The study of metamorphism plays an important role in deciphering the composition and evolution of the deep crust, restoring the thermal evolution history of the crust, and guiding the prospecting. Both ancient continental blocks and Phanerozoic orogenic belts in northwest China are the key areas for the study of metamorphism in China. This paper reviews ultra-high pressure (UHP) metamorphism, ultra-high temperature (UHT) metamorphism, crustal anatexis, fluid activity in subduction zone and metamorphic mineral prospecting in northwest China in the past decade. In terms of UHP metamorphism, based on the new discoveries of evidences of UHP metamorphism represented by coesite, the fact of deep subduction of rocks has been further strengthened for previously established UHP metamorphic belts, and the East Kunlun UHP metamorphic belt was firstly established. In terms of UHT metamorphism, progresses in P–T paths, metamorphic ages and genesis of UHT metamorphism have been achieved in the Altai and Altyn orogen, and new outcrops of UHT metamorphic rocks have been identified in the East Kunlun, Qinling orogens and western Qaidam. The study of partial melting has been the focus of the study of orogenic metamorphism in the past decade, mainly including the products of partial melting, the tectonic setting and mechanism of melting. Studies on fluid activities in subduction zones focus on fluid identification and composition characterization, which provide a basis for further study of mass transfer in subduction zones. New discoveries of metamorphic ore deposits, represented by rutile and crystalline graphite, have been made.

The southern margin of the Central Asian Orogenic Belt (CAOB) represents one of the world’s most important provinces of amazonite-bearing granites and associated rare-metal deposits. However, the genesis and coloration mechanism of amazonite remain insufficiently constrained, which limits a deeper understanding of the petrogenesis of amazonite granites and the related rare-metal mineralization (e.g., Rb and Cs). In this study, amazonite samples were collected from five representative amazonite granite–type rare-metal deposits along the southern CAOB, namely Zhangbaoshan, Jiangjunshan, Yilanlik, Guobaoshan, and Shihuiyao. Detailed mineralogical and spectroscopic investigations were conducted, including X-ray diffraction (XRD), Raman spectroscopy, and UV-Vis spectroscopy, together with major- and trace-element analyses by LA-ICP-MS.The results show that the mineralogical and spectral characteristics of amazonite are overall consistent with those of microcline, indicating that the primary crystal structure remains relatively stable. UV-Vis spectra generally display absorption peaks at 248 nm and 382 nm and a broad absorption band between 620 and 740 nm, suggesting that color-center absorption is closely associated with the blue green hue. Trace-element data reveal systematic enrichment of Rb, Cs, and Pb in amazonite. Integrating these observations, we propose that the blue–green coloration of amazonite is unlikely to be controlled by a single element; instead, it is more plausibly related to the coupled enrichment of Rb and Pb via isomorphous substitution for K in the feldspar lattice. Substitution of Rb⁺ for K⁺ induces subtle lattice adjustments, whereas substitution of Pb²⁺ for K⁺, owing to charge imbalance, more readily generates localized defects that facilitate the formation of color centers, ultimately producing the characteristic blue green coloration. This interpretation is further supported by the UV-Vis responses linked to color-center absorption. Based on comparisons with previous studies, amazonite in the southern CAOB is inferred to have formed predominantly during the late stage of highly fractionated granitic magmatism, closely associated with the enrichment of rare metals (Rb\Cs) and the role of volatiles (e.g., F). Amazonite is therefore suggested to be a useful indicator mineral for Rb-related rare-metal mineralization in granitic systems.

Crystal-rich fluid inclusions serve as a crucial carrier in the evolution of pegmatitic melts-fluids, providing the most direct evidence for unraveling the origin, migration, phase transitions, and associated element enrichment mechanisms of pegmatitic fluids. The Jing'erquan rare metal deposit is a typical granite-pegmatite type lithium-beryllium deposit in the East Tianshan, western Central Asian Orogenic Belt. However, the source and evolutionary characteristics of its ore-forming fluids remain unclear. This study conducted detailed petrographic observations, along with laser Raman spectroscopy, microthermometry, gas chromatography, and ion chromatography analyses on fluid inclusions from pegmatites in this deposit. The results indicate that the fluid inclusions at Jing'erquan are diverse in type. They are generally characterized by moderate-low temperatures (mainly ranging from 240 ℃ to 380 ℃) and salinities (predominantly between 1.0 wt% NaCl_eqv and 5.5 wt% NaCl_eqv), as well as low densities (0.5～0.9 g/cm³). The fluid is rich in CO₂, H₂O, and N₂, with minor amounts of C₂H₂ and CH₄, and is relatively enriched in F⁻, Cl⁻, and alkali metal cations. This study proposes that the ore-forming fluids for the Jing'erquan Li-Be deposit were primarily magmatic in origin, resulting from the high fractional crystallization of granitic magma in a relatively closed environment. Two distinct pegmatite veins, dominated by spodumene and beryl, respectively, were formed during different stages of granitic magma differentiation. During the mineralization process, the fluid properties transitioned from moderate-low temperature-low salinity-low density to low temperature-moderate-low salinity-low density. The primary reason for this shift is that CO₂ gradually reached saturation and separated from the ore-forming fluid, as the temperature, pressure, and solubility of CO₂ and NaCl-H₂O decreased. In this process, CO₂ acted as an important carrier, facilitating the transportation and enrichment of lithium. Furthermore, the relative enrichment of F⁻, Cl⁻, and alkali metal cations played a significant role. Specifically, F⁻ was conducive to the formation of complexes or compounds with rare metal cations such as Li⁺ and Be²⁺, aiding their migration and subsequent precipitation and enrichment to form ore.

The Western Tianshan Orogen is located in the southwestern Central Asian Orogenic Belt (CAOB). The widespread magmatic rocks provide a critical window for investigating regional tectonic-metallogenic dynamics. To address controversies regarding the petrogenesis, tectonic setting of granitoids, and the closure timing of the North Tianshan Ocean in the Western Tianshan region, this study focuses on the Late Paleozoic granitoids (Guozigou, Halegati, Jinghe, and Nalati plutons) located along the northern margin of the Yili Block, through integrating geochronological, whole-rock elemental, and Sr-Nd-Hf isotopic analyses. The studied plutons are predominantly composed of monzonitic granite and potash feldspar granite. Zircon LA-ICP-MS U-Pb dating reveals that these plutons were emplaced between (368.1±1.5) Ma (Late Devonian) and (301.9±2.8) Ma (Late Carboniferous). Combined with regional geochronological data, the magmatism in the northern Yili Block can be temporally subdivided into two stages, late Devonian to early Carboniferous and late Carboniferous. The studied granitoids exhibit high silica (SiO₂ = 66.62%–76.08%) and total alkali (K₂O+Na₂O=6.72%–8.85%) contents. In terms of rare earth elements, the studied samples show LREE-rich patterns with variable negative Eu anomalies (δEu = 0.30–0.97). The trace element patterns of the studied rocks are characterized by enrichment in Rb and Th and depletion in Nb, Ta, and Ti, comparable to those of continental arc granites. The late Devonian granitoid samples show slightly enriched radiogenic isotopic signatures, with negative ε_Nd(t) from –3.79 to –1.3 and ε_Hf(t) from +0.3 to +5.0, indicating magma sources dominated by ancient crustal materials with mantle-derived contributions. In contrast, the Late Carboniferous granitoids show more radiogenic ε_Nd(t) (+0.8 to +5.9) and ε_Hf(t) (+4.1 to +15.1) values, indicative of a juvenile lower crustal origin. Integrating previous studies, we propose that the 368–307 Ma granitoids are of I-type granite and were formed associated with the northward subduction of the Northern Tianshan Ocean beneath the Yili Block, whereas later A2-type potash feldspar granites and I-type monzonitic granites in the context of post-collisional lithospheric delamination initiated at ～305 Ma. Additionally, the Late Devonian-Early Carboniferous to Late Carboniferous granitoids in the Borohoro region exhibit significant potential for Cu-Mo mineralization.

Eudialyte is a critical ore mineral enriched in zirconium, niobium, and rare earth elements (Zr-Nb-REE), and often occurs in peralkaline rocks. Its composition records key information from magma genesis, evolution, to hydrothermal activities, providing important insights for evaluating the metallogenic potential of alkaline rocks. The Bashisuhong complex is located in the junction zone between the Northern Tarim Basin and the South Tianshan Orogen, where aegirine-augite syenite dikes host Zr-Nb-REE mineralization. These dikes, exhibiting a gray-black to purplish-red coloration, display irregular contact boundaries with the marble and locally visible plastic flow structures. Wollastonite-rich wall-rock xenoliths are commonly observed within these dikes, indicating material exchange with the marble. The dikes are 0.33–3.71 m wide, extend 30–170 m, and are generally oriented east-west. Gangue minerals primarily consist of perthite, aegirine-augite, and wollastonite, while ore minerals are mainly eudialyte, apatite, and titanite. Eudialyte is predominantly euhedral, with grain sizes ranging from 0.1 to 5 mm, and exhibits well-developed straight oscillatory zoning. Their trace element characteristics are controlled by charge-and-radius-controlled (CHARAC) substitution mechanisms, indicating a typical magmatic origin. Both whole-rock and eudialyte samples exhibit light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion, accompanied by significant negative Eu and Sr anomalies, indicating extensive fractional crystallization of plagioclase in the primary magma of the syenite dikes and compositionally similar to alkaline basalt. When alkaline magma intruded into marble, assimilation of the marble introduced substantial CaO components. This assimilation not only supplied critical materials for eudialyte formation but also, through increased CaO content, enhanced Cl solubility and lowered the solidus temperature, thereby facilitating further magma evolution and achieving supernormal enrichment of rare metals. Therefore, the interaction between alkaline magma and marble represents a crucial mechanism for eudialyte mineralization in the junction zone between Northern Tarim Basin and South Tianshan Orogen, making their contact zones promising targets for rare metal exploration.

The Beishan Orogenic Belt, situated in the central segment of the southern margin of the Central Asian Orogenic Belt (CAOB), has undergone prolonged, multi-stage subduction and accretion. It represents a key region for reconstructing the tectonic evolution of the southern CAOB margin and the closure of the Paleo-Asian Ocean. The Early Paleozoic was a significant crustal evolution period for the Beishan Orogenic Belt, characterized by frequent magmatic activity. Previous studies primarily focused on the central-western part of the belt, reporting a magmatic flare-up at 450−420 Ma. This study presents systematic geochronological and geochemical investigations of the Waizuishan pluton, located on the southeastern edge of the Shuangyingshan-Huaniushan tectonic unit within the Beishan Orogenic Belt. The Waizuishan pluton mainly comprises quartz diorite (and granodiorite. Zircon U-Pb dating yielded crystallization ages of (427.1±3.4) Ma and (418.6±2.8) Ma. The rocks belong to the metaluminous series (A/CNK＜1), exhibiting calc-alkaline and magnesian affinities. They possess low total rare earth element (ΣREE) contents, are enriched in light rare earth elements (LREEs), and show weak negative Eu anomalies (δEu=0.72−0.86). Geochemically, they are enriched in large-ion lithophile elements (LILEs: e.g., Rb, Th, U, K, Pb) and depleted in high-field-strength elements (HFSEs: e.g., Nb, Ta, P, Zr, Ti). Zircon εHf(t) values range from −2.0 to 0.6, corresponding to Hf crustal model ages (T_DMC) of 1.53−1.36 Ga. The geochemical signatures indicate that the Waizuishan pluton is an I-type granite formed within a subduction-related continental margin igneous arc. It was derived predominantly from the remelting of Mesoproterozoic crustal material with minor contributions from mantle-derived components. Nearly contemporaneous magmatism occurred within all four tectonic units of the Beishan Orogenic Belt. Zircon Hf model ages from Paleozoic igneous rocks (500−350 Ma) exhibit prominent peaks at 1.5−1.4 Ga and 0.8−1.0 Ga, correlating with Mesoproterozoic (～1.4 Ga) and Neoproterozoic (～0.9 Ga) tectonothermal events. This suggests that the various tectonic units of the Beishan Orogenic Belt likely share a common source region. Comparisons with the Yili Block and Central Tianshan Block indicate that these three terranes show stronger affinities with the Baltica and Laurentia cratons, whereas they lack affinity with the Tarim Craton, as represented by the Dunhuang Block.

The Mazongshan arc is an important component of the Beishan orogenic belt, and its widely distributed Early Paleozoic intrusive rocks are of great significance for studying the early Paleozoic tectonic and magmatic evolution in the Beishan area. This study conducted petrological, geochemical, and zircon U-Pb geochronological studies on the Pochengshan granodiorite in the Mazongshan arc. The LA-ICP MS zircon U-Pb age is 451.4 ± 1.9 Ma (MSWD=1.2), indicating an early Late Ordovician period. The rock has high SiO₂ (62.25-69.6%), Al₂O₃ (14.34-14.68%), Na₂O+K₂O (6.07-6.44%), and is a high potassium calcium alkaline, quasi aluminous granite. The distribution curve of rare earth elements shows a gentle right tilt, with light rare earth elements slightly enriched, enriched in large ion lithophilic elements (such as Rb, Ba, Th, K), and depleted in high field strength elements (such as Nb, Ta, Sr, P, Ti). The geochemical characteristics indicate that the Pochengshan granodiorite is a product of partial melting of the newly formed lower crust under the influence of mantle derived magma intrusion in a subduction environment, and the magma source area has been subjected to the alteration of subduction zone fluids and the addition of mantle derived components. It is a response to the northward subduction of the early Late Ordovician in the ancient ocean represented by the Hongliuhe Niujuanzi Xichangjing ophiolite.

The Beishan region of Gansu Province forms a significant metallogenic belt for non-ferrous and precious metals within the Central Asian Orogenic Belt in northwestern China, and has long been a focal area for mineral exploration and research. Recently discovered through systematic geological surveys in this region, the Dongshuangjingzi iron deposit is a medium-sized hematite resource. This paper systematically describes the deposit's geological characteristics, defines its ore types and mineral assemblages, analyzes its genetic mechanism, and evaluates the area's prospecting potential. The aim is to provide a scientific basis and new insights for regional iron ore exploration. The study employed an integrated methodology, including geological mapping, high-precision magnetic surveys, engineering verification, systematic petrographic and ore microscopic observations, phase analysis, and regional stratigraphic and tectonic analysis. This approach was used to constrain the deposit's metallogenic epoch and tectonic setting. Results indicate that the ore bodies are primarily hosted within low-grade metamorphic sedimentary rocks, with their occurrence strictly controlled by the host stratigraphy. The dominant natural ore type is hematite-quartzite, accompanied by minerals such as limonite, siderite, and magnetite. The ore typically exhibits a banded structure, characteristic of sedimentary-metamorphic iron deposits. Based on petrographic, geochemical, and regional geological evidence, the Dongshuangjingzi deposit is interpreted as a Paleoproterozoic sedimentary-metamorphic iron formation, subsequently modified by regional metamorphism. The spatial distribution of ore bodies, combined with stratigraphic, structural, and magnetic anomaly data, suggests that the deep and lateral extensions of the iron-bearing formations hold significant prospecting potential. Synclinal structures hosting the banded iron formation are identified as key geological indicators for exploring similar deposits. Therefore, subsequent exploration should prioritize the core and flanks of these synformal structures. This discovery enhances the understanding of metallogenic types in the Beishan belt and provides a new direction for regional iron ore prospecting.

The Shahongshan pluton is located at the junction of Gansu Province and Inner Mongolia, which is at the intersection of the North China plate, the Tarim plate and the Kazakhstan plate. In addition, the tectonic magmatic activity is widely distributed. In this paper, the LA-ICP-MS zircon U-Pb dating, petrology, major and trace element analysis were carried out on the rocks of Shahongshan pluton, including granite porphyry and syenogranite, in order to unravel the regional intrusion age, rock genesis and the tectonic evolution of the Beishan orogenic belt. LA-ICP-MS Zircon U-Pb dating show that the weighted average age of the granite porphyry and syenogranite was (294.7±4.0) Ma, and (284.2±4.0) Ma, respectively, indicating that they formed in Early Permian. Petrological geochemical analyses show that granites of the Shahongshan pluton belong to calcium-alkaline to high potassium-calcium alkaline rock series, which are characterized by high silicon (74.79%～76.28%), alkali-rich (6.01%～8.30%), and aluminous (A/CNK=1.40～1.89). The total amount of rare earth elements was high, with enrichment in the light rare earth element (LREE; average 251.60×10⁻⁶) and depletion in the heavy rare earth element (HREE; average 45.52×10⁻⁶). The standardization curve of chondrite meteorite was significantly right-tilted, the LREE/HREE ratios of 5.35～5.68 and La_N/Yb_N values of 7.93～9.81, indicating a remarkable fractionation of light and heavy rare earths elements. The samples had obvious negative Eu anomalies. Trace elements are relatively enriched with large ionic lipophilic elements Rb, strong incompatible elements Th, U and high field strength elements Zr and Hf, and significant losses are lost to high field strength elements Ba, Nb, Ti and P. In combination with the regional geological background, The A-type granite, represented by the flesh red granite porphyry, was formed in an extensional environment and has specific petrological, mineralogical and geochemical characteristics. Its magma source is mainly crust-derived material, and may be mixed with a small amount of mantle-derived material. The I-type granites, represented by the flesh red syenogranite, may be related to the crystallization differentiation of mantle-derived magma, the partial melting of metamorphic igneous rocks in the lower crust, or the remelting of crust sediments modified by mantle-derived magma. The formation of the Shahongshan pluton is related to the post-collisional tensile environment and local compressive stress in the Early Permian, and has undergone complex processes of magma ascent, separation and crystallization, assimilation and contamination, and mixing. It is concluded that the tectonic background of Shahongshan pluton is the post-collisional plate rift valley environment.

As a key tectonic unit in the southwestern margin of the Central Asian Orogenic Belt（CAOB）, the West Junggar region is critical for clarifying the provenance system and tectonic setting of the Late Paleozoic Kujiertai Formation. In this study, clastic rocks of the Kujiertai Formation were selected as the research object, and systematic LA-ICP-MS detrital zircon U-Pb dating and trace element analysis were carried out. A high-precision detrital zircon age spectrum and a supporting geochemical database of the formation were established. Combined with the method for reconstructing crustal thickness using zircon Eu anomalies, these data provide important constraints for revealing the provenance characteristics and tectonic evolution background. The results show that the Th/U ratios of detrital zircons from the Kujiertai Formation range from 0.81 to 4.03 (all greater than 0.4), indicating a typical magmatic origin. The zircon U-Pb age spectrum shows that the main ages are concentrated in the range of 510–290 Ma, with five distinct peak intervals: 430–390 Ma, 380–365 Ma, 365–340 Ma, 340–320 Ma and 320–290 Ma. Among them, the youngest zircon age is 298 Ma, which provides key chronological constraints on the sedimentary age of this stratigraphic sequence, suggesting that the sedimentation occurred no earlier than the Early Permian. Geochemical characteristics reveal that the provenance is dominated by acid granite (accounting for approximately 68%) and mafic basalt (accounting for approximately 30%), reflecting prominent magmatic rock features in the provenance area. Integrating with the regional geological background, this study holds that the provenance system of the Kujiertai Formation is mainly controlled by the multi-stage tectono-magmatic activities of the Boshkul-Junggar Magmatic Arc, the Zarma-Sawuer Magmatic Arc and the Darbut Ophiolite Belt. Through systematic analysis of zircon Eu anomaly characteristics and combined with the timing of regional magmatic activities, the Paleozoic crustal thickness variation sequence of the study area was reconstructed. This result provides independent geochemical evidence for clarifying the complex tectonic evolution process of "accretion-transformation-disturbance adjustment" experienced by the West Junggar region during the Paleozoic Era.