from the Taiyuan Formation in North China Basin is proposed in this paper. [ABSTRACT FROM AUTHOR]

The supercontinent Rodinia existed as a coherent large landmass from 900 to 750 Ma and is now dispersed over all current major continents. Controversy has long surrounded the reconstructions of the East Asian blocks in Rodinia, especially the South China craton and nearby microcontinents. The Central Qilian block is a Precambrian microcontinent in the early Paleozoic Qilian orogenic belt, which is located in the northeastern part of the Qinghai-Xizang (Tibet) Plateau and marks the junction of the North China, South China and Tarim cratons. The formation and tectonic affinity of the Precambrian basement in the Central Qilian block is unclear, which affects our understanding of the assembly of Rodinia. The Huangyuan Group and the Maxianshan Group crop out in the eastern part of the block and represent the lower part of the basement. In this paper, we present a systematic study of the petrology, whole-rock geochemistry, and geochronology of amphibolites and orthogneisses from the Huangyuan and Maxianshan Groups. The protolith of the amphibolites was tholeiitic and calc-alkaline gabbro or gabbroic diorite formed in a continental arc environment, with laser ablation-inductively coupled plasma mass spectrometry (LAICPMS) zircon U-Pb ages of 967-957 Ma, a wide range of eHf(t) values of -3.74 to +5.06 and TDM1 model ages peaking at 1470 Ma and 1607 Ma. Minor inherited zircon grains with older ages of 1207-1515 Ma were collected from the amphibolites. The primitive magma was derived from partial melting of a spinelfacies fertile (lherzolite) lithospheric mantle that was modified by fluids and melts from a subducted slab. Fractionation of olivine, Fe-Ti oxides and plagioclase played a dominant role in the magma differentiation for gabbroic rocks in the Huangyuan Group, while fractionation of olivine and clinopyroxene controlled differentiation to form Maxianshan Group gabbros. The protolith of orthogneisses includes weakly peraluminous I-type and A2-type granites with consistent LA-ICPMS zircon U-Pb ages of 963-936 Ma, a wide range of eHf(t) values of -3.86 to +6.15 and TDM2 model age peaks at 2001 Ma and 1772 Ma. A few inherited zircon grains yield ages of 1033-2558 Ma. The peraluminous I-type granites resulted from a low-pressure partial melting process and the peraluminous A-type granites were derived from a charnockite source heated by largescale magmatic underplating. Fractionation of plagioclase, biotite, and K-feldspar from the magma played the main role during the generation of the granitoids. The intrusion of these granites is related to a back-arc extension. It is inferred that the lower part of Precambrian basement of the Central Qilian block is composed mainly of early Neoproterozoic rock assemblages formed in a trench-arc-basin system during the assembly of the Rodinia supercontinent, with probable existence of late Paleoproterozoic to Mesoproterozoic continental nuclei. Combining our results with existing data, we identify a sequence of initial intra-oceanic subduction (ca. 1121-967 Ma) in front of a continental nucleus, continuous subduction of oceanic crust beneath the continental mass with formation of a mature continental arc and a back-arc basin (ca. 967-896 Ma) and continental rifting (

The spatiotemporal evolution characteristics of precipitation infiltration recharge during the past 50 years are discussed in this paper. This research is significant for groundwater resource rational utilization. The distribution of precipitation infiltration recharge coefficients in the 1960s, 1980s, and 2000s can be obtained using unsaturated zone lithology and depth to water table at different times. The amount of precipitation infiltration recharge in the 1960s, 1980s, and 2000s can be calculated using precipitation infiltration recharge coefficients and precipitation data from the Ministry of Water Resources of China. Results show that the change in the precipitation infiltration recharge coefficient is closely related to the water table decrease. From the 1960s to the 1980s, the precipitation infiltration recharge coefficient clearly increased in all units. From the 1980s to the 2000s, the value slightly increased in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains and slightly decreased in the piedmont alluvial-proluvial and central alluvial-lacustrine plains. The piedmont alluvial-proluvial and ancient Yellow River alluvial-proluvial plains exhibited a large precipitation infiltration recharge coefficient for the coarse lithology. The amounts of precipitation infiltration recharges were 16.23×10 (1960s), 19.11×10 (1980s), and 19.42×10 m/a (2000s). The amount of precipitation infiltration recharge increased from the 1960s to the 1980s then decreased from the 1980s to the 2000s in the piedmont alluvial-proluvial and the central alluvial-lacustrine plains. However, this value increased from the 1960s to the 2000s in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains. [ABSTRACT FROM AUTHOR]

The Shulu Sag is a typical rift valley basin in Eastern China, where the formation mechanism of Cenozoic salt-bearing series has been poorly understood. In this paper, petrologic analysis, X-ray powder Diffraction (XRD) analysis and the analysis of halite ion concentrations of the first member of the Shahejie Formation from two drilling cores were conducted to interpret the formation mechanism of these salt-bearing series in Shulu Sag. The results indicated that the salt-bearing series is mainly composed of calcilutite or mudstone at top and bottom, and anhydrite-bearing halite and thin interbeds of salt-bearing calcilutite and dark grey shale in the middle part. These thin interbeds with porphyritic or petalshaped glauberite crystals or some thinner dark grey shale interbeds separated halites into several members with the average thickness of only 9~12 cm in the two drilling holes. This typical rhythmic pattern due to frequent alternation of concentration was evidenced by the variation of chemical composition and hydrogen isotopes of halite fluid inclusions. The presence of large number of primary fluid inclusions within chevron crystals and vertically oriented bottom-growth crystals showed that the halite were precipitated in shallow water (<60 cm). These features are direct evidence for this frequent alternation of dissolution and concentration of brines and terrigenous detrital-chemical shallow-water sedimentary model of these small rift-valley basins in Eastern China. [ABSTRACT FROM AUTHOR]

The spatial-temporal extent and influence of the Mongol-Okhotsk and Paleo-Pacific tectonic regimes in northeast (NE) China and adjacent areas during late Mesozoic times have long been controversial. As a superimposed rift system which formed due to extensive intracontinental extension during the Late Jurassic to Early Cretaceous periods, the Hailar-Tamtsag basin is a key area to study the relationship between the Mongol-Okhotsk and Paleo-Pacific tectonic regimes and their superposition. With the aim of constraining the evolution of those two regimes, in this paper, the Tanan depression, which is a second-order structural unit in the western part of the Hailar-Tamtsag basin, has been chosen as the research object. On the basis of structural analysis of three-dimensional (3D) seismic data in the Tanan depression, and taking into account the controlling effect and influence of the pre-existing facies on the basin evolution, the deformation events in the Early Cretaceous can be subdivided into four periods: 1) A NW-SE trending extension during the deposition of the Tongbomiao Formation to the upper part of the second Member of the Nantun Formation; 2) A NW-SE trending compression during the deposition of the upper part of the second Member of the Nantun Formation to the first Member of the Yimin Formation; 3) A near EW trending extension during the deposition of the second Member to the lower part of third Member of the Yimin Formation; 4) A near EW trending compression during the deposition of the upper part of the third Member of the Yimin Formation. Additionally, we identify compressional structures in the basement in the southeast part of the depression, which is a key study that resulted from the Mongol-Okhotsk collisional orogeny during the Late Jurassic. The above five major deformational events make up a relatively complete tectonic deformation sequence of the Hailar-Tamtsag basin. Moreover, the deformation sequence, together with other available information from the literature in NE China and adjacent areas, including petrology, geochemistry and geochronology data, also record the whole process from the orogenic stage after the closure of the Mongol-Okhotsk Ocean, over the post-orogenic collapse of the Mongol-Okhotsk orogen, to the weakening of the influence of the Mongol–Okhotsk regime, and eventually to be replaced by the Paleo-Pacific tectonic regime. Considering that the superposition and transformation of the two tectonic regimes involves almost all the geological process in NE China and adjacent area during the late Mesozoic, the complete geological record in the Tanan depression during this period provides new constraints on the research of regional tectonic evolution, and the model of multiphase deformation is also expected to have useful implications for future studies of complex basin systems. • Subdividing the deformation events within the basin during Late Jurassic to the Early Cretaceous into five periods. • The basin was not continuously extended, and the alternation of extension and shortening occurred through the evolution. • Identifying the late Jurassic thrust fault system in the basement of the Tanan depression for the first time. [ABSTRACT FROM AUTHOR]

To accurately evaluate altered volcanic reservoirs in the Songliao Basin of China and study the effect of alteration on pore structure, this paper established a methodology for log evaluation based on conventional log data. The volcanic reservoir in the Songliao Basin, China is variable in lithology, complex in pore structure and widespread in alteration phenomena. Because of these problems, the conventional charting method is not good at lithological identification, and the reservoir interpretation conclusions based on interpretation of the conventional logging method are not consistent with the actual logging data, making it difficult to carry out accurate logging evaluation. To solve such problems, this study adopted the particle swarm optimization-support vector machine (PSO-SVM) for carrying out lithological identification. Then, alteration factors were established to evaluate the alteration degree of volcanic reservoirs and obtain the altered clay content by fitting to correct the effect of alteration. Designing the volume model that considered altered clay and selecting the Simandoux model that could correct the influence of clay to calculate relevant petrophysical parameters such as porosity and water saturation, thus formed a methodology of logging evaluation suitable for the altered volcanic reservoir in the study area. At the same time, the study found that for different volcanic rocks, the effects of alteration on pore structure are different. An analysis, in combination with alteration factors and T 2 NMR spectra, showed that for the volcanic reservoir of nonsevere alteration, the higher the alteration degree, the greater the total porosity and the void porosity. However, with increasing alteration degree, the effective porosity of andesite was higher, while that of tuff worsened. The findings may provide a new idea for the analysis of the pore structure of altered volcanic reservoirs. • This paper presents a workflow for logging evaluation of altered volcanic reservoirs. • Proposes a method to evaluate the degree of alteration. • Analyzes the influence of alteration on the pore structure of volcanic reservoir. [ABSTRACT FROM AUTHOR]

The Dasuji giant porphyry molybdenum deposit is one of the largest ore deposits recently discovered along the Yinshan–Yanshan–Liaoning molybdenum belt in China. Using this deposit along the Yinshan–Yanshan–Liaoning molybdenum belt as the study area, the present study proposed a two-stage approach aimed at marking out the hydrothermally altered anomalies in the study area for the guidance of future prospecting in other regions. First of all, the Principal Component Analysis (PCA) and specific Band Ratio methods were applied to the ASTER images from different acquisition dates to extract ferric oxides and hydroxyl alterations related to the porphyry molybdenum deposit. Then, the Fractal-Aided Anomaly-Overlaying Selection model was adopted to recognize two ferric and hydroxyl alteration layers for separating anomalies from the interferences caused by geology and random noise from the data. Furthermore, for lithological differentiation in the previously marked off area, the Random Forest Classifier (RFC) was applied to the composite data obtained via the ASTER, ETM, and DEM, and it is demonstrated that the DEM can significantly improve lithological mapping in areas with complex vegetation cover and topography. Based on field verification and comparison with geological maps, the research revealed that the suggested two-stage approach may effectively reduce erroneously recognized anomalies produced during the first stage while retaining ore-related anomalies for gigantic porphyry molybdenum deposit prospecting in the Dasuji area, which showed the good application potential of the proposed model to extract actual hydrothermally altered anomalies adopted for lithological discrimination and mapping. [ABSTRACT FROM AUTHOR]