Search Results (206)

Granite formations provide suitable geological conditions for building gravity dams. However, the presence of intruding granite creates a fractured zone. The interaction of this fractured zone with structural planes and faults can create geological conditions that are unfavorable for the anti-sliding stability of gravity dams. This paper identifies the dominant structural planes that affect the anti-sliding stability of dams by studying the three-dimensional intersection relationships between groups of structural planes, faults, and fracture zones. The three-dimensional distribution and occurrence of the dominant structural planes directly impact the anti-sliding stability and sliding failure mode of gravity dams. Through comprehensive field investigations and systematic analysis of engineering geological data, the spatial distribution characteristics of structural planes and fracture zones were quantitatively characterized. Subsequently, the potential for deep-seated sliding failure of the gravity dam was rigorously evaluated and conclusively dismissed through application of the rigid body limit equilibrium method. It was established that the sliding mode of the foundation of the dam under this combination of structural planes is primarily shallow sliding. Additionally, based on the engineering geological data of the area around the dam, a three-dimensional finite element numerical model was developed to analyze stress–strain calculations under seepage stress coupling conditions and compared with calculations made without considering seepage stress coupling. The importance of seepage in the anti-sliding stability of the foundation of the dam was determined. The research findings provide engineering insights into enhancing the anti-sliding stability of gravity dams in granite distribution areas by (1) identifying critical structural planes and fracture zones that control sliding behavior, (2) demonstrating the necessity of seepage-stress coupling analysis in stability assessments, and (3) guiding targeted reinforcement measures to mitigate shallow sliding risks. Full article

The Eastern Carpathians are thrust to the east and north over their Eastern European foreland, tectonically covering it over an area several hundred kilometers across. Information about the nature of the underthrust part of the Carpathian foreland can be obtained from the rock fragments preserved in the sedimentary successions of the Carpathian fold and thrust belt, specifically in the Outer Dacides and the Moldavides. Fragments of felsic rocks occurring within the sedimentary units of the Upper Cretaceous successions of the Moldavides have long been attributed to the Cuman Cordillera—an intrabasinal ridge in the Eastern Outer Carpathians. This work is the first complex geochemical and geochronological study on the exotic igneous clasts of the Cuman Cordillera. Igneous clasts from the southern part of the Moldavides (Variegated clay nappe/formation) are investigated here. They include mainly granites and rhyolites. Phaneritic rocks are composed of cumulus plagioclase, albite, amphibole and biotite, and intercumulus quartz and potassium feldspar, with apatite, magnetite, sphene, and zircon as main accessories, while the porphyritic rocks have a mineral assemblage similar to that mentioned above, displayed in a porphyritic texture with a usually crystallized groundmass. SHRIMP U-Pb zircon dating indicated the 583–597 Ma age interval for magma crystallization. Based on calcareous nannofossils, the depositional age of the investigated igneous clasts is Cenomanian to Maastrichtian, implying that the Cuman Cordillera was an emerged piece of land, herein an active source of sediments in the flysch basin for at least 40 Ma, from the Early Cretaceous (Aptian) to the Late Cretaceous (Maastrichtian). The intrusive and subvolcanic rocks show similar trends for trace and major elements, evincing their comagmatic nature. The enrichment in LILE and LREE relative to HFSE and HREE, as well as the element anomalies (e.g., negative Nb, Ta, and Eu and positive Rb, Ba, K, and Pb) suggest a convergent continental plate margin tectonic setting. Mineral chemistry suggests magma crystallization in relatively oxic conditions (magnetite series), during ascent within a depth of 15 km to 5 km. The igneous rocks attributed to the Cuman ridge display compositional and geochronological features similar to Brno and Thaya batholiths in the Brunovistulian terrane, which could be a piece of the Carpathian foreland not covered by the Tertiary thrusts. Our data confirm the non-Carpathian origin of the igneous clasts, revealing a Neoproterozoic history of the Carpathian foreland units, which include a Cadomian/Pan-African continental arc, exposed mainly during the Late Cretaceous as an intrabasinal island of the Alpine Tethys, traditionally known as the Cuman Cordillera. Full article

The Great Xing’ an Range is located in the eastern part of the Xing’ an-Mongolian Orogenic Belt, which is an important component of the Central Asian Orogenic Belt. To determine the emplacement age and petrogenesis of the granitoids in the Gegenmiao and Taonan areas of the central Great Xing’an Range, and to investigate its tectonic setting, petrographic studies, zircon U-Pb geochronology, whole-rock Sr-Nd isotopic analysis, zircon Hf isotopic analysis, and detailed geochemical investigations of this intrusion were carried out. The results indicate the following, in relation to the granitoids in the study areas: (1) The zircon U-Pb dating of the granitic rocks in the study areas yields ages ranging from 141.4 ± 2.0 Ma to 158.7 ± 1.9 Ma, indicating their formation during the Late Jurassic to Early Cretaceous; (2) the geochemical characteristics indicate that these rocks belong to the calc-alkaline series and peraluminous, classified as highly fractionated I-type granites with adakite features; (3) the Sr-Nd isotopic data show that the εNd(t) values of Gegenmiao granitic rocks are 2.8 and 2.1, while those of Taonan granitic rocks range from −1.5 to 0.7; (4) the Zircon εHf(t) values of the granitic rocks from Gegenmiao and Taonan vary from 2.11 to 6.48 and 0.90 to 8.25, respectively. They are interpreted to have formed through partial melting of thickened lower crustal material during the Meso-Neoproterozoic. The Gegenmiao and Taonan granitic rocks were formed in a transitional environment from post-orogenic compression to extension, which is closely associated with the Mongolia–Okhotsk tectonic system. Full article

The greisens discussed in the present study are associated with the Homrit Akarem post-collisional granites, which are exposed near the western edge of the Egyptian Nubian Shield in the Southeastern Desert of Egypt. The Homrit Akarem granites intruded into Neoproterozoic country rocks, with sharp intrusive contacts. The marginal parts of the Homrit Akarem intrusion underwent extensive post-magmatic metasomatism, resulting in the formation of albitized granite and greisens. The Homrit Akarem greisens occur as veins and stockworks, which can be classified into four types: muscovite-rich, cassiterite-rich, topaz-rich, and beryl-rich greisens. Based on petrographic inspection, we identified ore minerals (cassiterite, beryl, topaz, muscovite, Nb-Ta oxides, tourmaline, fluorite, and corundum) in the greisens using electron probe microanalysis. The Homrit Akarem mineralized greisens were formed in a magmatic cupola above A-type magma, where fluid–rock interactions played a significant role in their formation. The accumulation of residual volatile-rich melt and exsolved fluids in the apical part of the magma chamber produced albitized granite, greisens, and quartz veins that intruded into the peripheries of the granitic intrusion and its surrounding country rocks. The variation in the mineralogy of the studied greisens indicates the diverse chemical composition of both the hydrothermal/magmatic fluids and the host granites. The simultaneous decrease in temperature and pressure is considered a crucial factor that controlled mineralization in the apical parts of the magma chamber. The occurrence of cassiterite, beryl, topaz, tourmaline, muscovite, and Nb-Ta oxides in the studied greisens suggests a potential polymetallic deposit of industrial minerals. Full article

The Huanggang iron-tin deposit, located in the southern Greater Khingan Range, is one of the largest Fe-Sn deposits in Northern China (NE China). Iron-tin mineralization occurs mainly in the contact zone between granitoid intrusions and the marble of the Huanggang and Dashizhai formations. Six mineralization stages are identified: (I) anhydrous skarn, (II) hydrous skarn, (III) cassiterite-quartz-calcite, (IV) pyrite-arsenopyrite-quartz-fluorite, (V) polymetallic sulfides-quartz, and (VI) carbonate ones. Fluid inclusions (FIs) analysis reveals that Stage I garnet and Stage II–III quartz host liquid-rich (VL-type), vapor-rich two-phase (LV-type), and halite-bearing three-phase (SL-type) inclusions. Stage IV quartz and fluorite, along with Stage V quartz, are dominated by VL- and LV-type inclusions, while Stage VI calcite contains exclusively VL-type inclusions. The FIs in Stages I to VI homogenized at 392–513, 317–429, 272–418, 224–347, 201–281, and 163–213 °C, with corresponding salinities of 3.05–56.44, 2.56–47.77, 2.89–45.85, 1.39–12.42, 0.87–10.62, and 4.48–8.54 wt% NaCl equiv., respectively. The H–O–C isotopes data imply that fluids of the anhydrous skarn stage (δD = −101.2 to −91.4‰, δ¹⁸O_H2O = 5.0 to 6.0‰) were of magmatic origin, the fluids of hydrous skarn and oxide stages (δD = −106.3 to −104.7‰, δ¹⁸O_H2O = 4.3 to 4.9‰) were characterized by fluid mixing with minor meteoric water, while the fluids of sulfide stages (δD = −117.4 to −108.6‰, δ¹⁸O_H2O = −3.4 to 0.3‰, δ¹³C_V-PDB= −12.2 to −10.9‰, and δ¹⁸O_V-SMOW = −2.2 to −0.7‰) were characterized by mixing of significant amount of meteoric water. The ore-forming fluids evolved from a high-temperature, high-salinity NaCl−H₂O boiling system to a low-temperature, low-salinity NaCl−H₂O mixing system. The garnet U-Pb dating constrains the formation of skarn to 132.1 ± 4.7 Ma (MSWD = 0.64), which aligns, within analytical uncertainty, with the weighted-mean U−Pb age of zircon grains in ore-related K-feldspar granite (132.6 ± 0.9 Ma; MSWD = 1.5). On the basis of these findings, the Huanggang deposit, formed in the Early Cretaceous, is a typical skarn-type system, in which ore precipitation was principally controlled by fluid boiling and mixing. Full article

The chemical composition of apatite has been utilized as an indicator of magmatic fertility related to tungsten mineralization in skarn systems. In this study, we compiled 5776 apatite trace element data from 374 intrusions, along with records indicating magmatic fertility. Then we trained and validated machine learning (ML) models, specifically support vector machine (SVM) and random forests (RF), to classify magmatic fertility based on apatite chemistry in igneous rocks. RF model achieved high classification accuracies (~93%) on the test dataset, demonstrating that employing ML approaches to distinguish apatite derived from fertile versus barren magmas is feasible and effective. Furthermore, we optimized classification thresholds to maximize the model’s predictive accuracy for identifying potentially fertile magmas. Feature-importance analysis of the machine learning classifier shows that elevated La, Yb, and Mn, together with depleted Sr, Y, Gd, and Tb, constitute the most diagnostic elemental signatures of magmatic fertility. As a case study, we applied our trained ML model to predict the magmatic fertility of apatite samples from the Nanling Range (southern China’s largest skarn-type tungsten mineralization province). Benefiting from the application of GAN-based techniques to address sample imbalance, our ML models can effectively identify tungsten-mineralized favorable skarn areas. Additionally, the visualization technique t-distributed stochastic neighbor embedding (t-SNE) was employed to validate and assess classification outcomes. Results showed clear separation between fertile and barren categories within the reduced 3D space. Our findings emphasize apatite as a sensitive indicator mineral for granite-related magmatic fertility and metallogenesis, underscoring its significant potential in mineral exploration. Finally, we provide a convenient prediction software for magmatic fertility based on a machine learning model utilizing apatite trace element compositions. Full article

Late Mesozoic magmatism in Southeast China extensively reworked the Cathaysia Block’s crust, linked to the Paleo-Pacific Plate subduction beneath East Asia. The northeastern Cathaysia Block, largely covered by Cretaceous volcanic-sedimentary basins, has limited Jurassic exposure to Early Cretaceous intrusions, which provides critical insights into deep crust-mantle processes. In this study, we present zircon U-Pb geochronology and Hf isotope, whole-rock geochemistry, and Sr-Nd isotopes of the Middle Jurassic syenite-granite suites and Early Cretaceous granites with enclaves in the Qingyuan area (SW Zhejiang Province) to constrain their petrogenesis and tectonic significance. Middle Jurassic syenites and alkali-feldspar granites (169–167 Ma) exhibit calc-alkaline to shoshonitic affinities and weakly peraluminous compositions. Early Cretaceous granites (134 Ma) and their enclaves (136 Ma) are high-K calc-alkaline and weakly peraluminous to metaluminous. All samples show LILE and LREE enrichment, HFSE depletion, and negative Eu and Sr anomalies, with only syenites displaying negative Ce anomalies. We suggest that the Middle Jurassic syenites originated from the partial melting of an enriched lithospheric mantle influenced by subduction-related metasomatism. Alkali-feldspar granites derived from partial melting of the basement of the Cathaysia Block. Early Cretaceous granites formed by partial melting of lower crustal mafic rocks, with enclaves representing earlier crystallization products, which were then mechanically mixed with granites. We propose the NE Cathaysia Block underwent significant reworking from the Middle Jurassic to the Early Cretaceous. Middle Jurassic syenites formed in a compressional setting linked to Paleo-Pacific Plate subduction, while Early Cretaceous magmatism reflects lithospheric extension and crust-mantle interaction triggered by slab rollback. Full article

Awulale Mountain is one of the most important Fe-Cu concentration areas situated in the eastern part of Western Tianshan. The Cu deposits in the belt are genetically associated with the Permian intermediate and felsic intrusions. However, the precise age and magma source of the causative intrusions are currently not confirmed, constraining our understanding of regional mineralization. The Cahanwusu porphyry Cu deposit is located in the western part of Awulale Mountain. Field investigations have shown that the mineralization in the deposit is genetically associated with granitic porphyry and diorite porphyry. In this paper, we provide detailed zircon U-Pb ages and in-situ Hf isotopic compositions of the granitic porphyry and diorite porphyry. The granitic porphyry and diorite porphyry have zircon U-Pb ages of 328.6 ± 2.6 Ma (MSWD = 0.52; n = 23) and 331 ± 2.8 Ma (MSWD = 0.95; n = 21), respectively. This indicates that the Cahanwusu deposit was formed in the Carboniferous in a subduction setting. This is distinguishable from other porphyry Cu deposits in the belt, which were generally formed in the Permian in the post-collision extensional setting. The granitic porphyry and diorite porphyry exhibit positive ε_Hf(t) values varying from +2.8 to +5.4 (average of +4.1) and +2.0 to +5.1 (average of +4.1), respectively. The magmas of these causative intrusions were interpreted to be derived from the partial melting of the juvenile lower crust which originated from cooling of mantle-derived magmas related to the subduction process. Our new results highlight that the Cahanwusu deposit represents a new episode of Cu mineralization in the belt and the Carboniferous granitoids in Awulale Mountain are potential candidates for Cu exploration. Full article

This study focuses on the Fourque massif, one of the thirty Variscan plutons outcropping along the Axial zone of the Pyrenees. It hosts a significant tungsten deposit that was actively mined until 1986. However, since the closure of the mine, no detailed geochemical or geochronological studies have been conducted until recent investigations in 2019, leaving a significant gap in our understanding of this intrusion. This lack of research, along with the ongoing debate and uncertainties regarding the timing and magmatic processes of Variscan plutonism in the Pyrenees, underscores the importance of further investigations. To address these gaps, we present new zircon U–Pb geochronology, whole-rock and zircon geochemistry (X-ray fluorescence and LA-ICP-MS), and Ti-in-zircon thermometry. Our study compares nine new whole-rock geochemistry samples with the limited previous dataset from 1987, refining the petrogenetic interpretation of the intrusion. These efforts are framed within the ongoing debate surrounding the different Variscan intrusions in the Pyrenees, including the discussions on their emplacement age, magmatic context, type, and origin. Geochronological data indicate an age ranging from 304.6 ± 2.3 to 308.4 ± 2.6 Ma, with crystallization temperatures ranging from 700 to 800 °C. The granodiorite is characterized by differentiated petrogenetic facies, related to successive batches of magma rising from a deeper source. The granodiorite exhibits high ASI ratios (>1.3), classifying it as strongly peraluminous. While I-type granites are typically metaluminous to weakly peraluminous, such elevated ASI values suggest a significant influence of crustal assimilation during magmatic evolution. The geochemical signature of the intrusion is enriched in large ion lithophile elements (LILE) and light rare earth elements (LREEs) while showing depletion in heavy rare earth elements (HREEs), consistent with a high-K calc-alkaline, magnesian, syn-orogenic setting. Whole-rock and zircon trace element data suggest that the magma source involved partial melting of the continental crust, with evidence of interaction with a subduction-modified mantle component. By applying methods previously unapplied to this pluton, this study provides new data on its geochemistry and geochronology, revealing significant differences from previous interpretations. These findings offer deeper insights into the emplacement and evolution of the Fourque granodiorite, refining its role within the broader context of Variscan orogenesis in the Pyrenean Axial Zone and similar plutonic systems worldwide. Full article

The Bozhushan in southeastern Yunnan is a composite granite body that was formed by multi-phase magmatic intrusion. The genesis of the tourmaline-supergroup minerals occurring therein remains uncertain, as it has been the subject of only a limited number of studies. This investigation employs an integrated analytical approach combining EPMA, LA-ICP-MS, and boron isotope geochemistry, supplemented by detailed field geological investigations and petrographic observations of tourmaline textural characteristics. This study aims to elucidate the genetic relationships between distinct tourmaline varieties, establish temporal correlations between mineral crystallization stages and magmatic–hydrothermal evolution processes, and evaluate the petrogenetic significance of tourmaline geochemical signatures for regional mineralization events. This study analyzes tourmaline-supergroup minerals in granitic pegmatites and aplites, which occur as nodular, radial, and columnar aggregates. Most tourmaline crystals exhibit well-defined rhythmic zoning patterns, which are clearly observable under cross-polarized light microscopy. Chemical composition analysis has identified two tourmaline species: schorl and dravite. The formation of tourmaline is primarily of magmatic origin and is characterized by a magmatic–hydrothermal transition. It predominantly belongs to the alkali subgroup and is formed in Li-poor granitoids and associated pegmatites and aplites, Ca-poor metapelites, metapsammites, and quartz-tourmaline rocks. The inter-ionic substitution mechanism in this system is predominantly governed by Fe²⁺Mg₋₁ and (X_vacAl)(NaR²⁺)₋₁ exchange equilibria. Additionally, geochemical evidence indicates that the primary ore-forming fluids originate from granitic magmas, which are likely sourced from the partial melting of metasedimentary rocks. During the late Yanshan period, the upwelling of granitic magma in the Bozhushan area introduced a substantial heat source and mineralizing fluids, which interacted with the Cambrian units to form tungsten–tin mineralization. The geochemical data on tourmaline indicate that the Bozhushan granite body has considerable potential for ore mineralization. Full article

Longchahe porphyritic granite is the largest pluton within the western Gejiu complex, a series of mainly intermediate to felsic alkali intrusions in southwestern China. Our research indicates that the pluton intruded during the Late Cretaceous (82–84 Ma). The pluton is primarily a medium- to coarse-grained porphyritic granite, which shows weakly peraluminous (A/CNK = 0.92–1.82, with an average of 1.09) and alkali (shoshonitic) characteristics, exhibiting an affinity with highly differentiated I-type granite. The porphyritic granite is enriched in K and Rb, but depleted in Ba, P, and Ti, and displays significant enrichment of light rare earth elements with minor negative Eu anomalies (Eu/Eu* = 0.46–0.66). It has elevated (⁸⁷Sr/⁸⁶Sr)i ratios (0.71243–0.71301), negative εNd(t) values (−8.42–−6.46), and a broad range of εHf(t) values (−13.80–9.17). These geochemical characteristics indicate that the formation of Longchahe granite involved both crust–mantle assimilation and strong crystal fractionation. Additionally, the pluton demonstrates a significant enrichment of W. A factor analysis study suggests that the formation of granites is associated with F1 (Nb–Ta–Th–LREE–HREE–[W]), whilst F2 represents Sn–Pb–U–[Zn] polymetallic mineralisation in western Gejiu. Further, a score diagram indicates that the granites exhibit a high abundance of ore-forming elements, with potential for Pb and Zn mineralisation. Our study favours that the Longchahe granites likely formed within a continental arc–tectonic setting, related to subduction and subsequent rotation processes experienced by the Paleo-Pacific plate. Full article

The Ossa-Morena Zone (SW Iberian Massif) hosts the largest set of Cambro–Ordovician alkaline magmatic plutons related to the Palaeozoic rifting of the northern Gondwana margin so far described. An organized framework for their classification at different scales is proposed through data-driven ranks based on their distinctive petrological features relative to other rift-related magmatic rocks found throughout western Europe. The classification method aims to enhance geological mapping at different scales, regional- and continental-scale correlations, and, as such, facilitate the petrogenetic interpretation of this magmatism. The hierarchical scheme, from highest to lowest rank, is as follows: rank-1 (supersuite) assembles rocks that have distinctive characteristics from other magmatic units emplaced in the same magmatic event; rank-2 (suite) categorizes the units based on their major textural features, indicating if the body is plutonic, sub-volcanic, or a strongly deformed magmatic-derived unit; rank-3 (subsuite) clusters according to their spatial arrangement (magmatic centres) or association to larger structures (e.g., shear zones or alignments); rank-4, the fundamental mapping unit, characterizes the lithotype (alkaline granite, alkaline gabbro, syenite, albitite, etc.) by considering higher ranks (alkalinity and textural aspects); rank-5 characterizes the geometry of individual plutons (with several intrusions) or swarms; rank-6 (smallest mappable unit) corresponds to each intrusion or individual body from a swarm. Although this classification scheme is currently presented solely for the Ossa-Morena Zone, the scheme can be easily extended to incorporate other co-magmatic alkaline bodies, such as those in the NW Iberian allochthonous units or other peri-Gondwanan zones or massifs, in order to facilitate regional correlations of the rift-related magmatism. Full article

The Cambrian period marks a crucial phase in the initial subduction of the Proto-Tethys Ocean beneath the East Kunlun Orogen. Studying the I-type granites and mafic–ultramafic rocks formed during this period can provide valuable insights into the early Paleozoic tectonic evolution of the region. This paper incorporates petrology, LA-ICP-MS zircon U-Pb geochronology, and whole-rock major and trace element data obtained from the Kekesha intrusion in the eastern section of the East Kunlun Orogen. The formation age, petrogenesis, and magmatic source region of the intrusion are revealed, and the early tectonic evolution process of the subduction of the Proto-Tethys Ocean is discussed. The Kekesha intrusion includes four main rock types: gabbro, gabbro diorite, quartz diorite, and granodiorite. The zircon U-Pb ages are 515.7 ± 7.4 Ma for gabbro, 508.9 ± 9.8 Ma for gabbro diorite, 499.6 ± 4.0 Ma for quartz diorite, and 502.3 ± 9.3 Ma and 501.6 ± 6.2 Ma for granodiorite, respectively, indicating that they were formed in the Middle Cambrian. The geochemical results indicate that the gabbro belongs to the high-Al calc-alkaline basalt series, the gabbro diorite belongs to the medium-high-K calc-alkaline basalt series, the quartz diorite belongs to the quasi-aluminous medium-high-K calc-alkaline I-type granite series, and the granodiorite belongs to the weakly peraluminous calc-alkaline I-type granite series, all of which belong to the medium-high-K calc-alkaline series that have undergone varying degrees of differentiation and contamination. Gabbro and gabbro diorite exhibit significant enrichment in light rare earth elements (LREEs), depletion in heavy rare earth elements (HREEs), and an enhanced negative anomaly in Eu (Europium). Compared to gabbro and gabbro diorite, quartz diorite and granodiorite exhibit more pronounced enrichment in LREEs, more significant depletion in HREEs, and an enhanced negative anomaly in Eu. All four rock types are enriched in large-ion lithophile elements (LILEs) such as Cs, Rb, Th, Ba, and U, and are depleted in high-field-strength elements (HFSEs) such as Nb, Ta, and Ti. This indicates that these rocks originated from the same or similar mixed mantle source regions, and that they are formed in the island-arc tectonic environment. This paper suggests that the gabbro and gabbro diorite are mainly derived from the basic magma formed by partial melting of the lithospheric mantle metasomatized by subducted slab melt in the oceanic crust subduction zone and mixed with a small amount of asthenosphere mantle material. Quartz diorite results from the crystal fractionation of basic magma and experiences crustal contamination during magmatic evolution. Granodiorite forms through the crystal fractionation of basic magma, mixed with partial melting products from quartz diorite. While the lithology of the intrusions differs, their geochemical characteristics suggest they share the same tectonic environment. Together, they record the geological processes associated with island-arc formation in the East Kunlun region, driven by the northward subduction of the Proto-Tethys Ocean during the Early Paleozoic. Based on regional tectonic evolution, it is proposed that the Proto-Tethys Ocean began subducting northward beneath the East Kunlun block from the Middle Cambrian. The Kekesha intrusion formed between 516 and 500 Ma, marking the early stages of Proto-Tethys Ocean crust subduction. Full article

The petrology, geochemistry, and zircon U-Pb chronology of the Huoshaodian pluton in the Liuba area of the western part of the South Qinling tectonic belt are investigated in this study. The Huoshaodian pluton consists of gabbro, quartz diorite, and granodiorite, and the dominated rock type is quartz diorite. The results indicate that the Huoshaodian pluton belongs to the calc-alkaline series. In the chondrite-normalized REE, all of the samples showed similar patterns, with an enrichment of light REEs and depletion of heavy REEs, but they showed slight differences in the degrees of Eu anomalies. The primitive mantle-normalized trace element diagram reveals an enrichment of large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), as well as depleted high field strength elements (HFSEs). The zircon U-Pb dating results reveal that the gabbro, quartz diorite, and granodiorite have crystallization ages of 214.9 ± 0.58 Ma, 215.0 ± 1.2 Ma, and 215.4 ± 1.9 Ma, respectively, indicating that the Huoshaodian pluton was emplaced during the late Triassic period (214.9–215.4 Ma). In terms of petrogenesis, the gabbro of the Huoshaodian pluton originates from a transitional lithospheric mantle that has undergone fluid metasomatism and partial melting. Specifically, it originated through 1%–2% garnet spinel peridotite undergoing partial melting. In addition, the gabbro underwent a slight degree of contamination by crustal materials during its ascent and intrusion, with some continental crust material being incorporated. The quartz diorite and granodiorite of the Huoshaodian pluton are formed through partial melting processes occurring within the normal lower crust. Combined with the previous studies on the early Mesozoic tectonic evolution of the South Qinling, this study proposes that the formation mechanism of the Huoshaodian pluton may be as follows: in the early Triassic, the Mianlue Ocean subducted northward beneath the Qinling microblock, resulting in a large-scale continental-continental collision between the North China Block and the Yangtze Block; when the oceanic crust subducted to a certain depth, the detachment of the subducting slab triggered the upwelling of mantle material. The heat from mantle-derived magma caused the partial melting of the mafic lower crust, while the mafic magma entered into the upper granitic magma chamber and began to mix. Due to the high viscosity contrast and temperature difference between the two end-member magmas, incomplete mixing led to the formation of a melt with distinct adakitic characteristics and a mafic melt representing mantle-derived material. Full article