Search

Different from the Dirac spinor, the localization of a five-dimensional Elko spinor on a brane with codimension one is very difficult because of the special structure of the Elko spinor. By introducing the coupling between the Elko spinor and the scalar field generating the brane, we have two mechanisms for localization of the zero mode of a five-dimensional Elko spinor on a brane. One is the Yukawa-type coupling and the other is the non-minimal coupling. In this paper, we investigate the localization of the Elko zero mode on de Sitter and Anti-de Sitter thick branes with the two localization mechanisms, respectively. It shows that both the mechanisms can realize the localization. The forms of the coupling functions of the scalar field in the two mechanisms have similar properties respectively and they play similar role for the localization., Comment: 15 pages, 5 figures

Background: Although variants in the three trypsin-dependent pathway genes, PRSS1, SPINK1 and CTRC, have been firmly associated with a risk of developing chronic pancreatitis, their potential impact on the clinical course of the disease remains unclear. Methods: We performed targeted next-generation sequencing of the PRSS1, SPINK1 and CTRC genes in 2 257 Han Chinese subjects, including 715 idiopathic chronic pancreatitis (ICP) patients, 206 alcoholic chronic pancreatitis (ACP) patients, 140 smoking-associated chronic pancreatitis (SCP) patients, and 1 196 controls. All called rare variants were subjected to Sanger sequencing; all validated variants were assigned as being either pathogenic or non-pathogenic in accordance with stringent criteria. The potential impact of pathogenic variants on disease onset and progression of ICP, ACP and SCP was evaluated using the Kaplan-Meier model. Findings: We identified rare pathogenic genotypes involving the PRSS1, SPINK1 and CTRC genes in 388 (54·27%) of ICP patients but in only 52 (4·35%) of controls (odds ratio=26·10; p

In this paper, we derive in a novel approach the possible textures of neutrino mass matrix that can lead us to maximal atmospheric mixing angle and Dirac CP phase which are consistent with the current neutrino oscillation data. A total of eleven textures are thus found. Interestingly, the specific texture given by the $\mu$-$\tau$ reflection symmetry can be reproduced from one of the obtained textures. For these textures, some neutrino mass sum rules which relate the neutrino masses and Majorana CP phases will emerge., Comment: 21 pages, 10 figures, version to appear in JHEP, a new paragraph discussing the physical meaning of the textures obtained is added at the end of section 3

Columbite–tantalite (Coltan) is the most important niobium (Nb)- and tantalum (Ta)-bearing economic mineral, commonly occurring in rare metal granite and pegmatite, alkaline granite, syenite and carbonatite. Its high U but low common Pb contents make it an ideal mineral for U–Pb isotopic dating of Nb–Ta mineralization. In order to establish a feasible coltan dating method by in situ laser-ablation (LA) ICP–MS, we determined the U–Pb ages of five coltan samples from different pegmatites and rare-metal granites in China. In order to evaluate the potential matrix effect between different minerals, a 91500 zircon was used as external standard during analyses. The results show that, compared to the recommended ages, approximately 7–15% younger ages were yielded for the analyzed coltan samples in both single spot and line raster scan analytical methods, indicating a significant matrix effect between coltan and zircon. However, by using a coltan standard from Namibia (Coltan139), the coltan sample from Dahe pegmatite (SNNT) has a weighted mean 206Pb/238U age of 363 ± 4 Ma (2σ, n = 25) and 357 ± 5 Ma (2σ, n = 20) in single spot and line raster scan analytical methods, respectively; the coltan samples from Altai No.3 pegmatite (713-79), Yichun topaz-lepidolite granite (Yi-1) and Huangshan albite granite (LS-15) have weighted mean 206Pb/238U ages of 218 ± 2 Ma (2σ, n = 20), 160 ± 1 Ma (2σ, n = 20) and 130 ± 1 Ma (2σ, n = 20), respectively, in single spot mode. These ages agree well with the previously published data, and hence support the reliability of our analytical method. Although the analyzed coltan minerals show a large variation of chemical compositions, no significant matrix effect was observed, which suggests that a coltan material should be used as an external standard for U–Pb dating of coltan by LA–ICP–MS. Using the established analytical protocol, we date the Nanping pegmatite (NP155), a main Nb–Ta deposit in China without known age, and obtain a weighted mean 206Pb/238U age of 391 ± 4 Ma (2σ, n = 20), which is considered as the best estimation of Nb–Ta mineralization time in the area.

Tungsten based vanadium alloys have been fabricated by powder metallurgy and consolidated by spark plasma sintering (SPS) at temperature of 1600 °C for 3–5 min at 50 MPa. Four different concentrations of vanadium ranging from 1 to 10 wt.% were used to investigate the behavior of the developed alloys. X-ray diffraction analyses were performed for all four compositions of tungsten vanadium alloys. The morphology of cross sectional crack surfaces of sintered alloys was analyzed by scanning electron microscopy. The variations of vanadium concentration has not only shown an obvious impact on the microstructures, but also improved the densification and mechanical properties of the tungsten based materials. The maximum relative density of 98.5% was achieved for the highest concentration (10 wt.%) of vanadium alloy with micro hardness of 507 HV and good bending strength of 692.5 MPa.

Endothelial dysfunction, regarded as a key step in the pathophysiological course of diabetic vascular complications, is initiated and deteriorated by advanced glycation end products (AGEs). DL-3-n-butylphthalide (DL-NBP) has been proven to have protective effects on neurons and vascular endothelial cells against ischemic and anoxic damage. The aim of the present study was to investigate whether NBP is able to attenuate AGE-induced endothelial dysfunction in vitro, and also elucidate the possible underlying mechanism. An injury model of human umbilical vein endothelial cells (HUVECs) induced by AGEs (200 µg/ml) was established. The results demonstrated that pretreatment with NBP (1-100 µM) significantly increased HUVEC viability and inhibited the apoptosis induced by AGEs. In addition, AGEs stimulated the expression levels of the receptor for AGEs protein and the downstream protein nuclear factor-κB in HUVECs, which were inhibited by pretreatment with NBP. Furthermore, it significantly reduced reactive oxygen species generation and the level of the inflammatory cytokines, intercellular cell adhesion molecule-1 and monocyte chemotactic protein-1, in HUVECs mediated by AGEs. The current findings indicated that NBP attenuated AGE-induced endothelial dysfunction by ameliorating inflammation and oxidative stress responses.

If massive neutrinos are the Majorana particles and have a normal mass ordering, the effective mass term $\langle m\rangle^{}_{ee}$ of a neutrinoless double-beta ($0\nu 2\beta$) decay may suffer significant cancellations among its three components and thus sink into a decline, resulting in a "well" in the three-dimensional graph of $|\langle m\rangle^{}_{ee}|$ against the smallest neutrino mass $m^{}_1$ and the relevant Majorana phase $\rho$. We present a new and complete analytical understanding of the fine issues inside such a well, and discover a novel threshold of $|\langle m\rangle^{}_{ee}|$ in terms of the neutrino masses and flavor mixing angles: $|\langle m\rangle^{}_{ee}|^{}_* = m^{}_3 \sin^2\theta^{}_{13}$ in connection with $\tan\theta^{}_{12} = \sqrt{m^{}_1/m^{}_2}$ and $\rho =\pi$. This threshold point, which links the {\it local} minimum and maximum of $|\langle m\rangle^{}_{ee}|$, can be used to signify observability or sensitivity of the future $0\nu 2\beta$-decay experiments. Given current neutrino oscillation data, the possibility of $|\langle m\rangle^{}_{ee}| < |\langle m\rangle^{}_{ee}|^{}_*$ is found to be very small., Comment: 9 pages, 3 figures, version to appear in Eur. Phys. J. C

Feiyan Shou,1,* Feng Xu,2,* Gang Li,1 Zhenhua Zhao,3 Ying Mao,4 Fangfang Yang,5 Hongming Wang,6 Hangyuan Guo5 1Department of General Practice, 2Department of Breast and Thyroid Surgery, 3Department of Radiology, 4Department of Special Inspection Section, 5Department of Cardiovascular Diseases, 6Department of Acupuncture and Moxibustion, Shaoxing People’s Hospital, Shaoxing, People’s Republic of China *These authors contributed equally to this work Objective: Previous studies have reported that Ras-associated domain family 1A (RASSF1A), the most commonly silenced tumor suppressor via promoter methylation, played vital roles in the development of carcinogenesis. The purpose of this meta-analysis was to determine whether RASSF1A promoter methylation increased the risk of thyroid cancer. Methods: PubMed, Embase, ISI Web of Knowledge, and Chinese National Knowledge Infrastructure databases were searched to obtain eligible studies. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the strength of the associations, using Stata 12.0 software. The methodological quality of included studies was evaluated using Newcastle–Ottawa scale table. Egger’s test and Begg’s test were applied to detect publication biases. TSA 0.9 software was used to calculate the required information size and whether the result was conclusive. Results: A total of 10 articles with 12 studies that included 422 thyroid cancer patients, identifying the association of RASSF1A promoter methylation with thyroid cancer risk, were collected in this meta-analysis. Overall, RASSF1A promoter methylation significantly increased the risk of thyroid cancer (total, OR=8.27, CI=4.38–15.62, P

Genesis of adakites in arc and nonarc tectonic settings plays an important role in magmatic processes and material recycling along convergent margins. However, little is known about characteristics of pristine adakitic melts due to late stage magma evolutionary processes that dilute or obscure primary melt features, and thus, the genesis of adakites remains controversial. Here we present a detailed analysis of amphibole composition from Early Permian Awulale postcollisional adakitic diorite and granodiorite porphyries in the core of Tianshan Orogen, the central Asian orogenic belt. Two distinct populations of amphiboles, with markedly different aluminum contents, are observed in the adakitic rocks. These are (1) high-Al amphiboles, crystallizing as an early mineral phase at about 1 GPa, and (2) low-Al amphiboles, as a late mineral phase at 220–400 MPa, estimated on the basis of experimental phase equilibria data. Trace element modeling indicates that melts in equilibrium with the high-pressure amphiboles are of adakitic composition, suggesting that the Awulale pristine magmas already had an adakitic nature before the amphibole crystallization. This is consistent with the mafic lower crustal melting model, rather than a high-pressure basaltic melt fractionation, for adakite petrogenesis. Our results lend new insights into how amphibole composition can be used to constrain the geochemical characteristics of pristine adakitic magmas.

The Leigh syndrome (LS), characterized by psychomotor retardation, seizures, nystagmus, ophthalmoparesis, optic atrophy, ataxia, dystonia, or respiratory failure, is one of the most severe mitochondrial diseases. In the majority of cases, the disease is fatal and patients die before age 5. Mutation m.10197 G>A was found to relate to the severe phenotype of the Leigh syndrome. Here, we describe the first Chinese Leigh syndrome pedigree with this mutation. The proband had the characteristic brain lesions of the Leigh syndrome and presented a decrease in exercise tolerance and mild face paralysis. Sequencing the NADH dehydrogenase, subunit 3 (ND3) gene in the pedigree, revealed that the proband, as well as her unaffected brother, have a high mutant load in the ND3 gene, compared to their mother. Following one‑year treatment with the coenzyme Q10, an obvious improvement in clinical features was observed by magnetic resonance imaging (MRI) in the proband. Our study and previous reports highlight the variability of phenotypic expression of the m.10197 G>A mutation, and suggest that pathogenesis of the syndrome may be affected by a number of factors. This is the first report on successful treatment of an LS patient carrying the mutation m.10197 G>A with the coenzyme Q10, indicating that Q10 may attenuate the mitochondrial dysfunctions caused by the m.10197 G>A mutation.

The aim of the current study was to identify the genes on human chromosome 21 (HC21) that may serve important functions in the pathogenesis of Down syndrome (DS). The microarray data GSE5390 were obtained from the Gene Expression Omnibus database, which contained 7 DS and 8 healthy normal samples. The data were then normalized and the differentially expressed genes (DEGs) were identified using the LIMMA package and Bonferroni correction. Furthermore, the DEGs underwent clustering and gene ontology analysis. Additionally, the locations of the DEGs on HC21 were confirmed using human genome 19 in the University of California, Santa Cruz Interaction Browser. A total of 25 upregulated and 275 downregulated genes were screened between DS and healthy samples with a false discovery rate of0.05 and |logFC|1. The expression levels of these genes in the two samples were different. In addition, the up‑ and downregulated genes were markedly enriched in organic substance biological processes (P=4.48x10‑10) and cell‑cell signaling (P=0.000227). Furthermore, 17 overexpressed genes were identified on the 21q21‑22 area, including COL6A2, TTC3 and ABCG1. Together, these observations suggest that 17 upregulated genes on HC21 may be involved in the development of DS and provide the basis for understanding this disability.

The Dongping gold deposit is a large deposit with total gold reserves of > 100 tons. It is located at the northern margin of the North China Craton, northwestern Hebei province, China. The ore-bodies are hosted by the Devonian Shuiquangou syenite complex and consist mainly of auriferous quartz veins and disseminated ore in the altered and silicified syenite. U–Pb dating of zircon from hornblende syenite on the western margin of the complex yields a crystallization age of 400 ± 3.5 Ma (MSWD = 0.018). Morphology, cathodoluminescence imaging and geochemical classifications of zircon from the first stage of disseminated ore and gray auriferous quartz veins, and from later stage, low grade quartz veins point to their newly crystallized hydrothermal origin. The hydrothermal zircon from the disseminated ore and auriferous gray quartz vein are dated at 389 ± 1.0 Ma and 385 ± 5.7 Ma, respectively, which are detectably younger than but close to the crystallization age of the syenite complex and might have been formed by post-magmatic hydrothermal processes. Both types of ore are dominant in the ore deposit, and we propose that the pervasive, post-magmatic hydrothermal alteration is the main ore forming stage. Hydrothermal zircon from a low grade auriferous quartz vein yields a U–Pb age of ~ 140 Ma, interpreted as forming during a younger period of superimposed Yanshanian hydrothermal mineralization. Thus, the ore of the Dongping gold mine represents a post-magmatic Devonian hydrothermal ore deposit with Jurassic–Cretaceous hydrothermal overprinting.

Mafic dike–granitoid associations are common in extensional tectonic settings and provide important opportunities for understanding mantle and crust melting during the tectonic evolution of host orogenic belts. We report results of petrologic, whole rock geochemical, Sr–Nd isotopic data and in situ zircon U–Pb and Hf isotopes for a mafic dike–granitoid association from the Zhongyangchang pluton in the western Tianshan, in order to constrain their petrogenesis and tectonic significance. The intrusive rocks are mainly composed of granodiorite, monzogranite, and minor granitic dikes, with mafic dikes intruded into the pluton. Zircon LA-ICP-MS U–Pb ages indicate that the Zhongyangchang intrusive rocks were all emplaced during a short interval in the Late Carboniferous (317–310 Ma), establishing that the mafic and felsic magmas were coeval. The mafic rocks have low SiO 2 and high MgO concentrations, with low 87 Sr/ 86 Sr ratios from 0.7048 to 0.7053 and positive e Nd (t) and zircon e Hf (t) values from + 2.9 to + 3.8 and + 12.2 to + 13.6, respectively. They are enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs), which can be explained by an origin from melting of a depleted lithospheric mantle source and source fluxing by fluids derived from the down-going slab. Granitoids from the pluton have high SiO 2 contents and low MgO concentrations, suggesting that they were mainly derived from crustal sources. They also have positive whole rock e Nd (t) and zircon e Hf (t) values ranging from + 0.2 to + 2.8 and + 6.6 to + 15.3, respectively, similar to those of the mafic dikes. They were generated by partial melting of juvenile basaltic lower crust as a result of magma underplating. The Late Carboniferous mafic dike–granitoid association was not related to a post-collisional setting, but rather formed in an arc environment related to oceanic subduction. The most likely tectonic model accounting for the genesis of these rocks involves an extensional environment in the western Tianshan during the Late Carboniferous as a tectonic response to the roll-back of subducted Junggar oceanic lithosphere, which could also account for the “flare-up” of Late Carboniferous magmatism.

Many Late Paleozoic Cu–Au–Mo deposits occur in the Central Asian Orogenic Belt (CAOB). However, their tectonic settings and associated geodynamic processes have been disputed. This study provides age, petrologic and geochemical data for andesites and granitic porphyries of the Taerbieke gold deposit from the Tulasu Basin, in the northwestern Tianshan Orogenic Belt (western China). LA-ICP-MS zircon U–Pb dating indicates that the granitic porphyries have an Early Carboniferous crystallization age (349 ± 2 Ma) that is broadly contemporaneous with the eruption age (347 ± 2 Ma) of the andesites. The andesites have a restricted range of SiO2 (58.94–63.85 wt.%) contents, but relatively high Al2O3 (15.39–16.65 wt.%) and MgO (2.51–6.59 wt.%) contents, coupled with high Mg# (57–69) values. Geochemically, they are comparable to Cenozoic sanukites in the Setouchi Volcanic Belt, SW Japan. Compared with the andesites, the granitic porphyries have relatively high SiO2 (72.68–75.32 wt.%) contents, but lower Al2O3 (12.94–13.84 wt.%) and MgO (0.10–0.33 wt.%) contents, coupled with lower Mg# (9–21) values. The andesites and granitic porphyries are enriched in both large ion lithophile and light rare earth elements, but depleted in high field strength elements, similar to those of typical arc magmatic rocks. They also have similar Nd–Hf–Pb isotope compositions: eNd(t) (+0.48 to +4.06 and −0.27 to +2.97) and zircons eHf(t) (+3.4 to +8.0 and −1.7 to +8.2) values and high (206Pb/204Pb)i (18.066–18.158 and 17.998–18.055). We suggest that the Taerbieke high-Mg andesitic magmas were generated by the interaction between mantle wedge peridotites and subducted oceanic sediment-derived melts with minor basaltic oceanic crust-derived melts, and that the magmas then fractionated to produce the more felsic members (i.e., the Taerbieke granitic porphyries) during late-stage evolution. Taking into account the Carboniferous magmatic record from the western Tianshan Orogenic Belt, we suggest that the formation of the Early Carboniferous andesites and granitic porphyries in the Taerbieke area were related to the Paleo-Junggar Oceanic plate southward subduction under the Yili–Central Tianshan plate. The close association of the Early Carboniferous magmatic rocks and Au mineralization in the Taerbieke area suggests that the arc magmatic rocks in the Tulasu basin may have a high potential for Au mineralization.

In order to study the effect of W–Ce alloy with helium implantation, W–Ce alloy has been exposed to helium beams with energy of 45 KeV and flux of 1.5–2.0 × 1013 ion/cm2 s−1. Surface morphology has been observed by scanning electron microscope, the composition of the samples is analyzed by energy dispersive spectrometer, and the mechanical property is tested by nano-hardness tester. The surface morphology indicated the blister and surface damage of tungsten strongly depend on fluence and affected by the element doping. Surface blister were observed for pure W while no blister was observed for W–Ce alloy. A lot of pores caused by sputtering were observed on the both types of samples. W–Ce alloy showed better performance on mechanical property compared with pure W. These results indicated that the He–Ce–V complexes and fine second phase sediments in the grain boundary can obstruct the migration and coalescence of helium atoms, and obstruct the slip of grain boundary resulting in the improvement of mechanical property.

In the framework in which supersymmetry is used for understanding fermion masses rather than stabilizing the electroweak scale, we elaborate the phenomenological analysis for the neutrino physics. A relatively large $\sin{\theta_{13}}$ is the natural result. The model further predicts vanishingly small CP violation in neutrino oscillations. And $\theta_{23}$ is not necessarily maximal. While the high scale supersymmetry generically results in a Higgs mass of about 141 GeV, our model reduces this mass via introducing SU(2)$_L$ triplet fields which also contribute to neutrino masses., Comment: 13 pages, no figure, revtex4, revised version

In light of the observation of a relatively large $\theta^{}_{13}$, one has to consider breaking the $\mu$-$\tau$ symmetry properly which would otherwise result in a vanishing $\theta^{}_{13}$ (as well as $\theta^{}_{23} = \pi/4$). Therefore, we investigate various symmetry-breaking patterns and accordingly identify those that are phenomenologically viable. Furthermore, the symmetry-breaking effects arising from some specific physics (e.g., the renormalization group equation running effect) are discussed as well., Comment: 14 pages, a contribution to the Conference on New Physics at the Large Hadron Collider (29 February to 4 March 2016), Singapore

Behind the observed pattern of lepton flavor mixing is a partial or approximate mu-tau flavor symmetry --- a milestone on our road to the true origin of neutrino masses and flavor structures. In this review article we first describe the features of mu-tau permutation and reflection symmetries, and then explore their various consequences on model building and neutrino phenomenology. We pay particular attention to soft mu-tau symmetry breaking, which is crucial for our deeper understanding of the fine effects of flavor mixing and CP violation., 105 pages, 10 figures. The text reorganized, more references added, minor typos fixed. Invited review article being published in Reports on Progress in Physics

A hydrochemical investigation was conducted in northwest margin of Lop Nur to evaluate the groundwater chemical patterns and the main hydrological processes occurring in the groundwater system. Fourteen representative groundwater samples were collected from different springs and boreholes. Hydrochemical data of the groundwater showed that SO4, Cl-Na and Cl, SO4-Na water types were dominant in this area, and the total dissolved solid (TDS) content rose along the flow path of the groundwater. Ionic relation analysis was used in conjunction with geochemical modeling to investigate the evolution of the chemical composition of groundwater. PHREEQC was used for inverse geochemical modeling. It is demonstrated that the groundwater, recharged mainly in the northern low mountains, acquired its mineralization properties principally from water–rock interactions, i.e., dissolution of evaporates and reverse cation exchange. The dissolution of halite, Glauber’s salt, dolomite and calcite determined the Na+, Cl−, Mg2+, Ca2+, SO4 2− and HCO3 − chemistry, but evaporation and precipitation also influenced the water composition. The shallow groundwater of Lop Nur was characterized by high salinity and slow circulation.

The latest LHC data suggest an intriguing excess at $m_{\gamma\gamma} = 750$ GeV which apparently requires an explanation from the beyond standard model physics. In this note we explore the possibility for this signal to arise from a top-pion in the Top Triangle Moose model which can be viewed as a dimensional-deconstruction version of the top-color assisted technicolor model. We demonstrate that the observed excess can be accommodated by and has important implications for this interesting model., Comment: 12 pages, 3 figures, Int. J. Mod. Phys. A (2016)

We report results of petrologic, geochronological and geochemical investigation of the Late Carboniferous diorites, granodiorites, amphibole (Am)-bearing granites, and associated dioritic and monzonitic enclaves and mafic and granitic dikes in the Keramay area, of the western Junggar region of Central Asian Orogenic Belt (CAOB). Zircon U–Pb dating suggests that they were generated in the Late Carboniferous (316–304 Ma). The diorite and granodiorite compositions extend over a wide range of SiO2 (53–70 wt.%), Sr (240–602 ppm), and Mg# (41–58) values, and are characterized by moderately fractionated rare earth element (REE) patterns, Nb–Ta depletion and relatively low Y and Yb contents. The mafic dikes consist of dolerites, diorite porphyries and minor granodiorite porphyries, and have variable SiO2 (51–59 wt.%) and high Mg#, Cr and Ni values. With the exception of two samples with relatively high heavy REE (HREE) contents, the mafic dikes exhibit trace element characteristics similar to diorites and granodiorites. The Am-bearing granites and a granite porphyry dike sample have high levels of SiO2 (73–77 wt.%), HREEs (e.g., Yb = 3.46–15.7 ppm) and low Mg#, Cr and Ni contents, along with clearly negative Eu, Ba and Sr anomalies, similar to typical A-type granites. All granitoids, enclaves and dikes in this region have high positive eNd(t) (+ 7.13 to + 9.74) and zircon eHf(t) (+ 10 to + 16) values and moderate initial 87Sr/87Sr ratios (0.7004–0.7049). Mineral composition data suggest that the parental magmas for mafic dikes are similar to Cenozoic sanukitoids in the Setouchi arc area (Japan) and were possibly generated under water-rich and high oxygen fugacity (NNO + 1.5 to NNO + 2.7) conditions. They most likely originated from partial melting of a mantle source variably modified by subducted oceanic crust-derived melts and minor fluids and subsequently underwent fractional crystallization. The diorites and granodiorites were possibly generated by magma mixing between enriched lithospheric mantle and juvenile lower crust-derived magmas coupled with minor crystal fractionation. The Am-bearing granites and granite porphyry dike were produced by partial melting of juvenile crustal materials at shallow crustal levels. Taking into account widespread contemporaneous magmatism including “MORB-type” basalts and slab-derived adakites in western Junggar, we suggest that the Keramay intrusive rocks were generated in a special arc setting related to ridge subduction and resultant slab window, which played an important role in the crustal growth of the CAOB.

Tholeiites occur in a variety of geological settings, e.g., mid-ocean ridge, back-arc basin, ocean island, island arc and intra-continent, and their geochemical and isotopic characteristics vary according to the corresponding geodynamic environments. Here we investigated the Hatu tholeiitic basalts and basaltic andesites of the western Junggar region, Central Asian Orogenic Belt (CAOB). LA-ICPMS zircon U–Pb analyses indicate that the Hatu tholeiites were generated in the Late Carboniferous (~ 315 Ma). All the studied rock samples are characterized by flat rare earth elements pattern on chondrite-normalized plot, and negligible Nb, Ta and Ti anomalies on mid-ocean-ridge basalt normalized plots. They are also characterized by moderate positive eNd(t) (+ 5.25 to + 5.94), eHf(t) (+ 13.24 to + 14.89), highly radiogenic Os isotope compositions (187Os/188Os315Ma = 0.1338–0.3547), and relatively low (87Sr/86Sr)i ratios (0.7044 to 0.7048). Taking into account their geological characteristics, the occurrence of nearby ophiolites and the types of contemporaneous magmatic rocks found in the western Junggar region, we propose that the Hatu basalts were generated by slab window-related processes following a spreading ridge subduction beneath the Keramay intra-oceanic island arc. During this process, deep and enriched asthenospheric mantle rose to the edge of the subducted oceanic lithosphere, its melts infiltrating the subducted oceanic lithosphere and reacting with peridotites. Therefore, the Hatu tholeiites are interpreted as a result of melting of a mixed mantle source consisting of subducted depleted oceanic lithosphere and a deep, enriched upwelling asthenospheric mantle. Incongruent dynamic melting modeling of trace element compositions indicates that the Hatu basalts could have been derived from large degrees of melting (~ 10%) of such a mixed mantle source. This newly recognized mechanism is a natural consequence of the diversity of contemporaneous potential mantle sources available in slab window settings.

The juvenile component of accretionary orogenic belts has been declining since the Archean. As a result, there is often controversy regarding the contribution of oceanic basalts to Phanerozoic crustal growth, as in the case of the Central Asian Orogenic Belt (CAOB). Here we report on three groups of Late Carboniferous (316–305 Ma) granitoids in the western Junggar region of northern Xinjiang, NW China, which is part of the southwestern CAOB. They consist of adakites and I and A-type granites, and as a whole have the most depleted isotopic compositions (e Nd (t) = + 6–+9, ( 87 Sr/ 86 Sr) i = 0.7030–0.7045, and e Hf (t) = + 12–+16) among the granitoids of the CAOB. These features are nearly identical to those of pre-Permian ophiolites in northern Xinjiang, and are clearly different from those of Carboniferous basalts in the western Junggar region. These relationships indicate that the granitoids were mainly derived from recycled oceanic crust by melting of subducted oceanic crust (e.g., adakites), and of the middle–lower crust of intra-oceanic arc that mainly consisted of oceanic crust (e.g., I and A-type granites). Based on evidence from the CAOB, we suggest that recycling of oceanic crust has made a significant contribution to continental crustal growth and evolution during the Phanerozoic.

In this paper, we put forward a special neutrino mass matrix which is invariant under a modified Friedberg-Lee (FL) transformation nu(e) -> nu(e) -2 xi and nu(mu,tau) -> nu(mu,tau) + xi with xi being a space-time independent element of the Grassmann algebra. Compared to the original FL symmetry (with the transformation nu(e,mu,tau) -> nu(e,mu,tau) + xi) which results in the TM2 neutrino mixing, the modified FL symmetry will lead us to the TM1 mixing which has a better agreement with the experimental results. While the original FL symmetry has to be broken in order to produce a realistic neutrino mass spectrum, the modified FL symmetry is allowed to remain intact and give us a vanishing m(1). A combination of the FL symmetry with the mu - tau reflection symmetry is also discussed.

This study reports age, petrologic and geochemical data for andesites and dacites from the Late Triassic sedimentary strata of northern Hohxil, in the Hohxil–Songpan–Ganzi Block (northern Tibet), which constitutes the most voluminous Triassic strata on Earth. LA-ICP-MS zircon U-Pb analysis of dacite (210.4 ± 1.9 Ma) and whole rock 40Ar–39Ar analyses for both the andesites and dacites (211 ± 2 Ma and 210.9 ± 1.6 Ma) show that the rocks were almost contemporaneous. Both rock types are sodium-rich and calc-alkaline. The andesites, characterized by high MgO (up to 10 wt.%) or Mg# (~ 70), TiO2, Al2O3, Cr, Ni, La/Yb and Th/La, but low Nb/Ta ratios, are geochemically similar to sanukitoids in southeastern Japan. The dacites are strongly peraluminous, and have high Al2O3 and La/Yb, low Y and Yb, coupled with negligible to positive Eu and Sr anomalies, comparable to slab-derived adakites in the circum Pacific arc system. Both rocks exhibit strongly fractionated platinum group element patterns, with Pt/Pt* (Pt anomaly), (Pt/Ir)N and Re/Os ratios higher than those of the primitive mantle. They have uniformly low eNd(t) values (− 7.57–−9.59) and high (86Sr/87Sr)i ratios (0.7086–0.7106) that imply a continental rather than oceanic type magma source. We suggest that the northern Hohxil dacites were produced by partial melting of subducted sediments on the northward-subducting Songpan–Ganzi oceanic slab, and the high-Mg andesites were formed by subsequent interaction between the sediment-derived melts and mantle wedge peridotites. Taking into account the Triassic magmatic record from nearby regions, we suggest that the Late Triassic high-Mg andesite/dacite suites of northern Hohxil were generated in a forearc setting, and propose that double-sided subduction eventually closed the Songpan–Ganzi ocean during the Late Triassic.

Recently, the MINOS collaboration reported an anomaly that the mass-squared difference and mixing angle of $\bar{\nu}_\mu$ $\leftrightarrow$ $\bar{\nu}_\tau$ are both different from that of $\nu_\mu$ $\leftrightarrow$ $\nu_\tau$. In this paper, based on the framework of neutrino oscillations, terms that break the Lorentz symmetry are used as perturbation to explain this anomaly and satisfactory results are got. Remarkably, some surprising conclusions, one of which is that in the high energy limit (hundreds of GeV) neutrino oscillation pattern will be independent of energy, are also arrived., Comment: 9 pages, 4 figures, references added, accepted for publication in PLB

A novel illumination compensate method is proposed in this paper to improve recognition performance. A modified lighting model called Lambertin which includes additive noise and multiplicative noise are presented firstly. Then, additive noise is removed by using wavelet packet transformation. Next, the processed image is transformed into logarithm domain and the multiplicative noise, which has been named additive noise, is removed by means of the same above algorithm. Finally, a compensated face image is obtained. We examine the proposed method on Yale extended B database compared with other methods. Experimental results show that our algorithm improves by 3%~12% recognition rate. It can effectively adjust the facial images for varying illumination conditions and also improve the recognition performance and robustness.

In this paper, we realize the tri-bimaximal mixing in the lepton sector in the context of minimal seesaw in which only two right-handed neutrinos are introduced, with the discrete group $S4$ as the family symmetry. In order to constrain the form of superpotential, a $Z3$ symmetry is also introduced. In the model, the mass matrices for charged leptons and right-handed neutrinos are diagonal. The unitary matrix that diagonalizes the light Majorana neutrino mass matrix is exact tri-bimaximal at LO, and is corrected by small quantities of $\mathcal{O}(0.01)$ at NLO. The mechanism to get the particular scalar VEV alignments used is also presented. Phenomenologically, the mass spectrum is of normal hierarchy with $m_1=0$, and $\sum m_i$ and $|m_{ee}|$ are about $0.058 eV$ and $0.003 eV$ respectively., 11 pages, accepted for publication in PLB

Three generations of novel dendrimers (G1, G2, and G3) with an electron-deficient fluorinated starburst oxadiazole core and twisted carbazoles as dendrons were synthesized via aromatic nucleophilic substitution reaction at ambient temperature by the weak base potassium fluoride with a high selectivity in a nearly quantitative yield, which was attributed to the high reactivity of the para fluorine atom activated by oxadiazole and multiple fluorine atoms. 1H NMR, 19F NMR, elemental analysis, and MALDI-TOF MS results confirmed the designed chemical structures. Varying the generation to gradually modify the dendrons could gradiently modulate the HOMO−LUMO energy band gaps of Gn, which was verified by cyclic voltammetry results. Photoluminescent spectra showed the dual fluorescence emission of the dendrimers in solutions, which indicated that twist intramolecular charge transfer occurred between oxadiazole and carbazole separated by nonconjugated bonds. The Gn-based devices with the configuration of ITO/PEDOT:...

In order to find out the long-term deformation behavior of MgO concrete,the nearly 10 years prototype observation data of Dongfeng arch dam foundation is analyzed. The results show that the MgO concrete has excellent delayed micro-expansion character, and its long-term expansive deformation always tends to stable level without any trend to contraction or infinite expansion, and by adding appropriate MgO expanding agent which was calcined at some high temperature into concrete, the cracking resistance of the concrete is improved. It is an effective way to construct dams excellently, efficiently and economically by using MgO concrete technology.

The neutrino masses can be ascribed to some operators of higher dimension than the Weinberg operator, so that the energy scale of underlying theory can be lowered to an accessible level for the ongoing or upcoming colliders. We hereby consider an interesting model in this connection where quintuplet fermions with hypercharge [Formula: see text]2 are introduced and therefore the neutrino masses are produced by dimension-11 operators. These exotic fermions can be pairly produced at the LHC via electroweak interactions and subsequently decay to multiple leptons. We simulate the relevant signal and backgrounds of the triply charged fermion in this model, and give the needed integrated luminosity to observe such a particle at the 13 TeV LHC.

Voluminous Late Paleozoic igneous rocks and associated Cu–Au–Mo deposits occur in the northwestern Tianshan district, Xinjiang, west China. However, the tectonic setting and petrogenesis of these rocks remain controversial. This paper reports zircon U–Pb and Hf CUU isotopic data, major and trace elements, and Sr–Nd–Pb isotopic data for the intrusive rocks and minor dacites in the Lamasu–Dabate area of northwestern Tianshan adjacent to the Cu–Au–Mo deposits. LA-ICPMS U–Pb zircon analyses suggest that the Lamasu porphyries were formed at 366 ± 3 Ma and contain 907–738 Ma inherited zircons, the Dabate dacites were formed at 316 ± 4 Ma, and granite porphyries were formed at 289 ± 3 Ma with ~ 319 Ma inherited zircons. The Lamasu porphyries consist of plagioclase granite and granodiorite, and are geochemically similar to adakites, e.g., having high Al2O3 (14.54–19.75 wt.%) and Sr (308–641 ppm) and low Y (7.84–16.9 ppm) contents, with fractionated rare earth element (REE) patterns and slightly positive Sr anomalies. However, they have variable initial ratios of 87Sr/86Sr (0.7072–0.7076) and 206Pb/204Pb (18.139–18.450), and variable eNd(t) (− 5.6 to − 0.8) and positive eHf(t) (+ 1.4 to + 10.6) values. They also have variable Mg# (100 × Mg2+/(Mg2++ Fe2+)) (41–73) and low Th (3.13–8.09) and Th/Ce (0.14–0.28) values. We suggest that the Lamasu adakitic magmas were generated through partial melting of southward subducted Junggar oceanic crust, with subsequent melt-mantle interaction and assimilation of basement rocks. The Dabate dacites show typical arc-like geochemical characteristics (e.g., enrichment of large ion lithophile elements (LILE) and strong negative anomalies of Ta, Nb, P and Ti), with variable eNd(t) (+ 0.1 to + 3.3). They were probably generated by melting of juvenile basaltic lower crust as a result of magma underplating. The Dabate granite porphyries are geochemically similar to A2-type granites, e.g., high SiO2 (75.6–77.6 wt.%) and alkalis (Na2O + K2O = 8.27–8.70 wt.%), low CaO (0.28–0.34 wt.%) and Mg# (2–10), and obvious negative Eu, Ba and Sr anomalies. They have variable values of eNd(t) (− 1.7 to 0) and 206Pb/204Pbi (18.567–18.721) and zircon eHf(t) (+ 0.5 to + 11.1). The Dabate A-type granite porphyries contain Late Carboniferous residual zircon cores, suggesting that their source rock possibly contained Carboniferous arc igneous rocks. Taking into account all available data from Late Paleozoic magmatic rocks and Cu–Mo–Au mineralization in the northern Tianshan district, we suggest that the Dabate–Lamasu area was a continental arc during the Late Devonian–Carboniferous but had entered a post-collisional stage by the Early-Permian (~ 290 Ma).

The Central Asian Orogenic Belt (CAOB) is a natural laboratory for the study of accretionary tectonics and crustal growth owing to its massive generation of juvenile crust in the Paleozoic. There is a debate, however, on the mechanism of this growth. In the Baogutu area of the western Junggar region, northern Xinjiang (west China), diorite–granodiorite porphyry plutons and dikes are widely associated with Cu–Au mineralization. In this study, we present new results of zircon U–Pb geochronology, major and trace elements, and Sr–Nd–Pb–Hf isotope analyses for two diorite–granodiorite porphyry plutons and two dikes from this area. LA-ICP-MS zircon U–Pb analyses of four plutonic and dike samples yield Late Carboniferous ages of 315–310 Ma. The Baogutu diorite–granodiorite porphyries exhibit low-Fe and calc-alkaline compositions. They are also characterized by high Sr (346–841 ppm) contents, low Y (9.18–16.5 ppm) and Yb (0.95–1.60 ppm) contents, and relatively high Sr/Y (31–67) ratios, which are similar to those of typical adakites. In addition, some samples have relatively high MgO (2.35–8.32 wt.%) and Mg# (48–75), and Cr (22.7–291 ppm) and Ni (32.0–132 ppm) values, which are similar to those of high-Mg andesites. All rock samples exhibit mid-oceanic ridge basalt (MORB)-like Nd–Sr–Pb–Hf isotope features: high eNd(t) (+ 5.8–+8.3) and eHf(t) (+ 13.1–+15.7) values, and relatively low (87Sr/86Sr)i (0.7033 to 0.7054) and (206Pb/204Pb)i (17.842–18.055). The Baogutu adakitic rocks also contain reversely zoned clinopyroxene phenocrysts, which have low MgO cores and relatively high MgO rims. Geochemical modeling indicates that the Baogutu adakitic rocks could have been derived by mixing ~ 95% altered oceanic crust-derived melts with ~ 5% sediment-derived melts. Taking into account the regional geology, I- and A-type granitoids and Cu–Au mineralization, and the presence of Carboniferous ophiolite melanges in northern Xinjiang, we suggest that the Baogutu adakitic rocks were most probably generated by partial melting of a slab edge close to a subducting spreading ridge in the Late Carboniferous. Ridge subduction and the resultant slab window probably caused strong extension in the overlying lithosphere, extensive melting of subducting oceanic crust, mantle and juvenile lower crust, and interaction between slab-derived melts and the mantle. Thus, events associated with ridge subduction are likely to have played an important role in crustal growth in the CAOB in addition to previously recognized accretion of subduction and arc complexes and post-collisional crustal melting.

In this paper, a novel method for fixed-node quantum Monte Carlo is given. By comparing this method with the traditional fixed-node one, this novel method can be applied to calculate molecular energy more exactly. An expansion of the eigenvalue of the energy for a system has been derived. It is proved that the value of the energy calculated using the traditional fixed-node method is only the zeroth order approximation of the eigenvalue of the energy. But when using this novel method, in the case of only increasing less computing amounts ( < 1%), the first order approximation, the second order approximation, and so on can be obtained conveniently with the detailed equations and steps in the practical calculation to calculate the values of the zeroth, first and second approximation of the energies of 1 1A, state of CH2, 1A2(C4h, acet) state of C8 and the ground-states of H2, LiH, Li2, and H2O The results indicate that for these states it needs only the second order approximation to obtain over 97% of electronic correlation energy, which demonstrates that this novel method is very excellent in both the computing accuracy and the amount of calculation required.

A new type of REE tetrad effect, a composite M- and W-type, was recognized in the K-feldsparthized and silicificated Shuiquangou alkaline syenites, Dongping, Hebei Province. Different analytical methods such as ICP-MS and isotopic dilution thermal ion mass spectrometer were exploited to verify the REE concentrations of the samples in three laboratories in China, France and Korea. The results are reliable and consistent within errors. In situ quantitative analysis of REE concentrations of individual zircons and apatites extracted from the very same sample has shown that fractional crystallization of magma and the superimposed hydrothermal alteration might have taken place in at least two-stage hydrothermal activities to generate the composite M- and W-type REE tetrad effect. The coexisting melt and aqueous phases, the superimposed alteration by volatile (Cl, CO2)− and Si, K, Al-enriched high temperature hydrothermal fluids might be the important facts for this new MW-type of REE tetrad effect. In addition, the peculiar MW-type tetrad effect might be an indicator for Au mineralization of reworked plutons.

There are widespread Neoproterozoic (830–740 Ma) calc-alkaline intrusive rocks in the South China Block, which has been considered a part of the Precambrian supercontinent Rodinia. The tectonic setting of these rocks, however, remains in dispute. Two distinctly different interpretations, continental rift or volcanic arc settings, imply different positions for South China in the Rodinian reconstruction. It is also unclear how such a large-scale magmatic event led to significant crustal growth. This study presents data for ca. 780 Ma A-type granites in the northern Daolinshan area, South China. A relatively early granite mineral assemblage contains katophorite, ferrorichterite, zircon, titaniferous magnetite, ilmenite, fluorapatite, and/or fayalite ± arfvedsonite, and a relatively late mineral assemblage consists of perthite, ferrowinchite, riebeckite ± arfvedsonite, quartz, albite, ilmenite, rutile, magnetite, siderite, grunerite and chamosite. Fluorite and calcite occur at all stages. The granites exhibit low Al2O3, Eu, Ba and Sr contents, high Na2O + K2O, Zr + Nb + Ce + Y, 10,000 × Ga/Al and Zr values, and high FeOT/(FeOT + MgO) (0.90–0.95) ratios, which are similar to those of typical A-type granites. They also have high whole rock ɛNd(t) values (+3.6 to +6.2) and zircon ɛHf(t) (+6.7 to +17.4). Temperature and oxygen fugacity ( f O 2 ) estimates suggest that the northern Daolinshan A-type granitic magmas were generated at high temperature (960–990 °C), low f O 2 (on or slightly above the fayalite-magnetite-quartz (FMQ) buffer), and F- and CO2-rich but extremely H2O-poor conditions, indicating a rifting rather than arc setting for magma formation. Based on the compositions and geochronological and Hf isotope data of Neoproterozoic and older igneous rocks in the region, we suggest that the northern Daolinshan granites were most probably produced by high-temperature melting of slightly earlier tholeiitic rocks underplated in the lower crust as a result of a ∼780 Ma high-temperature mantle plume. The results support the hypothesis that the rifting away of South China from Laurentia was initiated by a ca. 780 Ma mantle plume during the breakup of Rodinia. The mantle plume activities also caused widespread crustal growth in South China in the Neoproterozoic (830–740 Ma).

Rationale Low-grade fibromyxoid sarcoma (LGFMS) is a pathological type of fibrosing fibrosarcoma that appears as a distinctive soft tissue masse with bland histological features. It is mostly located in the deep soft tissues of the extremities. Computed tomography (CT) plays an important role in diagnosing fibrosing fibrosarcoma in the abdomen. To date, several studies in the literature have reported on CT features of LGFMS. Patient concerns and diagnoses We report another case of LGFMS, which presented with certain unique CT feature. The anterolateral region and the wall of the cystic nodules showed gradual enhancement and several nourishing vessels were seen after contrast administration. These imaging features were consistent with the histologic findings of LGFMS. Interventions and outcomes The patient underwent tumorectomy and implantation of radioactive implants. Two years after the operation, 1 metastasis mass occur in the right psoas major. Lessons These CT features in LGFMS may be useful to assess the histological characteristics of LGFMS to facilitate preoperative diagnosis in the clinical setting and provide the supplemental imaging knowledge for future studies.

Shoshonitic series volcanic rocks (SSVR) and adakites are widely distributed in the Permian terrestrial volcanic strata of the Yishijilike–Awulale range of west Tianshan, north Xinjiang, China. Isotopic dating yields Permian ages of 280–250 Ma. The SSVR include absarokite, shoshonite and banakite which are characterized by enrichment of alkalis, particularly in K, combined with lower Ti, higher Al (A/NKC = 0.70–0.99, metaluminous) and Fe2O3 > FeO. The SSVR that are rich in LILE with high REE contents and Eu/Eu⁎ range from 0.59 to 1.30. They are rich in LREE ((La/Yb)N 2.15–11.97) and depleted in Nb, Ta and Ti (TNT negative anomalies). The adakites are metaluminous to weakly peraluminous (A/NKC = 0.85-1.16) and belong to the high-SiO2 type of adakite (HSA, SiO2 = 62%–71%). They are characterized by lower ΣREE with strong LREE enrichment ((La/Yb)N 13–35). Pronounced positive Eu anomalies (Eu/Eu⁎ = 1.02–1.27), very low Yb contents and distinct TNT-negative anomalies are evident. The SSVR have eNd(t) (+ 1.28 to + 4.92) and (87Sr/86Sr)i (0.7041–0.7057) that are similar to adakites in the regions which are characterized by eNd(t) = 0.95 to + 5.69 and (87Sr/86Sr)i = 0.7050–0.7053. Trace element, REE and Sr/Nd isotopic compositions suggest that both SSVR and adakites possess similar source regions associated with underplated mantle-derived basaltic materials. Lithosphere extension driven by magmatic underplating was responsible for the generation of both the SSVR and adakites. This magmatism serves as a petrological indicator of underplating during the Permian. Obviously thickened crust (62–52 km), a complex Moho discontinuity, high heat flow (~ 100 mw·m− 2), widespread contemporary alkali-rich granites, basic dike swarms (K–Ar ages of 187–271 Ma, Ar–Ar ages of 174–270 Ma and Rb–Sr ages of 255 ± 28 Ma; eNd(t) + 1.84 to + 10.1; (87Sr/86Sr)i 0.7035 and 0.7065), and basic granulites (SHRIMP U–Pb age of 268–279 ± 5.6 Ma) provide additional evidences for the underplating event in this area during Permian.

Disturbance of the zircon U-Pb isotopic system has been investigated extensively, but mostly in lab, in the last decades. Here, we reported a field-based study on intensive sericitization, K-feldsparthization and the im- pacts of mylonitization on zircons from the Fangcheng syenites.The Fangcheng syenites occur in the eastern part of the Qinling orogen and consist mainly of aegirine-augite syenite, aegirine nepheline syenite, biotite syenite and hornblende nepheline syenite. Zircons from the slightly sericitized aegirine augite syenite are colorless, transparent crystals and exhibit well-developed oscillatory and sector zoning on the cathodoluminescence (CL) images which are typical of magmatic zircons from alkaline rocks. Zircon U-Pb determinations by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) showed that the syenite was formed in Neoproterozoic time, the weighted average of 206 Pb/ 238 U ages is 844.3±1.6 Ma (MSWD=0.86). In contrast, the hydrothermally altered zircons (hydro- thermal zircon) from the intensively sericitized, K-feldsparthized, and weakly mylonitized aegirine augite syenite are conglomerates, yellowish to brown in color, generally translucent and internally textureless. The CL and backscatter electron (BSE) images of hydrothermal zircons exhibit fractured, textureless or mosaic textures, and occasionally show "sponge texture" with the veinlets and inclusions of K-feldspar; however, relicts of magmatic oscillatory zon- ing can still be discerned locally in individual grains. LA-ICPMS analyses of the hydrothermal zircons demonstrated that the zircons are chemically inhomogeneous, with enhanced and widely varied Pb, U, and Th contents. The U and Th contents of the hydrothermal zircons are estimated to be 32×10 -6 -1550×10 -6 and 188×10 -6 -4059×10 -6 , respec- tively, with Th/U ratios within the range of 0.7-44.9. 206 Pb/ 238 U apparent ages of the hydrothermal zircons are nega- tively correlated with the contents of U, and radiogenic and common Pb. As the U and Th concentrations of the magmatic zircons are rather low, the α-decay doses (3.65×10 14 -2.04×10 15 α-decay events/mg) are much lower than those at the first percolation point (3.5× 10 15 a-decay events/mg), thus, Pb mobility resultant from diffusion could be safely neglected. Disturbance of the U-Pb isotopic system of zircons is most likely to be attributed to the intensive sericitization and K-feldsparthization coupled with mylonitization, the hydrothermal fluids reacted with zircons along the rims and fractures of the distorted zircon crys- tals, giving rise to the chemically inhomogeneous hydrothermal zircons through a series of complicated mechanisms such as dissolution-reprecipitation. The significance of the U-Pb age (the lower intercept age on the discordia U-Pb plot) of hydrothermal zircons is uncertain. We argued that interpretations of the hydrothermal zircon data as the age of hydrothermal events or hydrothermal ore-forming processes are questionable and hence cautions must be taken.

Middle Devonian magnesian andesites (MAs) are widely distributed in south Altay and Carboniferous MAs are present in Alataoshan and west- and east-Tianshan in the north Xinjiang region. These MAs are andesitic rocks with 53–65% SiO2, 15 ppm), low Sr/Y ratios (4.4–6.2), low (La/Yb)N, and high Mg# of the MAs in north Xinjiang provide evidence of interaction of such melts with mantle wedge peridotite. New petrographic, chemical and isotopic [(143Nd/144Nd)I = 0.51221–0.51255 (eNd(t) +0.28 to +7.2); (87Sr/86Sr)I = 0.7029–0.7065] data suggest that the petrogenesis of the MAs in the north Xinjiang region may have involved: (1) multiple source materials including subducted oceanic slab, juvenile crustal materials (mainly volcanic-volcanoclassic rocks with low maturity and clear mantle geochemical signatures) coming from the forearc accretionary prism and mantle wedge peridotite; (2) a combination of different petrogenetic processes including partial melting of subducted oceanic slab and juvenile crustal materials, followed by interaction of slab melts with the mantle wedge peridotite; (3) high geothermal gradient creating a high temperature (>1,000°C) environment in a volatile-rich source region; (4) unique tectonic settings including oblique subduction, slab break off resulting in slab window formation and asthenosphere upwelling, and subduction erosion resulting in transfer of forearc accretionary materials into the source region of MA magma.

Finding of Neoproterozoic syenites at Fangcheng in the northern Qinling region of the East Qinling orogen provides an important constraint on timing of tectonic transformation to extensional regime. The alkaline pluton consists mainly of nepheline syenite, aegirine syenite, and alkali-feldspar syenite. The syenites are of intermediate (SiO2 = 54%–62%), rich in alkali (K2O+Na2O = 12%–15%), aluminum (Al2O3 = 16.81%–23.26%) and large ion lithophile elements (LILE), without any obvious Nb, Ta, Zr, and Hf anomalies. The Fangcheng syenites are geochemically characterized by relative enrichment of LREE, minor differentiation of HREE, significant negative Eu anomalies (Eu = 0.13–0.23), less negative eNd(t) values of −1.37 to −3.90, young Nd model ages of 1364 to 1569 Ma, and high zircon saturation temperatures of 915 to 1044°C. The syenitic magmas probably originated from small proportion melting of upper mantle in an extensional regime of intraplate-anorogenic tectonic setting, and have been slightly contaminated by crustal materials during ascending and/or emplacement. LA-ICP-MS zircon U-Pb dating yields ages of 844.3±1.6 Ma (MSWD = 0.86), suggesting that the Fangcheng alkaline syenites formed in the early Neoproterozoic. They are the oldest Neoproterozoic alkaline rocks ever recognized in the Qinling orogen as well as in South China. This implies that the tectonic regime of the Qinling region would have transformed from post-collisional stretch to intraplate-anorogenic extension no later than 844 Ma.

Mineralization with exchangeable rare earth element (REE) and yttrium (MEX-REY) has been recognized in the weathering profiles in South China since the early 1970's. This type of REY mineralization occurs in weathering profiles of parent rocks ranging in composition from granite to acidic volcanic rocks and lamprophyre. The majority of the known resources occurring in the weathering profiles of granitic rocks. Total resources of this type of REY amount to millions tons of rare earth oxides, and therefore represent one of the most important types of rare earth resources in China, particularly for heavy rare earth elements (HREE) and yttrium. Accumulation of REY in the weathering profiles of granitic rocks is strongly controlled by the resistance to weathering of the principal REY-bearing accessory minerals in the parent rocks; only a limited proportion of total REY ( 4+ and Na + etc. in electrolyte solutions and can be removed by complexing agents such as EDTA, are commonly the major form of REE occurrence in the B horizon. Cerium is enriched in the top layer (A horizon) and depleted in the subsurface horizons of the weathering profiles, most likely due to the oxidation of Ce(III) to Ce(IV) followed by cerianite formation or absorption onto clays and/or Fe and Al oxyhydroxides.

New chronological, geochemical, and isotopic data are reported for Triassic (219–236 Ma) adakite-magnesian andesite-Nb-enriched basaltic rock associations from the Tuotuohe area, central Qiangtang terrane. The adakites and magnesian andesites are characterized by high Sr/Y (25–45), La/Yb (14–42) and Na2O/K2O (12–49) ratios, high Al2O3 (15.34–18.28 wt%) and moderate to high Sr concentrations (220–498 ppm) and eND (t) (+0.86 to +1.21) values. Low enrichments of Th, Rb relative to Nb, and subequal normalized Nb and La contents, and enrichments of light rare earth elements combine to distinguish a group of Nb-enriched basaltic rocks (NEBs). They have positive eND (t) (+2.57 to +5.16) values. Positive correlations between Th, La and Nb and an absence of negative Nb anomalies on mantle normalized plots indicate the NEBs are products of a mantle source metasomatized by a slab melt rather than by hydrous fluids. A continuous compositional variation between adakites and magnesian andesites confirms slab melt interaction with mantle peridotite. The spatial association of the NEBs with adakites and magnesian andesites define an “adakitic metasomatic volcanic series” recognized in many demonstrably subduction-related environments (e.g., Mindanao arc, Philippines; Kamchatka arc, Russia; and southern Baja California arc, Mexico). The age of the Touhuohe suite, and its correlation with Triassic NEB to the north indicates that volcanism derived from subduction-modified mantle was abundant prior to 220 Ma in the central Qiangtang terrane.

To date, few adakitic rocks have been reported in direct association with contemporary intra-continental extensional structures, which has cast doubt on genetic models involving partial melting of the lower crust. This study presents Early Cretaceous (143–129 Ma, new Sensitive high-resolution ion microprobe (SHRIMP) zircon U-Pb ages) adakitic granites, which are directly associated with a contemporary metamorphic core complex (i.e., the Northern Dabie Complex in the Dabie area). These granites exhibit relatively high Sr contents, negligible to positive Eu and Sr anomalies, high La/Yb and Sr/Y ratios, but very low Yb and Y contents, similar to subducted oceanic crust-derived adakites. They are also characterized, however, by very low MgO or Mg# and Ni values, and Nd–Sr isotope compositions (eNd(t) = −14.6 to −19.4 and (87Sr/86Sr)i = 0.7067–0.7087) similar to Triassic continent-derived eclogites subducted in the Dabie–Sulu Orogen. Additionally, late granitic dikes in the adakitic intrusions exhibit low Sr contents, clearly negative Eu and Sr anomalies, low La/Yb and Sr/Y ratios, but relatively high Yb and Y contents, similar to 118–105 Ma granites in the Northern Dabie Complex. Based on composition and geochronology data of Neoproterozoic amphibolites and orthogneisses, Triassic high- to ultra-high pressure metamorphic rocks, and Early Cretaceous mafic–ultramafic intrusive rocks, and the constraints provided by experimental melt data for tonalites, metabasaltic rocks and eclogites, we suggest that the adakitic granites were most probably generated by partial melting of thickened amphibole or rutile-bearing eclogitic lower crust as a consequence of Triassic–Middle Jurassic subduction and thrusting. The late dikes probably originated from plagioclase-bearing intermediate granulites. Moreover, we suggest that late Mesozoic delamination or foundering of thickened eclogitic lower crust is also a more plausible mechanism for the petrogenesis of Early Cretaceous mafic–ultramafic intrusive rocks in the Dabie area, and probably involved partial melting of a mixed source comprising eclogitic lower crust that had delaminated or foundered into upper lithospheric or asthenospheric mantle peridotite. Asthenospheric upwelling in response to post-collisional delamination of lithospheric mantle was likely to have provided the heat source for the Cretaceous magmatism.