Geological Journal最新文献

To investigate the evaluation performance of different models across various evaluation units, 174 landslide samples were selected from Xide County, Sichuan Province, China, as the study area, considering 12 conditioning factors such as aspect, slope and elevation. Using software tools such as ArcGIS and SPSS, the landslide susceptibility in the study area was assessed across different units (12.5 and 30 m grid units and slope units). Four models were employed for this evaluation: the information value model (IV), the logistic regression model (LR), the information value–logistic regression coupled model (IV-LR) and the decision tree model (DT). The evaluation accuracy of various models across different evaluation units was analysed using rationality testing and ROC curves. The results indicate that, within the same evaluation model, the landslide susceptibility assessment accuracy for the 12.5 m grid unit surpasses that of the other two evaluation units, with an average AUC value of 0.849. Under the same evaluation unit, the IV-LR coupled model consistently demonstrated strong performance across all units, achieving the highest AUC value of 0.881 with the 12.5 m grid unit.

The final closure time and tectonic evolution of the middle segment of the Paleo-Asian Ocean (PAO) remain poorly constrained. The northern part of the Zhusileng-Hangwula arc, located in the middle segment of the Central Asian Orogenic Belt, is crucial for understanding its tectonic evolution and for constraining the closure time of the middle segment of the PAO. Field structural, microstructural, and fabric analyses reveal that the NE-trending ductile shear zone within the Baishan Formation has undergone sinistral shearing. Zircon U–Pb and ³⁹Ar/⁴⁰Ar dating indicate that the shear zones formed at 216 Ma. In addition, the northern part of the Zhusileng-Hangwula arc experienced superimposed folding deformation. Kinematic studies show that the second phase of folding refolded the tightly upright NE-trending F1 folds into NE-trending asymmetric steeply plunging F2 folds under a sinistral transpression regime. ⁴⁰Ar/³⁹Ar geochronology data indicate that the first phase of folding deformation occurred at 215 Ma, while the second phase of folding deformation occurred slightly later than 215 Ma. Geochemical characteristics indicate that the Baishan Formation formed in an active magmatic arc setting during the Late Permian. Combined with published data, the final closure time of the northern part of the Yagan and Zhusileng-Hangwula arcs in the middle segment of the PAO can be constrained to the Late Permian–Early Triassic. The formation of the shear zones and the superimposed folding deformation can be attributed to the oblique convergence orogenic process between the South Gobi Zone and the Yagan and Zhusileng-Hangwula arcs during the Late Triassic.

In carbon capture and storage system (CCS), the task of the CO₂ source–sink matching involves optimising source–sink cluster deployment, transportation path, and pipe network layouts. This task is an integral aspect of the CCS commercialization process and constitutes a combinatorial optimization problem aimed at achieving low cost and maximum storage capacity within the system. Here, a novel mathematical model of source–sink matching combinatorial optimization is established. (1) The model can account for various factors, including the lifespan of the source–sink, the capture (injection) rate of CO₂ sources (sinks), and the duration of the CCS system. The objective aimed to maximise CO₂ storage capacity while minimising transportation costs over the entire operational period. Additionally, based on genetic algorithm, a rapid solution approach was introduced to address the objective. (2) A comparative study was conducted through existing cases. The results show that, compared to the Pinch analysis method, the newly constructed optimization model in Case 1 can increase the total storage of the system by 4.6%. Similarly, the results of Case 2 demonstrate that the matching results of the new model can increase the total storage by 13.3%. (3) Through Case 3, the model provides a preferred but not unique matching scheme, which meets the criteria of maximising storage while minimising transportation costs at any given time. Finally, the practicability and reliability of the novel model were verified through the cases. The model can provide a framework for the development of source–sink matching decision system and CCS planning.

The Bocaranga area belongs to the northern part of the Adamawa-Yadé Domain (AYD) in the Central African Republic (CAR) where the occurrence and petrogenesis of mafic rocks still remain a subject of debate. New field observations, petrographic, mineralogical, and geochemical data of mafic rocks from Bocaranga show palaeo-oceanic crust character within the Adamawa-Yadé domain on the northern margin of the Congo Craton. These mafic rocks consist of amphibolites (biotite-amphibolites, garnet-amphibolites, epidote-amphibolites and actinolite-amphibolites) and amphibole-pyroxenites associated with gneisses of trondhjemite, tonalite, and granodiorite compositions (TTG). These mafic rocks display basalts, dioritic basalts, and diorites geochemical character, sub-alkaline to tholeiitic N-MORB and E-MORB affinities, with Th (0.03–1.60 ppm) and U (0.01–0.49 ppm) contents very close to the average values for oceanic crust (Th = 0.40 ppm, U = 0.12 ppm). Amphibolites derived from 5% to 15% degrees of partial melting of a mantle source are enriched in LREE relative to HREE ([La/Sm] _N  = 1.53–2.04; [Gd/Yb] _N  = 0.98–1.54; [La/Yb] _N  = 1.60–3.80), show slight Nb, Zr, Hf, and Ti negative anomalies, as well as low ratios of (Dy/Yb)_N (1.1–1.3) < 1.6 and of Nb/Y (0.1–0.2) which are compatible with the contribution of subduction components. These data are different from those from the Ngaye amphibolites (Cameroon) and those in the Adamawa-Yadé domain, which are almost similar to those of the Banda tholeiites in south-eastern CAR on the Congo Craton edges, in terms of petrography and geochemistry. Amphibole-pyroxenites show a relatively low REE fractionation ([La/Sm] _N  = 0.53; [Gd/Yb]N = 1.04; [La/Yb]_N = 1.0), derived from a relatively high degree of partial melting (35%) which is compatible with their low HFSE levels and low ratios in (La/Yb) _N  = 0.58. Similar results are described in neighbouring regions (Sudan, Chad and Cameroon) for the Bayuda Desert amphibolites, the South Ouaddaï amphibolites, the Ngaye amphibolites, Banda, and Mbomou amphibolites (Congo Craton). The petrographic and mineralogical data indicate that mafic rock from Bocaranga underwent prograde-(peak?)-retrograde metamorphism whose prograde-peak phase was attained in the upper amphibolites– to low granulite facies, coeval to the continent–continent collision between the Saharan Metacraton and the Congo Craton. The retrograde phase followed peak metamorphism in amphibolite facies for P–T conditions of 1.4–5.2 kbar and 742°C–876°C related to decompression coeval to the post–collisional history of Western Gondwana.

The Pleistocene reef terraces of the Red Sea serve as a valuable geological archive, reflecting past marine conditions and environmental fluctuations. Among these, the Farasan Islands, located in the southern Red Sea off the Saudi Arabian coast, host a remarkable diversity of coral families, including Acroporidae, Agariciidae, Euphylliidae, Fungiidae, Lobophylliidae, Merulinidae, Pocilloporidae, and Poritidae, underscoring the region's ecological significance during the Pleistocene epoch. This study focuses on the taxonomy, biogeography, and evolutionary trends of three previously unreported scleractinian coral families Diploastraeidae, Pachyseridae, and Rhizangiidae from the Pleistocene reef units at the Seir Peninsula, Farasan Islands. We document, for the first time, the occurrence of Diploastrea heliopora and Pachyseris inattesa in the Pleistocene of the Red Sea, with P. inattesa representing the first known fossil record of this species globally. A comparison between Pleistocene and extant populations reveals a significant decline in D. heliopora abundance, reflecting substantial environmental and ecological shifts over time. P. inattesa, historically misidentified under different taxonomic names, is an endemic Red Sea species with a cryptic nature, whose first fossil occurrence in this study provides new insights into its evolutionary history and biogeographic distribution. This study advances our understanding of coral diversity and environmental changes in the Red Sea's Pleistocene reefs. It highlights the importance of fossil records in tracking biodiversity shifts and underscores the need for further research on the geographic distribution and conservation of these coral genera.

Landslides present a significant danger to both infrastructure and human lives in the challenging terrain of the Himalayas. Therefore, it is crucial to accurately map areas prone to landslides to facilitate informed decision-making and proactive planning, allowing for effective management of this hazard. Since the landslide occurrences are accentuated by floods through toe erosion, and wildfires through this research aims to integrate machine learning techniques with the analysis of multiple hazards, such as floods and forest fires, as novel conditioning factors to create a comprehensive map of landslide susceptibility. Geospatial analysis was conducted to examine the relationship between 19 conditioning elements, including factors related to flood and forest fire susceptibility, which contribute to the occurrence of landslides. This study tested the efficacy of three machine learning models for mapping landslide-prone areas: eXtreme Gradient Boost (XGBoost), Random Forest (RF) and Artificial Neural Network (ANN). These models can identify complex correlations and patterns among conditioning elements, resulting in more accurate mapping of regions prone to landslides. A regression analysis was performed to evaluate multicollinearity and confirm the association between the dependent and independent variables. The analysis revealed a variance inflation factor within acceptable bounds, providing validation for the correlation. The ROC–AUC curve approach was used to assess the models' accuracy. Among the models tested, XGB exhibited the highest accuracy at 94%, followed by RF at 92% and ANN at 77%. The results of this study offer insightful information about how to combine data from various hazard occurrences to forecast landslide susceptibility. This work can be instrumental for local authorities and disaster management organisations in prioritising resources, implementing mitigation plans and enhancing resilience against landslide threats.

Tjörnes Transform Zone (TTZ) and Reykjanes Rift Zone (RRZ) are two transform zones connecting Icelandic rift zones with Reykjanes and Kolbeinsey spreading ridges, respectively. They are strikingly different from the majority of transform zones that develop under the strong influence of the Icelandic plume. TTZ has a complicated pattern comprising several active and inactive rift and transtensive structures. RRZ has a relatively simple structure including several en-echelon volcanic systems. The transform zones have a similar position between the spreading ridges and the Icelandic rift zones within a large igneous province, but a very different structure. We have used physical modelling with lithospheric accretion to reproduce the conditions for the evolution of the present-day structure of the TTZ and RRZ. The modelling results show that the main conditions for the TTZ include the presence of a crustal thickness gradient, the interaction of overlapping structures, structural inheritance, and the magmatic pulses of the Icelandic plume. The specific feature of TTZ is Húsavík-Flatey Fracture Zone with a transtensive pattern. We rely on it could onset from Northern Rift Zone and predefine the whole pattern of the TTZ western branch. The main conditions for the RRZ are crustal thickness and its variation with distance from the centre of the Icelandic plume, and structural control of the Reykjanes Ridge. Nowadays, its active part is an analogue of a small part of TTZ. Another method, morphometric analysis of fault scarps, has been used to reflect the current structure and activity of the transform zones. Within the TTZ, the western branch shows decreasing tectonic activity, while the eastern branch shows increasing activity. In the RRZ, the most active volcanic systems are those adjacent to the Western Rift Zone and the Reykjanes Ridge. There is currently a southward displacement of all extension centres. The current evolution trend of both transform zones supposes their structural simplification.

The late Paleogene sedimentary succession exposed in the north Sulaiman fold-thrust belt (SFTB), Pakistan, provides a critical record of the tectono-sedimentary processes associated with the transition from the remnant Tethys Sea to a foreland basin. This study integrates sedimentary facies and biostratigraphy data of these sediments to unravel the dynamics of this transition, closely linked with the early stages of the Himalayan orogenic evolution. The Pirkoh Formation, characterised by three microfacies, indicates deposition in inner to open shelf settings. The overlying Drazinda Formation comprises six microfacies and two lithofacies, indicating deposition in semi-restricted lagoon to middle shelf environments. The Chitarwatta Formation comprises five distinct lithofacies, with the lower unit reflecting deposition in tidal flat settings and the upper unit representing deposition in a fluvial floodplain. An assemblage and two taxon range larger benthic foraminiferal and two planktic foraminiferal assemblage biozones in the Pirkoh and Drazinda formations were identified. These biozones suggest a Lutetian to Bartonian (Middle Eocene) age for the Pirkoh and the lower part of the Drazinda formations, and a Priabonian (Late Eocene) age for the upper part of the Drazinda Formation. No age-diagnostic fauna was retrieved from the Chitarwatta Formation. Therefore, an Oligocene age has been retained for it based on previous studies. The integration of sedimentary facies with biostratigraphic ages reveals a final transgression of the Tethys Sea in the SFTB in the Lutetian–Bartonian following the initial India–Asia collision in the early Eocene in the region. The Tethys Sea started to gradually retreat in the Priabonian with the deposition of dominantly semi-restricted lagoonal shales in the upper part of the Drazinda Formation. The Tethys Sea further retreated at the start of the Oligocene with the deposition of the transitional marine tidal flat sediments in the lower part of the Chitarwatta Formation. The cessation of the Tethys Sea occurred in the late Oligocene, represented by the deposition of the fluvial sediments in the upper part of the Chitarwatta Formation in the SFTB. The typical Miocene Himalayan foreland basin molasse sediments overlie the Chitarwatta Formation, representing the establishment of the foreland basin sedimentation in the SFTB by the late Oligocene to Miocene. This transition from remnant Tethys Sea to Himalayan foreland basin sedimentation in the SFTB can be linked with the southward migration of the Himalayan deformation front.

The Late Permian sedimentary sequences of the Northern Qiangtang Terrane are closely related to the formation of late Palaeozoic basins and the sub-duction of the Paleo-Tethys Ocean. Here we present new insights into the paleoenvironment and provenance of the southern margin of the Northern Qiangtang Terrane (NQT) during the Late Permian to Middle Triassic, integrating existing petrological, geochemical and detrital zircon U–Pb age data. The Chemical Index of Alteration (CIA) and Ln (Al²O³/Na²O) ratio indicate that the Late Permian sediments experienced moderate chemical weathering under warm and humid conditions, while the Early to Middle Triassic sediments underwent weak chemical weathering under cold and arid conditions. Paleo-salinity indicators (Sr/Ba, CaO/(CaO + Fe)), suggest that the Northern Qiangtang Terrane transitioned from brackish to saline marine environments. Redox-sensitive indicators, including V/(V + Ni) and Ce/La, reveal that the anoxic conditions persisted from the Late Permian to the Middle Triassic, with a significant increase in the degree of anoxia. Provenance-sensitive geochemical indicators (La/Th vs. Hf, La/Sc vs. Co/Th, TiO²/Al²O³ vs. TiO²/Zr), along with tectonic setting discrimination diagrams based on zircon trace elements, indicate that the clastic contributions to the Northern Qiangtang Basin during the Late Permian to Middle Triassic were dominated by felsic volcanic arc-derived sources. Detrital zircon age spectra show a notable shift in provenance from the Late Permian to Early Triassic, with Late Devonian to Early Carboniferous volcanic rocks from the western Northern Qiangtang Terrane contributing partially to the southern Northern Qiangtang Terrane, while Late Permian to Early Triassic continental arc magmatism provided proximal volcanic sources. We conclude that the development of the Late Permian to Middle Triassic sedimentary sequences in the southern Northern Qiangtang Terrane was closely linked to the subduction of oceanic crust beneath the Northern Qiangtang Terrane and subsequent closure of the Paleo–Tethys Ocean. These findings provide an improved understanding of the climatic, depositional and tectonic evolution of the NQT during the Permian–Triassic transition and have significant implications for further exploration of the early evolution of the Paleo-Tethys Ocean and regional tectonic frameworks.

The Cretaceous-Paleogene (K/Pg) transition is a global mass extinction event that affected the paleoenvironment, palaeogeography, and biota of the Earth. In this study, we investigated the sedimentary record of the K/Pg transition in the Hazara Basin, a part of Eastern Tethys in Pakistan, using an integrated approach of sedimentology, micropaleontology, geochemistry, and mineralogy. We identified eight biozones based on benthic and planktonic foraminifera, ranging from Middle Cenomanian to Thanetian in age. We also recognised 10 microfacies, reflecting different depositional settings from middle-outer ramp to inner ramp and shoreface environments across the K/Pg transition. We used geochemical proxies and indices to infer the paleoredox conditions, paleosalinity, paleotemperature, detrital input, and paleoproductivity of the basin. We found that oxygenated conditions prevailed across the K/Pg transition, with normal salinity in marine settings and lower salinity in continental settings. The Sr/Ca and Mn/Ca ratios indicated moderate paleotemperature and low terrigenous input, except for shale intervals with higher detrital input. The chemical weathering proxies showed moderate to intense weathering in the source area. The organic matter was mainly of type-III and type-IV, with low total organic carbon and hydrogen index values. The clay mineralogy was dominated by kaolinite, indicating warm and humid conditions, followed by smectite, chlorite, and illite. The K/Pg boundary could not be constrained by the fossil record due to the absence of Late Maastrichtian and Danian fauna in the Hazara region, which may be attributed to tectonic uplift, erosion, and non-deposition of sediments during the collision of the Indian Plate and Kohistan Island Arc. However, the boundary could be recognised by the facies change corresponding to lateritic and oolitic haematite at the base of the early Palaeocene Hangu Formation.