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Administrative regions are fundamental geographic elements on maps, thus making their detection in map images crucial to enhancing intelligent map interpretation. However, existing methods in this field primarily depend on the texture features within the images and do not account for the influence of spatial and co-existence relationships among different targets. In this study, taking the administrative regions of the Chinese Mainland, Taiwan, Tibet, and Henan as test targets, we employed the spatial and co-existence relationships of pairs of targets to improve target detection performance. Firstly, these four regions were detected using a simple Single-Target Cascading detection model based on RetinaNet. Subsequently, the detection results were adjusted with the spatial and co-existence relationships of each pair of targets. The adjusted outcomes demonstrate a significant increase in target detection accuracy, as well as precision (from 0.62 to 0.96) and F1 score (from 0.76 to 0.88), for the Chinese Mainland target. This study contributes to the advancement of intelligent map interpretation. [ABSTRACT FROM AUTHOR]

Objective To explore the current situation and development trend of coupling coordination between medical and health resource allocation and service utilization in eastern, central, and western regions and provinces of China, and to provide suggestions for promoting the coordinated development of medical and health resource allocation and service utilization. Methods The related index data of medical and health resource allocation and service utilization from 2018 to 2022 were selected, and the comprehensive development level index and relative development degree were used to evaluate the medical and health resource allocation and service utilization. The coupled coordination degree model was used to analyze the coupling coordination relationship and development trend of the two systems. Results There were significant differences in the comprehensive development level of medical and health resource allocation among provinces, and the overall structure of relative development degree in 2021 was "9-11-11". From 2017 to 2021, the coupling coordination degree of medical and health resource allocation and service utilization decreased, showing a decreasing trend from east to west as a whole. The overall coordination between the allocation of medical and health resources and the utilization of services in China was poor. Only 12 provinces achieved coordinated development in 2021. Xizang was still in the dilemma of serious imbalance. Conclusion It is suggested to improve the accuracy of medical and health resources allocation, reduce the differences in the develop-ment level of resource allocation between provinces, and build a multi-party co-governance pattern. The improvement strategy of coordination level should be accurately formulated according to the relative development of medical and health resource allocation and service utilization in each province. [ABSTRACT FROM AUTHOR]

As one of the most important livestock breeds on the Qinghai-Tibet Plateau, Tibetan sheep are of great importance to the local economy, agriculture and culture. Its adaptive mechanism in low temperature and low oxygen at highland altitudes has not been reported. In this study, transcriptome sequencing was used to analyze the heart, liver, spleen, lung, kidney, and muscle tissue of sheep at low and highland altitudes. LOC101112291, SELENOW, COL3A1, GPX1, TMSB4X and HSF4 were selected as candidate genes for adapting to plateau characteristics in Tibet Sheep. Besides, glutathione metabolism, arachidonic acid metabolism, nucleotide excision repair, regulation of actin cytoskeleton, protein digestion and absorption, thyroid hormone synthesis, relaxation signaling pathways may play important roles in the adaptation to plateau hypoxia, and cold tolerance. Structural analysis also showed that sequencing genes related to the adaptation mechanism of Tibet sheep to highland altitude. This study will lay a certain foundation for Tibet sheep research. Tibet sheep are an ancient species in the Qinghai Tibet Plateau. After a long period of domestication. Tibet sheep adapt to the hypoxic environment of the plateau in terms of physiology and morphology. At the same time, Tibet sheep is also one of the major sources of material for herdsmen in tibetan. In this study, six different tissue samples (heart, liver, spleen, lung, kidney, and muscle) of Tibet sheep were analyzed to reveal the underlying mechanisms of different tissues respond to hypothermia condition. The results showed that six key genes and eight important signaling pathways involved in regulating the adaptation of Tibet sheep to the plateau. In addition, there were more alternative splicing (AS) events and single nucleotide polymorphism (SNP) sites in highland altitude Tibet sheep than in lowland altitude sheep, which was also a concern in the highland altitude adaptability of Tibet sheep. [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]

There is a critical need for detection of administrative regions through network map pictures in map censorship tasks, which can be implemented by target detection technology. However, on map images there tend to be numerous administrative regions overlaying map annotations and symbols, thus making it difficult to accurately detect each region. Using a RetinaNet-based target detection model integrating ResNet50 and a feature pyramid network (FPN), this study built a multi-target model and a single-target cascading model from three single-target models by taking Taiwan, Tibet, and the Chinese mainland as target examples. Two models were evaluated both in classification and localization accuracy to investigate their administrative region detection performance. The results show that the single-target cascading model was able to detect more administrative regions, with a higher f1_score of 0.86 and mAP of 0.85 compared to the multi-target model (0.56 and 0.52, respectively). Furthermore, location box size distribution from the single-target cascading model looks more similar to that of manually annotated box sizes, which signifies that the proposed cascading model is superior to the multi-target model. This study is promising in providing support for computer map reading and intelligent map censorship. [ABSTRACT FROM AUTHOR]

The Kenbale Cu mineralization occurrence related to the diorite is a newly discovered Cu mineralization event in the Bangong-Nujiang metallogenic belt, Tibet, China. The Cu mineralization is hosted in the contact between the monzogranite or biotite quartz diorite and the fine-grained diorite, which is the mineralization related intrusion. In order to constrain the Kenbale mineralization age, petrogenesis and tectonic setting, we conducted LA-ICP-MS zircon U-Pb dating and Hf isotopic analyses of the biotite quartz diorite and fine-grained diorite and also the whole-rock geochemical study of the biotite quartz diorite. Zircon UPb dating show that weighted mean 206Pb/238U ages of the biotite quartz diorite and fine-grained diorite are 123.5 ± 1.9 Ma (MSWD = 2.3, n = 16) and 118.9 ± 1.3 Ma (MSWD = 2.5, n = 18), respectively. The biotite quartz diorite is a high-K calc-alkaline I-type magma rock and was controlled mainly by partial melting process during the magma formation and evolution. This intrusion is characterized by positive εHf(t) values (2.6 to 5.8) and old Hf crustal model ages (813 to 1016 Ma), indicating that the magma was sourced from partial melting of the Mesoproterozoic to Neoproterozoic juvenile crust of the northern Lhasa Terrane. Compared with the biotite quartz diorite, the mineralization associated fine-grained diorite has much higher zircon εHf(t) values (8.2 to 11.4) and younger Hf crustal model ages (450 to 650 Ma). These characteristics are similar with those of the coeval magmatic rocks induced by slab break-off of the southward subducted Bangong-Nujiang Ocean. The geochronology and geochemical results show that the Kenbale Cu mineralization was controlled by the slab break-off of the southward subducted Bangong-Nujiang Ocean. [ABSTRACT FROM AUTHOR]

Under the background of global warming, some lakes on the Tibetan Plateau (TP) are potentially sensitive to temperature change. With a case study of Pumayum Co, where glacier meltwater is important to supply (we call this a glacier-fed lake hereafter), we analyze the sensitivity of lake sediment grain size to temperature change. This is done by resolving the modern hydrodynamic process, coupled with comparison of paleoclimatic proxies. According to the spatial distributions of parameters, percentage of grain size and the grain size frequency distribution curve, hydrodynamic processes are analyzed. Five clastic sedimentation types are thereby discriminated. In the open lake area, suspended load transport is the main transport agent. Grain Size Trend Analysis (GSTA), a sediment dynamics model, reveals a trend toward eastward transport. This indicates that the largest and glacier-fed river, the Jiaqu River, influences the entire lake (not just the subsurface alluvial fan), and that lake sediment grain size may serve as a temperature indicator. Time series comparison between grain size of a short core from the central lake and meteorological data confirms this temperature indication, which in turn shows reliability of the method discriminating the hydrodynamic process. This case study will improve the ability of paleoclimatic reconstruction using lake sediment in glacier-fed lakes on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

A 380-cm-long sediment core was acquired from the deep water area of Pumoyum Co, southern Tibet. Twenty-five plant residue samples were selected, and organic carbon stable isotopes were obtained using the AMS C chronological method. The C age and carbon reservoir effect were calibrated with surface sedimentation rate measurements using Pb dating. Results showed that the core sediment deposited over 19 cal ka BP. Based on a multi-proxy analysis of TOC and IC contents, grain size and pollen assemblage data, the palaeoclimatic evolution of Pumoyum Co was reconstructed since the last glacial. Pumoyum Co was a shallow lake prior to 16.2 cal ka BP; although the glacier around the lake began to melt due to increasing temperatures, climate was still cold and dry. In the interval of 16.2-11.8 cal ka BP, the sedimentary environment fluctuated drastically and frequently. Two cold-events occurred at 14.2 and 11.8 cal ka BP, and these may correspond to the Older Dryas and the Younger Dryas events, respectively. After 11.8 cal ka BP, Pumoyun Co developed into the deep lake as it is now. The lake water temperature was relatively lower at that time because of influx of cold water from glacial meltwater entering the lake. As a result, the multi-proxy indicators showed no sign of warm conditions. Comparisons between the sedimentary record of Pumoyum Co with that of other lakes of the same age in southern Tibet indicate a warmer climate following the last deglaciation influenced the southeastern Tibetan Plateau. These results imply that the southwest Asian monsoon gradually became stronger since the deglaciation during its expansion to the inner plateau. The glacial-supplied water of the lake responded sensitively to cold-events. The entire southern Tibet region was dominantly influenced climatically by the southwest Asian monsoon during the Holocene. [ABSTRACT FROM AUTHOR]

In the "Central Uplift" of Qiangtang, Northern Tibet, a large scale of mafic dyke swarms extended in E-W direction. Zircon SHRIMP U-Pb dating on two representative samples of diabase dyke yield weighted mean ages of 284 ± 3 Ma and 302 ± 4 Ma, respectively, suggesting they emplaced in the Late Carboniferous to Early Permian. Zircon 176Hf/177Hf ratios range from 0.282852 to 0.283041, with ϵHf(f) values of +12.1 to +12.2 and Hf modal (TDM) ages of -440-460 Ma. These data indicate that these mafic dykes were mainly derived from the depleted mantle. In addition, geochemical data suggest that these mat ic dyke swarms are of intra-plate origin. Therefore, the mafic dyke swarms represent products during the extensional process associated with the opening of the Paleo-Tethys Ocean in the area. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Jiaoxi tungsten deposit comprises three stages, i.e., the oxide, sulfide, and fluorite stage. • Mineralization involves a low-salinity aqueous fluid. • Mineralization occurred as a result of fluid-fluid mixing induced cooling and dilution. The Jiaoxi deposit, located in the western part of the Lhasa terrane, is the first discovered Miocene (ca. 13 Ma) quartz vein-type tungsten deposit in this belt. Ore bodies mainly occur as wolframite-bearing veins hosted in the shales and granite. Three stages were identified for the formation of the Jiaoxi deposit, including the oxide stage (dominated by wolframite and quartz), the sulfide stage (quartz-sulfides veins) and the fluorite stage (late veins comprising fluorite, calcite, and quartz). Here, we investigate the genesis of this deposit based on fluid inclusion and H-O-S-Pb isotope studies. Fluid inclusion microthermometry and oxygen isotope data reveal that the wolframite precipitated from a moderate temperature (340–380 °C), low salinity (2.1–7.5 wt% NaCl equivalent) hydrothermal fluid at a depth of ∼ 6 km. The sulfides from the oxide and sulfide stage have uniform δ34S CDT values (+2.5 to + 3.7‰), and consistent Pb isotope compositions with the coeval granites (206Pb/204Pb: 17.866–18.789; 207Pb/204Pb: 15.555–15.743; 208Pb/204Pb: 37.157–39.335). The δ18O VSMOW value of the hydrothermal fluid decreased from the oxide (δ18O VSMOW = +7.2 to +14.2‰) to the fluorite stage (δ18O VSMOW = +2.1 to +5.7‰), indicating that the exsolved magmatic hydrothermal fluid mixed with meteoric water. This is also suggested by the positive correlation between the salinity and homogenization temperature of the aqueous fluid inclusions. LA-ICP-MS analysis of individual fluid inclusion reveals that the W concentrations of ore-forming fluid in the oxide stage (1.2–70.2 ppm) are much higher than those in the sulfide and fluorite stage (1.1–2.2 ppm) and show positive correlations with the homogenization temperatures and the Cl concentrations. We propose that fluid dilution and cooling due to fluid mixing played an important role during the wolframite precipitation in the Jiaoxi deposit. [ABSTRACT FROM AUTHOR]

• Highly evolved parental magma controls formation of the Jiaoxi W deposit. • New geodynamic setting for Miocene granite-related W deposits in central Lhasa subterrane. • Mantle-derived melts play an important role in mobilizing the W from crust materials. The Jiaoxi deposit is the first Miocene quartz vein-type W deposit discovered in the western part of the Lhasa Terrane comprising with 39,000 metric tons of WO 3. The mineralization occurs in wolframite-bearing hydrothermal tensional quartz veins and is associated with Miocene granites. The mineralization event can be divided into an early quartz-oxide stage succeeded by a sulfide stage, and a final fluorite-carbonate stage. Magmatic intrusions at the deposit include biotite monzogranite porphyry, biotite monzogranite, granite porphyry, and muscovite granite at depth and show crystallization ages ranging between 14.5 and 13.7 Ma. Whole-rock geochemistry shows that the intrusions are alkali-rich peraluminous granites that experienced strong fractional crystallization. The most evolved muscovite granite has high W, Nb and Cs contents and is considered to be the source for mineralization. During the late crystallization stage of the highly fractionated muscovite granite, exsolved hydrothermal fluids interacted with the muscovite granite magma and migrated along extensional fractures forming the Jiaoxi deposit. Zircon grains from the granites show uniform ε Hf (t) values with a wide range between −7.08 and +3.87. The granites have initial Sr isotopic compositions ranging between 0.7094 and 0.7124 and negative ε Nd (t) values ranging between −4.9 and −9.4. The Sr-Nd-Hf isotope data indicate that the granites were derived from partial melting of a crustal source with minor contributions from the lithospheric mantle. The 3He/4He ratios for wolframite and pyrite vary between 0.30 and 0.74 Ra (Ra = 1.4 × 10–6 for air), confirming that W was mainly sourced from the crust. Collectively, the regional geology, geochronology and geochemistry, indicate that the Miocene post-collisional peraluminous granites and associated W mineralization were triggered by the roll-back and gradual break-off of the northward-subducting Indian continental lithosphere slab. The less evolved biotite monzogranite porphyry, which contains ore-bearing veins and local greisen alteration, appears to be unrelated to W mineralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • First direct timing constraints on the Jiaoxi and Anglonggangri W mineralization. • Garnet-muscovite granite provided most Fe in Anglonggangri ore-forming metals. • Varied fluid component and redox state in wolframite and scheelite precipitation. • Highly-evolved granites play critical roles on the Fe-rich wolframite formation. Critical factors controlling Fe-enriched wolframite formation in the quartz vein-type wolframite deposit are in controversy. The Jiaoxi and Anglonggangri are typical examples of quartz vein-type wolframite mineralization found in western Lhasa terrane. The Jiaoxi wolframite comprise dominantly early hübnerite with late ferberite, whereas, the Anglonggangri wolframite are mainly ferberite. Wolframite U-Pb dating yields direct timing of 11.0 ± 0.2 Ma and 9.7 ± 0.2 Ma for Jiaoxi and Anglonggangri tungsten mineralization, respectively. Ages together with enrichment of Nb, Ta, Ti, and Sc and depletion of Sr and most Eu anomaly within Anglonggangri wolframite confirm that metals and fluids were mainly derived from the ore-forming garnet-muscovite granite. Iron and Mn mapping of garnet in the garnet-muscovite granite suggests this granite has changed from the early Mn-enriched to late Fe-rich affinity. Therefore, initial ore-forming fluids exsolved from garnet-muscovite granite have Fe-rich composition, that was significantly modified during tungsten mineralization. Positive trend between Mg and Fe/(Fe + Mn) of wolframite indicates biotite breakdown from country rock of biotite-muscovite granite to add Fe and Mg into fluid during greisenization. Meanwhile, decomposition of plagioclase and K-feldspar provided Ca, Sr, and Eu to form late scheelite. Enrichment of Sr with positive Eu anomaly and decline of REE, Nb, and Ta are typical features of the highly evolved and modified fluid. Positive and negative Eu anomalies within the same wolframite grains reveal the oxidized character and fluctuating composition of fluid during wolframite precipitation. By contrast, negative Eu anomaly and low Mo abundance of scheelite indicate the reducing fluid during scheelite crystallization. Identification of metal and fluid sources for Anglonggangri ferberite highlights the evolved granites play more crucial roles on ferberite formation than early hübnerite crystallization and Fe addition from country rocks during hydrothermal interaction. [ABSTRACT FROM AUTHOR]

An abstract of the article "Late Pleistocene (MIS 2) climate change on the Northern Tibetan Plateau inferred from pollen and geochemical records from Lake Gomo Co." by Wang Yong and colleagues is presented.

Sediments from lakes provide one of the most important archives for past environmental changes on the Tibetan Plateau. The recent sedimentation rate of modern lakes is widely used as an independent method to calibrate 14 C-derived chronologies because 14 C values are often affected by a reservoir effect. Terrestrial plant residues in lake sediments are believed to be the ideal material for 14 C dating because they normally provide the true ages of the sediments. In this study, we present the spatial and temporal variations in modern sedimentation rates over the past ∼150 years and evaluate the reservoir effects of 14 C ages determined from bulk sediments and plant residues from Lake Tangra Yumco on the central Tibetan Plateau. The results show that ages determined from plant residues are systematically younger than those of the bulk sediments. However, the reservoir effects associated with the bulk sediments are much more constant than those of the plant residues, highlighting the complicated composition of these macro-remains and the fact that they might not be the best dating materials in Tangra Yumco, especially in southern part. A similar reservoir effect of ∼2200 years is observed in the southern and northern parts of Tangra Yumco, based on the dating of modern surface sediments and aquatic plants. This study demonstrates the complexity of the reservoir effect in a closed lake on the Tibetan Plateau, and careful consideration must be paid to the use of different approaches to date different materials in order to establish a reliable chronology. [ABSTRACT FROM AUTHOR]

The hydrogen isotope composition (δ D) of paleoclimatic archives is increasingly being used as a proxy for the reconstruction of Quaternary hydroclimatic variability, but the factors controlling δ D in arid/semi-arid regions remain poorly understood. We compared the hydrogen isotope composition of individual n -alkanes in the surface sediments of a series of lakes and puddles in Tibet with local meteorological and hydrological data. The results show that the δ D of short-chain and long-chain n -alkanes is sensitive to hydroclimatic conditions, with δ D p being the predominant control. δ D becomes less depleted where precipitation amount and humidity are lower or evaporation is stronger. In addition, temperature is a significant factor affecting δ D of mid-chain n -alkanes, with a significant negative correlation, and the temperature in spring, autumn and winter is an important influence on it. We believe that the δ D of long-chain n -alkanes is still a good paleohydrological index in the arid/semi-arid region; δ D indices of mid-chain and short-chain n -alkanes are also useful, and more mechanism research is needed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Bangbule deposit experienced two rapid exhumation events (52–24 Ma and 12 Ma to present) after mineralization. • There is still potential for mineral exploration in the Bangbule deposit. • The western Gangdese Metallogenic Belt experienced less exhumation than that in the eastern part since Oligocene. The Bangbule Pb-Zn-Cu deposit is a large-scale skarn deposit that was recently discovered in the western Gangdese Metallogenic Belt. Previous studies have focused mainly on ore genesis and ore-forming fluid, while exhumation and preservation after mineralization have not been the focus. We report fission track ages (ZFT: 43 ± 3 to 52 ± 3 Ma; AFT: 24 ± 2 to 32 ± 3 Ma, MTL: 12.2 ± 1.9 to 13.0 ± 1.6 μm) and the timing of fault activation (44.3 ± 0.9 Ma), revealing the processes of cooling/exhumation and we evaluate the preservation of the deposit. The Bangbule deposit experienced two rapid exhumation events since the Eocene (52–24 Ma and 12 Ma to present) and a slower stage during the late Oligocene to middle Miocene (24–12 Ma). The exhumation thickness (1.6–3.1 km) after mineralization was similar to the metallogenic depth (peak: 1.5–2.5 km). The volcanic rocks of the Dianzhong Formation partially protect the deposit, making mineral exploration of the Bangbule deposit feasible. Since the Oligocene, due to climate change and deep subducted slab tearing, the exhumation thickness in the western Gangdese (∼0.6–3.1 km) has generally been lower than that in the middle-eastern part (∼3–8 km). The lower degree of exhumation may be one of the reasons why less large-scale deposits have been discovered in the western Gangdese. [ABSTRACT FROM AUTHOR]

[Display omitted] • High Sr/Y granite can be responsible for the granite-related tungsten deposit. • The amphibolite lower crust is an effective magma source for granite-related tungsten deposit. • Magmatic process is more critical than magma source to form granite-related tungsten deposit. Magmas for the granite-related tungsten deposits (GTD) are commonly considered to be generated from the upper to middle crustal metasedimentary protoliths, and these magma source materials have previously been regarded as the determinant factor to the granite-related tungsten mineralization. Here we demonstrate, based on high Sr/Y and (La/Yb) N granites related to wolframite mineralization from the Jiaoxi, Jiaodong and Anglonggangri wolframite mining districts in the northern Lhasa terrane, Xizang that this viewpoint is not necessarily correct. Petrological and geochemical evidences suggest that the wolframite mineralization related granites in these mining areas were sourced from partial melting of the K-rich amphibolite lower crust of the Lhasa terrane and underwent significant fractional crystallization. These results indicate that the amphibolite lower crust can also be a candidate magma source for the GTD and the high evolution processes of granite is more important than the nature of the source materials during tungsten mineralization. [ABSTRACT FROM AUTHOR]

The Longmala deposit is a representative of the skarn Pb-Zn-Cu deposits found in the Nyainqêntanglha area of Tibet, China. The mineralization is hosted by skarn and marble of the Permian Wululong Formation intruded by an early Eocene biotite monzogranite, which is associated with the Pb-Zn-Cu mineralization. The genesis of the deposit is related to a four-stage progression involving: Stage I involves the development of prograde skarn; Stage II is a pre-ore retrograde skarn; Stage III is the emplacement of quartz-sulfides ore; and Stage IV is the emplacement of post-ore carbonate. The biotite monzogranite is a high-K calc-alkaline highly fractionated I-type granite characterized by its elevated SiO 2 (68.38–72.62 wt%), Fe T (4.09–6.19 wt%), and K 2 O + Na 2 O (7.82–8.33 wt%) contents. Its aluminum saturation index of 0.97–0.99 and a high differentiation index of 79–86 are indicative of a last-stage fractionation of the magma. The monzogranite is relatively enriched in light rare-earth elements, Th, U, and Rb, depleted in Sr, Ba, K, Nb, P, and Ti, and has a negative Eu anomaly. The εHf (t) values (−6.2 to +1.5), two-stage Hf model ages (average T DM2 = 1224 Ma) for zircons, and whole rock Pb isotopic compositions ( 206 Pb/ 204 Pb = 18.806–18.938, 207 Pb/ 204 Pb = 15.676–15.697, and 208 Pb/ 204 Pb = 39.234–39.376) indicate that the source of the magma is the crust of Lhasa Terrane. The study of fluid inclusions from each of the four stages mentioned above show that garnet and diopside from the prograde skarn (Stage I) are characterized by high temperatures and high oxygen fugacity indicative of magmatic fluids. The succeeding mineralization (Stage III) is characterized by moderate to high temperature and a reducing fluid, and final carbonate veining (Stage IV) with a decreased fluid temperature and salinity. The δ 18 O w values range from 1.3 to 10.8‰, and the δD w values are −123.5 to −93.4‰, indicating that the ore-forming fluids were derived from mixture magmatic and meteoric fluids, and the δ 34 S values of sulfides have a relatively narrow range of 0.3–3.6‰, suggestive of a magmatic source. The 206 Pb/ 204 Pb (18.571–18.722), 207 Pb/ 204 Pb (15.707–15.796), and 208 Pb/ 204 Pb (39.116–39.448) values of sulfides show that ore-forming metals were derived from the crust in the Lhasa Terrane. Major and trace elements characteristics of the ore-associated biotite monzogranite, combined with the dating results, suggest that the Longmala deposit were formed within the India-Asia continental-collision tectonic setting. [ABSTRACT FROM AUTHOR]

The apatite chemical compositions show that the parental magma of the Pulang pluton is more fertile for Cu mineralization than those of the Cuojiaoma, Dongcuo, and Daocheng plutons, because it is more oxidized and richer in Cu, Cl, and S. • Apatite is an efficient probe for magmatic fertility. • The parental magma of the Cu-mineralized Pulang pluton is more fertile than that of the non-mineralized plutons. • The difference in magmatic fertility results from magma sources. The Paleo-Tethyan granitoids in eastern Tibet are generally Cu-barren, and only a few can generate porphyry Cu deposits. It is still unclear what magmatic differences cause these coeval granitoids to have different mineralization potentials. In this study, the major, minor, and trace element abundances and Nd isotope in the apatites from four Triassic granitoids from eastern Tibet have been determined using EPMA, LA-ICP-MS, and LA-MC-ICP-MS. The following are the selected plutons: the Pulang pluton, which is associated with the porphyry-type Cu deposit, and the coeval Cuojiaoma, Dongcuo, and Daocheng plutons, three of which do not generate any Cu mineralization. Our study reveals that Ga, Ce, S, Cl, and Cu in apatite are effective indicators for both magmatic oxidation states and the abundances of volatiles and ore-forming metals. The Nd isotope of apatite can be used to trace the magma source. According to the above chemical compositions of apatite and Ce4+/Ce3+ ratio of zircon, the parental magma of the Pulang pluton is identified to be more fertile for Cu mineralization than those of the other three plutons, i.e., Cuojiaoma, Dongcuo, and Daocheng, because it is more oxidized and richer in Cu, Cl, and S. The aforementioned differences in magmatic physical and chemical conditions among the plutons investigated are ascribed to the different sources and natures of magmas, as revealed by both the Nd isotope and δEu, Sr/Y, and La/Yb values of apatite. Generally, the results indicate that magmatic fertility mainly governs the Cu-mineralization potential of Paleo-Tethyan granitoids in eastern Tibet, and that apatite is a robust probe for magmatic fertility. [ABSTRACT FROM AUTHOR]