Search Results (220)

Natural fracture development in tight-sand gas reservoirs is strongly controlled by tectonic evolution yet remains difficult to characterize using conventional seismic interpretation due to limited resolution. This study presents a damage-mechanics-based approach that integrates 2D seismic data, well logs, and drilling information to construct a 3D geological model and simulate tectonically induced fracture development under regional orogenic loading. The approach is applied to the Permian formation in the Ordos Basin. Modeled damage zones, interpreted as areas of enhanced natural fracture development, show strong spatial correspondence with high-productivity wells. The results demonstrate that damage mechanics provides an effective framework for linking tectonic processes with fracture distribution in tight-sand reservoirs and offers new insights into fracture-controlled gas accumulation and productivity. This case demonstrates the applicability and effectiveness of the technology of continuum damage mechanics for 3D natural fracture distribution based on sets of 2D seismic data plus drilling data. Although sets of 2D seismic data cannot replace real 3D seismic data for all its usage, it can produce numerical results of natural fractures with reasonable accuracy for calculation of natural fractures with damage mechanics method. Full article

Variscan two-mica granites are widespread in the Trás-os-Montes region (NE Portugal), yet their emplacement ages, petrogenesis, and relationship with Variscan deformation phases remain poorly constrained. This study integrates U–Pb zircon geochronology, whole-rock geochemistry, and oxygen isotope data to characterise four peraluminous two-mica granites in the Trás-os-Montes area (Fornos, Carviçais, Fonte Santa, and Bruçó) and to refine their tectonomagmatic context within the Central Iberian Zone. All granites are S-type, ilmenite-series, and derived from reduced magmas, as indicated by their strongly peraluminous compositions, mineral assemblages (muscovite ± biotite), absence of magnetite and presence of ilmenite, and high δ¹⁸O values (>11‰), consistent with partial melting of metasedimentary crust. U–Pb ages reveal two distinct magmatic pulses: an older event at ~340 Ma (Fornos and Fonte Santa granites), predating the onset of C3 deformation and likely associated with late C1 crustal thickening to early C2 tectonics, and a younger pulse at ~320–318 Ma (Carviçais and Bruçó granites). These magmatic pulses are linked to contrasting structural controls, with the older granites emplaced within regional-scale antiforms and the younger intrusions localised along structures related to C3 deformation. Together, these results document two discrete crustal melting events separated by ~20 Ma and record a progressive shift from fold-controlled to strike-slip-dominated granite emplacement during Variscan orogenic evolution. Moreover, the study highlights that tungsten mineralisation is preferentially associated with reduced, crust-derived granites emplaced during specific tectonic regimes, providing new constraints for metallogenic models in NW Iberia. Full article

Pegmatites with miarolitic cavities have not previously been reported from the Larsemann Hills, East Antarctica, and their age and origin remain poorly constrained. We report the first geochemical and geochronological data for fluorapatite from a newly discovered pegmatite with miarolitic cavities in the Larsemann Hills. Large Fe-rich fluorapatite crystals (up to 5 cm) contain abundant oriented monazite-(Ce) inclusions and display elevated REE (1397–7966 ppm), relatively high Y (945–4192 ppm), and low Sr (52.2–83.5 ppm). Their trace-element signatures plot within the fields of partial melts, high-grade metamorphic rocks, and evolved fluid-rich magmatic systems. U–Pb dating of fluorapatite yields concordant ages of 519 ± 4 Ma (ID-TIMS) and 521 ± 31 Ma (LA-ICP-MS), indicating crystallization during the D₄ stage of the Pan-African orogeny. The isotopic equilibrium between apatite and monazite inclusions suggests synchronous formation and late-stage fluid overprinting. Combined geological, geochemical, and isotopic evidence shows that the pegmatite formed in situ as a product of anatexis of the Broknes paragneisses and evolved within a volatile-rich magmatic–hydrothermal system. These results provide the first direct age constraints on pegmatites with miarolitic cavities in Antarctica and shed new light on the final stages of East Gondwana assembly. Full article

The Neoproterozoic Paraguay Belt (western Brazil), formed by the Brasiliano/Pan-African Orogenic Cycle during Western Gondwana amalgamation, hosts tens of gold occurrences and deposits. This review provides new insights into the metallogeny and tectonics of the Paraguay Belt Gold Province, based on previous and new data on stratigraphy, structural geology, metamorphism, hydrothermal alteration, and gold grades. The mineralizations correspond to turbidite-hosted orogenic gold systems, with quartz veins cutting metasedimentary rocks with minor metavolcanics. A six-phase tectonic–metallogenic evolution model is proposed. The early stages correspond to glaciolacustrine deposition in a rift that evolved into a passive margin and then into a foreland basin, with glaciomarine sediments. Late sedimentation corresponds to glacial-to-post-glacial shallow marine units in the foreland. The orogeny progressed with cratonic collisions, resulting in three deformation (two compressional and one extensional) and three metamorphic (regional, dynamic, and contact) phases. The Au mineralization results from metamorphic fluids that transported metals from the metasedimentary pile and deposited them in reactive rocks (rich in magnetite or organic carbon). Gold occurs in sulfide-rich (pyrite and galena) veins and hydrothermal alteration zones. The metallotects and structural controls highlighted here are useful tools for prospecting gold in the Paraguay Belt and similar geological terranes. Full article

The scorpion genus Hottentotta Birula, 1908 is widely distributed across Africa and the Middle East, extending to Pakistan, India and Sri Lanka. The processes which resulted in their evolution and diversification across this vast area are poorly understood. The present study investigated the phylogeny and historical biogeography of the genus in the Iranian Plateau and the Zagros Mountains based on nuclear and mitochondrial DNA sequences from four African species, an Arabian species and eight species from the Middle East, most of which are endemic to Iran. Phylogenetic analyses confirmed the monophyly of all species included in the analysis and recovered a clade comprising Iranian and Afro-Arabian species. S-DIVA and BBM analyses demonstrated that the species of Hottentotta occurring in the Iranian Plateau and the Zagros Mountains originated from an African ancestor and then dispersed to their current geographical ranges. Further divergence coincided with the orogeny of the Zagros Mountains and climatic changes during the Miocene epoch. The results support the hypothesis that the Zagros Mountains formed a geographical barrier which promoted vicariance and diversification on the Iranian Plateau. Full article

Snakeheads of the genus Channa display remarkable diversity in body size and ecology, yet evolutionary relationships within several species complexes remain unresolved. Channa pyrophthalmus, a recently described dwarf species endemic to Myanmar, represents a key lineage for investigating allopatric diversification in freshwater fishes. Here, we report the first complete mitochondrial genome of C. pyrophthalmus and perform comparative mitogenomic analyses across 18 Channa species. Phylogenetic analyses based on mitochondrial protein-coding genes robustly place C. pyrophthalmus as the sister lineage to C. gachua sensu stricto, supporting recent taxonomic revisions. While mitochondrial coding regions are highly conserved across the genus, the control region exhibits pronounced lineage-specific structural variation driven by tandem repeats. Divergence-time estimation dates the split between C. pyrophthalmus and C. gachua to ∼7.1 Ma (Late Miocene), a timeline congruent with the Late Miocene accelerated uplift of the Indo-Burman Ranges. Selection analyses reveal contrasting evolutionary regimes: pervasive purifying selection characterizes the dwarf lineage, whereas episodic positive selection on ND5 marks the ancestral lineage of giant snakeheads, indicating adaptive shifts in mitochondrial bioenergetics. Additionally, accelerated evolution in ATP8 was detected in rheophilic lineages. Together, these findings link geological vicariance and mitochondrial metabolic evolution to body size diversification in Channa. Full article

The Felbertal tungsten mineralisation in the Tauern Window (Eastern Alps) is hosted by the Early Paleozoic Habach Complex belonging to the Lower Schieferhülle. In predominantly mafic meta-volcanic rocks, mostly amphibolites, green amphibole crystallised in assemblages with plagioclase, epidote, chlorite, sphene and quartz. Microstructural features and preferential orientation of the amphiboles define planar-linear structures of finite strain and indicate that their crystallisation is coeval to the main deformation event. Amphibole crystals display core-to-rim zonations with increasing ^IVAl, ^VIAl, Na and Ti and decreasing Si, covering actinolite over magnesio-hornblende to tschermakite compositions. Amphibole zonations and assemblages are similar to metabasites in the classical Barrovian mineral zones in the Dalradian of Scotland and typical of a prograde metamorphism from the greenschist over epidote-amphibolite to the lower amphibolite facies. Amphibole endmember geothermobarometry defines an early P-T path segment from 400 °C/2 kbar to 540 °C/6 kbar, and a consecutive later P-T path segment from ~500–540 °C/6 kbar to maximal P-T conditions of ~620–640 °C/7–8 kbar. As Carboniferous granitoid intrusions within the Habach Complex underwent penetrative ductile deformation, an Alpine Tertiary age of the lower amphibolite facies metamorphism, as observed in other parts of the Lower Schieferhülle, appears suitable. Full article

As a tectonically stable and extensively superimposed basin situated in the North China Craton, the Ordos Basin hosts abundant reserves of oil, natural gas, and coal within its Paleozoic strata, rendering it a focal area in energy-related geological research. The basin’s evolutionary history provides a comprehensive record of key geological transitions—from an Early Paleozoic carbonate platform to Late Paleozoic marine–continental transitional deposits and ultimately to continental clastic sedimentation—largely governed by the regional tectonic dynamics associated with the North China Plate. This study presents a systematic review of the sedimentary and tectonic evolution of the Paleozoic sequence in the basin. Findings indicate that during the Early Paleozoic, the basin developed under a passive continental margin setting, characterized by widespread epicontinental marine carbonate deposition. By the Late Ordovician, subduction of the Qinqi Ocean triggered the Caledonian orogeny, resulting in regional uplift across the basin, widespread erosion, and a significant hiatus in Middle to Late Ordovician sedimentation, which facilitated the formation of paleo-weathered crust karst reservoirs. In the Late Paleozoic, the basin evolved into an intracratonic depression. From the Late Carboniferous to the Early Permian, the Hercynian tectonic event influenced the transformation from isolated rift basins to a broad epicontinental sea, leading to the deposition of critical coal-bearing strata within marine–continental transitional facies. Starting in the Middle Permian, the closure of surrounding oceanic domains induced widespread tectonic uplift, shifting the depositional environment to a terrestrial fluvial-lacustrine system and marking the termination of marine sedimentation in the region. Based on the comprehensive research findings, this study underscores that the superposition, inheritance, and interaction of multiple tectonic events are the primary controls on the paleogeographic architecture and sedimentary. Full article

Chelmos Vouraikos UNESCO Global Geopark is located in North Peloponnesus, Greece. As a member of the Global Geoparks Network, it is valued for its rich geoheritage in combination with its natural and cultural wealth. Several different landforms of international value are located in the area. The scope of this work is to present an overview of its geomorphological features, link them with biodiversity and highlight their value for geotourism. Its geology is complicated due to intense tectonism. Three geotectonic units of the Alpine Orogeny can be found along with post-Alpine sediments related to the Corinth Gulf rifting. The area is highly covered by limestone creating important karst landforms. High peaks surround river valleys and deep gorges create breathtaking landscapes. Some of them cut through high and steep conglomerate slopes. Remnants of past glaciation have been preserved on Mt Chelmos. The exceptional geodiversity of the area is linked with rich vegetation and high endemism. The many identified geomorphological sites highlight the Geopark’s strong commitment to geomorphology and its importance as a key geomorphological destination. Highly visible geomorphological sites with ecological value can also promote environmental awareness and contribute to the protection of biodiversity. Full article

This study takes the Jiangligou Plutonic Complex (JPC) in the Western Qinling tectonic belt as the research object and systematically investigates the crystallization age, magmatic genesis, and tectonic setting of the plutons. Results indicate that the Jiangligou Plutonic Complex was formed during the Triassic period (252–216 Ma, corresponding to the “Indosinian” regional tectonic stage in East Asia). Six plutons are recognized in the Jiangligou region. Plutons IV (246 ± 3 Ma) and V (252 ± 2 Ma) record Early Triassic magmatism, and Plutons I (238 ± 1 Ma), II (216 ± 2 Ma), III (216 ± 2 Ma), and VI (224 ± 2 Ma) correspond to Middle-Late Triassic magmatic activity. Furthermore, the data from this study indicate that a Th/U ratio > 0.4 serves as a more effective criterion for identifying reliable magmatic zircons. Our data indicate that the Jiangligou Plutonic Complex represents a multi-stage magmatic system generated in response to the tectonic evolution of the West Qinling, spanning from the late subduction of the Mianlue Ocean to the peak collision between the North China and Yangtze blocks during the Indosinian orogeny. The region is dominated by a collisional setting, with magmas primarily derived from crustal remelting. This study provides key chronological and geochemical constraints on the Indosinian tectonic–magmatic evolution of West Qinling. Full article

Detrital zircon U–Pb dating from the Muti Formation sheds light on sediment sources and foreland basin development along the northeastern Arabian margin during the Late Cretaceous. The siliciclastic-rich Muti Formation was deposited in a syn-obduction foreland basin that formed as the Semail Ophiolite advanced. Zircon age spectra from eastern (Nakhal and Sayga) and western (Murri) sections are dominated by Neoproterozoic–Cambrian ages (450–900 Ma), linked to the Pan-African orogeny and the Arabian–Nubian Shield, indicating these as the main sediment sources. The Murri section also contains older Mesoproterozoic to Archean zircons, likely recycled from the Nafun Group (part of the Huqf Supergroup), suggesting reworking of ancient Gondwanan cover sequences rather than direct input from the Indian craton. Additional Permian zircons reflect input from Arabian Plate magmatic rocks, while Jurassic–Cretaceous grains indicate material derived from the Semail Ophiolite and related arc terranes. Overall, the Muti Formation records a mixed sediment supply from the Arabian Shield, reworked Gondwanan sandstones, and ophiolitic detritus, marking the transition from a passive margin to a flexural foreland basin. The dominance of Pan-African zircon ages highlights continued recycling of Gondwanan sequences and refines models of Late Cretaceous basin evolution in northern Oman, underscoring the complex, multi-cycle nature of sedimentation in this tectonically active setting. Full article

During the course of the Carboniferous to Permian, large parts of eastern Laurentia and northern Gondwana were affected by the Variscan Orogeny accompanying the assembly of Pangea. Here, we concentrate on the Appalachian belt of eastern Laurentia and the Mauritanide of western Gondwana. Owing to the irregular shapes of the craton margins, the collision between Laurentia and the West African Craton provides several conjugate promontories and embayments alongside both cratons. Among others, the coupled pair formed by the African Reguibat promontory and its counterpart in North America, the Pennsylvania embayment, is the principal subject of this study. The western movement of the Reguibat Shield had initially imprinted the West African belts but finally also affected the Appalachians. Acting as a “hallmark”, it produced two specific lobes (stacks of nappes) on both sides of the promontory. The southern NW-SW lobe (Akjoujt nappes) is long known. However, the northern lobe of the “Adrar Souttouf Massif” has not been identified previously, owing to being partially covered and also to its N-S alignment instead of an expected symmetrical SW-NE direction. Furthermore, the Adrar Souttouf Massif is partially covered by allochthonous terranes (Western Thrust Belt, TB, or Appalachians). This new discovery supports a classical impingement model for the deformation of the North American and African belts by westward displacement of the Reguibat Shield. Full article

This study presents stratigraphic and structure findings from the southeastern Bannu Basin, a structurally complex segment of the Sub-Himalayan foreland in Pakistan. Two dimensional seismic reflection data were integrated with well-log data from the Chonai-01 and Marwat-01 wells to reconstruct the subsurface basin architecture and to evaluate its hydrocarbon potential. In general, the deformation in the region is strongly controlled by the Neoproterozoic Salt Range Formation, with salt tectonics generating anticlines, deep salt detachment, and fault systems that form favorable structural traps. Seismic interpretation reveals both normal and reverse faulting, and multiple unconformities, indicating episodic tectonic activity linked to Himalayan orogeny. Well correlation of individual formations highlights lateral stratigraphic variations, including thick Siwalik Group deposits and key reservoir units such as the Datta and Lumshiwal formations. These findings demonstrate that mild salt-related deformation and stratigraphic discontinuities play a central role in hydrocarbon migration and entrapment. The structural and stratigraphic similarity of the Bannu Basin to the Potwar Plateau underscores its significant exploration potential within the Himalayan foreland system, while the integrated seismic–well workflow provides a robust framework for future exploration. Full article

The Khanbogd-Erdene region in southern Mongolia is a globally important copper–polymetallic metallogenic province, hosting large to super-large deposits, such as Oyu Tolgoi and Tsagaan Suvarga. The area experiences frequent tectonic–magmatic activity, particularly Late Paleozoic subduction-related magmatism, which controls the occurrence of large-scale copper–polymetallic mineralization. This study focuses on the Late Paleozoic granitic intrusive rocks in the Khanbogd-Erdene region of southern Mongolia. Using LA-ICP-MS and SHRIMP dating techniques, precise zircon U–Pb ages were obtained for 10 samples. A total of 209 zircon grains from these 10 intrusive rocks were analyzed, with most cathodoluminescence (CL) images of zircon grains showing distinct oscillatory zoning. Th/U ratios ranging from 0.11 to 2.92 indicate they are magmatic. The younger group of granitic rocks yielded ages between 260.2 ± 1.2 Ma and 286.6 ± 0.9 Ma, indicating an Early Permian geological age. The other seven samples yielded older ages between 315.9 ± 1.8 Ma and 340.9 ± 0.9 Ma, indicating a Carboniferous geological age. These large-scale Carboniferous to Early Permian intrusive rocks in the Khanbogd-Erdene region are products of tectonic–magmatic activity during specific stages of crustal evolution. The findings provide reliable chronological data for regional tectonic–magmatic activity and offer new evidence for constraining the timing of the Variscan orogeny in southern Mongolia. Full article

The Dingri–Gangba fault, a major structure within the Himalayan Orogenic Belt, records significant geological events, including the tectonic evolution of the northern margin of the Indian plate and the uplift of the Tibetan Plateau. However, its geometry, kinematics, and tectonic characteristics remain debated. To constrain the tectonic evolution of the Dingri–Gangba fault, this study integrates detailed field investigations and structural analysis with Electron Spin Resonance (ESR) dating to characterize its three-dimensional architecture and quantify the timing of its deformation phases. The results show that the fault trends nearly E–W and exhibits multi-phase structural superimposition, including thrusting (60–40 Ma), normal faulting (35–11 Ma), and strike-slip shear (18–6.8 Ma). These phases reflect a multi-stage tectonic evolution following the India–Eurasia collision. Stratigraphic comparisons reveal that during the Mesozoic, the Dingri–Gangba fault played a significant basin-controlling role, marked by variations in sedimentary thickness, soft-sediment deformation, and volcanic activity. The sedimentary evolution alternated between periods of “differentiation” and “uniformity”. A comprehensive analysis suggests that the tectonic evolution of the Dingri–Gangba fault is closely linked to the dynamic transition of the Tethys Himalaya from a passive continental margin to a collision orogeny, also reflecting changes in the tectonic stress field following the India–Eurasia collision. These findings provide valuable insights into the tectono–sedimentary–magmatic coupling along the southern margin of the Tibetan Plateau. Full article