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The Tieshanlong ore field is an important part of the Nanling Range, which is famous worldwide for its W‐Sn mineralization. Notably, the mineralization age of the Tieshanlong ore field is not well constrained, and our field investigation reveals that granitic emplacement occurred at different stages. However, previous studies have not distinguished these multiple stages of magmatism. The Tieshanlong granite complex is closely related to the Huangsha quartz vein‐type W‐Sn deposit and Tongling skarn‐type Cu‐W‐Sn deposit in this field. Through field investigations and isotopic age analyses, this work studies the relationship between multistage magmatic activity and mineralization in the Tieshanlong ore field. LA‐ICP‐MS zircon U‐Pb isotope analyses revealed that the first‐ and second‐staged granites formed at 154.2 ± 0.6 Ma (MSDW = 1.4) and 151.2 ± 0.4 Ma (MSDW = 1.5), with zircon εHf(t) values ranging from ‐13.1 to ‐10.5 and from ‐14.7 to ‐11.1, respectively. These data suggest that the Tieshanlong granite complex was derived from the partial melting of ancient crustal material. LA‐ICP‐MS U‐Pb dating of wolframite and cassiterite reveals that W‐Sn mineralization occurred at 160–150 Ma, which agrees well with the U‐Pb dating results of the second‐staged granite within analytical errors. The magmatic activity in this ore field can be divided into three stages: 175–154 Ma, 154–150 Ma and 150–145 Ma. The quartz vein‐ and skarn‐type W‐Sn mineralization is closely related to second‐staged fine‐grained two‐mica granite, and formed earlier than skarn‐type Cu‐ mineralization. This study establishes a metallogenic model for the Tieshanlong ore field, and this model has important practical significance for identifying concealed W‐Sn(‐Cu) deposits around other granitic complexes in the Nanling Range. [ABSTRACT FROM AUTHOR]

Multistage tungsten mineralization was recently discovered in the Mamupu copper‐polymetallic deposit in the southern Yulong porphyry copper belt (YPCB), Tibet. This study reports the results of cathodoluminescence, trace element and Sr isotope analyses of Mamupu scheelite samples, undertaken in order to better constrain the mechanism of W mineralization and the sources of the ore‐forming fluids. Three different types of scheelite are identified in the Mamupu deposit: scheelite A (Sch A) mainly occurs in breccias during the prograde stage, scheelite B (Sch B) forms in the chlorite‐epidote alteration zone in the retrograde stage, while scheelite C (Sch C) occurs in distal quartz sulfide veins. The extremely high Mo content and negative Eu anomaly in Sch A represent high oxygen fugacity in the prograde stage. Compared with ore‐related porphyries, Sch A has a similar REE pattern, but with higher ΣREE, more depleted HREE and slightly lower (87Sr/86Sr)i ratios. These features suggest that Sch A is genetically related to ore‐related porphyries, but extensive interaction with carbonate surrounding rocks affects the final REE and Sr isotopic composition. Sch B shows dark (Sch B‐I) and light (Sch B‐II) domains under CL imaging. From Sch B‐I to Sch B‐II, LREEs are gradually depleted, with MREEs being gradually enriched. Sch C has the highest LREE/HREE ratio, which indicates that it inherited the geochemical characteristics of fluids after the precipitation of HREE‐rich minerals, such as diopside and garnet, in the early prograde stage. The Mo content in Sch B and Sch C gradually decreased, indicating that the oxygen fugacity of the fluids changed from oxidative in the early stages to reductive in the later, the turbulent Eu anomaly in Sch B and Sch C indicating that the Eu anomaly in the Mamupu scheelite is not solely controlled by oxygen fugacity. The extensive interaction of magmatic‐hydrothermal fluids and carbonate provides the necessary Ca2+ for the precipitation of scheelite in the Mamupu deposit. [ABSTRACT FROM AUTHOR]

Chlorite is present extensively in many types of deposits. The mechanism underlying the chemical variations in chlorite remains unclear. The Naruo porphyry deposit is a giant copper porphyry deposit in the Duolong ore district of Tibet. Chlorite, which is abundant in this deposit, has yet to be studied systematically; hence, we used principal component analysis (PCA) to assess the correlation between chlorite elements and various types of mineral deposits. We then conducted a preliminary investigation into its mineralogy and geochemistry to better understand its formation process and identify potential prospecting indicators. The PCA method proved effective in discerning two distinctive element signatures within the chlorite and categorising them into four deposit types: orogenic Au deposits, granite-type U deposits, and skarn-type Sn deposits that exhibit high FeOand low MgO distinguishing them from porphyry copper deposits. The chlorite in the Naruo deposit is classified as either early metasomatic (M-type), consisting mainly of clinochlore, or late hydrothermal (H-type), primarily consisting of clinochlore and chamosite. This classification suggests that H-type chlorite formed in a reductive environment conducive to Cu precipitation at medium temperatures (255°C-342°C). Al-Si and Fe-Mg substitutions were found to be the primary processes involved in its generation. Additionally, from the mineralisation centre outwards, there was an observed decrease in Si content as well as the Fe/(Fe+Mg) ratio in H-type chlorite, along with decreases in temperature, sulphur, and oxygen fugacity of allchlorites; conversely, increases were observed for Al content along with Mg and Mn elements in H-type chlorite. Chlorite is useful for exploring porphyry copper systems as an indicator mineral. [ABSTRACT FROM AUTHOR]

The Jiama deposit, a significant porphyry‐skarn‐type copper polymetallic deposit located within the Gangdese metallogenic belt in Tibet, China, exemplifies a typical porphyry metallogenic system. However, the mineral chemistry of its accessory minerals remains under‐examined, posing challenges for resource assessment and ore prospecting. Utilizing electron microprobe analysis and LA‐ICP‐MS analysis, this study investigated the geochemical characteristics of apatite in ore‐bearing granite and monzogranite porphyries, as well as granodiorite, quartz diorite, and dark diorite porphyries in the deposit. It also delved into the diagenetic and metallogenic information from these geochemical signatures. Key findings include: (1) The SiO2 content, rare earth element (REE) contents, and REE partition coefficients of apatite indicate that the dark diorite porphyry possibly does not share a cogenetic magma source with the other four types of porphyries; (2) the volatile F and Cl contents in apatite, along with their ratio, indicate the Jiama deposit, formed in a collisional setting, demonstrates lower Cl/F ratios in apatite than the same type of deposits formed in a subduction environment; (3) compared to non‐ore‐bearing rock bodies in other deposits formed in a collisional setting, apatite in the Jiama deposit exhibits lower Ce and Ga contents. This might indicate that rock bodies in the Jiama deposit have higher oxygen fugacity. Nevertheless, the marginal variation in oxygen fugacity between ore‐bearing and non‐ore‐bearing rock bodies within the deposit suggests oxygen fugacity may not serve as the decisive factor in the ore‐hosting potential of rock bodies in the Jiama deposit. [ABSTRACT FROM AUTHOR]

Rubidium (Rb) deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites. This study investigates a newly‐discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet. Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization. LA‐ICP‐MS U‐Pb dating of zircon yielded ages of 19.1 ± 0.2 Ma and 19.0 ± 0.2 Ma for greisenized monzogranite and fresh monzogranite, respectively. The monzogranites are characterized as strongly peraluminous, with high contents of SiO2, Al2O3, K2O and Na2O as well as a high differentiation index. They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high field‐strength elements. Petrological and geochemical features of these ore‐related monzogranites suggest that they are highly fractionated S‐type granites, derived from remelting of crustal materials in a post‐collisional setting. The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore‐related monzogranite during the magma's evolution. The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization. [ABSTRACT FROM AUTHOR]

The Xiongcun Cu–Au ore district is in the southern middle Gangdese Metallogenic Belt, Tibet, and formed during Neo-Tethyan oceanic subduction. The Xiongcun ore district mainly comprises two deposits, the No. I and No. II deposits, which were formed by two individual mineralization events according to deposit geology and Re–Os isotopic dating of molybdenite. The No. I deposit is similar to a reduced porphyry copper–gold deposit, given the widespread occurrence of primary and/or hydrothermal pyrrhotite and common CH4-rich and rare N2-rich fluid inclusions. The No. II deposit, similar to classic oxidized porphyry copper–gold deposits, contains highly oxidized minerals, including magnetite, anhydrite, and hematite. The halogen chemistry of the ore-forming fluid from the No. I and No. II deposits is still unclear. Biotite geochemistry with halogen contents was used to investigate the differences in ore-forming fluid between the No. I and No. II deposits. Hydrothermal biotite from the No. I deposit, usually intergrown with sphalerite, is Mg-rich and classified as phlogopite and Mg-biotite, and hydrothermal biotite from the No. II deposit is classified as Mg-biotite. Hydrothermal biotite from the No. I deposit has significantly higher SiO2, MnO, MgO, F, Li, Sc, Zn, Rb, Tl, and Pb contents and lower Al2O3, FeOtot, Cl, Ba, Cr, V, Co, Ni, Y, Sr, Zr, Th, and Cu contents than the biotite from the No. II deposit. Hydrothermal biotites from the No. I and No. II deposits yield temperatures ranging from 230 °C to 593 °C and 212 °C to 306 °C, respectively. The calculated oxygen fugacity and fugacity ratios indicate that the hydrothermal fluid of the No. I deposit has a higher F content, oxygen fugacity, and log(fHF/fHCl) value and a lower log(fH2O/fHF) value than the hydrothermal fluid from the No. II deposit. The biotite geochemistry shows that the No. I and No. II deposits formed from different hydrothermal fluids. The hydrothermal fluid of the No. I deposit was mixed with meteoric waters containing organic matter, resulting in a decrease in oxygen fugacity and more efficient precipitation of gold. The No. I and No. II deposits were formed by a Cl-rich hydrothermal system conducive to transporting Cu and Au. The decreasing Cl, oxygen fugacity, and temperature may be the key factors in Cu and Au precipitation. Biotite geochemistry allows a more detailed evaluation of the halogen chemistry of hydrothermal fluids and their evolution within porphyry Cu systems. [ABSTRACT FROM AUTHOR]

The Sinongduo mining region includes two types of mineralizations: the epithermal and the carbonate‐hosted Pb‐Zn‐Ag deposits. Despite being studied for many years, the ore formation process and genesis of the carbonate‐hosted Pb‐Zn‐Ag deposits remain poorly understood. The Pb‐Zn‐Ag ore bodies occur as veins and are hosted by limestone and dolostone of the Permian Xiala Formation. Three sulfide mineralization substages have been identified at the Sinongduo carbonate‐hosted deposit. Indium coupled with Cu, Co and Sn was incorporated into sphalerite as substitutions: 2Zn2+ ↔ Cu+ + In3+, (3n/2 + 1)Zn2+ ↔ Co2+ + nIn3+ or (2n + 1)Zn2+ ↔ Co2+ + n(Cu+ + In3+) (n > 1) and 4Zn2+ ↔ Sn2+ + 2In3+. Sphalerite and pyrite in the mineralization stage display δ34S values in a narrow range of +5.7‰ to +11.3‰, which are similar to those of Palaeocene igneous rocks, indicative of a magmatic source of sulfur. We present systematic carbon‐hydrogen‐oxygen isotope results that further support a magmatic source for the ore‐forming fluids that were influenced by meteoric water. Furthermore, the Pb isotope compositions of sulfide minerals in the Sinongduo carbonate‐hosted deposit overlap with the values of coeval Linzizong volcanic rocks and are similar to those of Indian Ocean sediments, indicating upper crustal sources of metals. We conclude that the Sinongduo carbonate‐hosted Pb‐Zn‐Ag deposit is a medium‐ to low‐temperature magmatic‐hydrothermal deposit related to Linzizong magmatism. [ABSTRACT FROM AUTHOR]

Jiama is a giant, high‐grade porphyry copper system in the Gangdese metallogenic belt, Tibet. Multistage intermediate–felsic porphyries intruded in this deposit, some of which are strongly associated with copper‐polymetallic mineralization. These ore‐bearing porphyries include monzogranite, granodiorite, and quartz diorite porphyries. A new granite aplite dyke was found in the south of Jiama. Its age, genesis, and relationship with ore‐related magmatism are obscure. Here, its emplacement age and petrogenesis were determined using mineralogy, zircon U‐Pb dating, geochemistry, and Sr‐Nd‐Pb isotope studies. The zircon LA‐ICP‐MS U‐Pb age of the aplite dyke is 16.66 ± 0.21 Ma (n = 14, MSWD = 0.66), earlier than that of the ore‐bearing porphyries (∼15 Ma) in Jiama. Furthermore, the aplite exhibits high amounts of silicon (SiO2 = 73.39%–74.74%), potassium (K2O = 5.12%–6.61%), aluminum (Al2O3 = 14.25%–14.69%), and light/heavy rare earth elements (LREE/HREE = 12.12–16.19) as well as negative europium (δEu = 0.47–0.72) and weak negative cerium anomalies (δCe = 0.84–0.93). The aplite dyke is characteristic of metaluminous–peraluminous I‐type granite, which is rich in large‐ion lithophile elements (Rb, Ba, Th and U) and depleted in high‐field‐strength elements (Nb, P and Ti). The aplite dyke and ore‐bearing porphyries in the Jiama deposit are the results of a partial melting of the juvenile lower crust, according to whole‐rock geochemistry and Sr‐Nd‐Pb isotope data, but the dyke and ore‐bearing porphyries were emplaced from the same magma chamber at different times. Thus, the aplite dyke shows the composition of the early evolution stage of shallow magma in the Jiama deposit and is the product of rapid condensation and crystallization. [ABSTRACT FROM AUTHOR]

We evaluate the controlling factors of hydrothermal wolframite and scheelite precipitation in the quartz vein-type Jiaoxi tungsten deposit situated in the western part of the Lhasa terrane (Tibet, China) using texture, major and trace element mineral geochemistry, and sulfur stable isotope geochemistry. Pyrite and chalcopyrite that are intergrown with Fe-enriched wolframite and siderite, have distinct in situ S isotope compositions (δ34SV-CDT) of −31.38 to +1.77‰, and +2.07 to +2.30‰, respectively. Major and trace element contents and in situ S isotope compositions of pyrite and chalcopyrite indicate that the hydrothermal evolution involved fluid-fluid mixing and greisenization. We report evidence for an early magmatic fluid, which is characterized by the enrichment of W, Mn, Zr, Ti, Sc, and Sn and depletion of Fe. This magmatic fluid was diluted by meteoric water and interacted with biotite monzogranite porphyry to leach Fe, Mg, and Zn into the system to form wolframites with variable Fe/(Fe+Mn) ratios ranging between 0.06–0.84. The late Fe-enriched magmatic fluid released from the muscovite granite mixed with meteoric water that leached minor Fe and S from shale to form late shale-hosted wolframite with a Fe/(Fe+Mn) mass ratio of >0.75 and coeval siderite and sulfides. This study highlights that multiple Fe sources were present in the system, including muscovite granite-released Fe through fluid exsolution, biotite monzogranite porphyry-released Fe during greisenization, and minor Fe released from the shale as a result of meteoric water leaching. [ABSTRACT FROM AUTHOR]

The subduction of the Bangong–Nujiang Ocean is important in the geological evolution of the Tibetan Plateau. In this paper, we report new zircon U-Pb age and Lu-Hf isotopic data and whole-rock elemental and Sr-Nd-Pb isotopic data for Early Cretaceous dacites from the Rena-Co area (RCA) in the southern Qiangtang Terrane (QT), central Tibet and use these data to better understand the tectonic evolution of the Bangong–Nujiang suture. LA–ICP-MS dating of zircons yields ages of 109.5 ± 0.6 Ma to 109.6 ± 0.8 Ma for the dacites from the RCA. Geochemically, these dacites are medium-K calc-alkaline and show high SiO2 contents of 64.79–70.37 wt.%, high Sr contents of 517–598 ppm and low Y contents of 8.45–10.7 ppm, similar to those of typical adakites. Additionally, all the rocks are strongly enriched in light rare earth elements and some large ion lithophile elements (e.g. Rb, U, K and Cs) but significantly depleted in high-field-strength elements (e.g. Nb, Ta and Ti), consistent with the geochemical characteristics of arc-type magmas formed in the subduction zone. Moreover, these adakite-like dacites show whole-rock initial (87Sr/86Sr)i ratios of 0.705119 to 0.705491, (206Pb/204Pb)i ratios of 18.489 to 18.508, (207Pb/204Pb)i ratios of 15.591 to 15.612, (208Pb/204Pb)i ratios of 38.599 to 38.686, ϵ Nd (t) values of −0.28 to +1.25 and single-stage Nd model ages of 642 to 818 Ma, as well as significantly positive zircon ϵ Hf(t) values of 3.9–13.1, with young Hf-depleted mantle ages of 331 to 923 Ma. These geochemical and isotopic data indicate that they are most likely derived from the juvenile thickened mafic lower continental crust, which contains partial melts of metasomatized peridotite and subduction-related fluids in the magma source region. Based on previous studies and our new data, we propose that the RCA adakite-like dacites are most likely a result of the northwards subduction of the Bangong–Nujiang Ocean lithosphere beneath the southern QT during the Early Cretaceous and that a slab rollback model could explain the formation of the RCA adakite-like dacites. [ABSTRACT FROM AUTHOR]

The Bangbule skarn lead‐zinc (Pb‐Zn) deposit (>1 Mt Zn + Pb) is located in the western Nyainqentanglha polymetallic metallogenetic belt, central Tibet. Lenticular orebodies are all hosted in skarn and developed in the contact zone between the quartz porphyry and carbonate strata of the mid Paleozoic Middle to Upper Chaguoluoma Formation as well as in carbonate and sandstone beds of the Upper Paleozoic Laga Formation. As a newly discovered skarn deposit, the geological background and metallogenesis of this deposit remain poorly understood. Detailed petrological, geochemical and geochronological data of the ore‐related quartz porphyry, helps constrain the mineralization age and contributes to discussion on the ore genesis of the Bangbule deposit. Both endoskarn and exoskarn are identified in the Bangbule deposit. From quartz porphyry to carbonate formation, the exoskarn is zoned from proximal garnet skarn to distal pyroxene skarn. Zircon U‐Pb dating results show that the quartz porphyry formed at 73.9 ± 0.8 Ma. Geochemical analysis results show that the quartz porphyry has high contents of SiO2 (71.40–74.94 wt%) and K2O + Na2O (3.76–8.46 wt%) with A/CNK values of 0.69 to 1.06. Besides, the quartz porphyry is enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and have low εNd(t) (from –8.25 to –8.19) and high initial (87Sr/86Sr)i values (0.713611–0.714478). Major, trace elements and whole‐rock F concentration analysis results from the endoskarn samples show higher TFe2O3, MgO, CaO, Pb + Zn, W, Sn, Mo and F etc., and lower alkalis (K2O, Na2O, Sr and Ba) than those of fresh quartz porphyry, indicating that the early ore‐forming fluids were an Ca‐Fe‐F‐enriched fluid. Massive ore in the proximal skarn might be related to the high F content in the magma, which lowered the solidus temperature of the quartz porphyry magma and caused a lower temperature of the ore‐forming fluids, as well as facilitating the precipitation of sphalerite and galena. Based on the geochemical characteristics presented in this study, we propose that the ore‐related quartz porphyry was formed by partial melting of crust materials with some juvenile crustal component input. The partial melting of the middle‐upper crust after the initial enrichment of lead and zinc elements are important for the formation of Pb‐Zn deposits. The case study of the Bangbule deposit has proven that there is still a crust‐derived magmatic source region in the western segment of the central Lhasa terrane. Therefore, there is still great potential for Pb‐Zn mineralization and Pb‐Zn exploration. [ABSTRACT FROM AUTHOR]

The Qushenla Formation volcanic rocks are widely exposed in the northern margin of the Bangong-Nujiang suture zone (BNSZ). Research on these rocks is of great significance for understanding the tectonic evolution of the Bangong-Nujiang Tethys Ocean (BNTO). In this study, a systematic geological survey was conducted on the Qushenla Formation volcanic rocks that are widely exposed in the Nawucuo area, in the northern margin of the western segment along the BNSZ. The whole-rock geochemistry, zircon U-Pb dating, and in situ zircon Lu-Hf isotopes were carried out in this study, aiming to constrain the formation age, rock genesis, magma source and tectonic setting of the volcanic rocks. The zircon U-Pb dating shows that the Qushenla Formation volcanic rocks in the western BNSZ erupted during the period of 120–108 Ma, i.e., Early Cretaceous. The Qushenla Formation volcanic rocks are a suite of intermediate-basic volcanic and pyroclastic rocks belonging to the medium-K calc-alkaline series. They are relatively enriched in light rare earth elements (LREEs) and incompatible elements such as Rb, K, La, Th, Sm, and Hf, whereas depleted in heavy REEs (HREEs) and high field strength elements (HFSEs) such as Nb, P, Zr, and Ti. The in situ zircon εHf(t) values of the volcanic rocks range from 8.95 to 12.57, with an average of 10.40. The Mg#, Th/La and Th/Ce values are between those of the mantle-derived magma and the continental crust. The formation of the Qushenla Formation volcanic rocks can be explained through the following process: (1) As the nospheric materials that upwelled during the rollback of the subducting Tethys Ocean slab induced the large-scale partial melting of the mantle wedge and the formation of the initial basaltic magma. (2) These mantle-derived magmas ascended and induced the partial melting of the lower crust to generate peraluminous melts. (3) The mixing of the peraluminous melts and mantle-derived melts generated the initial magma with homogeneous Sr-Nd isotope compositions. (4) Last, the eruption of the magma produced the widespread Qushenla Formation volcanic rocks at the surface. When combining this information with the regional geological background, it is believed that the Qushenla Formation volcanic rocks, the Meiriqicuo Formation volcanic rocks and the Late Jurassic–Early Cretaceous intrusive rocks together constitute the tectonic magmatic arc of the active continental margin on the southern margin of Qiangtang, which was formed in the tectonic setting of the northward subduction of the Bangong-Nujiang oceanic crust beneath the Qiangtang Block. [ABSTRACT FROM AUTHOR]

Abstract: The Jiama deposit is a large copper deposit in Tibet. Mineralization occurs in three different host rocks: skarn, hornfels and porphyry. A detailed fluid inclusion study was conducted for veins in the different host rocks to investigate the relationship between fluid evolution and ore‐forming processes. Based on examination of cores from 36 drill holes, three types of veins (A, B and D) were identified in the porphyries, four types (I, II, III and IV) in the skarn, and three (a, b and c) in the hornfels. The crosscutting relationships of the veins and that of the host rocks suggest two hydrothermal stages, one early and one late stage. Fluid inclusions indicate that the Jiama hydrothermal fluid system underwent at least two episodes of fluid boiling. The first boiling event occurred during the early hydrothermal stage, as recorded by fluid inclusions hosted in type A veins in the porphyries, type a veins in the hornfels, and wollastonite in the skarns. This fluid boiling event was associated with relatively weak mineralization. The second boiling event occurred in the late hydrothermal stage, as determined from fluid inclusions hosted in type B and D veins in the porphyries, type I to IV veins in the skarns, and type b and c veins in the hornfels. This late boiling event, together with mixing with meteoric water, was responsible for more than 90% of the metal accumulation in the deposit. The first boiling only occurred in the central part of the deposit and the second boiling event took place across an entire interlayered structural zone between hornfels and marble. A spatial zoning of ore‐elements is evident, and appears to be related to different migration pathways and precipitation temperatures of Cu, Mo, Pb, Zn, Au and Ag. [ABSTRACT FROM AUTHOR]

The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane. Its petrogenesis and tectonic setting have been studied for decades, but remain controversial. Here we report data on geochronology, geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith, which provide more evidence to uncover its petrogenesis and regional geodynamic processes. The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I‐type, S‐type and highly fractionated granites. The I‐ and S‐type granites exhibit medium SiO2, high K2O/Na2O with negative εNd(t) and εHf(t) values, whereas, the albite granites have very high SiO2 (79.04%–80.40%), very low K2O/N2O, negative εNd(t) and a large variation in εHf(t). Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area. The granodiorites involved had a hybrid origin from partial melting of basalt‐derived and Al‐rich rocks in the crust, the porphyritic monzogranites being derived from partial melting of pelitic rocks. The albite granites crystallized from residual melt separated from K‐rich magma within the 'mush' process and underwent fractionation of K‐feldspar. We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward‐subducting slab of the NTO. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau is a product of the continental collision between the Indian and Asian plates along the Indus-Yarlung suture zone that started in the early Cenozoic. This collision initially produced stress at the collisional boundary and later propagated with time on both the Indian plate and Asian plate. Many studies have reported tectonic deformation in the Himalayas representing the immediate response of continental collision on the Indian side near the collisional boundary. However, there have been only few studies on the early Cenozoic shortening structures in the Lhasa block that forms the southernmost part of the Asian plate. In this study, we performed Ar/Ar geochronology of syntectonic muscovite from the Sinongduo thrust system in the central Lhasa block. The results show that the Sinongduo thrust system was active in the Early Eocene. We interpret the Sinongduo thrust system as an immediate response to the India-Asia collision in the Lhasa block. This study reconciles the early Cenozoic India-Asia collision with the lack of tectonic response in the Lhasa block. [ABSTRACT FROM AUTHOR]

The Mamupu skarn‐type Cu‐Au polymetallic deposit represents the first discovery of a medium deposit in the southern Yulong porphyry copper belt (YPCB), eastern Tibet. The Cu‐Au mineralization mainly occurs as chalcopyrite in breccia, within the plate‐like carbonate interlayer, being closely related to chloritization (e.g., chlorite, magnetite and epidote) and skarnization (e.g., diopside, tremolite and garnet). The ore‐related quartz syenite porphyry (QSP) and granodiorite porphyry (GP) were emplaced at 40.1 ± 0.2 Ma and 39.9 ± 0.3 Ma, respectively. The QSP of Mamupu is an alkaline‐rich intrusion, relatively enriched in LREE, LILE, depleted in HFSE, with no significant negative Eu and Ce anomalies, slightly high (87Sr/86Sr)i, low ∊Nd(t), uniform (206Pb/204Pb)i and ∊Hf(t) values, which indicates that the porphyry magma may be caused by both the mixing of metasomatized EM II enriched mantle and thickened juvenile lower crust. The QSP in the Mamupu deposit shares a similar genesis of petrology to other ore‐related porphyries within the YPCB. High oxygen fugacity and water content of the magmas are essential for the formation of porphyry and skarn Cu deposits. The QSP has similar high magmatic oxidation states and water content to the Yulong deposit, which indicates that the Mamupu has a high prospecting potential. Differences in the geological characteristics and scale of mineralization between the Mamupu and other YPCB deposits may be due to the different emplacement depths of ore‐related intrusions, as well as differences in the surrounding rocks. [ABSTRACT FROM AUTHOR]

The Bangong–Nujiang suture zone (BNSZ), which separates the Gondwana-derived Qiangtang and Lhasa terranes, preserves limited geological records of the Bangong–Nujiang Ocean (BNO). The timing of opening of this ocean has been hotly debated due to the rare and complicated rock records in the suture zones, which span over 100 Ma from Carboniferous–Permian to Early Jurassic time, based on geological, palaeontological and palaeomagnetic data. A combination of geochemical, geochronological and isotopic data are reported for the Riasairi trachytes, central BNSZ, northern Tibet, to constrain its petrogenesis and tectonic settings. Zircon U–Pb dating by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) yields mean ages of 236 Ma. Geochemically, these rocks are high-K calc-alkaline with moderate SiO2 (59.1–67.5 wt%) and high K2O + Na2O (8.1–11.6 wt%) contents. They are enriched in light rare earth elements with negative Eu anomalies, and show enrichments in high-field-strength elements with positive 'Nb, Ta' anomalies, similar to the intra-continental rift setting-related felsic lavas from the African Rift System. The high positive zircon ϵHf(t) and bulk ϵNd(t) values, as well as high initial Pb isotopes, imply a heterogeneous source involving both asthenospheric and subcontinental lithospheric mantle. The field and geochemical data jointly suggest that the Riasairi trachytes within the Mugagangri Group were formed in a continental rift setting. We interpret that the continental-rift-related Riaisairi trachytic lavas as derived from the southern margin of the Qiangtang terrane, implying that the BNO would have opened by Middle Triassic time, well after the commonly interpreted break-up of the Qiangtang terrane from Gondwana. [ABSTRACT FROM AUTHOR]

In order to understand how the metallogenic process of porphyry deposit specifically and directly respond to regional uplifting and exhumation, we compiled previous fluid inclusion data of 32 porphyry deposits in China by recalculating the fluid trapping depths and trapping depth reduction magnitude from early to late mineralization stage veins. The data reveal that the average trapping pressure ratio (Ave TPE/TPL) between early‐ and late‐stage veins of the these deposits are 1.2–18.4, mainly in the range of 1.35–5.83, with average trapping pressure reduction (1–Ave TPL/TPE) from early‐ to late‐ stage veins are 17%–95%, and mainly in the range of 25%–83%. The fluid trapping pressure based mineralization depths most of the porphyry deposits in China had decreased from early to late vein stages by at least 450 m (900–5800 m predominant), or greater than 950 m when take the average depth reduction value, which is greater than the current gap between early‐ and late‐ stage veins of each deposit. We propose that the apparently greater mineralization depth reduction magnitude than the current elevation gaps between early and late veins are likely a consequence of syn‐mineralization uplifting and exhumation process that often occurs in porphyry systems. [ABSTRACT FROM AUTHOR]

Continental crust has long been considered too buoyant to be subducted beneath another continent, although geophysical evidence in collision zones predict continental crust subduction. This is particularly significant where upper continental crust is detached allowing the lower continental crust to subduct, albeit the mechanism of such subduction and recycling of the upper continental crust remain poorly understood. Here, we investigate Paleocene S-type magmatic and volcanic rocks from the Linzizong volcanic succession in the southern Lhasa block of Tibet. These rocks exhibit highly enriched 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb together with depleted 143Nd/144Nd isotope ratios. The geochemical and isotopic features of these rocks are consistent with those of modern upper continental crust. We conclude that these Paleocene S-type volcanic and magmatic rocks originated from the melting of the upper continental crust from microcontinent subduction during the late stage of India–Asia convergence. [ABSTRACT FROM AUTHOR]

The Tiegelongnan deposit is a newly discovered super-large porphyry-epithermal Cu-(Au) deposit in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet (China). Field geology and geochronology indicate that the porphyry mineralization was closely related to the Early Cretaceous intermediate-felsic intrusions (ca. 123-120 Ma). Various epithermal ore and gangue mineral types were discovered in the middle-shallow part of the orebody, indicating the presence of epithermal mineralization at Tiegelongnan. Potassic, propylitic, phyllic and advanced argillic alteration zones were identified. 40Ar/39Ar dating of hydrothermal biotite (potassic zone), sericite (phyllic zone), and alunite (advanced argillic zone) in/around the ore-bearing granodiorite porphyry yielded 121.1±0.6 Ma (1σ), 120.8±0.7 Ma (1σ) and 117.9±1.6 Ma (1σ), respectively. Five hydrothermal mineralization stages were identified, of which the Stage IV pyrite was Rb-Sr dated to be 117.5±1.8 Ma (2σ), representing the end of epithermal mineralization. Field geology and geochronology suggest that both the epithermal and porphyry mineralization belong to the same magmatic-hydrothermal system. The Tiegelongnan super-large Cu-(Au) deposit may have undergone a prolonged magmatic-hydrothermal evolution, with the major mineralization event occurring at ca.120-117Ma. [ABSTRACT FROM AUTHOR]

This paper presents new apatite fission track (AFT) and apatite (U-Th)/He (AHe) data from the Duolong ore district. The corresponding AFT and AHe ages provide insights into the uplift and exhumation history of the Duolong ore district, revealing rapid exhumation with an erosional exhumation rate of 0.067 km/Ma between 65 and 35 Ma, and slow exhumation with an erosional exhumation rate of 0.023 km/Ma since 35 Ma. The new data in this study, along with previous low-temperature thermochronology data, show that samples with ages from 130 to 83 Ma are distributed close to Shuanghu in the central Qiangtang, samples with ages from 65 to 45 Ma are distributed evenly across the whole Qiangtang terrane, and several samples with ages from 20 to 7 Ma are distributed at the edge of the Qiangtang terrane. The Qiangtang terrane experienced heterogeneous surface uplift. The central Qiangtang was initially uplifted during the Early Cretaceous, and the weathered paleosoil dated between 120 and 110 Ma in the Duolong ore district is consistent with the exhumation during this period. Large-scale uplift and exhumation of the Qiangtang terrane between the Palaeocene and Eocene is consistent with the rapid exhumation of the Duolong ore district between 65 and 35 Ma; finally, the uplift and exhumation at the edge of the Qiangtang terrane since the Eocene caused the Duolong ore district to be uplifted to its present elevation. [ABSTRACT FROM AUTHOR]

The Xin'gaguo deposit is representative of the skarn Pb–Zn polymetallic zone in the northern Gangdese porphyry metallogenic belt, Tibet. Pb–Zn mineralization is hosted in the Take'na formation skarn. The Xin'gaguo ore‐forming process can be divided into prograde skarn, retrograde skarn and quartz‐sulfides. Skarn minerals include garnet, diopside, and epidote, with minor wollastonite, actinolite, and chlorite. Metallic minerals are mainly sphalerite, galena, chalcopyrite, magnetite, and pyrrhotite, with minor arsenopyrite, marcasite, native bismuth, cosalite, and gersdorffite. The LA–ICP–MS zircon U–Pb age of the diorite is 59.66±0.52 Ma. Diorite samples are characterized by fractioned REE patterns with marked positive Eu anomalies, enriched LILEs (Rb, Ba, Th, U, and K) and depleted HFSEs (Ta, Nb, Zr, Hf, and Ti), belong to the calc‐alkaline series and have metaluminous compositions. Zircon εHf(t) values of the diorite are positive (5.7–11) and lie between the chondrite and mantle values. These geochemical characteristics suggest that the diorite was formed by the partial melting of a young metasomatized asthenospheric mantle wedge deriving basaltic rocks. The δ34S values of sulfides range from −4.7 to 4.5‰ and show a bimodal distribution, indicating interactions of magma‐derived ore fluid with biogenic sulfide minerals from the Take'na formation. The 206Pb/204Pb (18.5–18.629), 207Pb/204Pb (15.599–15.704), and 208Pb/204Pb (38.616–38.975) of sulfides show that ore‐forming metals were derived from mixed sources, in part from the Lhasa Terrane basement. Skarn mineral compositions imply that the ore‐forming environment was variable, and underwent at least three changes in oxidation‐reduction state. The geochemical characteristics of diorite indicate that the Xin'gaguo deposit formed within the Indo‐Asian continental collision tectonic setting. [ABSTRACT FROM AUTHOR]

The Bangong–Nujiang collision zone (BNCZ) is an ideal area for studying postcollisional magmatism. A series of late Early Cretaceous Cu‐bearing magmas are found in this collision zone, which has implications for studying the sources of postcollisional magmas. We completed detailed fieldwork and reported zircon U–Pb and Hf‐isotopic and whole‐rock geochemical data on the Daguo volcanics, Shesuo monzogranite‐granodiorites, and Xiongmei granodiorite porphyries, which represented different types of the Cu‐bearing rocks in the BNCZ. The Shesuo samples are characterized by high contents of SiO2, K2O, and total alkali, with high contents of heavy rare earth elements (HREEs) and Y, and are enriched in large‐ion lithophile elements (LILEs), depleted in Nb and Ta, with a marked negative Eu anomaly (0.29–0.92). The Xiongmei granodiorite porphyries are characterized by moderate SiO2 and MgO, high Al2O3 contents, depletion in Nb, Ta, Ba, Sr, and Ti, enrichment in LILEs, high HREEs and Y contents, and relatively low Sr/Y ratios. Both Shesuo monzogranites and Xiongmei granodiorites belong to calc‐alkaline I‐type magmas, which are associated with a wide range of zircon εHf(t) values (−15.3 to +5.8; −15.4 to +3.2). These geochemical features suggest that the Xiongmei granodiorite porphyries and Shesuo monzogranite‐granodiorites are derived from the melting of a juvenile mafic crust with ancient crustal contamination, and the juvenile mafic crusts are derived from a lithospheric mantle enriched by slab melt (including recycled subducting sediments). The Daguo basalt is derived from the partial melting of a mantle wedge metasomatized by subduction‐related fluids and/or melts and the involvement of asthenospheric mantle. The Daguo intermediate‐felsic rocks are derived from the partial melting of a juvenile crust from a metasomorphic mantle wedge. Our study implies that the genesis of these Cu‐bearing magmas is associated with slab break‐off at the end of the southward subduction of the Bangong–Nujiang Ocean lithosphere. In addition, the postcollisional magmas are multisourced, with a juvenile component from either the metasomorphic lithosphere mantle or the juvenile crust, an ancient crustal component and a subducted‐related component from the recycled subducting sediments, the subducted slab, and/or the asthenosphere. [ABSTRACT FROM AUTHOR]

The Tiegelongnan is the first discovered porphyry–epithermal Cu (Au) deposit of the Duolong ore district in Tibet, China. In order to constrain the thermal history of this economically valuable deposit and the rocks that host it, eight samples were collected to perform a low‐temperature thermochronology analysis including apatite fission track, apatite, and zircon (U‐Th)/He. Apatite fission track ages of all samples are between 34 ± 3 and 67 ± 5 Ma. Mean apatite (U‐Th)/He ages show wide distribution, ranging from 29.3 ± 2.5 to 56.4 ± 9.1 Ma. Mean zircon (U‐Th)/He ages range from 79.5 ± 12.0 to 97.9 ± 4.4 Ma. The exhumation rate of the Tiegelongnan deposit was 0.086 km m.y.−1 between 98 and 47 Ma and decreased to 0.039 km m.y.−1 since 47 Ma. The mineralized intrusion was emplaced at a depth of about 1400 m in the Tiegelongnan deposit. Six cooling stages were determined through HeFTy software according to low‐temperature thermochronology and geochronology data: (i) fast cooling stage between 120 and 117 Ma, (ii) fast cooling stage between 117 and 100 Ma, (iii) slow cooling stage between100 and 80 Ma, (iv) fast cooling stage between 80 and 45 Ma, (v) slow cooling stage between 45 and 30 Ma, and (vi) slow cooling stage (<30 Ma). Cooling stages between 120 and 100 Ma are mainly caused by magmatic–hydrothermal evolution, whereas cooling stages after 100 Ma are mainly caused by low‐temperature thermal–tectonic evolution. The Bangong–Nujiang Ocean subduction led to the formation of the Tiegelongnan ore deposit, which was buried by the Meiriqiecuo Formation andesite lava and thrust nappe structure; then, the Tiegelongnan deposit experienced uplift and exhumation caused by the India–Asia collision. [ABSTRACT FROM AUTHOR]

Biotite is an important hydrated ferromagnesian silicate mineral in igneous rocks and porphyry deposits. The determination of chemical compositions of biotite plays an important role in both igneous petrology and ore forming processes. This paper summarizes research results of magmatic and hydrothermal biotites exemplified by the Lakange porphyry Cu–Mo deposit and the Qulong porphyry Cu deposit in the Gangdese porphyry–skarn metallogenic belt, Tibet. Biotite mineral chemistry can provide critical insights into classification, geothermometer, geothermobarometry, oxygen fugacity, petrogenesis and tectonic setting, evaluating magmatic‐hydrothermal process by halogen and halogen fugacity ratios, and distinguishing between barren and mineralized rocks. Biotite provides the latest mineralogical evidence on metallogenic prognosis and prospecting evaluation for porphyry Cu polymetallic deposits or magmatic hydrothermal deposits. [ABSTRACT FROM AUTHOR]

The Duolong area is the most important part of the Western Bangong-Nujiang Suture Zone porphyry Cu(Au) metallogenic belt, in Tibet, China. Here new detailed data are presented from LA-ICP-MS zircon U-Pb, whole-rock geochemical, and in-situ zircon Hf isotope analyses for igneous rocks in the large Naruo deposit (2.51 Mt of Cu and 82 t of Au) which is located ∼2 km NE of the Duolong (Duobuza and Bolong) super-large gold-rich porphyry copper deposit. We integrated our results with previous research of other porphyry deposits in the Duolong area and have identified the timing, geodynamic setting, and petrogenesis of the mineralization-associated magmatic events. Based on the measurements, the Duolong area porphyry Cu(Au) deposit formations are associated with Early Cretaceous intermediate-felsic magmatism, which is consistent with U-Pb zircon ages of 120 Ma. All the main intrusive rocks in the ore-concentrated area have similar lithogeochemical characteristics; they show a relative enrichment in both light rare earth elements (LREEs) and large-ion lithophile elements (LILEs: Rb, Ba, K, etc.) and relative depletion in both heavy rare earth elements (HREEs) and high field strength elements (HFSEs: Nb, Ta, Zr, Hf, etc.). Moreover, the granite porphyry shows positive εHf( t) values between 1.38-7.37 suggesting that magmas were potentially derived from the partial melting of a depleted mantle wedge that had been metasomatized by subducted slab-derived fluids or melts. This paper points out that the formation of the porphyry-epithermal Cu(Au) deposit in the Duolong area was dominated by northward subduction of the Bangongco Tethys Plate beneath the Qiangtang block in the Early Cretaceous (124-114 Ma), when the subducted oceanic crust reached 50-70 km underground and generated different degrees of phase transformation, which lead to a melt produced by dehydration of amphibole minerals, a metasomatized mantle wedge, and induced mantle partial melting that produced the magma. Those deposits occurred in a continental arc tectonic setting, which is similar to the continental margin arc environment of the ocean-continent subduction setting of the Andes metallogenic belt in South America. [ABSTRACT FROM AUTHOR]

The article presents a study to determine geological importance of rhenium (Re)-osmium (Os) isotopic dating of molybdenites in the Galale skarn copper (Cu)-gold (Au) deposit in Tibet, China. Topics discussed include determination of the age of granodiorite by using the laser ablation-inductively coupled plasma-mass spectrometry, isochron ages of Re-Os testing, and galale deposit and gaerqiong deposit resulting from magma-mineralization.

The article offers information on the research "Construction of the Three-dimensional Model for Jiama Deposit, Tibet, and its Significance in Geological Study" by Tang Pan and colleagues. Topics discussed include copper-polymetallic porphyry deposit, the rock forming and ore-forming chronology, and the construction of a 3D deposit model by Micromine software. Also mentioned are the geological and mineralized model of the Jiama deposit, the porphyry orebody output, and dikes and apophysis.

The mechanisms triggering the emplacement of Cretaceous magmatic rocks related to Neo-Tethyan subduction in the southern Lhasa subterrane (SLT) remain controversial because geochronological, geochemical, and isotopic data from the Cretaceous magmatic rocks in the western portion of the SLT are lacking. This paper provides the first report indicating that the Dazhuqu hornblende gabbro and Xietongmen granite porphyry were generated in the Late Cretaceous (ca. 100 Ma and ca. 68 Ma, respectively) in the western portion of the SLT. The Dazhuqu hornblende gabbro is characterized by high MgO, Na2O, Cr, Co, and Mg# values, enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), and depletion in high field strength elements with no Eu anomalies. The Xietongmen granite porphyry displays high SiO2, low MgO, Mg#, Cr, Co, and Ni, enrichment in LREEs and LILEs, flat heavy rare earth element (HREE) patterns and negative Eu anomalies. Zircons from the Dazhuqu hornblende gabbro and Xietongmen granite porphyry display high positive εHf(t) ranges from 11.79 to 14.91 and from 9.05 to 12.38, respectively. The Dazhuqu hornblende gabbro was produced by the partial melting of 12–15% garnet peridotite in the depleted mantle that was metasomatized by fluids released from the dehydrating subducted Neo-Tethyan oceanic slab. This magma was then emplaced at an upper crustal depth of 5.3–7.0 km. The Xietongmen granite porphyry was generated by the partial melting of underplated basaltic crust during the subduction of the Neo-Tethyan oceanic crust and formed in the presence of pyroxene, plagioclase, and minor hornblende in its magmatic source. In combination with previously published data from Cretaceous magmatic rocks in the SLT, our data suggest that the petrogenesis of the Dazhuqu hornblende gabbro was related to flat or low-angle slab subduction of the Neo-Tethyan oceanic crust during 109–97 Ma and that the formation of the Xietongmen granite porphyry was related to lithospheric delamination in the western portion of the SLT after ca. 68 Ma. [ABSTRACT FROM AUTHOR]

Jurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period. [ABSTRACT FROM AUTHOR]

Diabase dikes are extensively distributed in the Xiongcun porphyry copper–gold district in the southern margin of the Lhasa terrane. Here, we report zircon U–Pb ages determined by laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) along with Hf isotopic, whole‐rock elemental, and Sr–Nd–Pb isotopic data for these diabase dikes. Zircons from one of the Xiongcun diabase dikes yielded an emplacement age of 165.3 ± 1.0 Ma. The Xiongcun diabase dikes display subalkaline features and tholeiite compositions. They are enriched in large‐ion lithophile elements (e.g., Rb, Ba, and K) and light rare earth elements and are depleted in high‐field‐strength elements (e.g., Nb, Ta, and Ti). The Xiongcun diabase dikes exhibit relatively low ratios of (87Sr/86Sr)i (0.70386–0.70501), (206Pb/204Pb)i (18.15–18.40), (207Pb/204P)i (15.52–15.57), and (208Pb/204Pb)i (38.06–39.46) and relatively high values of εNd(t) (5.85–6.92) and εHf(t) (+12.58 to +14.03). Combined with previous research results, these findings suggest that the Xiongcun diabase dikes and Early Mesozoic magmatic rocks in the southern margin of the Lhasa terrane formed in an active continental margin magmatic arc setting related to the northward subduction of the Neo‐Tethys oceanic slab; however, the possibility that the Xiongcun diabase dikes were formed in an intra‐oceanic arc setting cannot be excluded. Their parental magmas were formed by the partial melting of the depleted mantle source that was modified by fluids released from the Neo‐Tethys oceanic slab. The magmas experienced fractional crystallization of olivine and clinopyroxene and underwent limited crustal contamination during magma emplacement. The ~165 Ma Xiongcun diabase dikes, which probably originated under an extensional stress condition in a magmatic arc setting, correspond to the timing of Middle Jurassic subduction‐related porphyry copper mineralization (161–172 Ma) in the southern margin of the Lhasa terrane, likely suggesting that this episode of mineralization occurred during a period of changing stress from compression to extension. [ABSTRACT FROM AUTHOR]

The Jurassic magmatic and volcanic rocks are widespread along the west central Lhasa subterrane. However, the petrogenesis of these rocks is poorly understood because of lacking high-quality geochronology and geochemical data. Here, we present new zircon U-Pb age and Hf isotopic data, whole-rock geochemical and Sr-Nd-Pb isotopic data for the Songduole and Qiangnong plutons in Geji area. LA-ICP-MS dating of zircon yield crystallization ages of 172.1 ± 1.9 and 155.9 ± 1.2 Ma for the Songduole and Qiangnong plutons, respectively. Geochemically, Songduole and Qiangnong granodiorite are characterized by high MgO (2.63-3.49 wt%), high Mg# (49-50), and low TiO2 (0.48-0.57 wt%). Besides, all rocks show metaluminous, calc-alkaline signatures, with strong depletion of Nb, Ta, and Ti, enrichment of large-ion lithophile (e.g. Rb, Th, K), and a negative correlation between SiO2 and P2O5. All these features are indicative of arc-related I-type magmatism. Five samples from the Songduole granodiorite have whole rock (87Sr/86Sr)i of 0.71207-0.71257, εNd(t) values of −15.1 to −13.9, zircon εHf(t) values of −17.4 to −10.5, (206Pb/204Pb)t ratios of 18.402-18.854, (207Pb/204Pb)t ratios of 15.660-15.736, and (208Pb/204Pb)t ratios of 38.436-39.208. Samples from the Qiangnong granodiorite have (87Sr/86Sr)i of 0.71230-0.71252, εNd(t) values of −15.1 to −14.2, zircon εHf(t) values of −12.6 to −6.4, (206Pb/204Pb)t ratios of 18.688-18.766, (207Pb/204Pb)t ratios of 15.696-15.717, and (208Pb/204Pb)t ratios of 38.546-39.083. These geochemical signatures indicate that the two plutons most likely originated from partial melting of the ancient Lhasa lower crust with obvious inputs of mantle-derived melts. Combined with regional geology, our results indicate that the Jurassic magmatism in the west central Lhasa subterrane most likely resulted from the southward subduction of the Bangong Ocean lithosphere beneath the central Lhasa terrane. [ABSTRACT FROM AUTHOR]

This article reports new zircon laser ablation-multicollector-inductively coupled plasma-mass spectrometry U-Pb and Hf isotope, whole-rock major and trace element, and Sr-Nd isotope data for mineralized and barren intrusions associated with the Duolong porphyry-epithermal copper-(gold) deposit (DPCD, a mining camp containing several individual deposits) in the western Qiangtang Terrane (QT), central Tibet. These data are used to further our understanding of the geological evolution of this region. The mineralized and barren DPCD intrusions are typical I-type granitoids that were synchronously emplaced at ca. 112.6-125.9 Ma. These igneous rocks show arc affinities that are characterized by enrichments in the light rare earth elements (LaN/YbN = 4.08-15.23) and the light ion lithophile elements (Rb, Th, U, K, and Pb), and depletions in the high field strength elements (Nb, Ta, and Ti). They have 87Sr/86Sr(i) values of 0.7046-0.7079, Nd(t) values of -6.0 to +1.1, and two-stage Nd model ages of ca. 823-1410 Ma. Zircons from these intrusive rocks have variable but generally positive εHf(t) values (-2.7 to +13.7) and relatively young zircon Hf crustal model ages of 335-1351 Ma. Combining these data with geochemical data reported in recent studies, we infer that the mineralized and barren DPCD intrusions formed in a continental marginal arc setting and likely originated from a common parental magma that was result of magma mixing of juvenile crust-derived basaltic melts and old lower crust-derived melts. The formation of the DPCD intrusions indicates that the Bangongco-Nujiang oceanic lithosphere was still undergoing northward subduction beneath the western QT at ca. 112.6-125.9 Ma, suggesting in turn that the oceanic basin have not closed completely during the Early Cretaceous. These new data also indicate that the processes that occur during the subduction of oceanic crust in continental marginal arc settings produce and preserve juvenile crustal material, leading to net continental crust vertical growth and thickening. [ABSTRACT FROM AUTHOR]

The article discusses a study that focuses on the minerals, geological alteration and fluid basics of the first high sulfidation epithermal-porphyry copper-gold deposits in Tibet, China. Topics discussed include discovery of some new copper-sulfur and copper-iron-sulfur minerals; role of temperature and salinity in fluid inclusions and mixing of meteoricwater and porphyry fluid to form deposits in low temperature and salinity.

The article discusses the petrogeochemistral features of the acid intrusive rocks in Zhaxikang Deposit, Xizang Region. Topics discussed include geochemical analysis of granite porphyry samples that revealed high alumina, high silica and low magnesium oxide; rare earth element geochemistry of granite porphyry samples; and positive Europium (Eu) anomalies in which concentration of Eu increases in the mineral.

We report the copper isotopic composition of Cu sulfides in the Tiegelongnan high-sulfidation (HS) copper deposit, Tibet, and investigate the possible application of Cu isotopes to mineral exploration. The copper isotopic values of samples from four drill holes display consistent progressive increase with depth to 400 m below surface, with an overall variation of δCu of up to 7.60‰ (−4.76 to 2.84‰). Such a large range is very different from that observed in Cu porphyry deposits which commonly exhibit a small δCu range (<1‰), with decreasing values with depth. The large δCu variation is likely of supergene origin and reflects strong leaching under oxidized conditions. The systematic increase of δCu with depth can be explained by the release of isotopically heavy Cu at the top and its transport downward, which is supported by the coupling of positive δCu values with high Cu grade and the occurrence of both negative and positive δCu values in two drill holes. Mass-balance consideration on the basis of Cu isotopes can indicate mineralized zones which have been eroded or have not been found yet. Such mineralized targets, if buried at depth, could be located using Cu isotopes. [ABSTRACT FROM AUTHOR]

The article discusses a study that focuses on the geological characteristics of Rongna copper-gold-silver epithermal ore deposits located in Duolong copper ore concentration area in Northern Tibet, China. Topics discussed include classification of epithermal-porphyry copper mineralization system into high-sulfidation, medium sulfidation and low sulfidation types; composition of copper sulfides including digenite, enargite, bornite; and impact of deposits discovery on mineral prospecting.

The Longmala and Mengya’a deposits are two representative skarn Pb–Zn deposits of the Nyainqêntanglha Pb–Zn–(Cu–Mo–Ag) polymetallic belt in the Gangdese region, Tibet, China. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating of the mineralization-related biotite monzogranite from the Longmala deposit yielded a weighted mean age of 55.7 Ma, which can be interpreted as the emplacement age of the pluton. Re–Os dating of three molybdenite samples from the Longmala deposit yielded model ages of 51.8–54.3 Ma, with a weighted mean age of 53.3 Ma, which is interpreted as the mineralization age of the deposit and overlaps the age of the causative intrusion. The Re–Os dating of four molybdenite samples from the Mengya’a deposit yielded model ages of 60.4–65.8 Ma, with a weighted mean age of 63.6 Ma, which represents the mineralization age of this deposit. Our new precise age data for these two deposits are consistent with the existing ages of ca. 65–51 Ma for other skarn polymetallic deposits in the Nyainqêntanglha metallogenic belt. In addition, these new age data, combined with existing information on the geological evolution history of the Lhasa terrane, indicate that the belt of skarn deposits is closely related to initial collision between India and the Asian continents. [ABSTRACT FROM PUBLISHER]

Copper resources in China are rich, but imported copper products are still required. Researches on metallogenic regularity of major types of copper deposits by geologists have involved in worldwide classification, significant copper belts, representative copper deposits, etc. Studies on metallogenic regularity of copper deposits in China also have made achievements with a long-term work. Combined with latest exploration advances obtained in recent ten years, this review aims to conclude the achievements of researches on copper metallogenic regularity in China. Based on data of 814 copper deposits and other ore (mineralized) occurrences, ten prediction types of copper deposits have been suggested. Porphyry and skarn copper ores are taken as the key targets. Porphyry copper deposits are the most important one which concentrate in Gangdese, Changdu-Sanjiang, Dexing and East Tianshan. The Cenozoic and Mesozoic are the major metallogenic epochs. Four main metallogenic epochs are been studied based on the copper ore geochronological data including Precambrian Era (Archean and Proterozoic), Paleozoic Era, Mesozoic Era and Cenozoic Era. Based on the study of metallogenic series of ore deposits in China, twenty-seven metallogenic series of copper deposits are proposed. This is suggested to deepen the study of metallogenic regularity of copper ore and provide the theory guide for copper resources prediction in China. [ABSTRACT FROM AUTHOR]

The Jiama copper deposit is one of the largest deposits recently found in Tibet and is composed of three types of mineralization including skarn, hornfels and porphyry. To investigate the relationship between mineralization, structure and alteration, we report new zircon U-Pb age and present field observations on the deformation characteritics associated with the copper mineralization in Jiama. Two main periods of deformation were identified, represented by D1 and D2 in Jiama. The first deformation ( D1) occurred around 50 Ma, whereas the second deformation ( D2) that was closely related to mineralization occurred later. Previous zircon U-Pb and molybnite Re-Os dating results indicate that the mineralizatoin occurred at ∼15 Ma and thus the D1 regional deformation significantly occurred before the mineralization time, although the D1 deformation probably provided important space for the development of significant copper deposition. Our new mapping and observations on the D2 deformation demonstrate that the mineralization was closely coeval with or slightly later than the time of D2 deformation. The new U-Pb zircon age further indicates that the aplite formed in ∼17.0 Ma and thus the D2 deformation happened later than this time because the D2 deformation cut across the aplite, which is proposed to be the key control for copper mineralization. Altered laminated hornfels including three types of alteration ( A-, K- and S-type) were found spatially associated with the D2 deformation. The type- A is mainly silicification, with fine sericite or chlorite, as well as abundant disseminated sulphides on fracture surfaces; the type- S is mainly fine-grained silicification with patches of chlorite, epidote and common sulphides; the type- K (potassic alteration) appears to be fine-grained biotite. Such types of alteration indicate the presence of skarns at depth where ore shoots are located. Taken together, the multiple structural-magmatic-mineralization events contributed to the formation of the supergiant Jiama porphyry copper deposit in Tibet. The results have general implication for regional exploration. [ABSTRACT FROM AUTHOR]

The article offers information on the geochemical features and prospecting development of Southern Tiegelong Giant Epithermal Copper Deposit in Tibet, China. Topics discussed include types of metallic sulphides ores detected by energy spectroscopy scanning; metallogenic stages of mineralization such as sedimentary diagenesis and hydrothermal mineralization; and formation of deposits in Early Cretaceous era.

The article discusses the research study conducted to examine the genesis and main differences of Jiama and Qulong Super-Large Deposit in Gangdese metallogenic belt in Tibet, China and providing a necessary reference for regional deposit prospecting. It mentions that rocks including skarn, porphyry, and hornfels serve as main ore hosts in the Jiama deposit. It further mentions the difference in the mineral resource composition and useful element series and have a regional denudation.

The article discusses the research study conducted that examines the genetic types of mineral deposits of Xiongcun District in Gangdese porphyry copper belt in Tibet, People's Republic of China (PRC). It mentions the genesis of the Gangdese deposit as epithermal, porphyry, and porphyry-epithermal deposit. It further mentions that the deposit is characterized by developed pyrrhotite and ilmenite, that have similar mineral assemblages to the reduced porphyry copper-gold deposit (RPCDs).

The article presents brief information on the geological characteristics of Xiachahe aluminum deposit at Zhenyuan, in Yunnan, China. Topics discussed include geological overview of mineral deposit in the north western region of the Ailaoshan golden belt in China, brief information on the characteristics of mineral orebody and ores, and impact of mineral alternation on the gathering and mineralization of the gold.

The article reports on the discovery of 341 Ma gabbro, that is located inXiongcun copper-gold district at southern margin of Lhasa terrane, Tibet. The methods employed and photographs of Xiongcun gabbro, marble and migmatization gneissare are presented. Zircon U-Pb ages of the gabbro in west of Xiongcun district are 341.55±0.89 Ma

The article discusses about Apatite Fission Track Ages in Duolong Ore District and the Uplift Time in Qiangtang Terrrane, Tibet. It is mentioned that AFT of the Duolong ore district would provide clues on uplift-exhumation history of Duolong ore district and Qiangtang Basin. The methods used and the results of the study are mentioned.

The article discusses about First Discovery of Colusite in Tiegelongnan Supper-large Copper (Silver, Gold) Deposit and also reports on the Significance for the Genesis of the Deposit. The chemical formula for Colusite and the methods used and result of the study and characteristics of colusite are mentioned.

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The article offers information on the geological features of the porphyry deposit of Jiama in Tibet, China. Topics discussed include scientific and economic significance of Jiama porphyry at Gangdese metallogenic belt due to the presence of copper metal reserves, molybdenum, and silver reserves, Copper-Molybdenum ore found in bathy-hidden porphyry, and disseminated ore and veinlet ore as the main types of ores found in the porphyry.