Geological Setting Research Articles

Genesis of Yongping copper deposit in the Qin-Hang Metallogenic Belt, SE China: Insights from sulfide geochemistry and sulfur isotopic data

Yongping copper deposit is a large-scale polymetallic mine that contains 1.6 Mt of proven Cu metal reserves with an average grade of 0.74 % and contributes significantly to China’s production of copper. This deposit is situated in the eastern part of the Qin-Hang Metallogenic Belt (Jiangxi province, SE China) at the contact zone between the Yangtze Cu–Mo metallogenic belt and the Jiangxi W–Sn–REE metallogenic belt. The thick stratiform and lenticular-shaped orebodies are hosted in the Carboniferous Yejiawan Formation, consisting of sandstone, limestone, mudstone, and chert-rich clastic rocks. Dominant metal-bearing minerals are chalcopyrite and pyrite with a minor amount of sphalerite, tetrahedrite, galena, molybdenite, pyrrhotite, magnetite, hematite, and scheelite. Although intensive research has been done on its geological setting, geochemical characteristics, and geodynamic evolution over the past thirty years, the origin and depositional environments have remained controversial. In the current research, in situ trace element geochemistry and sulfur isotope analyses, coupled with microscopic investigation, were conducted on sulfide minerals using the LA-ICP-MS technique. The results display that Yongping pyrite rich in Co, As, Ni, Zn, Cu, and Te and deplete in other trace elements. Sphalerite rich in Fe, Mn, Cu, and Cd, followed by In, Co and Ga. The calculation results of formula T(°C) = (Fe/Zn + 0.2953)/(0.0013) reveal that sphalerite was formed in medium–high temperature conditions (262 °C–377 °C). The δ34SV-CDT values of studied sulfides (pyrite, chalcopyrite, sphalerite, and tetrahedrite) varied from −1.52 ‰ to 5.13 ‰ with an average of 2.36 ‰, which are highly consistent with those recorded from porphyritic biotite granite stock of Shizitou (from 2.20 ‰ to 4.5 ‰), suggesting a dominantly magmatic origin. Collectively, trace element compositions of analyzed sphalerite and pyrite from the Yongping area exhibit characteristics of typical skarn deposits. Combined with previous studies, we can conclude that the Yongping Cu deposit is a skarn deposit that was most likely formed by contact metasomatism after the intrusion of the Jurassic Huoshaogang-Shizitou granitic stock into the Carboniferous Yejiawan Formation.

Icehouse mixed carbonate and siliciclastic sequence evolution based on 3D seismic analysis: Insights from the Eastern Shelf of the Permian Basin, Texas

Reciprocal model was introduced for mixed carbonate and siliciclastic sequences within the Virgilian (Upper Pennsylvanian – Gzhelian) and Wolfcampian (Lower Cisuralian) on the Eastern Shelf of the Permian Basin in Texas. This model emphasizes carbonate dominance during transgressive and highstand on the slope, and siliciclastic dominance in the basin during lowstand. Contradictory observations from other mixed basins, such as compositionally mixed lithology in slope cores, accumulation of siliciclastics behind carbonate highs on the outer shelf, off-shelf transport of siliciclastics during highstands, and carbonate deposition on the slope during falling stage, require a re-evaluation of the reciprocal model. This research examines mixed sequences in the Cisco Group and maps lithology distribution by integrating geological and geophysical data, using advanced seismic interpretation techniques, wireline-log crossplot analyses, model-based post-stack inversion, probabilistic neural networks, and supervised Bayesian classification. Observations from the investigation are presented at two scales. In ∼400kyr sequences, relative sea level fall starts with carbonate deposition on the slope while siliciclastics persist near the inner shelf. As the falling stage progresses, siliciclastics reach the shelf edge, forming offlapping fans at the toe of the slope, likely truncating part of the siliciclastic topsets. Subsequently, mixed facies were deposited during the early stages of rising relative sea level, followed by carbonate deposition on the slope and shelf throughout transgression. The mixed facies found inland of transgressive carbonates indicate that prodelta siliciclastics mixed with carbonate mud. Occasionally, transgressive carbonates create shelf-edge build ups, hindering the transport of highstand siliciclastics to the slope. In the composite sequence spanning ∼1200kyr, siliciclastic input decreases significantly with the onset of sea-level fall. The fall truncates topsets with limited siliciclastics, preserving carbonate and mixed facies-dominated foresets with offlapping fans at the toe of the slope. This study advances our understanding of mixed sequences, challenges existing models and lays the groundwork for future investigations in similar geological settings.

Viability of fracture characterization using seismic attributes through seismic physical modeling

Abstract Seismic attributes have been widely utilized for fault detection; however, accurately characterizing mesoscale fractures (1/10 to 1/4 wavelength) using these attributes remains challenging, particularly in complex geological setting. To explicitly reveal the effectiveness of seismic attributes in fracture characterization, we constructed a realistic physical model based on the stratigraphic structure of a real shale-gas play. This model incorporates several faults and six fracture zones containing vertically aligned mesoscale fractures of varying fracture densities, embedded in a target layer of 40 m equivalent thickness. Through a comprehensive evaluation of various seismic attributes, we demonstrate that, while these attributes effectively map faults or macroscale fractures, they are less reliable for characterizing mesoscale fractures. Although mesoscale fractures induce anomalies in seismic amplitude and attributes, the magnitude of these anomalies does not correlate with the fracture density. To address this limitation, we introduce the amplitude at the dominant frequency (ADF) attribute, designed to characterize fracture density in thin-beds with mesoscale fractures. A strong relationship is observed between fracture density and the ADF attribute, with a correlation coefficient of 0.8067. Thus, the ADF attribute serves as a valuable tool for interpreting seismic data in the context of mesoscale fracture density.

Predicting thermochemical sulfate reduction reaction process and H2S generation in carbonate reservoirs using comprehensive kinetics modeling

Thermochemical sulfate reduction (TSR) is a critical process controlling hydrogen sulfide (H2S) generation in carbonate reservoirs, posing significant economic and safety challenges for the oil and gas industry. This study develops a comprehensive model that integrates detailed thermal, burial, and hydrocarbon generation histories with key TSR kinetic parameters, such as reaction rate constants and activation energies, to predict TSR evolution and H2S generation accurately. A notable feature of the model is to separate and quantify the contributions of different hydrocarbon species (CH4, C2-5, C6-14, and C15+) to the overall TSR process, using the Arrhenius equation to simulate the temperature-dependent behavior of TSR for each hydrocarbon group. The model also accounts for the in-reservoir thermal cracking of heavier hydrocarbons into light hydrocarbons, ensuring predictions closely align with geological processes. Modeling results show that TSR reactions accelerate the depletion of oil and wet gas components. A large amount of CH4 is generated due to both kerogen thermal cracking and alteration of heavy hydrocarbon. Our modeling also allows for accurate prediction of TSR reactions as well as the timing and extent of H2S and CO2 generation over the history of a reservoir. Applications in the Puguang and Hetianhe gas fields validate the model's broad applicability and reliability, capturing extensive TSR activities and being consistent with the observed data. These results underscore the models' robustness in detailed predictions of TSR dynamics across diverse geological settings and its potential as a valuable tool for managing sour gas production, aiding in risk assessment and resource management.

Carbonatites and related mineralization: an overview

Despite of their scarcity, carbonatites are documented from diverse geological settings, including cratons, continental rifts, orogenic belts and large igneous provinces, which range in age from the Archean to Recent. This study provides a concise overview of the evolution of igneous carbonatites, compiling data on their diverse characteristics and classifying them into mantle- and crustal-derived subtypes. Mantle-derived carbonatites, typically associated with alkaline rocks, are enriched in rare earth elements (REEs) and display geochemical affinities to the mantle. By contrast, crustal-derived carbonatites usually show much lower REE contents and crustal-affinity geochemical features similar to sedimentary carbonaceous rocks. Our study documents the significant economic potential of carbonatites that can host world-class deposits of REE, rare metals, alkaline earth metals and non-metallic resources. Typically, the key processes controlling REE mineralization include the low-degree melting of refertilized mantle, liquid immiscibility, fractional crystallization and hydrothermal fluids. Thus, carbonatites are of significant economic value due to the rapidly increasing global demand for REEs, mainly driven by the ‘green energy transition’.

Spatiotemporal evolution of the early Permian multi-source-to-sink system in the northwestern margin of the North China Block: Implications for the paleogeographic reconstruction along the southern margin of the Paleo-Asian Ocean

The northwestern margin of the North China Block, situated at the intersection of multiple tectonic units, presents a complex geological setting that challenges paleogeographic reconstructions. The subduction and closure of the Paleo-Asian Ocean have further complicated the understanding of sediment provenance during the Early Permian. In this study, we integrated sedimentological, geochemical, and UPb dating methods to delineate the Early Permian source-to-sink systems along the northwestern margin of the North China Block. The identification of four key source-to-sink systems—the Alxa, Langshan, Serteng–Wula, and Jining–Daqing—reveals a pronounced east–west provenance differentiation, indicative of the regional tectonic and sedimentary responses to subduction of the Paleo-Asian Ocean.During the Shanxi Formation deposition, the western regions were dominated by the Inner Mongolian continental island arc as a principal sediment source, fostering distal meandering river deltas. Conversely, the eastern regions were predominantly influenced by the North China Block basement, leading to the deposition of proximal, shallow meandering river deltas. As the Shihezi Formation deposition ensued, the western source-to-sink systems continued to receive sediments from the uplifted Inner Mongolian Arc, transitioning to distal braided river deltas amidst an orogenic setting. Meanwhile, the eastern systems, particularly Jining–Daqing, showed increased contributions from the North China Block basement, forming mixed-source, shallow braided river deltas.This research provides a refined understanding of the spatiotemporal evolution of source-to-sink systems and their responses to the tectonic setting, offering valuable insights into the paleogeographic evolution along the southern margin of the Paleo-Asian Ocean.

Pleistocene Glacial Transport of Nephrite Jade from British Columbia, Canada, to Coastal Washington State, USA

Since prehistoric times, indigenous residents of southwest British Columbia, Canada, collected water-worn nephrite specimens from the gravel bars along the Fraser River, using the stone for the manufacture of tools that were widely traded with other tribes. Allochthonous nephrite occurs in another geologic setting. Late Pleistocene continental glaciers transported nephrite and many other rock types from western Canada to northwest Washington State, producing extensive sediment deposits that border the Salish Sea coast in Whatcom and Island Counties, Washington. This material was little utilized by indigenous residents, but “black jade” specimens are prized by modern collectors. The depositional history and mineralogy of this material has received little attention. X-ray diffraction and SEM/EDS analyses indicate that the Salish Sea “black jade” is a form of impure nephrite that probably originated from metamorphism of a mafic igneous parent material (metabasite). The texture consists of prismatic amphibole crystals (ferro-actinolite) set in a matrix rich in plagioclase feldspar. Pyrite inclusions are locally present. A second material, sometimes erroneously labelled “muttonfat jade” by amateur collectors, consists of an intermixture of quartz and sillimanite.

The Urban Geo-climate Footprint approach: Enhancing urban resilience through improved geological conceptualisation

Urban resilience is critical to allow cities to withstand the challenges of the 21st Century. One factor that is often overlooked in such assessments is the role of the subsurface. A novel methodology called the Urban Geo-climate Footprint (UGF) has been developed to classify cities quickly and comprehensively from geological and climatic perspectives. The method operates on the fundamental assumption that cities with similar geological-geographical settings will face similar challenges, due to both common geological issues and associated climate impacts. The UGF approach has been applied to 41 European cities in collaboration with 17 Geological Surveys of Europe, the results of the UGF analysis are presented along with a regional classification of the geological resilience indicators. The UGF tool provides a semi-quantitative representation of the pressures driven by geological and climatic complexity for the cities presented, providing for a first time such classification of the urban environment. The advantage of this methodology lies in increasing awareness among non-experts and decision-makers of the interplay between geological settings, climate change pressures, and anthropogenic activities. Furthermore, it facilitates the exchange best practices among city planners to increase resilience, supporting knowledge based decision making to promote actions and policies, that enhance geoscience-informed climate justice.

Cumulative effects of natural and anthropogenic processes on groundwater chemistry of a small karst island—case study of Vis (Croatia)

Many coastal and island communities depend on groundwater as the only source of freshwater, making it an invaluable resource. In the Mediterranean region, groundwater resources are highly vulnerable to natural and anthropogenic pressures, such as overexploitation, climate change, seasonal variations in precipitation, and seawater intrusion. Hence, an understanding of hydrogeological processes and groundwater chemistry is a basis for the sustainable management of coastal and island groundwater resources. Vis, a small and remote karst island in the Adriatic Sea, exhibits peculiar geological and hydrogeological settings, resulting in the island’s autonomous water supply. The current pumping capacity (maximum of 42 l/s) meets most of the demand, but intensive summer tourism and climate change exert high stress on groundwater resources during the dry season. Consequently, in the last decade, occasional reductions for consumers occurred. Monitoring of in situ physicochemical parameters and groundwater sampling for chemical and isotopic analyses were conducted from 2020 to 2023 at deep borewells, shallow dug wells, and springs. Hydrochemical interpretation indicated that groundwater chemistry was affected primarily by carbonate and sulfate rock dissolution, mixing with seawater, reverse ion exchange, and dedolomitization. The majority of groundwater samples exhibit Ca–HCO3 hydrochemical facies, followed by Na–Cl and mixed facies. The low percentage of seawater in the mixture indicated that seawater intrusion is not too extensive even during prolonged dry periods, implying a favorable hydrostatic regime with relatively small but sufficient groundwater reserves of the island’s aquifers, although the investigated period was characterized by significantly lower precipitation with respect to the 30-year average.

CO2 trapping dynamics in tight sandstone: Insights into trapping mechanisms in Mae Moh's reservoir

The reliance on fossil fuels is a major contributor to increased anthropogenic CO2 emissions, driving global challenges such as climate change through the greenhouse effect. Carbon capture and storage (CCS) is a promising interdisciplinary technology aimed at mitigating these emissions by securely sequestering gigatons of CO2. This study focuses on the feasibility of storing point-source CO2 emissions in saline formations, with a particular emphasis on the Mae Moh coal-fired power plant in Lampang, Thailand, which is located near its associated coal mine. The region presents challenges due to tight sandstone reservoirs buried over 2000 m deep. With reservoir simulation, this study evaluates the impact of various factors on CO2 containment and trapping in these geological settings. Results show that elevated temperatures decrease structural trapping of 43.0%–28.9% and increase solubility trapping of 28.55%–46.5%, at 40 °C and 80 °C respectively. Hysteresis is found to enhance residual trapping by immobilizing up to 31.1% of CO2 within pore spaces at 0.5. Permeability heterogeneity has a minimal impact on overall trapping efficiency due to the less heterogeneity of the tight sandstone. However, the kV/kH ratio significantly influences vertical CO2 migration which resulted in residual trapping at its highest at the ratio of 0.1, while lower ratios support lateral dispersion. Moderate rock compressibility values are identified as optimal for structural and residual trapping, while extreme compressibility enhances solubility trapping by up to 30%. These findings emphasize the complexity of CO2 trapping mechanisms in tight sandstone formations, emphasizing the need for careful consideration of key factors in CCS projects.

Construction simulation and scheme optimisation of complex underground cavities

Underground cavities have complex spatial structures and geological settings, their arrangement is dense and crisscrossed. The construction system involves multiple work surfaces, levels, and processes. The close integration of construction simulation with actual production conditions is crucial for enhancing the guidance that simulation results provide for practical engineering. Therefore, from the perspective of optimizing construction organization and management, this article comprehensively considers various factors in the construction process, innovatively introduces the principle of production line balance and the concept of rule cycle, and combines technology and management, an underground cavities construction simulation system (UCCSS) is developed. In UCCSS, a hierarchical model is built and calculation are performed on models with different construction methods by modifying the parameters as per the actual engineering characteristics. The simulation results are comprehensively analysed to determine the optimal construction programme. An application case is proposed based on the construction organisation design of the long and parallel diversion tunnels at the CB Hydropower Station. The results show that the system has good practicality and credibility and can provide guidance for the construction organisation design of underground cavities with various features.

Total organic carbon content estimation for mixed shale using Xgboost method and implication for shale oil exploration

In this study, the Xgboost method is employed for TOC estimation in mixed carbonate and siliciclastic shale from the Hashan area, Junggar Basin. The results show that this approach is effective for TOC estimation in this area although the model performance is not very excellent with a correlation coefficient of 0.54 between measured TOC and predicted TOC values, likely due to a small samples dataset. Therefore, the PCA method is applied to debase dimension of well log data from five dimensional to two-dimensional data, which enhances the correlation coefficient between the predicted and measured TOC from 0.54 to 0.68. Based on the model, the isopleth maps of TOC distributions in Fengcheng Formation were redrawn showing two shale oil exploration targets, which likely correspond to two depositional centers of this strata. All the same, the model in this work provides reliable data for shale oil evaluation in the study area and a good example under similar geological setting.

Effect of bedrock, tree size and time on growth and climate sensitivity of Norway spruce in the High Tatras

AbstractTree growth is a multifaceted process influenced by various factors at different spatial and temporal scales, including intrinsic tree traits and environmental conditions. Climate factors have a significant impact on tree growth dynamics, while geological controls can also play a crucial role. However, our understanding of the interplay between these factors concerning tree growth is currently limited. This study focuses on Norway spruce (Picea abies [L.] Karst.), one of the economically most important coniferous tree species in Europe, to investigate the interplay of growth, climate, and environment at the forest and corresponding treeline sites in the High Tatra Mountains of Slovakia. Specifically, we developed chronologies of tree-ring width (TRW) and late-wood density (MXD) for different tree size classes across two limestone and granitic sites. Growth rates of Norway spruce trees have been increasing in forests since the 1930s and from the 1950s at treelines. Growth rates were consistently higher on limestone bedrock compared to granitic bedrock conditions. Variability of radial growth is primarily driven by climate at both geological settings with trees on granitic bedrock displaying more pronounced responses to climatic variables. We observed weakening (non-stationarity) in climate signals over time and across all size classes in both geological settings. The magnitude of these effects is small, but varies across size classes, with larger trees generally displaying stronger climate sensitivities compared to smaller ones. Therefore, our findings accentuate the potential implications of geological settings, climate, and environmental factors on the absolute growth and growth dynamics of Norway spruce, highlighting the need for further research to fully understand and manage forest ecosystems in mountainous regions.

Geological Setting and Formation of the Erosional Structure of Upper Miocene Deposits in Western Ciscaucasia

Geological Setting and Formation of the Erosional Structure of Upper Miocene Deposits in Western Ciscaucasia

Precipitation sensitivity of vegetation growth in southern China depends on geological settings

Southern China is in the only humid zone at its latitudes of Northern Hemisphere and has the most extensive karst landscapes. Although the region experienced significant greening, the fragile karst geological setting and reduced precipitation may affect the greening efforts. Here we analyze the sensitivity of vegetation to precipitation between karst and non-karst areas in the region. We find that in karst areas, vegetation growth is more affected by seasonal precipitation variations (Pre_season), with relative importance of 24.02 % for Leaf Area Index (LAI) and 25.27 % for kernel Normalized Difference Vegetation Index (kNDVI). In contrast, vegetation in non-karst areas is more temperature-dominated. After controlling temperature effects, mean annual precipitation (MAP) thresholds of 1337–1438 mm are established to identify precipitation-sensitive areas (below the thresholds), with slightly higher thresholds in karst areas. These findings imply the heightened vulnerability of southern China’s karst areas to ongoing drying trends, posing a threat to the region’s vegetation growth and the remarkable vegetation restoration achievements.

Offshore Tech Evolves for Deeper Waters, Deeper Reservoirs

_ Since the late 1930s, the offshore industry has moved from installing the first offshore platform in 14 ft of water to the ultradeepwater 20K era. Advances in seismic, drilling, and development technologies all helped move the industry from shallow waters to ultradeepwaters, from lower-pressure reservoirs to high-pressure/high-temperature (HP/HT) reservoirs, and beyond known hydrocarbon areas like the Gulf of Mexico (GOM) into frontier regions, like Guyana. Brent Gros, vice president of Chevron’s GOM business unit, told JPT there is a stark difference between the GOM of today and how it was when he first started working in the area 26 years ago. Now, he said, operating further from land in water depths of 4,000 to 7,000 ft is the norm. “We’re not really taking crew boats to those platforms, given the distance from shore. We operate as well at much higher pressures,” he said. Jayme Meier, ExxonMobil’s vice president of deepwater project delivery, echoed that sentiment. At the dawn of the offshore era, “anything that was in any amount of water was, by definition, deep water, because it was as far as you could go,” she told JPT. “And we are now at the stage where we are routinely doing things that are in 2000 m (6,560 ft) of water or more, and we continue to press boundaries and technical limits to be able to move further out in water depth.” As such, she said, the fundamental definition of deep water has shifted in the past quarter century. Where To Drill? “To find oil and gas resources, we rely on seismic, and we’ve seen huge advancements in seismic over the past 25 years,” Gros said. 3D seismic technology, pioneered half a century ago, sharpened the view into the world’s reservoirs, and new seismic processing methods have helped identify new opportunities. “Now we have ocean-bottom node surveys, which essentially take a lot of the noise out of surveys, allowing us to image deeper with a clearer image. We also have four-dimensional seismic, which helps us understand the performance of reservoirs through time,” he said. “If you compare the seismic capability today to what we had in the past, it’s like seeing the world with a new pair of glasses, and it really helps us understand potential prospects in a more-complex geological setting and pursue those opportunities in deeper water and deeper horizons than we previously would have been able to.” Deepwater Challenges Moving into ever deeper waters requires more tech and more-capable drilling rigs. It also requires precision, Meier noted. “Technology allows us to position a floating rig on the surface of the ocean. It’s got to be able to drill at very precise angles and precise locations, and significant extensions of technology were needed to enable that to happen. We’re at the point now where we’re even doing multizone completions on our wells in deep water,” she said. point now where we’re even doing multizone completions on our wells in deep water,” she said. She called deepwater “by far the most exciting space” to work in. It requires planning and designing for facilities that must withstand intense, harsh, and constantly changing conditions throughout its lifetime.

The role of the Messinian evaporites in the identification of potential gas storage sites: A review of the Adriatic foreland basin system (Italy)

AbstractFocusing on the late Miocene succession stratigraphic successions including the evaporite deposits from the Messinian salinity crisis (MSC) of the Adriatic foreland basin, a revision of available boreholes and seismic data allowed us to recognize the presence of reservoirs and seals systems that can be considered of potential interest for the storage of natural and synthetic gas. Potentially good reservoir sites can be found where porous rocks referable to siliciclastic turbiditites (Marnoso‐arenacea and Laga Fms) or shallow‐water carbonates (Bolognano Fm) preferentially involved in anticlinal structures and covered by thick MSC evaporites, which may represent effective reservoir seals. The integrated reconstruction of porous rocks distribution and facies, thickness, and lateral continuity of the overlying evaporites, allows the identification and zonation of geological settings in the Adriatic foredeep, backbulge and foreland with peculiar stratigraphy and deformations, only partially considered before, that may deserve consideration in the research of potential gas storage sites.

Probabilistic Programming for Transportable Source Characterization and Uncertainty Quantification of the North Korean Nuclear Tests 2006–2017

Abstract We introduce a transportable technique to determine the yield and depth of burial (DOB) from seismic source spectra of underground nuclear explosions. We demonstrate this technique on the six declared North Korean nuclear tests. This approach derives source spectra in absolute units from regional phase (Pg) amplitudes by correcting the observations for geometric spreading, attenuation, and site amplification. We couple the source spectra and explosion source models with a probabilistic programming framework that integrates deep learning techniques and Bayesian modeling. This approach permits the exchange of information across various data categories to quantify both the data and model uncertainty. This technique stands out as an innovative use of broad-area propagation models, making it transportable across various geologic settings. This method proves to be effective in scenarios with diverse and/or limited observational data, even when the source depth is unknown. We present new independent estimates of absolute yield and DOB that are consistent with the prior assessments, underscoring the potential of this method in enhancing transportable nuclear explosion monitoring capabilities.

LAND MOVEMENT VULNERABILITY ZONING IN THE HILLY AREA OF NORTHERN CILACAP, CENTRAL JAVA

The northern part of Cilacap has an area with hilly morphology with slopes that are relatively gentle to steep. The geological setting in this region is quite complex, the combination of tectonics and the physical properties of the rocks means that this region is strongly deformed. This has an impact on areas prone to landslides as one of land movement types. To what extent can this area be classified based on the vulnerability of its land to landslides is the problem be studied. There are five aspects used in this research, namely rainfall, rock type, slope, land cover and soil type. The multi-aspect overlay method is used to determine the spatial distribution of land movement-prone zones. Geographic Information System-based software support makes the data analysis process easier. Based on the results of the spatial analysis of five aspects, it was concluded that the North Cilacap area could be grouped into 3 land movement vulnerability zones, namely the low vulnerability zone with a score of 8-17, the medium vulnerability zone with a score of 18-27, and the high vulnerability zone with a score of 28-37. The complex tectonic order is the main controller of land movement events in this region.

Design and construction of tunnels and tunnelling: Understanding the importance of geological conditions, landslide susceptibility and risk assessment

Tunnel engineering is a complex and multidisciplinary field that requires the integration of geological expertise, advanced modeling techniques, and practical engineering solutions. The research compiled in the Special Issue "Tunnels and Tunneling" makes significant contributions to the field by addressing the diverse geological conditions and intricate challenges inherent in tunnel construction. These insights are crucial for enhancing the safety, efficiency, and sustainability of tunnel projects worldwide. The studies in this Special Issue provide a comprehensive understanding of the various challenges and innovative solutions in tunnel engineering. They offer valuable insights and practical guidelines for designing, constructing, and maintaining safe and stable tunnel structures across different geological settings. In addition, geological challenges in specific regions, such as the Three Gorges Reservoir area, the Hengduan Mountains, and the Tibetan Plateau, require tailored approaches. A key theme in many of the comparative studies is the importance of accurate risk assessment to ensure tunnel safety. In regions prone to geological hazards, landslide susceptibility mapping and risk assessment are critical. Innovative approaches, such as machine learning models, are highlighted for their potential to predict and manage landslide risks effectively.