Table of Content

20 December 2025, Volume 31 Issue 06

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New Thinkings on Studying Emplacement-Crystallization Ages of Granitic Plutons in the Nanling Range: Based on Calculations of the Cooling Process, Crystallization Latent Heat and Radiogenic Heat of the Granitic Melts 

ZHANG Bangtong, LING Hongfei, CHEN Peirong, WU Junqi

2025, 31(06):  647-663.  DOI: 10.16108/j.issn1006-7493.2024096

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Based on the element diffusion theory and analysis to the experiment of U-Pb diffusion in zircon, it is confirmed that
the“closure temperature of U-Pb isotope system in natural zircon >900 ℃”drawn from experiment of U-Pb diffusion in zircon by heating zircon crystals done by Lee et al. (1997) and Cherniak et al. (2000) can not be applied to the zircon crystallization process from the granitic melt. Using least squares regression procedure, a best regression equation (tZr= 1.00346tAr-1.03511) with high correlation coefficient (R=0.996) is fitted for 514 pairs of zircon U-Pb age and hornblend-biotite Ar40/Ar39 age of granite plutons world wide. The PDF of the frequency analysis for these granite plutons shows symmetrical normal distribution with skewness coefficient(CSK)-0.16. These statistical characteristics cofirmed that the zircon U-Pb age can not represents the emplacement age of a granite pluton, but represent crystallization age also. According to the time difference elapsed from granite melt to crystallization , (ΔtECTD) , these ΔtECTD (emplacement crystallization time difference) of 9 plutons were 52.0 my (Jiufeng), 26.1 my

(Xishan), 28.6 my (Jingjiling), 39.3 my (Guidongxiti), 42.7 my (Qitianling), 45.7 my ((Huashan), 42.7 my ((Guposhan), 9.74 my ((Pitou), 16.4 my (Zhaibei), respectively. Based on the zircon U-Pb ages, ΔtECTD of these granitoids and inversion calculation, these emplacement ages of 9 plutons in Nanling Rang were 219.4 my (Jiufeng), 182.1 my (Xishan), 184.6 my (Jingjiling), 199.4 my (Guidongxiti), 203.7 my (Qitianling), 207.7 my (Huashan), 205. 7 my (Guposhan), 192 my (Pitou), 190.2 my (Zhaibei), respectively. These data contribute important evidences to the Indosinian cycle emplacement of the Early Yanshanian plutons in Nanling Rang and display the double magmatic-tectonic features in NR i.e. the E-W trending Indosinian tectonic framework(representing by tE ) and the Early Yanshan granite plutons (representing by tC).

Study on the Physicochemical Characteristics of Primary Magma of the Metaluminous-Peraluminous Rare-metal Granitic System

DUAN Xinhao, XIE Lei, WANG Rucheng, LU Jianjun

2025, 31(06):  664-687.  DOI: 10.16108/j.issn1006-7493.2025006

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A series of metaluminous-peraluminous rare-metal granites formed at around 130 Ma is distributed in the Jiangnan Orogenic Belt in China. They are usually characterized by multiple phases with (amphibole-bearing) biotite granite as the early one and the biotite granite and zinnwaldite albite granite as the later phases. Their whole-rock chemical compositions are commonly rich in niobium (Nb), zirconium (Zr), and rare-earth elements (REEs), and columbite is the typical ore mineral. They are different from the peraluminous rare-metal granites formed at around 150 Ma (such as Yichun pluton) widely distributed in South China, which are mainly composed of muscovite granite and zinnwaldite and/or lepidolite granite, and are mainly rich in lithium (Li), tantalum (Ta), rubidium (Rb), and cesium (Cs). Three key factors govern rare-metal mineralization in granitic systems: the primary condition of magma, the fractional crystallization and evolution, and the effects of fluids hydrothermal fluids. Most studies have concentrated on the late-staged lithologies of the pluton, thereby providing significant insights in to the latter two factors. In order to better understand the influence of the primary condition of magma on late-stage mineralization, this study focuses on the early lithologies of the Lingshan pluton in the Jiangnan Orogenic Belt, including coarse-grained porphyritic amphibole-bearing biotite granite (AmBG) and the newly discovered fine-grained porphyritic amphibole-bearing biotite granite (F-AmBG) contacting with AmBG. Based on detailed and systematic petrographic and mineralogical results, this study estimated the primary physicochemical condition of the magma of the Lingshan metaluminous granites, including the temperature, pressure, oxygen fugacity, water content, and melt composition (especially Nb and halogen content) characteristics. Meanwhile, a series of calculation methods suitable for this system were suggested. The results show that the pressure of 300-330 MPa, the oxygen fugacity (ΔNNO) of -1.53 to -1.19, the water content of around 5 wt%, and the main crystallization temperature of minerals of around 720-800 ℃ . The clinopyroxene and columnar amphibole in the matrix found in the F-AmBG formed at 830-890 ℃ , as the products of rapid crystallization. The estimated Nb content of 27×10-6 -362×10-6 indicates the Nb enrichment in the initial magma. The highest Nb value in the melt composition is correlated to the Nb composition in titanite, which may be associated with the local enrichment of rare-metal caused by the volatile-rich components. 

LA-ICP-MS Mapping Analysis and Enrichment Mechanisms of Rare Earth Elements in Black Shales from the Cambrian  Barite Deposit, Tianzhu, Guizhou Province, China

Ferdon·Hamit, YANG Tao, YANG Liu

2025, 31(06):  688-697.  DOI: 10.16108/j.issn1006-7493.2024085

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Rare earth elements and yttrium represent key strategic mineral resources in China, and the research on their metallogenic mechanisms hold significant scientific importance. Previous studies have confirmed the presence of large barite deposits accompanied by notable REY enrichment in the Cambrian Niutitang Formation black shales of the Southeastern Guizhou- Western Hunan region. But the sources, occurrence states, and enrichment mechanisms of REY remain poorly constrained. This study selected REY-rich layers from the Tianzhu barite deposit and systematically applied laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) mapping and micro-X-ray diffraction (μ-XRD) to investigate the origin, occurrence, and enrichment processes of REY. Integrated analyses reveal: (1) REY distribution patterns exhibit strong consistency with modern seawater-pore water systems, where elevated Y/Ho ratios, Ce/Ce*, and Eu/Eu* in high-REY zones indicate predominant seawater-derived signatures, with minor terrigenous inputs; (2) P-Ca-REY ternary correlation analysis demonstrates a significant positive relationship between Ca content and REY abundance (R2= 0.80), whereas no significant causal links exist between Ca-P or REY-P. Micro-XRD confirms that REY primarily reside in authigenic carbonate crystal lattices; (3) A“seawater sourcediagenetic enrichment” model is proposed, elucidating that sulfate radicals in barite oxidize organic matter during diagenesis, releasing carbonate ions that promote Ca2+-carbonate precipitation, thereby driving REY enrichment via isomorphic substitution in carbonate minerals. Through multidisciplinary approaches, this study proposes the seawater-derived origin, carbonate-hosted occurrence, and diagenetic activation mechanisms of REY in the Tianzhu deposit, providing new insights into the enrichment patterns of REY in black shale systems.

Elemental, Lithium Isotopic Composition and Paleoclimatic Significance of Upper Silurian-Devonian Paleosols in Qujing, Yunnan Province

XU Chengxiao, YANG Hao, GUAN Yiting, WU Weihua

2025, 31(06):  698-710.  DOI: 10.16108/j.issn1006-7493.2024094

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To explore the influence of plant landfall in the early Paleozoic on climate and environmental change in southwest China, we conducted elemental and lithium isotopic analyses of late Silurian-Devonian paleosols from Qujing City, Yunnan Province. Clay separation experiments were performed to eliminate the interference of unweathered primary minerals on the Li isotopic composition. The results show that the Chemical Index of Alteration (CIA) ranges from 66.8 to 82.7 with mean the degree of chemical weathering is moderate to strong. Compared with the upper Silurian and middle Devonian, the CIA average values (77.9±1.9) of the lower Devonian paleosols are higher, indicating enhanced chemical weathering. The Li contents in the clay fraction (<2 μm) range from 24.1 to 383.3×10^-6, evidently higher than in the bulk samples (7.5 to 74.5×10^-6) and the upper continental crust average (35±11×10^-6), suggesting Li enrichment in the clay minerals during the chemical weathering process. The lithium isotopic compositions of the clay fraction (δ⁷LiClay, -7.0 ‰ to +2.2 ‰ ) are lower than the UCC (~0 ‰ ), with the greatest isotopic fractionation occurring in the early Devonian (-7.0‰ ). This is primarily due to stronger chemical weathering during this period, which led to the formation of more clay minerals that preferentially adsorbed lighter ⁶Li, resulting in more negative δ⁷Li values. Meanwhile, many well-preserved plant fossils have been found in the Xujiachong Formation of the Lower Devonian. Combined with plant fossil records from the same period globally, this suggests a link between the enhanced silicate weathering may be related to the evolution of higher plants. This study provides Li isotope evidence for the hypothesis that the landing of vascular plants in the early Devonian triggered enhanced chemical weathering and reduced CO2 levels, helping to improve the understanding of the interactions between vegetation, weathering, and climate.

Purification Synthesis and Dissolution Thermodynamics of Common Calcium Arsenate Minerals

TIAN Yile, ZHU Xiangyu, TANG Minghao, LU Xiancai, WANG Rucheng, TENG Hui

2025, 31(06):  711-719.  DOI: 10.16108/j.issn1006-7493.2025004

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Arsenic is a toxic metalloid that poses significant health risks, including chronic arsenic poisoning, cardiovascular diseases, and cancer. Due to both human activities and naturally high arsenic levels, arsenic contamination has become a global environmental and health concern. The World Health Organization (WHO) lists arsenic among the ten chemicals of major public health concern. In the environment, arsenic primarily originates from arsenic-bearing minerals, and its mobility is governed by their dissolution and precipitation processes. Understanding the thermodynamic and kinetic properties governing the dissolution and precipitation of common arsenic minerals is essential for quantitatively assessing arsenic migration and transformation processes in natural environments. Calcium arsenate minerals, commonly found in calcium-rich and iron-poor environments such as karst regions, are secondary arsenic minerals that regulate arsenic mobility in these settings. Thermodynamic parameters, particularly solubility product constants (Ksp), are critical for assessing their stability and determining potential risks of secondary arsenic pollution. Despite their importance, existing studies report substantial inconsistencies in the solubility product (Ksp) values for the three most common calcium arsenate minerals: weilite (CaHAsO4), haidingerite (CaHAsO4·H2O), and pharmacolite (CaHAsO4·2H2O). These inconsistencies may arise from: (1) the similar formation conditions of these minerals, leading to their frequent co-occurrence in natural settings and the challenges in achieving pure synthesis in laboratory conditions; (2) interconversion among the three minerals during dissolution, along with phase transitions or the formation of other calcium arsenate phases, resulting in non-uniform dissolution behavior; (3) neglectance of calcium-arsenic complexation reactions in Ksp calculations. This study addresses these challenges by synthesizing pure weilite, haidingerite, and pharmacolite through controlled adjustments of pH, temperature, Ca/As ratios, and Mg/Ca ratios. Consistent dissolution experiments were then performed under ambient temperatures and pressures with real-time control of solution conditions. Using equilibrium solution parameters and accounting for calcium-arsenic complexation reactions, coupled with an updated Ca-As-H2O thermodynamic model, the standard solubility constants (Ksp) for weilite, haidingerite, and pharmacolite were determined as 10^-4.90, 10^-4.64, and 10^-4.66, respectively. 

Analogue Modeling of the Formation Mechanism of Ultra-Long Distance Overthrust: A Case Study of the Karakash River Profile in Southwestern Tarim Basin

AZMAT Mirhalim, JIA Dong, ZHONG Cheng, YANG Shuang, MAO Yuqiong

2025, 31(06):  720-732.  DOI: 10.16108/j.issn1006-7493.2024095

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The maximum length of overthrusts has long remained an unresolved enigma in structural geology. Theoretical
calculations typically limit their lengths to approximately 16 kilometers, yet geological observations, particularly in foreland basins, often reveal overthrusts extending far beyond this limit, reaching hundreds of kilometers. For instance, overthrust in the Southwestern Tarim Basin spans 230 kilometers, significantly exceeding theoretical predictions. This study employs analogue modeling based on the geological prototype derived from structural interpretation of the Hetian-Mazhatage seismic reflection profile. Four experimental setups are designed to investigate the formation mechanisms of ultra-long-distance overthrusts by simulating syn-tectonic growth strata (via adjustments to brittle cover thickness) and modulating the shear yield strength of the ductile décollements (through variations in silicone viscosity). Experimental results demonstrate that the low-viscosity décollements significantly enhance the forward propagation of deformation in the foreland direction, increasing both the velocity and distance of strain transfer. Conversely, high-viscosity décollements impede such propagation. Additionally, the inclusion of syn-tectonic growth strata in the models amplifies decoupling effects, accelerating and extending strain transfer toward the foreland, thereby facilitating the development of long-distance overthrusts. The experiments reveal that the synergistic interaction between low-viscosity décollements and syn-tectonic growth strata constitutes a critical precondition for the formation of ultra-longdistance overthrusts in the Southwestern Tarim Basin. These findings provide novel insights into the mechanisms governing the development of ultra-long-distance overthrusts in natural settings.

Present-day Geothermal Characterization of the East China Sea Shelf Basin and Its Controlling Factors

DUAN Ankang, LI Yan, LIU Shaowen, ZHONG Kai

2025, 31(06):  733-745.  DOI: 10.16108/j.issn1006-7493.2025005

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Geothermal regime is essential for understanding the tectonic mechanism and geodynamics of marginal basins. The East China Sea Shelf Basin (ECSSB), located at the junction of the Eurasian Plate and Pacific Plate, has undergone multiple tectonic deformation, making its tectono-thermal evolution complex. Present-day geothermal regime could provide tight constrains for understanding the tectono-thermal process. However, due to the limited coverage and ambiguous quality of previous heat flow data, the thermal regime of the ECSSB remains poorly understood, posing challenges in exploring the relationship between the geothermal regime and tectonics. This study reports 52 new heat flow data estimated from the industry boreholes in the ECSSB, and integrate previous data to revisit the thermal regime of the ECSSB. The results show that the ECSSB has an average geothermal gradient of 32.0 ℃ /km and a mean seafloor heat flow of 67 mW/m², consistent with the average value of continental China. In addition, the western depression zone shows an average geothermal gradient of 30.7 ℃ /km and an average seafloor heat flow of 65 mW/m², while the eastern depression zone exhibits an average geothermal gradient of 32.4 ℃ /km and an average seafloor heat flow of 71 mW/m2, indicating an increasing from west to east in thermal regime. This geothermal trend is quite consistent with the migration of rifting process within the ECSSB, associated with the rollback of the Pacific Plate subduction. It is concluded that the tectonic evolution of the ECSSB controls the geothermal pattern. Besides, the basement topography and the radiogenic heat contribution by granite base also account for the localized heat flow anomalies. The findings provide new clues for understanding the tectonics of the ECSSB and assessing the hydrocarbon potential.

Effect of Secondary Aggregate Size on Lead Migration in Xiashu Soil

LI Xiang, SHEN Zhengtao

2025, 31(06):  746-755.  DOI: 10.16108/j.issn1006-7493.2025001

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With the acceleration of industrialization, the problem of heavy metal pollution in soil is becoming increasingly serious. Soil heterogeneity, especially the difference in the size of secondary aggregates (soil clods), significantly affects the pore structure, permeability and hydrological characteristics of the soil, thereby changing the migration process of heavy metals. Recently, although some studies have focused on the effect of soil aggregates on heavy metal migration, the mechanism of the role of soil clods of different sizes in actual soil pollution control is still lacking in-depth exploration. In this paper, the Xiashu soil which is widely distributed in the middle and lower reaches of the Yangtze River was taken as the research object. The microscopic pore distribution under different soil clod sizes was analyzed by mercury intrusion injection test (MIP), and the effect of soil clod size on the migration characteristics of typical heavy metals (lead) in the region was explored by semi-dynamic leaching test and constant head saturated permeability test system. The results show that with the increase of soil clod size, the porosity and saturated permeability coefficient of the soil body decreased. The 2-4 mm soil clod had a high lead leaching concentration in the early leaching process, resulting in a large amount of migration and dissolution; the <1 mm soil clods had a relatively uniform lead migration rate due to their strong structural connectivity, and their migration was controlled by a diffusion-based mechanism; the 1-2 mm soil clods had a moderate lead leaching concentration in the early stage and a low dissolution amount in the middle and late stages, showing a relatively strong ability to inhibit lead migration and diffusion. There fore that the reasonable distribution of soil clod size plays a key role in inhibiting the migration of heavy metals. Optimizing the size of soil clods to form a suitable soil structure can effectively slow down the migration of lead, The results provide a scientific basis for the long-term control and remediation of heavy metal-contaminated soils.

Research on Retrieval Technology for Geological Disaster Data

CHENG Gang, WU Yaxi, WANG Ye, SHI Bin, YOU Qinliang

2025, 31(06):  756-768.  DOI: 10.16108/j.issn1006-7493.2025003

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China is one of the countries with the most serious geological disasters in the world. Geological disasters occur frequently and are of various kinds. In recent years, the superimposed effects of extreme weather have accelerated the frequency and degree of various geological disasters, resulting in increasingly difficult monitoring and warning, emergency rescue, and postdisaster recovery and reconstruction of various geological disasters. How to introduce new information technology to carry out indepth analysis and utilization of geological disaster data has become a breakthrough in future geological disaster prevention and control. To carry out the research and analysis of geological disaster data comprehensively and accurately, this paper first analyzes the research background of geological disasters in China and the current development status of retrieval technology. Then, fromthe perspective of data types and data characteristics, this paper summarizes geological disaster data, systematically introduces three data retrieval technologies, namely the principal component analysis method, convolutional neural network method, and hash method, and takes the “1.22” landslide geological disaster in Zhenxiong, Yunnan in 2024 as an example. The data related to the landslide disaster in the microblog were retrieved and analyzed, and the cluster visualization was displayed. In addition, the research results guided the application and development of retrieval technology in the field of geological disaster prevention and control. Finally, from the aspects of future principal component analysis method improvement, hash method optimization, and limitation of thinking, it is proposed to strengthen the integration of data retrieval technology and geological disaster emergency response so as to continuously meet the needs of massive disaster data on retrieval speed and information processing performance.

Multi-scale Joint Characterization of Pore and Pore Size of Coal Rock in the Xishanyao Formation, Dinan Uplift, Junggar Basin

YAO Weijiang, HU Zhengzhou, PAN Tuo, HU Xin, CHEN Zhonghong, LI Lei1, XIE Junyang, JIN Xiaojie

2025, 31(06):  769-784.  DOI: 10.16108/j.issn1006-7493.2025002

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Compared with traditional coalbed methane reservoirs, the coal rock reservoir in the Dinan Bulge of Junggar Basin is generally deeper (>2500 m). In order to understand the pore structure characteristics of the coal rocks in this area and its influence on the occurrence and migration of coal gas, the coal rock of Jurassic Xishanyao Formation in the well DM-2-101 is taken as the research object. The coal quality, coal rank, physical properties (stress sensitivity, density, porosity and permeability) and gas bearing properties of the coal rocks were detected and analyzed. The characteristics of pore development of coal rocks were analyzed by casting sheet, full-diameter CT scanning, scanning electron microscopy (SEM), diffraction and energy spectrum analysis, and the pore distribution was quantitatively characterized by micrometer CT scanning, high pressure mercury injection, carbon dioxide adsorption and nitrogen adsorption. The results show that coal rock in well DM-2-101 has the characteristics of low moisture, extremely low ash and low volatile content. The maceral components of the coal rock are mainly inertinite and vitrinite, with an average content of 48.07% and 45.82%, respectively. There are numerous hydrostatic fractures, interlayer fractures, cell pores and a few pores in reservoir space, with the domination of cell pores. The specific surface area is mainly the contribution of micropores (<10 nm), which accounts for more than 95%. The pore volume is mainly the contribution of large pores (>1000 nm), and its volume proportion reaches 62.97%-65.92%. The second was micropores, which accounted for 24.98%- 20.39% of the volume. The overlying pressure has an exponential decreasing relationship with porosity and permeability, and the porosity and permeability under overlying pressure can reach 8.23% and 1.47 mD respectively, which indicates that the coal rock can form an effective reservoir, but there is a certain heterogeneity. The pore size distribution of coal rock affects its adsorption properties and gas content. Adsorbed gas is widespread in coal rock, which is mainly adsorbed around micropores. The free gas mainly accumulates in some large pores. This study clarified the pore distribution characteristics at multi-scale levels of deep coal rock reservoirs through multi-methods with full-aperture quantitative characterization, which provided data and theoretical support for the occurrence and production mechanism of coal rock gas, and had certain guiding significance for the evaluation of coal rock gas resource potential of the Jurassic Xishanyao Formation in Junggar Basin.