ABSTRACT Lepidolite‐bearing pegmatite, recently recognized as a major lithium (Li) resource, is exposed in Phang Nga, southern Thailand. This study investigates the geological relationships between Li‐pegmatites and granitic rocks and their formation processes within the tectonic evolution of the study area, using petrological, geochemical, and geochronological data. The granitic rocks in the study area are classified into three types: I‐type biotite granite, both I‐ and S‐type biotite–muscovite granite, and S‐type tourmaline granite. The Li‐pegmatite shows S‐type characteristics with peraluminous features. The primitive mantle‐normalized spider diagram of Li‐pegmatite and tourmaline granite reveals similar patterns, with enrichment in large‐ion lithophile elements (e.g., Cs, Rb, Li, and U) and depletion in Ba, Nb, and Sr, suggesting that the Li‐pegmatite evolved from a highly fractionated tourmaline granitic melt. Zircon U–Pb dating of the granites indicates three main magmatic events: Late Triassic biotite granite and tourmaline granite (216–214 Ma), Late Cretaceous biotite–muscovite granite and tourmaline granite (83–81 Ma), and Paleocene biotite granite (60–58 Ma). The cassiterite U–Pb ages of Li‐pegmatites are 81 and 69 Ma, which are coeval with the Late Cretaceous tourmaline granite. Newly found Late Triassic granites in the Western Granitoid Belt suggest that the Triassic granitic magmatism of the Central Granitoid Belt may extend further into southern Thailand than previously known. The formation of the Late Triassic biotite granite and tourmaline granite is related to the collision events between the Sibumasu and Indochina Terranes following the closure of the Paleo‐Tethys Ocean. Subsequently, during the Late Cretaceous, biotite–muscovite granite, tourmaline granite, and associated Li‐pegmatites formed due to the West Burma–Sibumasu collision and the subduction of the Neo‐Tethys oceanic plate beneath the western Sibumasu Terrane. The Paleocene biotite granite likely resulted from asthenospheric upwelling caused by the rollback of the Neo‐Tethys oceanic plate.

ABSTRACTZeolites are widely distributed in the Permian–Triassic conglomerates of the Junggar Basin and play an important role in reservoir quality. A better understanding of the matching relations between reservoir qualities and zeolitic diagenesis is of great importance for oil exploration in basins. In this study, Permian–Triassic conglomerates from southeast Junggar (SEJ), middle Junggar (MJ), and northwest Junggar (NWJ) were investigated, using casting thin section observations, SEM analysis, EPMA analysis, porosity, and permeability measurements. The Permian–Triassic conglomerates of all three areas have abundant volcanic lithics. The conglomerates from NWJ and MJ contain higher contents of sedimentary lithics and feldspars than those from SEJ. Zeolites of SEJ and NWJ originate from the alteration of volcanic lithics, occurring as pore filling in stage B of eodiagenesis. The zeolitic diagenetic process of SEJ is volcanic lithic–clinoptilolite–analcime–heulandite–laumontite, while that of NWJ is volcanic lithic–analcime. Zeolites of MJ originate from albitization of plagioclase, occurring as pore filling and replacement in stage A of mesodiagenesis. Its diagenetic process is a replacement of plagioclase by laumontite. Diverse zeolitic diagenesis played different roles in reservoir quality. Zeolite cementation and compaction both destroyed the reservoir qualities of SEJ and NWJ. In MJ, the reservoir quality was mainly destroyed by compaction, resulting in strong heterogeneity. In later diagenesis, the dissolution of zeolite cements improved reservoir qualities. SEJ is located farther from hydrocarbon generation sags than NWJ and MJ. As a result, zeolite dissolution pores are poorly developed in SEJ. Previous research has revealed that analcime dissolves more easily than laumontite. Zeolite dissolution pores developed better in NWJ than in MJ. In comparison of the conglomerates with zeolite dissolution pores in the Junggar Basin, NWJ conglomerates have the best reservoir quality, indicating that zeolitic diagenesis can provide implications for oil exploration in the Junggar Basin.

ABSTRACT Cobalt (Co), selenium (Se) and uranium (U) are strategic and critical elements with significant global demand. Typically, cobalt is mainly recovered as a by‐product from sulfide and sulfoarsenide minerals associated with copper, nickel, and iron, while its occurrence as independent minerals, particularly trogtalite (cubic CoSe 2 ), is rare. This study reports the presence of trogtalite in a sandstone‐type uranium deposit in China. It was identified in the Qianjiadian deposit in the southwestern Songliao Basin, through electron probe microanalysis (EPMA) and Raman spectroscopy analysis (wavenumber 188 cm −1 ). The trogtalite occurs as cubic or polyhedral microcrystals, distributing as detrital mineral dispersed in the clay matrix or enclosed in detrital quartz or feldspar in uranium‐mineralized sandstones from Upper Cretaceous Yaojia Formation. The sandstone also contains selenides, including clausthalite, ferroselite, and krut'aite, which are typical cobalt mineralization associations found in the deposits in Argentina and Congo. The uranium‐mineralized rocks in the Qianjiadian deposit are enriched in Se, suggesting the co‐enrichment of Se and U during the mineralization. Thus, Se serves as an indicator of uranium mineralization in this deposit.

ABSTRACT Bangka Island, situated within the Southeast Asian tin belt, is a prominent tin‐producing area in Indonesia. Primary tin deposits of Bangka Island are associated with two types of Late Triassic granites, namely biotite granite and hornblende‐biotite granite. In this study, we investigate petrography, bulk chemistry, and mineral chemistry of biotite and apatite for the biotite granite and hornblende‐biotite granite to elucidate their petrogeneses and physicochemical properties in relation to the formation of primary tin deposits in Bangka Island. Both granite types are composed of alkali feldspar, quartz, plagioclase, and biotite, with hornblende occurring only in the hornblende‐biotite granite, and accessory minerals including ilmenite, zircon, apatite, and monazite. They are classified as I‐type and ilmenite‐series, with A/CNK ranging mainly from 1.0 to 1.1 and absence of magnetite, as well as magnetic susceptibility values below 0.16 × 10 −3 SI unit. Apatite in both types of granite occurs as inclusions in biotite and quartz and is classified into three textural types. Apatite‐1 and apatite‐2 are hosted in the cores and rims of biotite, respectively, while apatite‐3 is hosted in quartz. All the types of apatite from both the biotite granite and hornblende‐biotite granite are identified as fluorapatite. Similarly, the chemical compositions of biotite in the biotite granite and hornblende‐biotite granite fall within the Fe‐biotite field. Whole‐rock Sn contents of the biotite and hornblende‐biotite granites vary from 3.0 to 51.0 ppm (av. 19.3 ppm) and 2.0 to 7.0 ppm (av. 3.3 ppm), respectively. The biotite granite has slightly higher silica contents (SiO 2 ~ 75 wt%) and relatively lower Eu anomaly (Eu/Eu* ~ 0.19), compared to those of the hornblende‐biotite granite (SiO 2 ~ 74 wt%; Eu/Eu* ~ 0.31). Both the granites were derived from crustal protoliths, as indicated by FeO T and MgO contents in biotite. Moreover, these granites exhibit comparable crystallization temperatures (zircon saturation temperatures = 728°C–872°C; apatite saturation temperatures = 831°C–939°C; Ti‐in‐biotite temperatures = 739°C–814°C). Al‐in‐biotite geobarometer indicates that the biotite granite and hornblende‐biotite granite crystallized at 69–177 MPa and 37–117 MPa, respectively, suggesting that both types of granite emplaced in the upper crustal level (1.3–6.4 km). A shallow emplacement of the biotite granite strongly favors magma degassing and extensive fluid exsolution in magmatic systems, as reflected by the decrease in calculated H 2 O contents from apatite‐1 to apatite‐3 and high Cl concentrations in magmatic fluids. Higher FeO and MnO and lower CaO contents of apatite, and higher Al T and Fe 2+ /(Fe 2+ +Mg) of biotite in the biotite granite indicate a more advanced degree of fractional crystallization compared to the hornblende‐biotite granite. In biotite granite, relatively low SO 3 contents of apatite and low X Mg , Mg#, and Fe 3+ /(Fe 3+ +Fe 2+ ) of biotite suggest a more reduced magma compared to the hornblende‐biotite granite. The fractionation of reduced magma of the biotite granite would have enhanced the concentration of Sn 2+ in the melt and promoted tin mineralization at shallow depths.

ABSTRACT The Qihe‐Yucheng region in Shandong Province, situated within the North China Craton (NCC), has become a prominent exploration frontier following the discovery of numerous high‐grade skarn‐type iron deposits. Current documented reserves exceed 117 million tons of high‐grade iron ore, primarily concentrated in the Litun, Dazhang, and Guodian districts. The orebodies are predominantly localized along contact zones between Paleozoic strata and Mesozoic intrusions, with subsidiary mineralization occurring within carbonate‐clastic horizons and intra‐intrusive fracture systems. Geochronological data constrain the mineralization to ~130 Ma, coinciding with a period of lithospheric thinning and extensional tectonics in the NCC. Integrated studies of ore‐forming intrusions, fluid inclusions, and isotopic tracers reveal that the metallic components were largely sourced from deep‐seated magmatic systems. Mineral exploration in the area primarily involves interpreting geophysical anomalies to infer the location of ore bodies, which are then verified through drilling operations to delineate the deposits. An analysis of the geophysical anomalies and the degree of ore body control in the area indicates that there remains significant potential for further mineral discovery. This study synthesizes the geological characteristics, metallogenic framework, and exploration methodologies of the Qihe‐Yucheng iron deposits, while highlighting recent advancements in prospecting techniques and predictive models. The findings provide critical guidance for future exploration targeting skarn‐type iron mineralization in the NCC.

ABSTRACTThe Akobo Greenstone Belt gold mineralization in the Western Ethiopian Greenstone Terrain is hosted by the Surma shear zone. Talc‐chlorite schist, chlorite schist, actinolite bearing rocks, granite, meta ultramafic rocks, felsic metavolcanic rocks, and Banded Iron Formation are the dominant rock types found in the Gindibab‐Wolleta and Chamo‐Segele areas. This study describes the geology, mineralogy, and mineral chemistry/alteration of host rocks associated to the gold mineralization. We conducted outcrop and hand specemen, petrography, and mineral chemistry analyses. The host rocks of the auriferous quartz vein in the Gindibab‐Wolleta area is felsic metavolcanics and banded iron formation. The metamorphosed felsic‐mafic igneous rocks of greenschist facies hosts the mineralization. Chloritization, carbonatization, sericitization, and biotitization are the common hydrothermal alteration associated with the host rocks. The hydrothermal alteration is characterized by the chlorite + plagioclase + ankerite + biotite + calcite + sericite assemblages. The chlorite geothermometery suggests that the temperatures of hydrothermal fluids associated to the gold mineralization in the Chamo‐Segele and Gindibab‐Wolleta areas ranges from 180°C to 350°C.

ABSTRACTVeins intersected by a ~600‐m‐long drill core into the Hokuryu epithermal Au‐Ag deposit in the northeastern part of Hokkaido, Japan, were investigated including mineralogy, texture, quartz composition, and fluid inclusion characteristics, with relation to elevation. Host rocks of these veins are flow‐banded rhyolite, pyroclastic breccia, and andesite and are mainly altered by illite and chlorite. The veins display crustiform and massive macroscopic textures. The crustiform veins generally located at higher elevations, contain Ag‐rich and Au‐Ag‐rich bands. The massive veins are mainly present at lower elevations, and they are generally barren of precious metals. The Ag‐rich bands in the crustiform veins contain mineral assemblage of hessite + sphalerite + pyrite + galena. These minerals, together with anhedral to rhombic adularia, exist within the interstices of quartz that display microspherical texture. The Au‐Ag‐rich bands contain mineral assemblage of electrum ± naumannite‐aguilarite associated with quartz with colloform, ghost‐sphere, and ghost‐bladed textures. Bulk compositions of the veins reflect the ore mineralogy observed in which Ag is strongly correlated with Pb, Te, Zn, Cd, and Bi. The barren massive veins are mainly composed of granular quartz. Textural and mineralogical characteristics of Au‐ and Ag‐bearing bands in the crustiform veins indicate amorphous silica and calcite precursors. Together with the coexistence of adularia, these suggest liquid boiling during vein formation. Quartz associated with Au‐ and Ag‐bearing minerals exhibits blue cathodoluminescence (ca. 400 nm wavelength) triggered by high Al impurity probably due to pH and pressure fluctuations or impurity redistribution during recrystallization from metastable amorphous silica. Fluid inclusions hosted in quartz and adularia, which contain negligible amounts of CO2, show a modal homogenization temperature range of 260°C–290°C and a salinity range of 1.2–6.9 wt% NaCl equivalent. The homogenization temperatures follow a boiling point curve and indicate an erosion of up to ~340 m for the deposit. The variable salinities in relation to elevation suggest extreme vapor loss during boiling at depth, episodic influx of high salinity fluids from deeper source, or mixing with high salinity fluids along anastomosing fractures at relatively shallower depths.

ABSTRACTThe Lanuoma deposit, situated in the Changdu Basin of Southwestern China, is a unique sediment‐hosted Pb‐Zn‐Sb deposit. Three hydrothermal stages are present: (1) premineral stage, oolitic pyrite + calcite + gypsum + barite; (2) syn‐mineral stage, further divided into (2a) early stage, with the main Zn‐Pb‐Sb precipitation (sphalerite + robinsonite + galena + calcite); (2b) late stage (orpiment + realgar + calcite + minor sulfides); and (3) postmineral stage, coarse‐grained calcite. The calcites of Stage 2a are characterized by lower ΣREE concentrations (0.97–3.32 ppm) associated with positive Eu anomalies (1.13–1.98) and higher ΣREE concentrations (10.65–17.17 ppm) associated with negative Eu anomalies (0.57–0.59), indicating that the ore‐forming fluids were a mixture of two distinct fluid sources. The increasing trend of Ce anomalies (Stage 2a = 0.97, Stage 2b = 1.05, Stage 3 = 1.08) shows enhancement of fluid reducing conditions during hydrothermal evolution. The δ13CV‐PDB and δ18OV‐SMOW values also differ between Stage 2a (δ13CV‐PDB = −4.9‰ to 3.0‰; δ18OV‐SMOW = 11.4‰ to 16.6‰), Stage 2b (δ13CV‐PDB = −4.7‰ to −0.4‰; δ18OV‐SMOW = 14.2‰ to 20.4‰), and Stage 3 (δ13CV‐PDB = −4.0‰ to 1.7‰; δ18OV‐SMOW = 17.1‰ to 20.6‰), indicating a mixture of deep‐seated magmatic fluid and dissolved marine carbonate rocks. Corresponding δ18Ofluid values of the hydrothermal fluid are 2.4‰–7.0‰ in Stage 2a, 4.9‰–8.5‰ in Stage 2b, implying a combination of deep‐seated magmatic fluids and sedimentary formation water. Initial 87Sr/86Sr ratios of calcite from Stage 2a (0.7084–0.7086) fall between the values characteristic of the mantle, metamorphic basement, and Bolila Formation, implying a mixed source. Calcite in Stage 2a has higher εNd(t) values (−0.51 to −1.82) compared to Stage 2b and Stage 3 (−3.91 to −9.96). This indicates there was more input of mantle‐sourced materials during Pb‐Zn mineralization. Systematic microthermometric analysis demonstrates an isothermal mixing of two fluid sources (averaging at 189°C) with different salinities (ranging from 3.87% to 19.05% NaCl eqv; i.e., low‐salinity magmatic fluid and high‐salinity brines) during Pb‐Zn mineralization. These results suggest that the Lanuoma Pb‐Zn deposit was formed by the mixing of two distinct mineralizing fluid sources: (1) magmatic‐hydrothermal fluids derived from deep‐seated magmas, which transported reducing agents such as sulfur; and (2) high‐salinity brines enriched in metals, likely leached from carbonate wall rocks and metamorphic basement.