Granite Research Articles

Early Cretaceous W–Nb–Ta Mineralisation in the Southeastern Xingmeng Orogenic Belt, NE China: Geochronological Evidence From the Jiabusi Nb–Ta and Narewula W Deposits

ABSTRACTThe Xianghuangqi region in the southeastern section of the Xingmeng Orogenic Belt (XMOB) has gained attention for its potential rare mineral yield, particularly from multiple W and Nb–Ta deposits. However, limited geochronological data limits our understanding of their origin and progress in W–Nb–Ta exploration. We thus performed 40Ar/39Ar muscovite and U–Pb wolframite, cassiterite and columbite dating on the Jiabusi Nb–Ta and Narenwula W deposits within the Xianghuangqi region. Our findings revealed that the 40Ar/39Ar plateau age of muscovite from the Jiabusi deposit (135.17 ± 1.34 Ma) aligns with that of the Narenwula W deposit (135.83 ± 1.43 Ma). This consistency is further supported by U–Pb dating of wolframite, cassiterite and columbite in Jiabusi, at 136.4 ± 2.0, 132.1 ± 3.1 and 136.0 ± 3.5 Ma, respectively. These data suggest that mineralisation of W–Nb–Ta in the Xianghuangqi area occurred during the Early Cretaceous, probably in association with the late‐stage evolution of intrusions within the granite complex. Zircon U–Pb dating of Jiabusi albite granites yielded an age of 137.5 ± 1.2 Ma, indicating later formation than the Kusigui biotite granites, which date at approximately 149 Ma in the same region. The geochronological data highlight a regional Early Cretaceous event of W–Nb–Ta mineralisation around 135 Ma, influenced by tectonic interactions between the Mongolia–Okhotsk Ocean and the Paleo‐Pacific Plate. We conclude that, most probably, W–Nb–Ta ore deposits of the southeastern segment of the XMOB in the Xianghuangqi area were emplaced during the Early Cretaceous.

Reduced Granitic Rocks and Related Gold Mineralisation: Implications From Chronology, Geochemistry and Sr–Nd–Hf–O Isotopic System of Early Cretaceous Granites From the Wulong Gold Deposit, Liaodong Peninsula, NE China

ABSTRACTThe Liaodong Peninsula is the northeastern part of the North China Craton and hosts abundant Late Mesozoic granites and associated gold deposits. The Wulong deposit contains 57.5 t Au with an average grade of 7.1 g/t and is the largest gold deposit in the Liaodong Peninsula. The Wulong gold orebodies are hosted in Mesozoic biotite granites and have a close association with synchronous granite porphyry dykes. In this study, we provide a systemic geochemical and chronological study to distinguish fertile granites from barren ones from the Wulong deposit. Our study shows that the Wulong fertile granite porphyry (high Sr/Y) and Sanguliu barren granite (low Sr/Y) have zircon U–Pb ages of 132 ± 1 and 136 ± 0.4 Ma, respectively. The fertile and barren granites share similar REE patterns by characteristic of LREE enrichment and HREE depletion. They are classified as reduced ilmenite‐type granitic rocks. Petrochemistry and Sr–Nd–Hf–O isotopes show that the Wulong fertile and Sanguliu barren granites were derived from intensive crustal reworking in the North China Craton. The Wulong fertile granites were derived from mixing of lithospheric mantle–derived and thickened ancient lower crust–derived magmas. The Sanguliu barren granites were derived from partial melting of the ancient lower crust with normal crustal thickness. Geochemical features of zircon and apatite indicate that the both fertile and barren granites are similar in crystallisation temperature, water content, and oxygen fugacity. Our study suggests that magma source composition is essential to gold metallogeny, and mantle‐derived components are a key indicator to distinguish fertile and barren granitoids. Exploration for gold deposits related to reduced intrusions may be promising within the Liaodong Peninsula.

Constructing the Cretaceous highly silicic plutons in SE China through the magmatic plumbing system

Abstract High-silica plutons (SiO2 > 75wt.%) play a key role in deciphering the evolution and origin of the upper continental crust. Therefore, studying vertical cross sections of high-silica plutons is essential for gaining new insights into magmatic evolution and the thermal and material processes that shape the Earth's crust during pluton formation. In this study, we present extensive data on the bulk-rock geochemistry, zircon U-Pb ages, Hf isotopes, and trace elements for a range of high-silicic rocks from top-to-bottom cross-section in the Jiuzhen batholith and Yunhe pluton in southeastern China. Geochemical and zircon trace element features of the granitic rocks from the Jiuzhen batholith and Yunhe pluton indicate that these high-silica rocks originated from middle- to upper-crustal magma reservoirs via crystal-melt segregation. In the Jiuzhen batholith, the coarse-grained porphyritic granite in the upper unit originated from the reactivation of a pre-existing, highly evolved, water-rich magma reservoir with lower crystallinity, while the coarse-grained porphyritic granite in the lower unit was segregated from the same magma reservoir with higher crystallinity and involved a higher proportion of mantle material in its formation. The fine-grained granite was later extracted from the nearby magma reservoir of coarse-grained porphyritic granite in the upper unit, indicating they were formed through in-situ differentiation of the silica magma reservoir in the shallow crust. Similarly, the geochemical characteristics of granites from different units of the Yunhe pluton suggest they were produced by the solidification of high-silica melts extracted from a common water-poor magma reservoir. As the high-silica magmas accumulated to form a magma reservoir in the shallow crust and subsequently underwent further cooling and crystallization, the proportion of melt decreased, leading to an enrichment of volatiles and silica in the residual melt. The upward migration of these residual melts within the high silicic magma reservoir resulted in vertical compositional variations within the Yunhe pluton. Our research on the Jiuzhen batholith and Yunhe pluton has revealed that the composition of high-silica magmas is influenced not only by crystal-melt segregation within deep magma reservoir but also by in-situ crystal-melt segregation occurring within magma reservoirs formed through the aggregation of felsic melts in the shallow crust.

Petrogenesis and Tectonic Setting of the Xishan Pluton in Nanling Range: Lithogeochemistry, Zircon U–Pb Chronology and Hf Isotope Evidence

ABSTRACTIn this article, a systematic LA‐ICP‐MS zircon U–Pb geochronology study was carried out on the Xishan pluton in Nanling Range. The results show that the formation ages of granitic porphyroclastic lava, medium‐fine‐grained porphyritic granite, and dacite are 154.0 ± 1.2–156.1 ± 2.0, 153.2 ± 0.9–157.3 ± 3.2, and 151.2 ± 3.1 Ma, which are determined to be the early Yanshanian. Geochemical data show that the Xishan pluton was characterised by rich silicone‐alkali and poor calcium–magnesium with K2O/Na2O ratios of 1.65–2.22, Al2O3 of 1.00–1.14, and FeO*/MgO ratios of 8.33–19.0 (with an average of 12.94). The rare earth content of granites ranges from 322.92 to 441.54 ppm, which is significantly higher than the world average. The rare earth element distribution curve is right‐leaning light rare earth enrichment type, with obvious negative europium anomaly, and the δEu values range from 0.06 to 0.24; These rocks are enriched in high‐field‐strength elements (HFSEs, e.g., Ga, Y, Nb, Zr, and Hf) and depleted elements such as Ba, Nd, Sr, P, Ti, etc, with Ga/Al ratios of 2.95 × 10−4 to 4.59 × 10−4 (with an average of 3.50 × 10−4); Zr + Nb + Ce + Y of 367.1–652.5 ppm (with an average of 441.95 ppm) and zircon saturation temperatures Tzr is 755.04°C–892.50°C (with an average of 810.04°C), similar to geochemical features of A‐type granites. The Hf isotope study shows that the εHf(t) of the Xishan pluton ranges from 2.11 to −8.77, and the petrographic, geochemical and available data confirm that it originates from the mixing of crustal and mantle‐derived magma, and the contribution of the latter is < 10%. The hafnium II model age of the Xishan pluton is 1251–1766 Ma, which confirms that its source rocks were detached from the mantle reservoir at the time of the Middle Proterozoic. Combined with the evolutionary history of the Nanling Range area, it is assumed that the Jiangnan Orogenic Zone was partially reactivated by the continuous lateral subduction of the ancient Pacific Plate in the Late Mesozoic, which triggered partial melting of the crust to form the A2‐type granite type, which is the origin of the Xishan pluton.

Magmatic evolution of the Paleoproterozoic A2-type granite along the northern Indian margin: insights from geochemistry and U-Pb geochronology of Baijnath Klippe, NW Himalaya

Abstract Paleoproterozoic granitoids of the lesser Himalayan belt are keys to understanding the evolution of the northern Indian continental margin and its position in the Columbia supercontinent assembly. We present whole-rock chemistry and zircon U-Pb geochronological data for Gwaldam Biotite Granite (GBGr) from the Baijnath Klippe (BK) in Kumaun Himalaya to elucidate their petrogenesis and geodynamic implications. Granites are characterized by ferroan, weakly peraluminous nature with high SiO2 and K2O contents, enrichment in LILE (Rb, Th, K and Pb), and depletion in Ba, Nb, P, Hf and Ti. Granites show enrichment in light rare earth element relative to heavy rare earth elements and pronounced negative Eu anomalies. Such chemistry suggests typical A-type granite with high Y/Nb >2 values that characterize it as A2-type granite. Zircon U-Pb ages for the granite yield upper intercept at 1900 ± 3 Ma (core) and 1854 ± 2 Ma (rim). Integrating the chemical and geochronological data, we propose a two-stage evolution model for the area. In the GBGr, the ∼1900 Ma date of zircon core is likely the date of crystallization of the melts presumably formed during the first extensional stage at uppermost mantle – lower crust levels caused by slab break-off/rollback, which followed a post-collisional setting. The second incipient rifting stage produced melt that entrained the zircon cores (∼1900 Ma) during its ascendance and crystallized as the GBGr at ∼1854 Ma when the zircon rims crystallized. It is further proposed that the Paleoproterozoic Northern Indian continental margin later underwent at least two crustal extensions during the Columbia supercontinent agglomeration.

Thermal Energy Storage and Recovery in Fractured Granite Reservoirs: Numerical Modeling and Efficiency Analysis

Although Aquifer Thermal Energy Storage (ATES) systems are widely researched, Fractured Thermal Energy Storage (FTES) systems are comparatively underexplored. This study presents a detailed numerical model of a fractured granitic reservoir at the Bedretto underground laboratory in Switzerland, developed using COMSOL Multiphysics. Energy efficiency was evaluated across different flow rates and well configurations, including single-well and doublet systems, as well as for two different temperatures, namely 60 °C and 120 °C. The doublet configuration at an injection temperature of 60 °C with a flow rate of 2 kg/s demonstrated the highest energy efficiency among the cases studied. Potential applications for the stored heat are discussed, with scenarios including district heating for the nearby village and greenhouse heating. The results show that although FTES is associated with unique challenges, it has significant potential as a reliable thermal energy storage method, particularly in regions without suitable aquifers. It can also be considered as a cost-effective and competitive approach for climate mitigation (assuming the system is solely powered by solar-PV). This study provides insights into the viability and optimization of FTES systems and highlights the role of fracture/fault properties in enhancing energy efficiency.

Comprehensive Technical Inspection of a Medieval Bridge (Ponte de Vilanova, in Allariz) Using Microtechnological Tools

Ponte de Vilanova, a masonry bridge, was built in Allariz, Galicia in the 13th–14th centuries. It is still standing. The structure, generally well preserved, shows minor deformations and wear signs caused by environmental factors. To conduct a comprehensive assessment without impacting the bridge’s integrity, drones equipped with thermal and underwater imaging technology were employed. Aerial inspections revealed vegetation growth and minor efflorescence (salt deposits) in some areas, while aerial thermography detected temperature variations along the stone joints, indicating the presence of moisture. The granite blocks comprising the bridge showed consistent quality and preservation. The underwater inspection confirmed that the bridge’s piers are well set on the riverbed, with no major damage observed, ruling out the immediate need for repair. This approach allowed a thorough evaluation of submerged parts without requiring divers, enhancing safety and reducing costs.

Caledonian Sn Mineralization in the Yuechengling Granitic Batholith, South China: Geochronology, Geochemistry, Zircon Hf Isotopes, and Tourmaline Chemistry and B Isotopes of the Lijia Sn Deposit and Its Hosting Granites

The Lijia Sn deposit, located in northeastern Guangxi Zhuang Autonomous Region of south China, occurs on the eastern margin of the Yuechengling granite batholith. The Sn deposit contains quartz vein type and greisen type ores and is spatially associated with the medium-coarse-grained biotite granite and the fine-grained tourmaline-bearing biotite granite. LA-ICP-MS zircon U-Pb dating gave an emplacement age of 431.7 ± 2.5 Ma for the medium-coarse-grained biotite granite and of 430.2 ± 2.4 Ma for the fine-grained tourmaline-bearing biotite granite. LA-ICP-MS cassiterite U-Pb dating yielded Tera-Wasserburg lower intercept ages of 429.1 ± 3.4 Ma and 425.7 ± 3.3 Ma for the quartz vein type and greisen type ores, respectively. The ages demonstrate near coeval Caledonian granitic emplacement and Sn mineralization events that have been considered uncommon in south China. Both granites might be derived from partial melting of the Paleoproterozoic basement, as evidenced from zircon ɛHf(t) values of −3.13 to −10.31 and TDM2 from 1627 Ma to 2134 Ma. Three different types of tourmalines have been identified, including (1) tourmaline in quartz–tourmaline nodules in the fine-grained tourmaline-bearing biotite granite (Tur 1), (2) tourmaline in quartz veins (Tur 2a), and (3) tourmaline in greisen (Tur 2b). Most of the tourmalines belong to the alkali group and the schorl-dravite solid-solution series. The hydrothermal tourmalines of Tur 2a and Tur2b showed similar δ11B values to those of the Tur 1 tourmalines in the fine-grained tourmaline-bearing biotite granite, suggesting ore-forming materials derived from granitic magmas. The hydrothermal tourmalines of Tur 2b had slightly lower δ11B values than Tur 1 and Tur 2a tourmalines as a result of progressive 11B depletion during early tourmaline crystallization.

Тhermal history and fluid regime during the formation of Eldjurta massif of biotite granites (Greater Caucasus): reconstructions based on isotope (δ<sup>18</sup>О, δD) and geochemical data

Based on the geochemical and isotopic (δ18О, δD) data the thermal and fluid conditions during the formation of the Eldjurta granite massif were reconstructed. Analysis of rocks collected from the core of the Tyrnyauz Superdeep Well (TSW) within the depth range of 1427–3923 m revealed their homogeneous isotopic parameters: the δ18О values of bulk samples, quartz, feldspars, and biotite in 12 samples of biotite granites are 8.50 ± 0.33, 9.55 ± 0.22, 8.40 ± 0.33 and 5.45 ± 0.40‰, respectively. The δD values in the biotite vary from −103.3 to −95.6‰. The closure temperatures of the oxygen isotope system of quartz are 440–980°C. The rock cooling history was reconstructed using a new approach based on the analysis of single quartz grains. This approach can be used for detailed reconstructions of thermal history during formation of intrusive bodies. The definite samples were used to demonstrate that Dodson’s equation is valid for description of the δ18О values of quartz in a granite system. The data obtained suggest that the studied part of the massif was formed in at least two almost simultaneous stages. The lower part of the massif was crystallized first, and the second injection of granite melt arrived immediately after the first portion has been crystallized, but had no yet had time to cool significantly. The Тс values in the lower part of the massif indicate the reopening of the oxygen isotope system of quartz, with subsequent long-term isotope re-equilibration between minerals. This leads to decrease of the observed Тс values and the calculated cooling rates, which is related to increasing volume of the intrusive body and cooling within already heated rocks. Estimates of the isotopic parameters of the water component indicate the absence of exotic water fluid (meteoric or buried waters) during cooling of the massif. The variations of the δ18О values in the minerals of the Eldjurta biotite granites can be described only in terms of a simple retrograde exchange at the cooling stage

Research on the Influence of Shallow Buried Tunnel Crossing on the Stability of Overlying Frame Structure Building

The land section of the Huangdao end of the Jiaozhou Bay Second Submarine Tunnel is extensively underlain by the Quaternary Loose Accumulation Layer. The tunnel passes through a weathered granite fracture zone with well-developed rock joints beneath the buildings. The tunnel excavation process significantly disturbs the buildings above, making them prone to settlement, cracking, and tilting. This research conducts numerical simulations of three tunnel excavation methods, and based on the results, compares the deformation behaviors of the ground surface and buildings under various conditions. The findings show that the double side-wall guide pit method has better adaptability in controlling surface settlement and building deformation than the vertical or curved CD method. Moreover, the removal of temporary supports significantly affects building settlement and tilt; this risk can be effectively reduced by controlling the stress relief ratio during the removal phase of the temporary supports in the tunnel. The significance of the study lies in the fact that by choosing an appropriate tunnel excavation support scheme, the disturbance impact on the overlying buildings can be minimized, and the construction safety and stability of the surrounding buildings can be guaranteed. The results of this study can provide initial guidance for constructing shallow-buried tunnels beneath existing buildings.

The Petrochemistry and Origin of Precambrian Gneisses around Madaka and Kwana-Bala Area, North Central Nigeria

This paper discusses the petrochemistry and origin of gneisses within basement complex of Nigeria around Madaka and Kwana-Bala area. The lithological units of rocks from Madaka and Kwana-Bala area comprises of gneisses (migmatitic, banded, granitic), kyanite-sillimanite schist, semi-pelitic schist, amphibolites, talcose rock, quartzite, phyllite, granodiorite, fine-medium-grained granites and porphyritic granite. Seven samples of gneisses were analyzed for major element oxides using (ICM-MS). The gneisses are often variable in colour which depending on the nature and proportion of the feldspar and the ferromagnesian minerals. The variation in textures of these rocks from study area is due to varying size and amount of the K-feldspar porphyroblasts couple with varying degree of foliation. In thin section, the characteristics granoblastic textures were observed in migmatitic and granitic gneisses. The mineral compositions of the gneisses rocks are variable, the common minerals assemblage includes: migmatitic gneiss quartz + plagioclase +microcline +biotite + chlorite +garnet, banded gneiss: quartz + plagioclase+ muscovite +biotite+sphene +chlorite+ garnet and granitic gneiss contain quartz +plagioclase+microcline + muscovite+ biotite + chlorite +garnet + opaque minerals. The gneisses of the study area are product of reworked rocks during the Pan-African with a positive DF values, this suggests igneous sources for the protoliths of these rocks in the study area. The chemistry of the gneissic rock also show a variable proportion of Na2O and K2O with alkali-calcic affinity, which suggests, a closed system behaviour during metamorphism on one hand, and possibly a co-magmatic origin of the igneous protolith on the other hand.

Discontinuum-based numerical analysis of thermoshearing in planar and rough granite fractures: A comparison with laboratory observations

Discontinuum-based numerical analysis of thermoshearing in planar and rough granite fractures: A comparison with laboratory observations

GEOCHEMICAL CHARACTERIZATION OF ORTHO-DERIVED GNEISS AND GRANITOIDS OF THE PAN-AFRICAN PROVINCE OF DAMAGARAM (SOUTH-EAST NIGER)

The Pan-African province of Damagaram, object of this study, corresponds to the north-eastern extension of the Benin-Nigerian Shield. The main geological formations that outcrop in this region consist of migmatitic gneiss, banded gneiss, mylonitic gneiss, porphyritic granites, two-mica granites, biotite granites and alkaline granites. The petrogenesis of ortho-derived gneisses and granitoids of Damagaram province was studied using the methods of geochemistry on total rock (major elements, trace elements and rare earth elements). The chemical composition (major elements and trace elements) shows that the precursor magmas come from the subalkaline series. The analyzed samples are characterized by a high SiO2 content (≥ 65%) and show a calc-alkaline potassium to shoshonitic affinity typical of the subduction zone. The high alkaline content (Na2O + K2O) and the A/CNK and A/NK parameters indicate that these rocks are aluminous to hyperalumino. Enrichment in certain large lithophilic elements (LILEs) (Rb, Ba, Th and Sr) and depletion in certain high field intensity elements (HFS) such as Nb, P and Ti are favorable criteria for the involvement of the crust in the genesis of these rocks. The light rare earth enrichment (LREE) and heavy rare earth depletion (HREE), as well as the negative europium (Eu) anomaly, suggest that these rocks as a whole would come from either fractional crystallization or partial melting of a pre-existing continental crust. The geochemical characteristics indicate that the geodynamic domain of these formations corresponds to the syn-collisional and intraplate volcanic arc geotectonic environments.

Assessment of Bedrock Depth Utilizing Vertical Electrical Sounding (DDBR)

This study is aimed at evaluating the depth to bed rock around Liji area of Gombe Northeastern Nigeria. The area covers 18𝒌𝒎𝟐and lies between Latitudes 11°11ʹ20.4ʺ, and 11°14′ 37.4″Eand Longitudes 10°16′ 20.8″, and 10°19′ 16.0″N, (Gombe N.W Sheet 152). The study area consists of Basement rocks (Coarse grained Biotite Granite,), Aptian-Albian indurated Bima Sandstone, Gombe Formation and Mudrock. Ten (10) Vertical Electrical Sounding (VES) were profiled around Liji and environs, employing Schlumberger array with a maximum electrode separation of AB/2 = 100m to determine the depth to bedrock. The data obtained were processed and interpreted using WinResist program. The results showed that seven (7) VES points (VES 1, 2, 3, 5, 6, 7 and 10) displayed three layers while the remaining (VES 4, 7 and 9) had four layers. The Geo-electric sections along profiles A-A’ and B-B’ revealed that the area is underlain dominantly bythree layers, (top soil, weathered sandstone and basement). Thefirst layer has a resistivity value ranging from 2.3 to 193.5Ωm witha thickness that ranges from 0.4 to 7.1m. The second layer isweathered Sandstone with a resistivity range of 2.8 to 4607.6Ωmand thickness of 0.8 to 7.3m while the third layer is Basement withresistivity value of 93.6 to 37356.9Ωm with an infinite thickness.VES 4, 7 and 9 had four layers and the third layer represent thefresh Sandstone with resistivity ranges of 290.2Ωm to 4607.6Ωmand a thickness of 3.3m to 17.3m while the forth layer in therespective three VES points is basement, having resistivity rangesof 3.1Ωm to 15717.4Ωm with an infinite thickness. At the end ofthe study, the results revealed that Basement rocks are present atVES 1, 2, 4, 5, 6, 7 and 10 at the depth of 10m, 9.3m, 19.7m, 6.5m,5.7m, 14.7m and 24.0m respectively with an infinite thickness,therefore these serves as the depths to be removed to reached thetop of the basement for the construction of a sound foundation.

Temperature Controls Initial REE Enrichment in Peraluminous Granites: Implication from the Parent Granites in the Shangyou Ion-Adsorption Type REE Deposit

The initial enrichment of rare earth elements (REE) in granites plays an important role for the generation of ion-adsorption type REE deposits. It has been summarized that the mineralization-related granitoids are mostly peraluminous, but the enrichment mechanism of REE in this peraluminous granite is currently not well understood. In this study, we conducted geochronology, petrological, and geochemical investigations on the biotite granite and muscovite granite from the Shangyou complex in Ganzhou, Jiangxi Province. Zircon U-Pb dating indicates that both the biotite granite and muscovite granite generated in the Early Silurian (ca. 433–434 Ma). The high aluminum saturation index and occurrence of muscovite and old zircon cores indicate that they belong to the S-type granite and are derived from the melting of metagreywacke. The relatively higher FeOT contents, Mg# values, and zirconium saturation temperatures (760–873 °C) for the biotite granite resulted from hydrous melting with the involvement of mantle material. In contrast, the muscovite granite with low FeOT contents, Mg# values, Nb/Ta ratios, and zirconium saturation temperatures (748–761 °C) indicates a purely crust-derived melt formed by muscovite dehydration melting. There is a positive correlation of REE contents with the formation temperature and Th contents in both the Shangyou granites and the data collected from global peraluminous granites. This indicates that temperature plays a key role in the REE enrichment in peraluminous granites, as the high-temperature condition could promote the melting of REE-rich and Th-rich accessory minerals of allanite and REE-phosphate and result in the increases in both REE contents and Th contents in the melts. Given the fact that the parent granites for ion-adsorbing REE deposits are mostly peraluminous and generated in the extensional setting in South China, we concluded that peraluminous granite formed under high-temperature extensional tectonic settings favors initial REE enrichment, which further contributes to the formation of ion-adsorbing REE deposits in South China.

Spatial, Functional, and Constructive Analysis of the Water Resource at the Archaeological Center of Tipon, Cusco, Peru, 2023

The objective of this research is to analyze the spatial, functional, and constructive aspects of the water resource at the Archaeological Center of Tipon, given the lack of awareness towards the timely preservation of archaeological heritage, the deterioration of the terraces, and the contamination of the rivers adjacent to the archaeological site due to the discharge of waste into the water bodies. The methodology employed consists of a site study analysis, considering data on terrain, environment, climate, and water flow in the spatial, functional, and constructive aspects, supported by digital tools (Google Earth Pro 2024, AutoCAD 2024, SketchUP 2024, Sun Path 3D 2024, Photoshop 2024, and Twinmotion 2024). The results yielded a spatial–functional–constructive hydrological analysis; the water flow, constructed underground through a masonry system with an approximate angle of 60° in stone or pink granite, also maintained a negative slope, generally between 1% and 3%, which facilitated a rapid and direct distribution, presenting a greater flow with a width and depth of 30 cm, in addition to a vertical drop of 240 cm. The efficient use of water in agriculture through interconnected terraces ensured the population’s sustenance by approximately 80%. In conclusion, the analysis not only provides information on the infrastructure and water management but also addresses current issues.

Mechanical properties and damage characterization of cracked granite after cyclic temperature action

Due to the unique geographical environment of the plateau, large-scale damage and destruction of fractured surrounding rock often occur during geotechnical engineering construction as a result of high-temperature cycles. Therefore, this study aims to investigate the mechanical properties and damage characteristics of fractured granite under the influence of cyclic temperature, uniaxial compression tests were conducted on granite specimens with pre-existing fractures at cyclic temperatures of 30 °C, 50 °C, 70 °C, 100 °C, and 130 °C. The study integrated analyses of characteristic stress, acoustic emission parameters, damage variables, fractal dimensions, and SEM to explore the mechanical properties and damage features of granite. The results indicated that at a 45° fracture inclination and a temperature of 70 °C, granite exhibited a distinct turning point in mechanical properties and damage characteristics. At the same cyclic temperature, granite with a 45° pre-existing fracture showed significant decreases in peak stress, elastic modulus, and σci/σm ratios, with the AE b-value drop point noticeably earlier, and both cumulative AE ring count and total energy reduced. The damage variable quickly reached its maximum, and the development of internal microcracks in the specimen is highly orderly. At the same fracture inclination, peak stress, elastic modulus, and σci/σm slightly increased at 70 °C, while AE ring counts and total energy were lower, indicating the degree of internal thermal damage in the specimen has significantly decreased, and the development of internal microcracks in the specimen has shown a marked reduction in orderliness. These findings provide theoretical insight into the meso-damage and failure mechanisms of granite influenced by different cyclic temperatures and fracture inclinations.

Apatite geochemical indicators for magma mixing and fractional crystallization in the origin of A-type granite

Geological and geochemical observations show that magma mixing and fractional crystallization are fundamental processes in the origin of A-type granites, with the dominant process determining their specific genesis. However, it is difficult to evidently distinguish such two processes using whole-rock geochemistry. Apatite has a long crystallization history and can precipitate from the melt during the whole magmatic evolution process, and its geochemical and Sr isotopic data would constrain the magma mixing and crystal fractionation processes. Here we present the integrated geochemical data and Sr isotopic compositions of apatite from mafic microgranular enclaves (MMEs) and their host A-type granites in the early Cretaceous Qianshan pluton to fingerprint apatite geochemical indicators for tracing magma mixing and fractional crystallization. The variable Sr isotopic compositions of apatites in the mafic microgranular enclaves (0.7097 to 0.7211) and the host biotite granite (0.7131 to 0.7171) suggest a magma mixing process, which cannot be revealed by consistent whole-rock Sr isotopic compositions. The trend between Eu/Eu* and rare earth elements + yttrium (REE + Y) contents and Sr contents in apatite among different samples mimics the magma mixing trend observed in whole-rock, suggesting that the broad range of Sr contents and abrupt increases in REE + Y contents can record the mixing process. However, the effect of fractional crystallization on the apatite composition depends on the partition behavior of elements in different minerals. Specifically, the continuous decreases in Eu/Eu* and Sr contents of apatites effectively indicate progressive feldspar crystallization, and the decreases in the (La/Sm)N and (La/Yb)N ratios of apatites suggest the crystallization of feldspar, biotite and apatite, while the increases of these ratios may trace the crystallization of minerals rich in MREE and/or HREE such as hornblende, zircon, and titanite. These observations confirm the sensitivity of apatite Sr isotopes and trace elements content, as well as REE patterns to magma mixing and fractional crystallization, thus providing valuable insights into the complicated magma evolution processes and petrogenesis of A-type granites. Furthermore, the universality of apatite in granitic rocks and the commonality of magmatic mixing and fractional crystallization in granite origin highlight the broader applicability of our study, offering a valuable perspective for understanding the origin of other granitoids.

The key controlling factors on Sn–Cu mineralization: A case study from the world-class Gejiu Sn–Cu-polymetallic deposit

Gejiu, a globally prominent Sn–Cu-polymetallic district, contains an extensive suite of magmatic rocks. Magmatic rocks in the southeastern portion of the Gejiu district comprise the Masong and Laoka equigranular and porphyritic granites, and basalts. Previous studies have suggested that Sn mineralization in this region is primarily associated with the equigranular granite, whereas Cu mineralization is predominantly associated with the basalts. Despite this, the major factors controlling the formation and distribution of Sn–Cu mineralization in this region remain poorly constrained. This contribution characterizes the mechanisms of formation of the Gaofengshan Sn–Cu and Zhuyeshan Cu–Sn deposits, focusing on the petrogenesis of the host Masong and Laoka equigranular granites, and the evolution of the ore-forming magmatic–hydrothermal fluids. This is accomplished by combining bulk-rock geochemistry of the Masong and Laoka equigranular granites, and basalt, with biotite geochemistry from both granites and pyrite geochemistry from associated skarns. The Masong and Laoka equigranular granites crystallized from hybrid crust–mantle-derived magmas. Reduced granites like the Masong that underwent high degrees of fractional crystallization, and have elevated halogen are prospective for Sn mineralization. The abnormally high concentrations of Cu in pyrite in the Zhuyeshan deposit suggest that the Cu was primarily derived from sources external to the granite. Garnets from skarn-type ores and stratiform ores at Gaofengshan and Zhuyeshan yielded U–Pb ages of 88.2 ± 1.4 Ma and 81.8 ± 3.7 Ma, respectively, while vesuvianite from the skarn-type ores at Zhuyeshan yield a U–Pb age of 84.1 ± 0.5 Ma. These ages confirm that both the Sn and Cu mineralizing events occurred during the Late Cretaceous, coeval with emplacement of the granitic intrusions. Notably, there is no direct geochronological link between Cu mineralization and the basalt (ca. 244.4 Ma), which has a close spatial relationship with the Laoka equigranular granite. Combined with previous S–Pb isotope data, we propose that large-scale Cu mineralization in Gejiu resulted from the extraction of Cu from basalt by fluids exsolved from the Late Cretaceous equigranular granitic magmas.

Petrogenesis of the Shibaogou Mo-W-Associated Porphyritic Granite, West Henan, China: Constrains from Geochemistry, Zircon U-Pb Chronology, and Sr-Nd-Pb Isotopes

The Shibaogou pluton, located in the Luanchuan orefield of western Henan Province in China, is a typical porphyritic granite within the Yanshanian “Dabie-type” Mo metallogenic system. It is mainly composed of porphyritic monzogranite and porphyritic syenogranite. Zircon U-Pb dating results indicate emplacement ages of 150.1 ± 1.3 Ma and 151.0 ± 1.1 Ma for the monzogranite and 148.1 ± 1.0 Ma and 148.5 ± 1.3 Ma for the syenogranite. The pluton is characterized by geochemical features of high silicon, metaluminous, and high-K calc-alkaline compositions, enriched in Rb, U, Th, and Pb, and exhibits high Sr/Y (18.53–58.82), high (La/Yb)N (9.01–35.51), and weak Eu anomalies. These features indicate a source region from a thickened lower crust with garnet and rutile as residual phases at depths of approximately 40–60 km. Sr-Nd-Pb isotopic analyses suggest that the magmatic source is mainly derived from the Taihua and Xiong’er Groups of the Huaxiong Block, mixed with juvenile crustal rocks from the Kuanping and Erlangping Groups of the North Qinling Accretion Belt. Combined with geological and isotopic characteristics, it is concluded that the Shibaogou pluton formed during the compression–extension transition period associated with the collision between the Yangtze Block and the North China Craton, reflecting the complex partial melting processes in the thickened lower crust. The present study reveals that the magmatic–hydrothermal activity at Shibaogou lasted approximately 5 Ma, showing multi-phase characteristics, further demonstrating the close relationship between the pluton and the Mo-W mineralization.