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The Western Qinling Orogen (WQO) is characterized by voluminous distribution of Indosinian granitoids, the formation of which provides an important window to unravel the geochemical and geodynamic evolution and associated metallogeny. Here we investigate a group of intrusions termed “Five Golden Flowers” based on petrological, geochemical, zircon U–Pb geochronological and Lu–Hf isotopic studies on the granitoids and their mafic microgranular enclaves (MMEs). Our results show that these intrusions are genetically divided into two types, namely, magma-mixing and highly fractionated. The Jiaochangba, Lujing, Zhongchuan, and Luchuba granitoids are biotite monzogranites (220 ​± ​0.8 ​Ma to 217 ​± ​2.6 ​Ma) with abundant coeval MMEs (220 ​± ​1.1 ​Ma to 217 ​± ​2.7 ​Ma). The rocks contain moderate to high SiO2, high MgO, Rb, Sr, Ba, and Th contents, but low TiO2, P2O5, and Sc values, A/CNK of

PurposeTo explore the clinical value of apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI) based on diffusion-weighted MRI (DW-MRI) for predicting genotypes and prognostic factors of breast cancer.Materials and MethodsA total of 227 patients with breast cancer confirmed by pathology were reviewed retrospectively. Diffusion-weighted imaging (DWI), IVIM, and DKI were performed in all patients. The corresponding ADC, true diffusion coefficient (D), perfusion-related diffusion coefficient (D*), perfusion fraction (f), mean diffusion rate (MD), and mean kurtosis value (MK) were measured. Multivariate logistic regression analysis and receiver operating characteristic (ROC) curve were used to analyze the diagnostic efficacy in predicting the Nottingham prognostic index (NPI), the expression of antigen Ki-67, and the molecular subtypes of breast cancer. The nomogram of the combined genotype-prediction model was established based on the multivariate logistic regression model results.ResultsD* and MK values were significantly higher in the high-grade Nottingham group (NPI ≥ 3.4) than the low-grade Nottingham group (NPI < 3.4) (p < 0.01). When D* ≥ 30.95 × 10−3 mm2/s and MK ≥ 0.69, the NPI tended to be high grade (with areas under the curve (AUCs) of 0.712 and 0.647, respectively). The combination of D* and MK demonstrated the highest AUC of 0.734 in grading NPI with sensitivity and accuracy of 71.7% and 77.1%, respectively. Additionally, higher D*, f, and MK and lower ADC and D values were observed in the high Ki-67 than low Ki-67 expression groups (p < 0.05). The AUC of the combined model (D + D* + f + MK) was 0.755, being significantly higher than that of single parameters (Z = 2.770~3.244, p = 0.001~0.006) in distinguishing high from low Ki-67 expression. D* and f values in the Luminal A subtype were significantly lower than in other subtypes (p < 0.05). Luminal B showed decreased D value compared with other subtypes (p < 0.05). The HER-2-positive subtype demonstrated increased ADC values compared with the Luminal B subtype (p < 0.05). Luminal A/B showed significantly lower D, D*, MD, and MK than the non-Luminal subtypes (p < 0.05). The combined model (D + D* + MD + MK) showed an AUC of 0.830 in diagnosing the Luminal and non-Luminal subtypes, which is significantly higher than that of a single parameter (Z = 3.273~4.440, p < 0.01). f ≥ 54.30% [odds ratio (OR) = 1.038, p < 0.001] and MK ≥ 0.68 (OR = 24.745, p = 0.012) were found to be significant predictors of triple-negative subtypes. The combination of f and MK values demonstrated superior diagnostic performance with AUC, sensitivity, specificity, and accuracy of 0.756, 67.5%, 77.5%, and 82.4%, respectively. Moreover, as shown in the calibration curve, strong agreements were observed between nomogram prediction probability and actual findings in the prediction of genotypes (p = 0.22, 0.74).ConclusionDWI, IVIM, and DKI, as MR diffusion imaging techniques with different mathematical models showed potential to identify the prognosis and genotype of breast cancer. In addition, the combination of these three models can improve the diagnostic efficiency and thus may contribute to opting for an appropriate therapeutic approach in clinic treatment.

The Wenquan Mo deposit in Gansu Province, China, is one of the large porphyry Mo deposits in the Western Qinling Orogen that associated with the Triassic continental collision between the North China Block and South China Block. In this study, detailed fluid inclusions (FIs) analyses were performed on early stage quartz–biotite–K-feldspar veins, middle stage quartz–polymetallic sulfide veins and late stage sulfide–calcite veins. Four compositional types of FIs are observed, including pure CO2 (PC-type), CO2-H2O (C-type), H2O-NaCl (W-type), and daughter mineral-bearing polyphase (S-type, with no halite daughter mineral). The early stage quartz contains all the four types, which are mainly homogenized between 285 °C and 495 °C, with salinities ranging from 4.2 to 17.6 wt% NaCl eqv. However, in the middle stage, PC-type FIs are not observed, and S-, W- and C-types FIs yield homogeneous temperatures (Th) of 200–397 °C and salinities of 2.4–13.1 wt% NaCl eqv. Late stage quartz contains only W-type FIs with Th of 102–246 °C and salinities of 1.2–10.1 wt% NaCl eqv. Results indicate that the fluid-system evolved from an initial CO2-rich magmatic-hydrothermal fluid to a late CO2-poor meteoric fluid. In the early and middle stages, it is possible that heterogeneous FIs associations may have been trapped from a fluid immiscibility system. The dramatically decreasing percentage of PC- and C-types FIs in the ore stage indicates that CO2 escaped, which is possibly the result of earlier fluid immiscibility and phase separation. In addition, there are double peaks of Th in this stage that are obviously lower than in the early stage, showing that meteoric water flowed into and mixed with magmatic fluids, thereby cooling the hydrothermal system. These results suggest that metal precipitation resulted from fluid immiscibility, CO2 escape, and inflow of meteoric water occurred in the middle stage. The initial fluids of the Wenquan deposit are characterized by relatively high temperature, high salinity, high fO2, and are CO2-rich and NaCl-poor, indicating that the Wenquan deposit is a collisional-type porphyry Mo deposit. The oxygen fugacity (fO2) constrained by trace element compositions of zircons from the Wenquan Mo-bearing porphyry is uneven with ΔFMQ −10.3–+4.68 (average of −4.32), which could result from the input of mafic magma and its inhomogeneous mixing with felsic magma. Such values are still much higher than those of the adjacent contemporaneous Mo-barren Lujing, Baijiazhuang, Jiaochangba, Luchuba, and Zhongchuan granitic plutons, which confirms the affinity between Mo mineralization and the oxidized melt system and implies that the Wenquan porphyry has relatively high fO2 characteristics for its tectonic location and epoch. Fluid inclusion, initial mineralization depth (∼8.6 km), magma fO2, and the zircon high U/Yb ratio of the Wenquan Mo deposit strongly suggest that Mo mineralization was related to continental collision, rather than oceanic crust subduction. This study therefore proposes that the Wenquan Mo deposit was formed in a rapid crust uplifting setting caused by syn-orogenic crustal thickening followed by post-orogenic delamination of the lithospheric root during the Late Triassic.

The western Qinling orogen (WQO) is one of the most important prospective gold provinces in China. The Maanqiao gold deposit, located on the southern margin of the Shangdan suture, is a representative gold deposit in the WQO. The Maanqiao deposit is hosted by the metasedimentary rocks of the Upper Devonian Tongyusi Formation. The EW-trending brittle-ductile shear zone controls the orebodies; they occur as disseminated, and auriferous quartz–sulfide vein. The ore-related hydrothermal alteration comprises silicification, sulfidation, sericitization, chloritization, and carbonatization. Native gold is visible and mainly associated with pyrite and pyrrhotite. Mineralization can be classified into the following three stages: bedding-parallel barren quartz–pyrite–(pyrrhotite) (early-stage), auriferous quartz–polymetallic (middle-stage), and carbonate–(quartz)–sulfide (late-stage). Detailed fluid inclusion (FI) studies revealed three types of inclusions in quartz and calcite: aqueous (W-type), CO2–H2O (C-type), and pure carbonic (PC-type) FIs. The primary FIs in the early-stage quartz are C- and PC-type, in the middle-stage quartz are mainly W- and C-type, and in the late-stage calcite are only W-type. During gold mineralization, the total FI homogeneous temperatures evolved from 189–375 °C (mostly 260–300 °C) to 132–295 °C (mostly 180–240 °C) to 123–231 °C (mostly 130–150 °C), and the salinities varied among 2.2–9.1 wt.% NaCl equiv. (mostly 5–8 wt.%) to 0.2–9.0 wt.% NaCl equiv. (mostly 3–6 wt.%) to 0.3–3.6 wt.% NaCl equiv. (mostly 2–4 wt.%). The ore-forming fluid was characterized as an H2O–NaCl−CO2−CH4–(N2) system with medium-low temperature and low salinity. The fluid immiscibility and fluid-rock interaction may be responsible for the precipitation of the sulfides and gold at the Maanqiao gold deposit. Three types of pyrite corresponding to the three mineralization stages, as well as pyrrhotite and arsenopyrite in the middle stage, are micro-analyzed for in-situ sulfur isotopic composition by LA-ICP-MS. Py1 yield near-zero δ34S values of −2.5‰ to 3.0‰, which are somewhat lower than that of the granite hosted pyrites (Py-g, 4.8‰ to 6.6‰). The result suggests a mixed sulfur source from magmatic-hydrothermal fluids and the metamorphism of diagenetic pyrite. Pyrite + pyrrhotite + arsenopyrite assemblages in the middle-stage have relatively higher δ34S values (6.6‰ to 12.3‰) and are mainly developed due to the metamorphism of the ore-host and underlying Devonian sedimentary sequences. The low δ34S values of the late-stage fracture-filled Py3 (−21.9‰ to −17.0‰) resulted from an increasing oxygen fugacity, which was caused by the inflow of oxidized meteoric waters. Based on our studies, the Maanqiao gold deposit is considered to be an orogenic type and closely related to the Indosinian Qinling orogeny.

Pb isotopes are considered an ideal tool for identifying material sources and tectonic settings of various petrogeneses and mineralizations. A high precision method for in-situ Pb isotopic analysis by femtosecond laser-ablation multi-collector inductively coupled plasma mass spectrometry (fsLA-MC-ICP-MS) was first established in China by the State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University. This new method has been used to measure Pb isotopic compositions for inclusions, minerals, glasses, metals, etc., because of its negligible element fractionation and well-corrected mass discrimination. However, Pb isotopic studies on typical deposits using fsLA-MC- ICP-MS have until now rarely been reported globally. The Tongyu copper deposit in the Shaanxi Province, China is one of the most important VHMS deposits with industrial value and is also a typical example of mineralization associated with subduction and metallogenesis during the Caledonian orogeny in the western part of the North Qinling Orogen. Previous studies of this deposit have focused mainly on geological features and ore-forming ages, but detailed isotopic geochemical studies on the ore-forming material sources and tectonic settings were lacking.

The Jinlongshan gold deposit, Shaanxi Province, central China, is a large deposit (>150 t Au) in the Southern Qinling Orogen. Gold mineralization is hosted in Upper Devonian to Lower Carboniferous carbonaceous clastic-carbonate sequences. Four stages of pyrite and paragenetic sulfides have been identified based on morphology and paragenesis. Laser-ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA–MC–ICP–MS) analyses were conducted to determine the chemical and S–Pb isotopic composition of the sulfides. Pre-ore stage pyrites (Py1 and Py2) contain relatively high concentrations of Mn, Co, Ni, Cu, Zn, Sb, and Pb exhibiting a wide range of δ34S values, ranging from –29.9‰ to +48.4‰. These two pyrites were formed by bacterial and thermochemical sulfate reduction of Upper Devonian marine sulfate, respectively. Main-ore stage pyrite (Py3) and arsenopyrite (Apy) contain high concentrations of Au, As, Cu, Sb, Hg, and Tl with restricted ranges of δ34S values from 9.6‰ to 15.3‰, which is interpreted as resulting from the underlying low-grade metamorphic Paleozoic sedimentary rocks by the decomposition of pyrite and/or inorganic reduction of sulfate. Late- or post-ore stage pyrite (Py4) is characterized by low concentrations of Au, Ag, Sn, Hg, and Bi and exhibited variable δ34S values, ranging from –4.4‰ to +27.7‰, that may reflect the mixing of metamorphic fluids with meteoric water. Similarly, the Pb isotope composition of ore-stage sulfides resembles those of underlying low-grade metamorphic Paleozoic sedimentary rocks whereas differs from Precambrian metamorphic basement rocks and granitoids around the basin, indicating that the metals of the Jinlongshan gold deposit were sourced from the underlying Paleozoic sedimentary rocks. Detailed fieldwork revealed that the deposit has mainly undergone four deformation events. The ore bodies developed in NE-trending dextral oblique-slip reverse faults of D3 that crosscut WNW-trending shear zones of D2. The timing and corresponding stress regimes of the D3 event suggest that it formed in a local extensional environment of Yanshanian intracontinental orogeny of Qinling orogenic belt. Gold metallogenesis of the Jinlongshan gold deposit occurred during the transition of tectonic setting from compression to extension, which reactivated the shear zones and migrated deep ore-bearing fluids to NE-trending brittle faults. The geological and geochemical features of the Jinlongshan gold deposit are more analogous to the Carlin-type deposits than other orogenic gold deposits worldwide; therefore, we propose it is a typical Carlin-type gold deposit in South Qinling Orogen.

The Xiaohekou copper deposit is one of the few typical skarn-type, commercial deposits in the Zha-Shan ore cluster area in the eastern part of South Qinling. The ore-related granitoids in the Xiaohekou mining district include a number of small plutons of granodiorite porphyry and granite porphyry, as well as numerous dykes. They are characterized by relatively low SiO2 (65.9–73.3 wt%) and MgO (0.26–1.72 wt%) contents, variable Mg# (29.4–64.0) values, high K2O (3.11–5.75 wt%) content and negligible δEu (1.00–1.15) values. The samples also exhibit depletion in Cr, Ni, Nb, Ta, and Ti content, and high Sr/Y (46.6–64.7) and La/Yb (17.0–25.0) ratios. These features are similar to those of high-K calc-alkaline adakite-like magma formed by partial melting of thickened lower crust in continental collision zones or intracontinental settings. The majority of the samples have TDM2(Hf) of 1.5–1.2 Ga, corresponding to weakly negative eHf(t) values (−4.75 to −0.13) typical of crustal material, but more than one quarter have TDM1(Hf) of 0.80–0.71 Ga, corresponding to positive eHf(t) values of +0.07 to +2.45, indicating that the granitoids resulted from partial melting of Mesoproterozoic lower crustal rocks with significant input from enriched lithospheric mantle-derived magmas. Zircons from the Xiaohekou granitoids have ΔFMQ values concentrated around −0.62 to +5.54, most of which show the magma fO2 of FMQ to HM, in accordance with the widespread occurrence of magnetite, hematite and specularite in the Xiaohekou skarn system, which is an indicator of relatively high fO2 for a magmatic–hydrothermal system. The granitoids exhibit similar or even higher Ce4+/Ce3+ (average of 452) and Eu/Eu* (average of 0.72) values in comparison with those of fertile Cu deposits worldwide, indicating that the Xiaohekou granitoids may possess the potential to form a large magmatic–hydrothermal Cu deposit. Zircons of the granitoids show obvious positive correlations between oxidation indices (Ce and Eu anomalies, Ce4+/Ce3+ ratios, and ΔFMQ values) and eHf(t) values, implying the involvement of an oxidized mantle component which might have caused the fO2 elevation and played an important role in the formation of Cu deposits. The zircon U–Pb ages (141.3 ± 1.3 and 138.1 ± 2.0 Ma) of the Xiaohekou ore-related granitoids obtained in this study are similar to the zircon U–Pb and molybdenite Re–Os ages yielded from porphyry Mo mineralization at the Chigou and Lengshuigou deposits in the Zha-Shan ore district, indicating that they are possibly part of a single tectonic, magmatic, and metallogenic event in the Yanshan orogeny. The ore-related granitoids in the Xiaohekou area were formed in a post-collisional compression–extension transition regime during the Early Cretaceous Qinling intracontinental orogeny. The orogeny can be attributed to the far-field effect of a switch from pre-Mesozoic Tethyan tectonics to Late Mesozoic Pacific tectonics. This triggered a stress field transition from N–S to E–W trending and from intracontinental subduction thickening to large-scale lithospheric delamination and thinning.

The Zhongchuan district is an important component of the metallogenic belt in the Western Qinling. The Zhongchuan granite pluton occurring in the centre of the Zhongchuan metallogenic area has been poorly constrained, though the Triassic granite in Western Qinling has been well documented. In-situ zircon U–Pb ages, Hf isotopic compositions and whole-rock geochemical data are presented for host granite and mafic microgranular enclaves (MMES) from the Zhongchuan pluton, in order to constrain its sources, petrogenesis and tectonic setting of the pluton. The distribution of major, trace and rare earth elements apparently reflect exchange between the MMES and the host granitic rocks mainly due to interactions between coeval felsic host magma and mafic magma. The zircon U–Pb age of host granite (231.6 ± 1.5 to 235.8 ± 2.3 Ma) has overlapping uncertainty with that of the MMES (236.6 ± 1.3 Ma), establishing that the mafic and felsic magmas were coeval. The Hf isotopic composition of the MMES (eHf(t) = −13.4 to 4.0) is distinct from the host granite (eHf(t) = −15.7 to 0.0), indicating that both enriched subcontinental lithosphere mantle (SCLM) and crustal sources contributed to their origin. The zircons have two-stage Hf model ages of 1064 to 1798 Ma for the host granite and 858 to 1747 Ma for the MMES. This suggests that the granitic pluton was likely derived from partial melting of a Late Mesoproterozoic crust, with subsequent interaction with the SCLM-derived mafic magmas in tectonic affinity to the South China Block. Copyright © 2012 John Wiley & Sons, Ltd.

East Qinling is the largest porphyry molybdenum province in the world; these Mo deposits have been well documented. In West Qinling, however, few Mo deposits have been discovered although granitic rocks are widespread. Recently, the Wenquan porphyry Mo deposit has been discovered in Gansu province, which provides an insight into Mo mineralization in West Qinling. In this paper we report Pb isotope compositions for K-feldspar and sulfides, S isotope ratios for sulfides, the results obtained from petrochemical study and from in situ LA-ICP-MS zircon U-Pb dating and Hf isotopes. The granitoids are enriched in LILE and LREE, with REE and trace element patterns similar to continental crust, suggesting a crustal origin. The Mg # (40.05 to 56.34) and Cr and Ni contents are high, indicating a source of refractory mafic lower crust. The e Hf( t ) values of zircon grains from porphyritic monzogranite range from − 2.9 to 0.6, and from granitic porphyry vary from − 3.3 to 1.9. The zircons have T DM2 of 1014 to 1196 Ma for the porphyritic monzogranite and 954 to 1224 Ma for the granitic porphyry, implying that these granitoids were likely derived from partial melting of a Late Mesoproterozoic juvenile lower crust. The Pb isotope compositions of the granitoids are similar to granites in South China, showing that the magma was sourced from the middle–lower crust in the southern Qinling tectonic unit. The Pb isotopic contrast between the Mo-bearing granitoids and ores shows that the Pb in the ore-forming solution was derived from fractionation of a Triassic magmatic system. δ 34 S values of sulfides are between 5.02 and 5.66‰, similar to those associated with magmatic-hydrothermal systems. LA-ICP-MS zircon U-Pb dating yields crystallization ages of 216.2 ± 1.7 and 217.2 ± 2.0 Ma for the granitoids, consistent with a previously reported molybdenite Re-Os isochron age of 214.4 ± 7.1 Ma. This suggests that the Mo mineralization is related to the late Triassic magmatism in the West Qinling orogenic belt. In view of these geochemical results and known regional geology, we propose that both granitoid emplacement and Mo mineralization in the Wenquan deposit resulted from the Triassic collision between the South Qinling and the South China Block, along the Mianlue suture. Since Triassic granitoid plutons commonly occur along the Qinling orogenic belt, the Triassic Wenquan Mo-bearing granitoids highlight the importance of the Triassic tectono-magmatic belt for Mo exploration. In order to apply this metallogenic model to the whole Qinling orogen, further study is needed to compare the Wenquan deposit with other deposits.

Rapid industrialization and economic take-off in coastal cities of China have placed great strain on the environment. In the this study, 40 aerosol samples were collected in the coast of Xiamen, Fujian province, west Taiwan Strait, P. R. China, from January to December 2003. The samples were analysed for the concentrations of elements (K, Ca, Na, Zn, Pb, W, Se, As, Ni, Ba, Nb, Ta, Zr, Hf, Th, U, Sr, REEs, etc.). All the elements display significant seasonal variations. The concentrations of most of the elements (except Na and Se) were high in January and February, abruptly decreased in March, kept relatively constant but low from April to August, and then gradually increased from September to December. This corresponds to the rainless climate and the influence of biomass burning from Southeast Asia in the winter and rain scavenging and the diffusion of typhoon in the summer. Thus, most of the elements have a good negative correlation with the monthly precipitation. The SEM/EDX studies indicate that the aerosols of Xiamen mainly consisted of soot grains, clay minerals, feldspar, gypsum, quartz, and biological particulates. The calculated enrichment factors indicate that Na and Br are derived from ocean, Pb, Zn, As, Sb, Se, W, and Ni are anthropogenic elements mainly derived from coal combustion, vehicle exhaust, and mining, and the other elements (i.e., Zr, Fe, Cr, Co, Rb, Sr, Cs, Ba, Hf, Ta, Th, U, and REEs) are crustal elements derived from weathered rocks and soil dust. The elemental concentrations of aerosols in Xiamen were compared with other cities, and the results indicate that Xiamen, like other coastal cities such as Qingdao, Dalian, Hong Kong, and Tokyo, has much lower concentrations of the elements such as Pb, Zn, and Cr than Beijing. The elemental deposition fluxes in Xiamen were also compared to other cities. The comparisons indicate that the elemental deposition fluxes in these cities are influenced not only by climatic characteristics (e.g., the precipitation and the sandstorm), but also by the industrial facility denseness.