Search Results (831)

The Galinge deposit in East Kunlun, China is a large Fe-polymetallic skarn system with a significant by-product, Co, but the respective roles of magmatism, skarn evolution, and wall rock interaction in Co enrichment remain incompletely understood. We integrate zircon and garnet U–Pb geochronology, zircon Lu–Hf isotopes and trace elements, whole-rock geochemistry, and SEM-EDS and EPMA mineral chemistry. Granodiorite and diorite porphyry yield zircon U–Pb ages of 230.09 ± 0.91 Ma and 229.4 ± 1.3 Ma, respectively, whereas skarn garnet yields 224.4 ± 9.3 Ma, placing intrusion and skarn formation within a Late Triassic magmatic–hydrothermal system. Both suites are metaluminous, LREE-enriched, and Nb–Ta–Ti-depleted; zircon ε_Hf(t) values of −9.4 to −1.8 indicate the predominant reworking of older crustal material with variable input from a more radiogenic component. Strictly screened Ti-in-zircon temperatures and lattice strain Ce anomalies yield median apparent ΔFMQ values of +3.36 for granodiorite and +3.04 for diorite porphyry, indicating comparably oxidized magmatic conditions. The analyzed intrusions contain 2.12–13.4 ppm Co, whereas cobaltite and Co-bearing arsenopyrite contain 32.83–34.14 wt% and 0.38–4.53 wt% Co, respectively. Spatial and paragenetic relations place Co enrichment after magnetite deposition, during an early sulfide-stage hydrothermal sulfarsenide event within the skarn system. We infer that Late Triassic intrusions supplied heat, fluids, and ligands, whereas structural focusing and cooling, coupled with carbonate wall rock reactions and a reduction in carbonaceous or Fe²⁺-bearing domains, promoted As–S-rich Co precipitation; the leaching of intermediate–mafic wall rocks may have supplemented the Co inventory. Full article

To elucidate the formation mechanisms of carbonate cement in the Chang 8 tight sandstone reservoir of the Upper Triassic Yanchang Formation (Jiyuan Area), the types, paragenetic stages, and genesis of the cement were investigated via thin-section petrography, carbon–oxygen isotope analysis, and fluid inclusion microthermometry. Results indicate two distinct generations of carbonate cement within the Chang 8 reservoir: early micritic calcite cement and late sparry to coarsely crystalline ferroan calcite cement. The late ferroan calcite cement exhibits δ¹³C_PDB values spanning from −7.02‰ to −12.51‰ and δ¹⁸O_PDB values ranging from −18.81‰ to −30.24‰. The early micritic calcite cement is interpreted to have precipitated from supersaturated alkaline pore fluids during the shallow burial stage (Stage A of early diagenesis) at the close of the Late Triassic. Conversely, the late ferroan calcite cement formed during the Early Cretaceous at temperatures between 100 °C and 110 °C, and its genesis is closely linked to organic-acid-related fluids. These findings elucidate the characteristics of carbonate cements across different stages and have significant implications for predicting the distribution of high-quality reservoirs and for providing guidance for future exploration and development. Full article

This study elucidated the spatial distribution characteristics of surface snow chemistry and stable isotope composition and their influencing factors in Antarctica’s coastal region. We analyzed data from eight surface snow chemical ion transects and five surface snow stable isotope transects to examine the distributions of sea-salt ions (Na⁺, Cl⁻, Mg²⁺, K⁺), non-sea-salt ions (NO₃⁻, methanesulfonic acid (MSA), non-sea-salt sulfate (nssSO₄²⁻), non-sea-salt Ca²⁺ (nssCa²⁺)), and the stable isotope δ¹⁸O. Concentrations of chemical ions were found to exhibit distinct source signatures. Principal component analysis indicated that the ranking of ion sources in Antarctica’s coastal areas is as follows: sea-salt aerosol transport, followed by marine biological activities and crustal dust and then atmospheric chemical reactions. Data from all transects exhibited a general pattern of diminishing δ¹⁸O with increasing distance from the coast but with marked regional differences in the δ¹⁸O–distance slope (−6.84 to −1.98‰/100 km), δ¹⁸O–altitude slope (−0.97 to −0.20‰/100 m), and δ¹⁸O–temperature slope (0.61 to 1.14‰/°C). The moisture source regions and transport pathways, local orographic uplift, and local temperature field jointly affect the differentiation of δ¹⁸O in coastal areas. The findings suggest that snow chemistry and isotopic composition in Antarctica’s coastal zones are controlled by marine source transport, biogeochemical cycling, and polar topographic and climatic processes. Full article

The object of this study is nephrite found on Mount Bikilyar, South Urals, Russia. The purpose of the study is to determine the mineral and chemical composition of the nephrite and host rocks and to develop a model of the nephrite’s formation. The mineral composition was studied using a scanning electron microscope with an energy-dispersive quantitative microanalysis system. We studied the chemical, trace element, and oxygen isotopic composition. The nephrite’s composition is dominated by tangled fibrous and downy aggregates, with large lamellar grains of actinolite. Magnesian hornblende and resorbed diopside grains, as well as chromite, titanite, apatite, chlorite, sulfides, and secondary minerals, are less common. The host rocks are metagabbro of diverse mineral compositions. The nephrite is characterized by a subchondritic trough-like distribution spectrum of REE with a negative Eu anomaly. The chondrite-normalized spectrum of the metagabbro is characterized by significantly higher REE content values. The δ¹⁸O isotopic composition of the nephrite is +5.53 to +5.80‰, indicating the deep origins of oxygen inherited from ultramafic rocks. The extremely heterogeneous and heavier composition of the metagabbro is +4.42 to +11.27‰, reflecting different contributions of the mantle and crustal sources to its formation. The nephrite was formed as a result of ultramafic xenoblock transformation under the influence of gabbro. Initially, serpentine was replaced by diopside, after which actinolite developed to form the nephrite. The Bikilyar nephrite differs in its mineral composition from the nephrite of other deposits. Despite the unique mineral composition, Bikilyar nephrite is a typical serpentinite in terms of paragenesis and chemical composition. The nephrite-specific mineral and chemical composition is explained by the small size of the ultramafic block that is in a significant volume of gabbro. Full article

Protonic ceramic electrochemical cells (PCECs), including protonic ceramic fuel cells, electrolysis cells and reversible cells, have attracted increasing attention as efficient solid-state devices for electricity generation, hydrogen production and chemical conversion at intermediate temperatures. Recent advances in electrolyte thinning, electrode nanostructuring and interface engineering have enabled remarkable device performance, including reversible operation at 500–650 °C, operation below 450 °C, and expanded fuel flexibility toward hydrogen, ammonia and methane-containing feeds. However, the working-state mechanisms governing their performance and durability remain insufficiently understood. In particular, proton incorporation, surface hydration, proton exchange, proton-coupled oxygen reduction/evolution, electrode reconstruction and buried interface degradation are highly dynamic processes that cannot be fully resolved by ex situ or post-mortem characterization. Operando characterization provides a powerful route to bridge this knowledge gap by directly correlating structural, chemical and electrochemical evolution under realistic temperature, steam, gas atmosphere and electrochemical bias. In this review, we summarize recent progress in operando and in situ characterization of PCECs, with emphasis on vibrational spectroscopy, X-ray-based techniques, neutron methods, electron microscopy and electrochemical diagnostics. We discuss how operando DRIFTS and H/D isotope exchange reveal voltage-dependent proton exchange kinetics, how operando Raman captures oxygen-electrode surface reconstruction, how X-ray and neutron methods probe redox chemistry and proton dynamics, and how EIS/DRT analysis links structural changes to reaction resistance. We further highlight current challenges, including limited access to buried interfaces, difficulty in quantifying protonic defects, insufficient multimodal correlation and the lack of standardized operando cell configurations. Finally, we propose future directions based on isotope-resolved spectroscopy, multimodal operando platforms, AI-assisted spectral/impedance analysis and theory-guided interpretation. This review aims to establish a working-state mechanistic framework for rationally designing durable, high-performance PCECs. Full article

Modern scientific research approaches to studying the hydrological cycle of water in nature, in addition to the mathematical modeling of hydrological–hydraulic processes that have expanded in recent years, increasingly include isotope hydrology on a global scale. This paper presents the preliminary results of research in the Vardar River basin. The research is in the field of isotope hydrology with the analysis of stable isotopes of hydrogen (δ²H) and oxygen (δ¹⁸O) in precipitation (P), surface water (SW) and groundwater (GW). For this purpose, a network for taking water samples in the Vardar River basin has been established. The isotopic composition of precipitation shows a relatively wide variability, with δ²H values ranging from −83.7‰ to −12.4‰ and δ¹⁸O values from −11.65‰ to −2.99‰. In contrast, groundwater samples exhibit a considerably narrower isotopic range, with δ¹⁸O values between −10.98‰ and −10.1‰ and δ²H values between −73.3‰ and −68.1‰. Surface water samples show δ¹⁸O values ranging from −10.7‰ to −9.11‰ and δ²H values from −70.6‰ to −61.6‰. The results of the study show that the waters in the Vardar River basin are predominantly of meteoric origin, with their isotopic composition being strongly influenced by climatic factors and altitude, varying from approximately 1400 m and 2000 m a.s.l. The study confirms that precipitation is the primary source of both surface and groundwater. Evaporation is the dominant process that modifies isotopic signatures during rainfall, surface runoff and groundwater recharge. Due to good fit and nearly parallel meteoric lines observed in the three different locations, preliminary LMWLs and RMWL were estimated. A similar isotopic composition of surface water (SW) and groundwater (GW) in some locations indicates the presence of a direct and active hydrological connection between these water bodies, which need to be investigated in more detail in future research. However, one of the groundwater sampling locations suggest more depleted isotopic composition, which is probably related to different recharge altitudes, but also possibly very interesting relationship between Vardar River, alluvial aquifers and karst aquifer in the Žeden massif. Full article

Vitamin D comprises a group of fat-soluble secosteroids traditionally associated with animal physiology, calcium-phosphate homeostasis, and skeletal metabolism. However, vitamin D and related compounds have also been reported in taxonomically distinct non-animal systems, including fungi, microalgae, other algae, phytoplankton, and higher plants, although the strength of evidence differs substantially among these groups. This review synthesizes current knowledge on the occurrence, structural chemistry, UV-B-driven photochemical mechanisms, environmental determinants, analytical challenges, and biofortification potential of vitamin D formation in photosynthetic organisms and fungi. Vitamin D synthesis is initiated by UV-B radiation, primarily within the 290–315 nm range, which converts sterol precursors such as 7-dehydrocholesterol and ergosterol into previtamin D intermediates and is followed by thermal isomerization to the corresponding vitamin D forms. Continued irradiation may additionally generate lumisterol, tachysterol, and other photoproducts, thereby limiting net vitamin D accumulation. This non-enzymatic mechanism supports the interpretation that vitamin D formation can occur outside vertebrates when an appropriate 5,7-diene sterol precursor is accessible to a sufficient UV-B dose. In photosynthetic organisms and fungal matrices, net vitamin D accumulation is constrained by the spectral dose of UV-B, environmental exposure, tissue architecture, sterol localization, oxygen availability, antioxidant capacity, and ROS-mediated degradation. Studies of microalgae and phytoplankton, including reports concerning Emiliania huxleyi, suggest the occurrence or UV-B-dependent formation of both vitamin D₂ and vitamin D₃. However, these findings require evaluation according to the analytical method, use of authentic standards, experimental conditions, and confidence of compound identification. In fungi, the UV-B-induced conversion of abundant ergosterol to vitamin D₂ is well established. Microalgae represent a developing source of vitamin D₂ and vitamin D₃, whereas evidence for nutritionally relevant vitamin D accumulation in higher plants remains limited and heterogeneous. Although higher plants contain diverse phytosterols, the formation of vitamin D₄, vitamin D₅, or related analogues requires appropriate photoreactive 5,7-diene precursors and should not be inferred directly from the presence of common phytosterols such as β-sitosterol. Analytical detection remains challenging because of low concentrations, complex lipophilic matrices, and structural similarity among secosteroids and photoproducts; therefore, reliable identification requires validated analytical procedures. LC-MS/MS provides high sensitivity and selectivity but should be supported by authentic standards, preferably isotope-labelled internal standards, retention-time agreement, quantitative and qualifying ions, matrix-recovery assessment, limits of detection and quantification, and evaluation of ion suppression. Structurally similar analogues and photoproducts may additionally require orthogonal confirmation. Nutritionally, post-harvest UV-B enrichment of edible mushrooms is currently the best-validated strategy for increasing non-animal vitamin D₂ content. Microalgae constitute a developing platform for vitamin D₂ and vitamin D₃ production, whereas biofortification of higher plants remains experimental. Full article

To reveal the impacts of long-term coal mining on groundwater flow fields and the environment, the Jinjitan Coal Mine in Shaanxi Province, China, was selected as the study area. A systematic investigation on the evolution of flow fields and migration of pollutants under long-term coal mining impact was conducted using methods including Self-Organizing Map (SOM) clustering analysis, water isotope analysis, and numerical simulation. The results show that groundwater in the study area is mainly derived from atmospheric precipitation, and the mine water is a mixture of 55% coal seam water and 45% Quaternary groundwater; long-term coal mining has led to two types of Quaternary groundwater level changes (stable and continuously declining); The groundwater level of the Jurassic aquifer shows an overall decline. However, where the aquifer is locally recharged by the Quaternary groundwater, the groundwater level shows a decline-then-rise variation. The overall groundwater flow field maintains the pattern of runoff from northeast to southwest and discharge into the Yuxi River, with no local or regional groundwater depression cones observed; numerical simulation results indicate an average groundwater level drop of 1.36 m over an 10-year period, with a maximum decrease of 4.89 m; the migration scope of oxygen demand and petroleum pollutants caused by domestic sewage pond leakage is limited, their maximum long-term (3650 d) migration distances are 253.47 m and 254.27 m, respectively, and their concentrations are far below the limit of the Class III groundwater quality standard. The research findings provide a scientific basis for the environmental protection, rational development, and utilization of groundwater in the Jinjitan Coal Mine area. Full article

Geothermal energy is a low-carbon baseload renewable energy that plays a key role in global energy transition. Jinlun of Taitung is a region with high potential for geothermal energy. However, sustainable resource utilization requires a comprehensive understanding of fluid sources, recharge mechanisms, and circulation systems. This study integrated δ¹⁸O, δD, ⁸⁷Sr/⁸⁶Sr and elemental geochemistry to clarify the underlying hydrogeochemical mechanism and develop an underground fluid circulation model for Jinlun. The water compositions indicate that water–rock interactions are the dominant control on fluid chemistry. Hydrogen and oxygen isotope analysis revealed a geothermal water recharge elevation of 1321–1478 m, slightly higher than that of hot spring water (951–1459 m). The natural recharge amount of a corresponding area was approximately 13.57 × 10⁶ t/yr. A strontium isotope mixing model indicated that the fluids were affected by three end members of deep geothermal water, shallow groundwater, and seawater. Shallow groundwater had a contribution rate of 92–98% to noncoastal hot spring water and up to 81% to geothermal water. The coastal hot spring was most affected by seawater at 48%. Rainwater infiltrated into E2 to form shallow groundwater. Some of the infiltrated water reached a deep circulation into the M3 layer and formed deep-source thermal water. Overall, this study establishes a hydrogeochemical model for Jinlun and provides scientific foundation for geothermal well design and sustainable resource management. Full article

Caledonian hydrothermal vein-type Mo deposits are largely restricted to eastern Guangxi, South China, yet the magmatic controls on molybdenum (Mo) mineralization remain poorly constrained. The adjacent Guiling (Mo–mineralized) and Daning (Mo–barren) plutons in this region represent a natural pair for deciphering these issues. Zircon U–Pb dating, whole-rock geochemistry, and mineralogical characteristics indicate that the Daning pluton (~440 Ma) is an I-type granite, whereas the younger Guiling pluton (~425 Ma) is a more evolved I-type granite, with higher SiO₂ contents (avg. 71.17 wt.% vs. 65.88 wt.%), stronger negative Eu anomalies (avg. 0.53 vs. 0.63), lower Nb/Ta ratios (avg. 6.5 vs. 9.9), and Zr/Hf ratios (avg. 30.6 vs. 33.4), as well as higher Rb/Sr ratios (avg. 3.6 vs. 1.1). Sr–Nd–Hf isotopes are consistent with a Paleoproterozoic crustal source for both plutons, whereas coeval mafic microgranular enclaves in the Guiling pluton exhibit positive ε_Nd(t) values (+3.43 to +3.58), providing evidence for mantle input. Biotite geochemistry shows that the Guiling pluton is enriched in F and Cl, as reflected by lower log(ƒ_H2O/ƒ_HF)^fluid values and higher log(ƒ_H2O/ƒ_HCl)^fluid values. Our integrated study suggests that the Daning and Guiling plutons were emplaced in an intracontinental orogenic setting during the transition from compression to extension, but the more pronounced extension facilitated a greater input of mantle-derived heat and volatiles into the Guiling pluton, favoring Mo enrichment. However, the similar biotite crystallization temperatures and moderate oxygen fugacities of both plutons suggest that these factors were not the decisive factors. Collectively, we propose that the contrasting Mo fertility between the two plutons reflects the interplay of magmatic and structural factors. Magmatically, crust–mantle source mixing, high degrees of fractionation, and volatile enrichment promoted Mo concentration, whereas ductile shear zones likely served as fluid conduits that facilitated mineralization. Accordingly, the southwestern segment of the Yingyangguan (YYG) ductile shear zone between the Daning and Guiling plutons could be a prospective target for Mo prospecting in eastern Guangxi. Full article

The development of sustainable and climate-resilient food systems increasingly relies on robust analytical methodologies capable of integrating environmental, biochemical, and management-related signals. In this study, a multi-isotope framework based on δ²H, δ¹⁸O, δ¹³C, and δ¹⁵N was applied to assess its capacity to discriminate between contrasting raspberry production systems and to provide chemically grounded indicators of agroecosystem functioning. Raspberry fruits (Rubus idaeus L.; cultivars Opal and Delniwa) were collected during the 2024–2025 growing seasons from two distinct systems in Romania: an organic open-field system and a rainfed agroforestry system. Stable isotope ratio analysis revealed system-dependent isotopic patterns, with the strongest differentiation observed for δ¹⁵N. Nitrogen isotope composition (δ¹⁵N) provided the strongest discrimination, with enriched values in organic fruits (2.73–9.77‰) and depleted values in agroforestry fruits (−3.01 to 0.62‰), reflecting differences in nitrogen sources and cycling pathways. Hydrogen and oxygen isotopes (δ²H: −60.46 to −4.62‰; δ¹⁸O: −6.19 to 10.41‰) were consistent with hydroclimatic variability and evaporative fractionation processes associated with soil–plant–atmosphere interactions. Carbon isotopes (δ¹³C: −28.14 to −22.62‰) provided complementary insights into plant water-use conditions. Multivariate statistical analysis supported the separation between production systems, while short-term fertilisation effects were secondary to system-level controls. The results suggest that raspberry fruits preserve an integrated isotopic fingerprint of production environment and management practices. From an analytical chemistry perspective, this work highlights the relevance of multi-isotope approaches as transferable tools for food authentication, traceability, and sustainability assessment, contributing to the broader application of stable isotope techniques across complex biological systems. Full article

Nitrate is one of the most prevalent inorganic pollutants in groundwater systems. Its concentration directly affects the safety assessment of groundwater quality. To scientifically identify nitrate sources in strontium-rich mineral water and facilitate the protection of mineral water resources, this study selects Chengde City, Hebei Province, as the study area. Nitrate source apportionment was quantified using the MixSIAR model, with uncertainties assessed via cumulative probability distributions. The results show that the nitrate concentration in strontium-rich mineral water of the study area ranges from <0.003 to 70.2 mg/L, with a coefficient of variation of 1.24, indicating high data dispersion. The nitrate sources present a mixed pollution characteristic dominated by natural processes and supplemented by human activities. Nitrification dominates biogeochemical processes of strontium-rich mineral water. Soil nitrogen is the primary contributor to nitrate in mineral water, with an average contribution rate of 70.4%, followed by manure; synthetic fertilizers and rainwater together account for less than 1% of the total. Uncertainty analysis shows that contributions of rainwater, synthetic fertilizer, manure, and soil nitrogen to nitrate in strontium-rich mineral water remain stable (UI₉₅ < 0.15), verifying reliable results. This study provides guidance for protecting mineral water quality and sustainable resource exploitation. Full article

The North China Craton hosts abundant skarn iron resources, yet the regional large-scale mineralization mechanism remains incompletely understood. The Litun deposit is a newly discovered skarn iron deposit in the North China Craton. Integrated field geological investigations, petrographic observations, fluid inclusion microthermometry and stable isotope geochemistry are applied to constrain evaporite contributions to metallogenic processes. Four mineralization stages are identified: skarn, oxide, sulfide, and carbonate. Early skarn-stage fluids are iron-rich magmatic hydrothermal fluids with high temperatures (498 to >550 °C), high salinities (18.6 to 59.4 wt% NaCl eqv.), and magmatic δ¹⁸O values of 8.3 to 10.8‰. Subsequent oxide to late carbonate stages record continuous infiltration of meteoric water, supported by H–O isotopic trends of rising meteoric water proportions. Pyrite from the magnetite ores has δ³⁴S_V-CDT values between 12.0 and 15.0‰, significantly higher than those of pyrite in the Litun diorite (−0.8 to 1.1‰), indicating the contributions of sulfur from evaporites (δ³⁴S_V-CDT 26.9 to 28.6‰) in the mineralization process. Moreover, vein pyrite formed in later stages displays even higher δ³⁴S values (17.3 to 20.9‰), demonstrating progressive enrichment of evaporite-derived sulfur as hydrothermal activity evolves. Synchronous rises in meteoric water fraction and evaporite sulfur proportion indicate evaporites are delivered into the ore-forming system via meteoric water mixing. The mixing of meteoric water containing dissolved evaporites and iron-rich magmatic-hydrothermal fluids may be the major mechanism of magnetite precipitation in the Litun deposit. Full article

Phosphorites are a vital source of phosphorus for agricultural and industrial applications and are increasingly recognized for their potential as secondary repositories of critical raw materials (CRMs) such as rare earth elements plus yttrium (REYs). This study investigates deep-sea phosphorites from the Galicia Bank, Madeira, and Canary Seamounts, in the NE Atlantic Ocean, which are spatially associated with ferromanganese (Fe-Mn) mineralization. Through integrated petrographic, geochemical, and in situ isotopic analyses (O and Sr), we assess the timing, processes, and paleoenvironmental conditions of phosphogenesis and its implications for CRM enrichment. Rare earth element patterns in apatite reflect a predominant seawater-derived signature with variable Ce anomalies. Nevertheless, variable Y/Ho ratios point to evolving fluid sources including a hydrogenous component (directly derived from seawater), modified porewaters and, locally, volcanic or possibly hydrothermal inputs. Oxygen and strontium isotope compositions constrain phosphogenesis to several episodes ranging from the Upper Cretaceous to the Middle Miocene, with distinct isotopic shifts identifying both primary formation and later overprinting processes mostly linked to Fe-Mn oxyhydroxide growth or volcanic–hydrothermal activity. These findings highlight the dynamic and multiphase nature of phosphorite formation in deep-marine settings. The integration of high-resolution geochemical and isotopic tools proves essential for reconstructing genetic histories, defining metallogenic context and evaluating CRM prospectivity in complex submarine systems. Full article

The Late Triassic Bolila Formation in the central Qiangtang Basin is a typical carbonate buildup deposited during a regional transgression in the eastern Tethyan realm. Understanding its sedimentary evolution and reservoir-forming mechanisms is crucial for hydrocarbon exploration. This study integrates petrology, detrital zircon U-Pb geochronology, carbon-oxygen isotopes, and reservoir property analysis of the Quemudongda section. The results show: (1) detrital zircon dating provides a maximum depositional age of 225.7–235.7 Ma (Carnian–Norian), correcting the previous Jurassic misassignment on the 1:250,000 geological map. Carbon-oxygen isotopes (average δ¹³C = +3.2‰, δ¹⁸O = −11.1‰) are consistent with the global Carnian–Norian positive δ¹³C excursion. (2) The section reveals a platform-margin reef (hexactinellid and calcareous sponges) and slump breccia (seven layers) association, representing a steep-rimmed carbonate platform margin. The sedimentary evolution comprises three stages: reef initiation, reef flourishing with frequent slumping, and reef decline with dolomitization. (3) Reservoirs are mainly breccia and reef dolostones, with intergranular, intercrystalline, and fracture-related pores. Porosity averages 2.8% (0.8%–7.2%), permeability averages 0.35 mD (0.001–8.5 mD), defining a low-porosity, ultra-low-permeability fracture-pore reservoir. Breccia dolostone has better properties (porosity 3.71%, permeability 2.412 mD). (4) Reservoir formation is controlled by sedimentation (platform-margin facies), diagenesis (dolomitization generates pores, but high-temperature recrystallization causes densification), and tectonics (microfractures enhance permeability). High-quality reservoirs occur where breccia dolostone and fractures overlap. (5) The Bolila reef-shoal complex and the overlying Bagong Formation source rocks form a “lower reservoir—upper source” assemblage, representing a new exploration target in the Tuonamu area. The breccia dolostone–fracture overlap zone is the core “sweet spot”. Full article