Table of Content

20 October 2026, Volume 32 Issue 05

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U-Pb Chronology, Geochemical Characteristics and Tectonic Significance of Indosinian Granite in the Hongshuihe Area of the Eastern Part of East Kunlun Orogen

HE Zhenkai, LI Ruibao, PEI Xianzhi, LI Yulong, LI Zuochen, ZHOU Xiao, PEI Lei, CHEN Youxin, WANG Meng, LIU Chengjun

2026, 32(05):  605-623.  DOI: 10.16108/j.issn1006-7493.2025050

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A set of Late Triassic granite is exposed in the Hongshuihe area of the eastern section of the East Kunlun Orogenic
Belt, which has typical adakite granite characteristics and is of great significance for the study of the time constraint on the closure process of the Paleo-Tethys Ocean on the northern margin of the Gondwana continent. A detailed petrology, zircon U-Pb chronology, and geochemical study of the granite in the area was carried out in this study. The results show that the weighted average ages of granodiorite and diorite inclusions in this area are 225±1 Ma and 223±1 Ma, indicating a Late Triassic age. Geochemical analysis shows that the SiO2 content of the granodiorite is 63.85%-65.87%, the value of Na2O/K2O is 0.99-1.42, the value of Mg# is 42.76-49.15, and the value of A/CNK is 0.90-1.03. The fractionation of light and heavy rare earths in rocks is obvious, and it has the characteristics of enrichment in light rare earths and loss of heavy rare earths. The trace elements show high Sr (360.10×10-6-483×10-6), low Y (8.54×10-6-14.3×10-6), Yb (0.97×10-6-1.23×10-6), high Sr/Y (27.05-36.65) ratio, and weak positive or no Eu anomaly, with the characteristics of adakitic granite. The content of diorite inclusions in SiO2 was
59.15%-61.80%, the average value of Na2O/K2O was 1.84, the value of Mg# was 46.12-48.02, and the value of A/CNK was 0.85- 0.92. The diorite inclusions also show the right-dipping characteristics of light rare earth element enrichment and heavy rare earth element loss, and their trace elements also display the characteristics of high Sr (447.30×10-6-482.70×10-6), low Y (8.54×10-6 - 10.36×10-6), low Yb (0.67×10-6-0.78×10-6) and high Sr/Y (43.18-56.52). Petrogenetic studies indicate that the granodiorite in the Hongshuihe area of the eastern East Kunlun Orogen originated from partial melting of amphibolite in the thickened lower crust, with subsequent contamination by mantle-derived magmas. Combined with the regional data and the discriminant diagrams of tectonic environments, it is believed that the Hongshuihe granodiorite mass was formed in the post-collisional tectonic
environment, which further indicates that the East Kunlun orogenic belt had entered the post-collisional tectonic evolution stage in the Late Triassic. 


Mineralogical and Diagenetic Study of Banded Iron Formation from Griqualand West in South Africa

FANG Zhou, YUAN Yuli, HUANG Qilin, ZHANG He, XU Jingbo, CAI Yuanfeng

2026, 32(05):  624-638.  DOI: 10.16108/j.issn1006-7493.2025058

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The two oxygenation events in the Precambrian were not only continuously rebuilding Earth’s surficial system but also fostering the evolution of habitable environment for life. The globally distribution of banded iron formations (BIFs) respond to the changes of surficial system. BIFs also record abundand information regarding the evolution of the atmosphere, lithosphere, hydrosphere, and biosphere. They are of great scientific significance, as they provide a crucial window for understanding Precambrian geological environments and evolutionary characteristics. This study focuses on the BIFs in the Griqualand West region, South Africa, and utlizes techniques including X-ray diffractometry, SEM equipped with EDS etc, to conduct a detailed mineralogical investigation. We aim to constrain the mineral assemblages, formation conditions, and genesis of the BIFs. The results show that the BIF consists of iron minerals including hematite, magnetite, siderite, goethite, as well as non-iron minerals such as quartz, calcite, rhodochrosite, and rhodonite. These minerals are composed of nanosized grains and occur as granular or oolitic particles. The BIFs display extremely fine banded laminaes, generally 50-250 μm in thickness. These bands comprise alternating layers dominated by iron-rich minerals and chert or silicate-rich minerals, deposited sub-parallel to one another. Irrespective of grain size, numerous iron-bearing mineral grains show well-developed euhedral morphologies, frequently with banded zoning textures. SEM-EDS mapping reveals the native carbon grains and coupled Fe-Mn-C distributions, which may point to a microbial role in the formation of the BIFs.

Review of Methods for Inter-comparison and Evaluation of Plate Tectonic Models

YANG Jiangen, LI Haipeng, HOU Mingcai, CHENG Han

2026, 32(05):  639-658.  DOI: 10.16108/j.issn1006-7493.2025051

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Plate tectonic models provide the fundamental spatiotemporal framework for deep-time research, including paleogeography, paleoclimate reconstruction, geodynamic modeling, and resource exploration. However, significant discrepancies exist among current models due to variations in data and methodology, severely compromising the reliability of research grounded in these models. To address the lack of a unified evaluation framework, this study establishes a five-dimensional evaluation system—encompassing geometry, kinematics, dynamics, comparison of model predictions with independent observational data, and model-driven forward simulations with indirect validation-anchored in the principle of “consilience”. This framework aims to reduce model uncertainty through the cross-validation of independent chains of evidence. Applying this system to the  controversy over the position of the North China Block (NCB) at 380 Ma reveals a high convergence between kinematic trajectories and paleobiogeographic distributions. These findings strongly support that the NCB was located in the Southern Hemisphere during this period, drifting northward from the margin of Gondwana. This consilience of multi-source evidence demonstrates that the Scotese model aligns more closely with geological facts than the Matthews model. We propose that establishing a quantitative evaluation framework integrating multidisciplinary evidence is essential for resolving model discrepancies and ensuring the robustness of deep-time research.

Risk Assessment of Groundwater DNAPL Pollution Considering Model Uncertainty Based on the Duration of Field Pollution#br# Exceeding the Standard

PAN Yue, YANG Mohan, LUO Jiannan, ZENG Xiankui, WU Jichun

2026, 32(05):  659-669.  DOI: 10.16108/j.issn1006-7493.2025053

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Groundwater pollution risk assessment is a critical foundation for the prevention and control of groundwater
pollution. Dense Non-aqueous Phase Liquid ( DNAPL ) pollutants exhibit distinct physicochemical properties and complex migrationtransformation behaviors in groundwater, posing substantial threats to ecological and environmental integrity. Therefore, urgent efforts are required to conduct risk assessments for groundwater contaminated by DNAPLs. In this paper, a novel groundwater DNAPL pollution risk-assessment framework is proposed based on field-scale pollution exceedance duration. By constructing an ideal three-dimensional heterogeneous soil-groundwater model for PCE transport, the spatial-temporal distribution of contamination is simulated. Risk classification criteria are developed using site-boundary concentration exceedance time as the partitioning indicator. Bayesian theory is employed to quantify model uncertainty, and the MCMC algorithm is adopted for parameter calibration. Process-based numerical simulations are applied to analyze the impacts of model uncertainty on riskassessment outputs. The results indicate that the proposed evaluation method can reasonably chracterize risk levels under different remediation scenarios, and the inclusion of model uncertainty can markedly enhance the accuracy and reliability of the risk assessment results.

Experimental Study on Factors Influencing the Solidification of Sandy Dolomite by Staphylococcus Epidermidis X-NM1

BI Gang, CHENG Qi, XU Yinqiu, SONG Jiexia, TAO Wenxin, XU Hongzhong

2026, 32(05):  670-679.  DOI: 10.16108/j.issn1006-7493.2025055

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Staphylococcus epidermidis X-NM1 is a highly efficient carbonate-mineralizing bacterial strain isolated from soil near
a saline lake. This study is focused on the heavily sandy dolomite from the Yuxi section of the Central Yunnan Water Diversion Project, using Staphylococcus epidermidis X-NM1 for its solidification. The effects of inoculum size, calcium source type and concentration, and bacterial grouting strategies on urease activity and calcium carbonate precipitation were systematically examined. The solidification performance was comprehensively evaluated by integrating unconfined compressive strength tests, micro-penetration tests, and scanning electron microscopy (SEM) to assess the strength, uniformity, and microstructures of the treated samples. The results show that: (1) The inoculum size significantly affected bacterial growth and metabolism, with an optimal inoculum size of 10%, at which the OD600 value of the bacterial solution and urease activity reach 2.19 and 3.3 mM urea/min, respectively, achieving the optimal growth level; (2) Among the bacterial grouting strategies, the mixed bacterial solution method yields the best bacterial adsorption effect, with an adsorption rate as high as 97.91%; (3) Calcium source screening shows that calcium chloride was most conducive to calcium carbonate generation, significantly outperforming calcium acetate, calcium lactate, and calcium oxide; (4) When calcium chloride is used as the calcium source, the solidified specimens exhibit the highest unconfined compressive strength, reaching 355 kPa and 817 kPa at cementation solution concentrations of 0.5 M and 1.0 M, respectively, with the best uniformity observed in the specimens. (5) Microbially induced calcium carbonate crystals effectively filled the pores of the heavily sandy dolomite, thereby enhancing the overall strength of the specimens.  Among all the calcium sources, calcium chloride demonstrated the most superior and stable cementation effect.

Mechanical Response Characteristics of Tunnel Surrounding Rocks with Overlying Cobble-Gravel Strata Based on a Coupled#br# Continuum-Discrete Model

SHI Lianghong, FU Gang, ZHU Yihuan

2026, 32(05):  680-688.  DOI: 10.16108/j.issn1006-7493.2025048

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Against the backdrop of the rapid development of urban underground engineering, tunnel construction faces challenges from complex geological conditions. The cobble-gravel stratum, a common but adverse geological formation, poses a threat to the stability of tunnel surrounding rocks and construction safety due to its weak inter-particle cohesion, sensitivity to environmental disturbances, etc. This study, based on the Nanjing Shangyuanmen River-Crossing Tunnel Project, employs a coupled FLAC3D and PFC3D modeling approach to develop a hybrid continuum-discrete numerical model to investigate the mechanical response characteristics of shield tunnel surrounding rocks under overlying cobble-gravel strata conditions, with a comparative analysis against conditions without cobble-gravel strata. The results show that the hybrid model effectively reveals the complex mechanical behavior of the cobble-gravel strata. Excavation disturbances induce a shear dilation effect in the cobble-gravel strata, exerting additional pressure on the surrounding rock mass, leading to stress redistribution. In the model with the cobble-gravel strata, both tunnel crown settlement and segment deformation are greater than those in the model without cobble-gravel strata, with the settlement range approximately twice the width of the cobble-gravel strata. Surface settlement follows a Gaussian curve, with the presence of the cobble-gravel strata slightly increasing the settlement magnitude. Furthermore, particle contact force analysis reveals that excavation disturbances weaken inter-particle interactions in the cobble-gravel strata, further confirming the existence of a shear dilation-pressure mechanism. In conclusion, the cobble-gravel strata significantly impact local mechanical responses, necessitating further checks on deformation and stress in tunnel design to ensure structural safety. This study provides a theoretical basis and technical support for the design optimization and risk control of shield tunneling in complex geological formations.

Research and Application of Fiber Optic Monitoring for Safe Coal Mine Exploitation under an Integrated “Sensing-ransmission-Computation-Control” Architecture

CHENG Gang1, 2, 3, GUO Yumiao1, CAO Desheng1, SHI Bin2, CAI Tianlu3

2026, 32(05):  689-704.  DOI: 10.16108/j.issn1006-7493.2025054

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As China’s foundational energy source, coal has long played an irreplaceable role in safeguarding national energy security and supporting social stability. Given China’s complex coal‑seam geological conditions, the continuous expansion of mining depth and scale has raised new requirements for the safety monitoring of deep‑mining geological hazards, including roof collapse, water inrush, and rock burst. This study first elaborates on the strengths and limitations of major research methods currently adopted in the field of coal‑mine safety monitoring. Subsequently, it presents a comparative analysis of the principles  and performance characteristics of mainstream Distributed Fiber Optic Sensing (DFOS) technologies. On this basis, the workflow for DFOS‑enabled coal‑mine safety monitoring is outlined, with emphasis on two critical links: sensing cable (sensor) selection and monitoring system workflows. The study further illustrates the practical performances of DFOS technology across five typical application scenarios: mining‑induced overburden deformation monitoring, shaft deformation monitoring, coal‑mine temperature and fire hazard monitoring, goaf‑stratum deformation monitoring, and coal‑mine microseismic monitoring. Finally, an integrated “Sensing-Transmission-Computation-Control” technical system is proposed based on DFOS technology. This system is systematically analyzed from four dimensions: multi‑source sensing, reliable transmission, efficient computation, and risk control. Guided by this framework, a field application was implemented in the grouting curtain project at the Zhuxianzhuang Coal Mine. The results varify the feasibility and accuracy of this integrated system for the real-time monitoring, early warning, and risk control of curtain stability under complex geological conditions. This work offers a replicable technical reference for guaranteeing full‑lifecycle safety within China’s coal‑mining sector.

Stress-driven Evolution and Clustering Analysis of Pore Structures in Deep Reef Limestone

GAO Zilong, MA Linjian, XU Wenhan, LI Hongya, ZI Jianjun, ZHANG Wei

2026, 32(05):  705-717.  DOI: 10.16108/j.issn1006-7493.2025057

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Coral-reef limestone, as a typical heterogeneous porous medium, possesses pore structures that undergo complex
evolution under external stress, which exerts a substantial control over its seepage and mechanical behaviors. To elucidate the stress-driven mechanisms governing pore evolution, three-dimensional digital cores of reef limestone were reconstructed from X-ray micro-computed tomography (micro-CT) scans of coral reef limestone specimens. Via image segmentation and geometric reconstruction, multi-dimensional pore-structure parameters were extracted, including fundamental geometric descriptors, Feretdiameter metrics, shape factors, structural anisotropy indices, and spatial-position parameters. Axial step-loading tests were performed on the core specimens across five stress stages spanning 0 to 5.4 MPa, with micro-CT scans performed at each loading step. On the basis of connectivity analysis, pores were categorized as connected pores and isolated pores. The results reveal that connected pores undergo pronounced compaction, fracturing, and reconfiguration during loading, and their morphological parameters exhibit highly sensitivity to stress changes. By comparison, isolated pores retain geometric stability and dominate total porosity variation. K-means clustering was employed to further classify the connected pore structures under different stress stages, yielding three representative pore classes: dense auxiliary pores, transitional transport pores, and primary skeletal channel pores. These pore types differ markedly in scale, connectivity, and morphology, recording a structural evolutionary pathway of “compression-collapse-reconnection.” This work establishes a multi-parameter clustering analytical framework, offering a quantitative support for deciphering pore-vug evolutionary mechanisms within limestone subjected to stress fields. 

Model-scale Test on Microbial Grouting Strengthening of Granular Strongly Weathered Granite in Seawater Environment

LIN Wenbin, LIU Jiahao, GAO Yupeng, ZHANG Zhichao, LUO Chenghao, LU Yanbao, LUO Lijin

2026, 32(05):  718-728.  DOI: 10.16108/j.issn1006-7493.2025052

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Model-scale solidification tests were conducted on granular strongly weathered granite using microbially induced
calcite precipitation (MICP) grouting technology. The physical-mechanical properties and microstructural characteristics of the solidified specimens were systematically investigated. The results demonstrate that MICP successfully consolidated the modelscale granular strongly weathered granite (Φ25×50 cm) into a stiff coherent structure. Physical-mechanical analyses revealed spatial heterogeneity of cementation performance: optimal in the middle section, moderate in the lower section, and poorest in the upper section. The solidified specimens exhibited an average calcium carbonate content of 12.42% and a dry density of 1.85 g/cm3. The permeability coefficient decreased by an average of 76.1% compared to untreated material. The maximum unconfined compressive strength reached 5.01 MPa, with an average value of 3.42 MPa. The mean ultrasonic velocity was 2.919 km/s along the diameter direction (13.5% higher than untreated specimens at 2.571 km/s) and 2.957 km/s along the axial direction. Microscopic analyses indicate that MICP grouting mainly produces calcite cement with columnar, acicular-clusters, and platy morphologies, alongside minor spherical vaterite and rhombohedral magnesium-calcite. Cementation within the mid-lower sections shows relatively uniform distribution and dense packing, forming a compact network, whereas the upper section is relatively loose. This study provides theoretical basis and experimental data support for MICP-mediated solidification of granular strongly weathered granite. 


Source Analysis of Groundwater Chemical Components and Health Risk Assessment: A Case Study of the Plain Area in Baoding City

YE Fei, LIU Shengqian, SUN Hui, CHEN Sijie, WANG Zihao

2026, 32(05):  729-742.  DOI: 10.16108/j.issn1006-7493.2025056

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Groundwater, an essential component supporting the ecological environment, requires analysis of its hydro-chemical
characteristics, pollution status, and potential human health risks to ensure its effective protection and sustainable utilization. This study integrates hydro-chemical analysis, the absolute principal component score-multiple linear regression (APCS-MLR) model, the entropy weighted water quality index (EWQI), and the human health risk assessment (HHRA) model to conduct source analysis of groundwater chemical components and health risk assessment in the plain area of Baoding City, with an aim to provide a scientific basis for groundwater environmental protection and high-quality ecological development in the study area. The results show that the groundwater in the study area is generally weakly alkaline with coefficients of variation for Mn, NO₃ -, and Se ranging from 1.08 to 1.89, suggesting uneven spatial distribution and high local enrichment. The groundwater is dominated by the HCO₃- Ca·Mg and HCO₃-Na·Ca·Mg types, accounting for 63.33% and 18.89% of the total samples, respectively. The APCS-MLR model identifies the primary sources influencing groundwater hydro-chemical composition, including water-rock interaction and agricultural activities (45.61%), cation exchange (13.77%), reductive dissolution of Mn (9.55%), K+-specific adsorption and fixation (9.40%), and unidentified sources (21.68%). Meanwhile, the EWQI values range from 15.45 to 109.51, with water quality being categorized as excellent, good, and medium in 77.78%, 20.00%, and 2.22% of the samples, respectively. TDS, Se, Mn, and pH are identified as the key parameters controlling the EWQI. According to the HHRA model, the exceedance rate of noncarcinogenic risk in children (26.67%) is significantly higher than that in adults (4.44%). Spatially, high-risk areas for children are mainly distributed in the northern, central, and southwestern parts of the study area, while those for adults are primarily located in the main urban area of Baoding and the southeastern part of Dingxing County.