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• We report in situ S isotope analysis for multiple types of sulfides by LA-MC-ICPMS. • In situ S isotope analysis is applied to the study of the Erlihe Zn-Pb ore deposit. • Sulfur of the massive ores is likely sourced from the TSR process for the deposit. Sulfur isotopic composition is useful for tracing sources of ore-forming materials. In situ sulfur isotope analysis by laser ablation coupled with multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) has an advantage over traditional bulk analysis in tracing sources of sulfur in an ore deposit that has complex mineral types and multiple ore-forming processes. However, in using this method, matrix effects exist widely for sulfides from ore deposits. In this work, matrix effects of different sulfides were examined by matrix-unmatched tests, in which the δ34S values of different types of sulfides were calibrated against a laboratory pyrite standard. The results show that the δ34S values of pyrrhotite, chalcopyrite, molybdenite, sphalerite, and arsenopyrite are in agreement with the reference values, suggesting that the matrix effect was negligible. However, a significant matrix effect occurred in the analyses of Ag 2 S and galena, leading to significant deviations in δ34S values of up to 1.2‰ and 3.2‰, respectively. The matrix effect occurred not only during the laser ablation stage but also during the transition of ions into the mass spectrometer, resulting in significant space charge effects caused by heavy-mass elements. Thus, pyrite can be used as an external bracketing standard for sulfides that do not have a heavy-mass matrix. Based on our matrix-effect study, the following available external standards were selected for the in situ sulfur isotope analysis of complex-type minerals from the Erlihe Zn-Pb deposit. The coarse-grained sphalerite grains (Sph1) and euhedral to subhedral pyrite grains (Py1) from massive ores have δ34S values ranging from 9.2‰ to 18.1‰. Such heavy sulfur isotopic compositions indicate the derivation of sulfur from the deposits of seawater sulfate, related to a thermochemical reducing process. Fine-grained sphalerite (Sph2) and pyrite (Py2) from vein and disseminated ores coexist with pyrrhotite and chalcopyrite, and have relatively light sulfur isotopic compositions, with δ34S values of about 7‰. The slightly positive δ34S values are similar to those of sulfides from sulfide-rich quartz veins, which contain δ34S values of about 4‰, and granodiorite rocks, with δ34S values of about 6‰. Based on previous studies, the light sulfur of the late-stage sulfides may have resulted from a metamorphic or magmatic hydrothermal event during the Indosinian orogeny. In situ sulfur analysis by LA-MC-ICPMS provides new evidence for sources of sulfur from each stage of mineralization in the Erlihe deposit, suggesting that this is a promising method for studying complex ore deposits. [ABSTRACT FROM AUTHOR]

We herein report the coupling of a nanosecond laser ablation system with a large-scale multi-collector inductively coupled plasma mass spectrometer (Nu1700 MC-ICPMS, NP-1700) and a conventional Nu Plasma II MC-ICPMS (NP-II) for the simultaneous laser ablation and determination of in situ S and Pb isotopic compositions of sulfide minerals. We found that the required aerosol distribution between the two spectrometers depended on the Pb content of the sample. For example, for a sulfide containing 100–3000 ppm Pb, the aerosol was distributed between the NP-1700 and the NP-II spectrometers in a 1:1 ratio, while for lead contents >3000 and <100 ppm, these ratios were 5:1 and 1:3, respectively. In addition, S isotopic analysis showed a pronounced matrix effect, so a matrix-matched external standard was used for standard-sample bracketing correction. The NIST NBS 977 (NBS, National Bureau of Standards; NIST, National Institute of Standards & Technology) Tl (thallium) dry aerosol internal standard and the NIST SRM 610 (SRM, standard reference material) external standard were employed to obtain accurate results for the analysis of Pb isotopes. In tandem experiments where airflow conditions were similar to those employed during stand-alone analyses, small changes in the aerosol carrier gas flow did not significantly influence the accurate determination of S and Pb isotope ratios. In addition, careful optimization of the flow ratio of the aerosol carrier (He) and makeup (Ar) gases to match stand-alone analytical conditions allowed comparable S and Pb isotope ratios to be obtained within an error of 2 s analytical uncertainties. Furthermore, the results of tandem analyses obtained using our method were consistent with those of previously reported stand-alone techniques for the S and Pb isotopes of chalcopyrite, pyrite, galena, and sphalerite, thus indicating that this method is suitable for the simultaneous analysis of S and Pb isotopes of natural sulfide minerals, and provides an effective tool to determine S and Pb isotope compositions of sulfides formed through multi-stage deposition routes. [ABSTRACT FROM AUTHOR]

In the wastewater treatment, achieving low phosphate concentrations is important to meet the increasingly stringent discharge requirements and alleviate eutrophication. Calcium aluminate decahydrate (CAH 10) was prepared by a facile hydration method as a novel phosphate adsorbent. CAH 10 exhibited a maximum adsorption capacity of 89.58 mg P/g at 25 °C in batch experiments. The phosphate adsorption followed the Elovich kinetic model and Freundlich isotherm model. The adsorption capacity at the equilibrium concentration of 0.1 mg P/L reached 3.27 mg P/g. High adsorption selectivity was obtained in the presence of common anions and humic acid. The phosphate adsorption mechanism mainly involved inner-sphere complexation and surface precipitation, which were supported by the SEM-EDS, FTIR and XPS results. The fixed-bed column adsorption performance demonstrated that CAH 10 could effectively remove phosphate from real secondary effluent and achieve a low concentration of 0.1 mg P/L. The study indicated that CAH 10 is a suitable adsorbent to remove phosphate in the context of secondary effluent polishing in wastewater treatment plants. [Display omitted] • P adsorbent was prepared by a facile hydration method using industrial material. • Adsorption capacity reached 3.27 mg P/g at a low P concentration of 0.1 mg P/L. • Phosphate was adsorbed mainly through ligand exchange and surface precipitation. • High removal performance was observed in fixed-bed test at a low EBCT of 1.18 min. • A low concentration of 0.1 mg P/L was achieved in real wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Cretaceous magmatism in southern Lhasa subterrane, Tibetan plateau has been investigated for many years and a series of models have been proposed to illustrate their petrogenesis and geodynamic implications. But rare work has been done on the Cretaceous magmatism in central Lhasa subterrane. Here we report the petrology, zircon in situ U–Pb geochronology, Hf isotopes, trace element, and whole-rock elements and Sr–Nd isotopic geochemical data of the host granodiorites, and gabbroic and dioritic enclaves in Mamba area, central Lhasa subterrane. Zircon U–Pb dating for a Mamba host granodiorite yields a crystallization age of ~84Ma, with in situ Hf isotopic analyses for 18 spots of the same zircons of εHf (t) ranging from −7.5 to −0.3. A dioritic enclave (85.2Ma) is coeval with the host granodiorite and shows similar zircon Hf isotopic compositions (εHf (t)=−4.0 to +0.2). Mamba granodiorites (SiO2 =66.6–67.5wt.%) and dioritic enclaves (SiO2 =53.9–57.6wt.%) are high-K calc-alkaline, and a gabbroic enclave is shoshonitic (K2O=2.81%). All these samples are metaluminous, and enriched in large ion lithophile elements (LILEs, such as Rb, Ba, K, U, Th) and depleted in high field strength elements (HFSEs, e.g., Nb, Ta, Ti, and Zr). The host granodiorites are enriched in light rare earth elements (REEs), depleted in heavy REEs with weakly negative Eu anomalies (δEu=0.86–0.88), with high Al2O3 (15.0–15.7wt.%), high Sr/Y ratio (58.1–68.3) and Sr (680–755ppm), and low Y (10.8–13.0ppm) abundance, suggesting adakitic affinities. Mamba adakitic granodiorites, gabbroic and dioritic enclaves exhibit homogeneous Sr isotopes ((87Sr/86Sr)i =0.7066–0.7067, 0.7073, and 0.7067, respectively) and Nd isotopes (εNd(t)=−5.7 to −4.4, −4.0, and −3.6, respectively). These geochemical features allowed us to conclude that the adakitic host granodiorites and mafic (gabbroic–dioritic) enclaves were derived from magma mixing between ancient thickened lower crust and enriched fluid-metasomatized mantle. The distance between Mamba and the suture zone was more than 200km when the intrusives emplaced at ~85Ma, which implies that these rocks cannot be resulted from the mid-ocean ridge subduction. Combining of the intra-plate environment indicated by the gabbroic enclave of this study, the presence of the coeval bimodal igneous rocks in the similar latitude in central Lhasa subterrane, and other records in late Cretaceous sedimentary basin, the Mamba ~85Ma magmatism were attributed to the back-arc extension of Neo-Tethyan Ocean. [Copyright &y& Elsevier]

Abstract: An integrated study of petrology, zircon U–Pb age, and geochemistry was reported for a Paleoproterozoic granitic pluton from the Kongling terrain in the northern part of the Yangtze Block. The Quanqitang pluton is composed mainly of alkali feldspar, quartz, biotite and plagioclase. Zircon U–Pb dating yields a 207Pb/206Pb age of ca.1.85Ga, which represents its intrusion age. The Quanqitang pluton has high SiO2 (72.6–74.4wt.%), K2O (5.09–5.56wt.%) and Na2O (3.02–3.36wt.%), and low Fe2O3 (2.56–3.19wt.%) and MgO (0.25–0.37wt.%). It is metaluminous (A/CNK=0.93–0.98) and belongs to the high-K calc-alkaline series. On the chondrite-normalized REE diagram, all the samples invariably show a relatively enrichment in light rare earth elements (LREEs) with high (La/Yb)N ratios (10.6–21.7) and strong negative Eu anomalies. Their primitive-mantle normalized spidergrams display negative Ba, Nb, Ta, Sr, P, Eu and Ti anomalies. The calculated zirconium saturation temperatures range from 802 to 861°C with an average of 845°C. Zircons from the granites have ε Hf(t) values ranging from −17.6 to −20.9, corresponding to two-stage Hf modal ages of 3.6 to 3.8Ga. Based on the geochemical features, it is inferred that the granites were generated by the dehydration melting of Archean tonalitic gneisses with a plagioclase-rich residual assemblage. The granites chemically belong to the A2-type granites, and have an intrusion age younger than the possible ca. 2.0Ga collisional event in the Yangtze Block. This suggests that they formed in a post-collisional tectonic setting, and thus a tectonic regime switch from collision to extension might have occurred in the Yangtze Block before ca. 1.85Ga. The occurrence of the A2-type granite indicates that the Kongling microcontinental block became a stabilized craton at ca. 1.85Ga. [Copyright &y& Elsevier]

• A novel depth refinement algorithm that respects photo-consistency and edge preservation to correct misalignment between color-and-depth image pairs and fill missing depth information. • A novel adaptive view selection approach that effectively avoids selecting redundant and useless input views to improve the quality of synthesized images and the rendering speed. • A novel rendering algorithm providing high-quality free-viewpoint synthesized images, which is based on layered 3D warping to deal with occluded elements and lower the rendering complexity. Our aim is to give free-viewpoint photo-realistic rendering of real indoor scenes, using a sparse collection of RGB-D image as input. Image based rendering (IBR) is an effective way to achieve both realism and interactivity. However, there are several challenges for IBR: misalignment of object boundaries between color-and-depth image pairs often leads to ghost contours; projection errors result in the visibility failure; and useless and redundant input views often produce blurring images. To address these issues, we propose a pixel-to-pixel multi-view depth refinement method to produce pixel-accurate alignment between color-and-depth image pairs, and an adaptive view selection approach to avoid choosing redundant or useless input views. Furthermore, we propose a layered 3D warping to handle occluded elements. These components are designed to work together, reducing visual artifacts and providing plausible free-viewpoint synthesized images. The evaluation results indicate that our method achieves good performance on a wide variety of challenging scenes and performs best among popular IBR algorithms designed for dynamic scenes. [ABSTRACT FROM AUTHOR]

Hydrous minerals in the hybridized zone at the slab-mantle interface play a critical role in retaining and transporting fluid mobile elements in subduction zones. The observed high B and As concentrations and high δ11B values in arc magmas were previously thought to have been resulted from the mechanical transport of forearc serpentinites down to subarc depths by mantle corner flows or through subduction channels because B, As, and Sb are mostly released during early stages of subduction. This study provides new insights into the recycling of B, As, and Sb in subduction zones via an in-situ study on a set of carbonate-bearing serpentinite samples from the Mianlue mélange complex in the Qinling Orogen. Petrological observations and bulk-rock Sr-Pb isotopes reveal that the Jianchaling serpentinites were formed by interactions between forearc peridotites and sediment-derived fluids at a shallow depth in the subduction channel. Some Jianchaling serpentinites experienced the lizardite to antigorite transition at 300–400 °C with infiltrations of CO 2 -rich fluids. In contrast, the Liangyazi antigorite serpentinites were produced at a greater depth. Antigorite grains in the Jianchaling serpentinites have lower Fe apfu than those in the Liangyazi serpentinites and most antigorite with geochemical data in the literature. Meanwhile, B, As, and Sb concentrations of Fe-poor antigorite from the Jianchaling serpentines (385–653 ppm B, 198–334 ppm As, and 6.24–8.01 ppm Sb) are not only higher than those of the Fe-rich antigorite from the Liangyazi serpentinites but also 2–3.5 times higher than those of the surrounding lizardite. The lower modal percentage of spinel and ferritchromite in antigorite veinlets, together with the lower bulk-rock FeO content of antigorite-lizardite serpentinites than that of lizardite serpentinites from the Jianchaling region, indicates that some FeO might be lost during the lizardite to antigorite transition. The presence of carbonate minerals in the antigorite veinlets and the remarkably high B, As, and Sb concentrations in the Jianchaling antigorite indicate that the penetrating fluids during the lizardite to antigorite transition are most likely derived from sediment and metabasite decarbonations at <350 °C. Infiltrations of CO 2 -rich fluids at the slab-mantle interface could buffer a relatively low pH to significantly enhance the mobility of Fe2+, which is produced by reduction of the cronstedtite component in lizardite or Fe3+ in magnetite during the lizardite to antigorite transition, and facilitate the formation of Fe-poor antigorite at the slab-mantle interface. The oxygen fugacity in such a CO 2 -rich water–rock system is also high enough for the occurrence of As5+ in the surrounding fluids. Therefore, once IVFe3+ is lost from the serpentine lattice structure during the lizardite to antigorite transition, B3+, As5+, and Sb5+ in the surrounding fluids can occupy the tetrahedral sites in the newly formed Fe-poor antigorite. The formation of Fe-poor antigorite at the slab-mantle interface is therefore made available to transport shallow slab-derived B, As, and Sb to a greater depth, where destabilization of antigorite at 600–700 °C liberates these elements into the arc magma source. [ABSTRACT FROM AUTHOR]

Knowledge of the evolution of the East Asian Summer Monsoon (EASM) provides a valuable opportunity to uncover the dynamic interactions of land-ocean-atmosphere system in the late Cenozoic. However, the evolutionary history of EASM remains debatable, mainly due to the difficulty in separating EASM precipitation and temperature signals. In this study, precipitation proxies of Sr/Ca ratio and δ26Mg value in loess secondary calcite (carbonate nodule (NC) and fine carbonate (FC) (grain size < 4 μm)) are further verified, with high precipitation corresponding to high δ26Mg FC but low δ26Mg NC and Sr/Ca NC ratio, and vice versa. Then, these proxies are investigated in well-researched Chinese loess eolian deposits since ∼22.5 Ma. Results suggests that the EASM precipitation was staged enhancement in the mid-Miocene (∼16.5–14.0 Ma) and the Quaternary (∼2.6–0 Ma). The mid-Miocene enhancement can be compared with the strong EASM intensity and the warmest global temperature since the Miocene. Global warming thus is considered as the dominant force for this enhancement via an expansion in the latitudinal extent of the Indo-Pacific Intertropical Convergence Zone (ITCZ). In contrast, the Quaternary enhancement was accompanied by decreases in global temperature. We propose their linkage via the reinforcement of the Pacific Walker Circulation and a northward shift of the subtropical ridge in the western Pacific. Our study provides a new insight into EASM evolution and its dynamic linkage with global climate changes. [ABSTRACT FROM AUTHOR]

Abstract: Different types of metamorphic zircon are recognized by a combined study of petrography, U–Th–Pb and Lu–Hf elements and isotopes in zircons from eclogite-facies metagranites in the Dabie orogen. The results provide petrological distinction between metamorphic growth and recrystallization with respect to protolith inheritance, fluid and melt effects. Zircon U–Pb dating for the metagranites yields two groups of ages at 778±13 Ma and 223±4 Ma, respectively, corresponding to protolith formation in the Neoproterozoic and metamorphic modification in the Triassic. Metamorphically grown zircons from the aqueous fluid are characterized by concordant Triassic U–Pb ages, relatively high U contents but low Th contents, low Th/U and 176Lu/177Hf ratios, and elevated Hf isotope ratios. Metamorphically grown zircons from the hydrous melt show concordant Triassic U–Pb ages, very high contents of both Th and U, elevated 176Hf/177Hf ratios, but almost unchanged 176Lu/177Hf ratios. Metamorphic recrystallization is commonly associated with discordant U–Pb ages between Neoproterozoic and Triassic, but availability of fluid/melt dictates the extent to which internal structure, morphology, U–Th–Pb and Lu–Hf element and isotope systems of protolith zircon were modified by metamorphic dehydration and partial melting. While the zircon U–Th–Pb isotope systems can be variably reset by solid-state recrystallization, its initial Hf isotope signature keeps unchanged at the same conditions. On the other hand, dissolution recrystallization causes almost complete resetting of the U–Th–Pb chronometric systems to concordant ages at the metamorphic time, but it does not significantly change the Lu–Hf isotope compositions. Replacement recrystallization resets the zircon U–Th–Pb and Lu–Hf isotope systems to variable degrees, depending on the activity of metamorphic fluid/melt. Consequently, the five types of metamorphic zircon are distinguished not only between growth from the aqueous fluid and the hydrous melt but also between the recrystallization via the solid-state, replacement and dissolution mechanisms. This provides insights into the behavior of zircon during subduction-zone metamorphism, particularly that concerning dehydration melting during exhumation. [Copyright &y& Elsevier]

Here, we demonstrate the potential advantages of using isotope tracers to test hypotheses of reaction mechanisms near-equilibrium. Using non-traditional stable Si isotopes as tracers, we measured albite unidirectional dissolution rates (r +) across a range of Gibbs free energy of reaction (Δ r G) close to equilibrium (−26 to −2 kJ/mol). Thirteen batch experiment series were conducted at 50 °C and pH ∼ 8 ± 0.25. Different distances from equilibrium were achieved by a stepwise increase of concentrations of Si (0–600 μM), Al (0–10 μM), and Na (0–1000 μM). The temperature, pH, sample preparation, and reaction duration were kept identical to isolate the Δ r G effect. Secondary phase precipitation, which is difficult to avoid in near-equilibrium, near-neutral pH experiments renders the rate measurement method based on changes in Si and Al concentration unworkable, but it should not impact the Si isotope ratios-based rates. The resulting r + values were nearly constant in the experimental Δ r G range, signaling no major Δ r G -related switch of reaction mechanisms. Our results suggest that the switch from etch pit opening at far-from-equilibrium to step retreat at near-equilibrium does not operate under circum-neutral pH in low-temperature systems; this mechanism switch was proposed based on experimental data in alkaline solutions at hydrothermal temperatures. The nearly constant r + values at pH 5–8 also suggest that an H 2 O-catalyzed reaction mechanism dominant at circumneutral pH, in addition to the H+- and OH–-catalyzed reaction mechanisms dominant at acidic and alkaline pH, respectively. The experimental results have implications for geochemical modeling of low-temperature geological and environmental processes. The results suggest that a term of H 2 O-catalyzed reaction mechanism should be included in rate laws and that the parallel rate law with a mechanism-switch is not applicable in the pH range of 5–8. [ABSTRACT FROM AUTHOR]

• Novel Si isotope tracer method deconvoluted feldspar dissolution and precipitation. • Feldspar backward reaction is insignificant at low temperatures. • Recommend forward dissolution rates only in low-temperature kinetics models. • This approach for weathering, geological carbon sequestration, and diagenesis. Here we show that the isotope tracer experimental method for kinetic studies, aided by the recent advance and accessibility of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) analysis for non-traditional stable isotopes, can provide unidirectional dissolution rates at near-equilibrium conditions. For a long time, the only rates available at near-equilibrium were net reaction rates—dissolution rates minus precipitation rates. This is because the conventional experimental method of kinetic studies is based on element concentrations and can only provide net rates. The availability of unidirectional rates allows us to re-examine some fundamental concepts and practices of modeling weathering in geochemistry. In this study, we used the 29Si isotope tracer to conduct albite and K-feldspar dissolution experiments at near-equilibrium conditions in near-neutral pH solutions at 50 °C. Results show that the saturation indices (SI) of solutions approached zero with respect to albite and K-feldspar after ∼240–360 h (h), but 29Si/28Si ratios of the experimental solutions indicated continual dissolution for another 720–1440 h. The rates of total Si precipitation were much smaller than the rates of Si dissolution. The experimental solutions were supersaturated with respect to amorphous Al(OH) 3 , gibbsite, quartz, allophane, imogolite, and kaolinite. The SI of the solutions remained constant with respect to these phases while Al concentrations slightly decreased and Si concentrations slightly increased, indicating the coupled feldspar dissolution and precipitation of secondary phases, such as albite → amorphous Al(OH) 3 + quartz or albite → solution + Al-Si phase(s), instead of significant albite and K-feldspar precipitation (the reverse reaction) at 50 °C. Reaction path modeling of the temporal evolution of Si, Al, Na, and pH revealed that albite dissolution (without significant backward reaction) coupled with the precipitation of a secondary phase with a Si:Al ratio of ∼2:1 can successfully match the experimental data. Given the negligible feldspar precipitation reactions in low-temperature systems (e.g., T < 100 °C), we recommend modeling feldspar weathering using unidirectional forward rates together with secondary phase precipitation rates in near-equilibrium, feldspar-undersaturated systems. This can be accomplished with minor modifications in geochemical modeling software or input files. The coupled feldspar dissolution with secondary phase precipitation arrests the system in a near-equilibrium steady state. Using affinity-based rate equations such the classical linear Transition State Theory rate law or the Burch empirical relation together with far-from-equilibrium rate data will predict significant feldspar precipitation in solutions undersaturated but close to equilibrium with respect to feldspars, which is unlikely at near ambient temperatures. [ABSTRACT FROM AUTHOR]

In this paper, A new plate heat exchanger is proposed based on topology optimization applying the moving asymptote method (MMA), in which, an alternative projection function is applied, and the parameter ranges affecting the topology structure are present. The channel composition, thermal performance, and hydraulic performance of the optimized structure are analyzed. Numerical simulation and experimental analysis are conducted between the topology and the chevron plate heat exchanger for performance comparison. The results present that the parameter ranges affecting the key issues of the topology are provided, which provides reference for parameter selection. The alternative projection function can effectively eliminate grey scale and checkerboard phenomenon. The comparison shows that the comprehensive performance of the topology structure is enhanced, with a maximum increase of 19.85%. • The optimal structure of the plate heat exchanger is obtained with MMA based on topology. • Experimental and numerical studies are carried out to investigate thermal and hydraulic performance. • The alternative projection function is proposed to eliminate grey scale and checkerboard phenomenon. [ABSTRACT FROM AUTHOR]

The widespread aeolian deposits on the Chinese Loess Plateau (CLP) have been investigated intensively as an outstanding archive of information on past variations of the East Asian Monsoon (EAM). However, differentiating the impacts of precipitation and temperature on loess-based proxies is difficult and complex, which hampers our ability to understand the variability and dynamics of the EAM. In this study, we investigated the Mg isotope composition (δ26Mg) of the secondary carbonates in fine-grained loess samples from ten Holocene profiles and a loess-paleosol sequence, as well as in the primary carbonates of nine loess-source samples from the Asian inland deserts. Our aim was to explore the potential of the δ26Mg values of secondary carbonates in tracing precipitation changes. The results demonstrate that δ26Mg values are homogeneous (−2.07‰) in primary carbonates from different loess-sources, but display large variations in secondary carbonates of loess, increasing from −3.33‰ in the northwest CLP to −1.80‰ in the southeast CLP, and from −3.58‰ during the last glacial to −1.65‰ during the last interglacial. The variations were mainly controlled by EAM precipitation via the migration of isotopically light Mg, because Mg isotope fractionation during the formation of secondary carbonates is temperature insensitive, and the primary carbonate in different loess-sources has relatively constant δ26Mg values. This conclusion is further supported by high correlation (r 2 = 0.84) between modern mean annual precipitation (MAP) and δ26Mg in the secondary carbonates of spatial loess samples. Based on this δ26Mg-MAP relationship, temporal variations in MAP were quantitatively estimated, ranging from 670 mm during the last interglacial to 270 mm during the last glacial at the southern CLP. Compared with previous estimates, our MAP exhibits a larger amplitude of glacial-interglacial fluctuations (∼400 mm) with a less uncertainty (53–76 mm), implying that δ26Mg values in secondary carbonates of loess can serve as a novel precipitation proxy to infer EAM variability and dynamics. [ABSTRACT FROM AUTHOR]

This paper is an in-depth look at the problem of removing the blur from a complex motion-blurred star image. Accordingly, a simple yet effective l p ( 0 < p ≤ 1 ) -regularized deblurring method based on stars image intensity is proposed. The model builds on the principle that the intensity of clear star image is in accordance with Laplacian distribution or generalized p Gaussian distribution. Further, two algorithms are introduced to solve the ensuing non-smooth ( p = 1 ) or non-convex ( p < 1 ) constrained optimization problem. Simulations and actual star image restoration experiment are implemented to demonstrate that the centroids extraction accuracy of the proposed method is higher than 0.1 pixel, the running time is 3 to 5 times better than Richardson–Lucy filter or other methods based on image gradient constraint, and the peak signal to noise ratio (PSNR) of recovered star images excel results of several other image deconvolution methods. [ABSTRACT FROM AUTHOR]

• A new structure with 2.3∼19.59% performance enhancement is proposed based on MO-optimization. • The Double-layer multi-objective optimization algorithm is applied in the convex plate heat exchanger. • PEC and FSP analysis are used to evaluate the heat transfer and flow characteristics. • An experiment platform is designed for performance exploration and verification. The convex plate heat exchanger is one of the new types of plate heat exchangers that have specific functional properties compared to conventional plate heat exchangers, the structural parameters of convex plate heat exchangers are important in affecting the heat transfer performance. In this paper, based on two-layer multi-objective optimization which is aimed at maximum performance evaluation criterion (PEC) and maximum field synergy number (Fc), the heat transfer and flow characteristics of convex plate heat exchanger are investigated experimentally and numerically. The optimization findings are broken down into single factor, response surface, and sensitivity analysis. The optimal results under different objective functions are analyzed and the optimal structural parameters obtained which are the welding hole radius (R) is 5.81 mm, the ellipse radius (L) is 5.02 mm, and the welding hole spacing (P) is 64.00 mm; Compared to the structure before optimization, the size-optimized structure may enhance the temperature differential between the inlet and outflow of the cooling water by less than 8.27%, the heat transfer performance is increased by 20.43%, and the comprehensive performance is improved by 2.3∼19.59%. [ABSTRACT FROM AUTHOR]

Abstract: The petrology, mineral compositions, whole rock major/trace element concentrations, including highly siderophile elements, and Re–Os isotopes of 99 peridotite xenoliths from the central North China Craton were determined in order to constrain the structure and evolution of the deep lithosphere. Samples from seven Early Cretaceous–Tertiary volcanic centers display distinct geochemical characteristics from north to south. Peridotites from the northern section are generally more fertile (e.g., Al2O3 =0.9–4.0%) than those from the south (e.g., Al2O3 =0.2–2.2%), and have maximum whole-rock Re-depletion Os model ages (T RD) of ∼1.8Ga suggesting their coeval formation in the latest Paleoproterozoic. By contrast, peridotites from the south have maximum T RD model ages that span the Archean–Proterozoic boundary (2.1–2.5Ga). Peridotites with model ages from both groups are found at Fansi, the southernmost locality in the northern group, which likely marks a lithospheric boundary. The Neoarchean age of the lithospheric mantle in the southern section matches that of the overlying crust and likely reflects the time of amalgamation of the North China Craton via collision between the Eastern and Western blocks. The Late Paleoproterozoic (∼1.8Ga) lithospheric mantle beneath the northern section is significantly younger than the overlying Archean crust, indicating that the original lithospheric mantle was replaced in this region, either during a major north–south continent–continent collision that occurred during assembly of the Columbia supercontinent at ∼1.8–1.9Ga, or from extrusion of ∼1.9Ga lithosphere from the Khondalite Belt beneath the northern Trans-North China Orogen, during the ∼1.85Ga continental collision between Eastern and Western blocks. Post-Cretaceous heating of the southern section is indicated by high temperatures (>1000°C) recorded in peridotites from the 4Ma Hebi suite, which are significantly higher than the temperatures recorded in peridotites from the nearby Early Cretaceous Fushan suite (<720°C), and likely reflects significant lithospheric thinning after the Early Cretaceous. Combining previous Os isotope results on mantle xenoliths from the eastern North China Craton with our new data, it appears that lithospheric thinning and replacement may have evolved from east to west with time, commencing before the Triassic on the eastern edge of the craton, occurring during the Jurassic–Cretaceous within the interior, and post-dating 125Ma on the westernmost boundary. [Copyright &y& Elsevier]

Abstract: A pilot-scale hybrid membrane bioreactor (HMBR) was developed by introducing biofilm carriers into a conventional membrane bioreactor (CMBR) and operated for about one year for municipal wastewater treatment. Experiments were conducted to investigate the performances of the HMBR for organic removal, nutrients removal and membrane fouling control comparing with the CMBR. The comparative study results indicated that at a constant hydraulic retention time (HRT) of 10h and sludge retention time (SRT) of 10d, the HMBR apparently improved the organic removal. To be specific, the effluent COD in the CMBR averaged 44mg/L, but it dropped to 24.5mg/L in the HMBR. Correspondingly, the COD removal rate increased from 90.4% to 94.2%. Regarding NH4 +–N, TN and TP, the HMBR improved the removal rate by 4.2%, 13.7% and 1.7%, respectively. Another eye-catching feature of the HMBR was that the increase of transmembrane pressure (TMP) was slowed down during the operation at a constant flux of 10L/m2 h. In CMBR, the duration for TMP to reach the prescribed maximum of 20kPa after chemical washing was 57–65days, while in the HMBR it was prolonged to 92days or longer. This indicated a favorable condition of membrane fouling control by HMBR operation. [Copyright &y& Elsevier]

Abstract: TTG rocks are commonly assumed to form by partial melting of oceanic crust during slab subduction or anatexis of thickened lower crust. The two models are tested by an integrated study of geochronology and geochemistry for a composite batholith of Neoproterozoic granitoids (mainly TTG-like) from the Yangtze Gorge in South China. Zircon U–Pb dating indicates that all granitoids crystallized in a period of 820 to 800 Ma. Zircon δ 18O values are 4.85 to 6.84‰, suggesting limited contributions from supracrustal materials to magma sources. Zircon ε Hf(t) values for syn-magmatic domains range from −3.6 to −29.7, concordant with whole-rock ε Nd(t) values of −2.1 to −21.3. Correspondingly, zircon Hf model ages are 2.09 to 3.16 Ga, suggesting their derivation from ancient crust of Paleoproterozoic to Archean ages. TTG-like rocks contain inherited zircon cores that yield two groups of U–Pb ages at Paleoproterozoic (1.8 to 2.0 Ga) and Archean (~2.9 Ga), respectively. They show variable ε Hf(t) values from −48.4 to −33.4. Because the Neoproterozoic magmatism leads to variable increases of ε Hf(t) values for some inherited cores, only the lowest ε Hf(t) values for the inherited cores are assumed to represent the original Hf isotopes in source rocks. The screened results are consistent with those for Archean TTG gneiss and migmatite in this region. In addition, the TTG-like rocks have lower ε Nd(t) and ε Hf(t) values, higher Sr/Y and (La/Yb)N ratios and stronger depletion in Nb, Ta and Ti than the other granitoids. Two alternative scenarios are proposed to account for their petrogenesis: (1) anatexis of Archean and Paleoproterozoic mafic crust in the stable depths of garnet and amphibole, respectively; or (2) anatexis of Archean TTG and Paleoproterozoic mafic rocks in amphibole-stable depths. Nevertheless, the second one is preferred because the inherited zircons with Paleoproterozoic to Archean U–Pb ages are preserved in the TTG-like rocks, which is incompatible with high temperatures to generate the primary TTG magmas. Therefore, the Neoproterozoic TTG-like rocks were derived from the anatexis of ancient non-thickened lower crust, with the TTG features inheriting from their source. [Copyright &y& Elsevier]

Abstract: Herein we present new U–Pb zircon ages, whole-rock geochemical data and Nd–Sr–Hf isotopic data for an Early Palaeozoic monzogranite batholith from the Tengchong–Baoshan Block, Western Yunnan Province, China. Mineralogical and geochemical features suggest that this granitoid is a high-K, calc-alkaline, I-type granite. SHRIMP and laser ablation ICP-MS (LA-ICP-MS) analysis of zircon yields ages of between 499±5Ma and 502±5Ma, for three samples from the batholith. The monzogranite is characterised by high initial 87Sr/86Sr (0.7132–0.7144), negative ε Nd(t) (−9.7 to −9.40) and ε Hf(t) (−10 to −13.1), and is interpreted to derive from remelting of pre-existing Palaeoproterozoic, high-K, metabasaltic rocks of the upper crust. The granitoid magma underwent extensive fractional crystallisation of biotite±hornblende, ilmenite, titanite, K-feldspar and plagioclase during emplacement. The crystallisation temperature of the magma lies in the range 633–733°C, however, there is no evidence to suggest crustal assimilation occurred during its ascent. Like the ∼500Ma, I-type granite of this study, there occur numerous granitoid rocks of Early Palaeozoic age (490–470Ma) in adjacent regions across the entire Tengchong–Baoshan Block (). This episode of plutonism is coeval with the widespread granitoid magmatism found throughout the Indian Plate and the Himalayan Orogenic Belt that are both subordinate parts of the ancient, Gondwana supercontinent. We infer, therefore, that the Tengchong–Baoshan Block may also have formed part of Gondwana, and that it separated from this supercontinent along with other crustal blocks during the Late Palaeozoic. Moreover, based on the findings of this study, we document the occurrence of arc-related magmatism in the Tengchong–Baoshan Block during the late Palaeoproterozoic. [Copyright &y& Elsevier]

Abstract: Clastic sedimentary rocks are samples of the exposed continental crust. In order to characterize the crustal growth history of North China and its possible regional variations, 479 concordant detrital zircons in three sand samples from the lower reach of the Yellow River (which drains the Tibet–Qinghai Plateau, the Western Qinling Orogen, the Qilian Orogen and the North China Craton) and two sand samples from the Luan River and the Yongding River (which run entirely within the North China Craton) were measured for U–Pb age and Lu–Hf isotopic compositions by excimer laser-ablation ICP-MS and MC-ICP-MS. Although regional variations exist, concordant detrital zircons from the Yellow River reveal three major age groups of 2.1–2.5Ga, 1.6–2.0Ga, and 150–500Ma. Detrital zircons from the smaller Luan and Yongding Rivers show three broadly similar major age groups at 2.3–2.6Ga, 1.6–2.0Ga, and 140–350Ma, but with narrower age ranges. Compared to the Luan and Yongding River zircons, the Yellow River zircons are characterized by a significant number of Neoproterozoic grains. Although Hf isotopic compositions show both juvenile crustal growth and crustal reworking for all age groups, much of the crustal growth of North China occurred in the Neoarchean and Mesoproterozoic. All three rivers are characterized by a common prominent group of Hf crust formation model ages at 2.4–2.9Ga with a peak at 2.7–2.8Ga. A less significant age group lies between 1.4 and 1.8Ga for the Yellow River, and between 1.6 and 1.9Ga for the Yongding River and Luan River. Crustal growth rates based on Hf continental crust formation model ages suggest 45% and 90% of the present crustal volume was formed by 2.5Ga and 1.0Ga, respectively, for the drainage area of the Yellow River. In comparison, 60% and 98% of the present crustal volume of the North China Craton was generated by 2.5Ga and 1.0Ga, respectively, for the Luan and Yongding Rivers. The 2.7–2.8Ga age peak observed in all river samples agrees well with the coeval major peak for global crustal growth. However, the other suggested global peaks of crustal growth at 3.4 and 3.8Ga are insignificant in North China. Taken together with our previous studies of the Yangtze Craton, which show insignificant crustal growth at 2.7–2.8Ga, we suggest that these advocated worldwide crust formation peaks be re-examined and treated carefully. Our results also show that Phanerozoic zircons may have been derived from crustal sources separated from the mantle up to 2.0Ga ago before the zircons crystallized, suggesting long-term preservation, reworking and recycling of the continental crust. [Copyright &y& Elsevier]

Abstract: Unusual 18O depletion, with δ18O values as negative as −10‰ to −4‰ relative to VSMOW, was reported in zircons from ultrahigh-pressure eclogite-facies metamorphic rocks in the Dabie-Sulu orogenic belt, China. But it is critical for the negative δ18O zircons to be distinguished between magmatic and metamorphic origins, because the 18O depletion can be acquired by high-T eclogite-facies metamorphism of meteoric-hydrothermally altered low δ18O rocks. While zircon O diffusion kinetics has placed a reasonable constraint on this, zircon trace element compositions can provide a straightforward distinction between the magmatic and metamorphic origins. This paper reports our finding of unusual 18O depletion in zircon from granitic gneiss in the northeastern end of the Sulu orogen. Zircon δ18O values vary from −7.8‰ to −3.1‰ along a profile of 50m length at Zaobuzhen. They are close to extremely low δ18O values of −9.0‰ to −5.9‰ for metagranite at Qinglongshan and adjacent areas in the southwestern end of the Sulu orogen. CL imaging suggests that the low δ18O zircons at Zaobuzhen are primarily of magmatic origin, but underwent different degrees of metamorphic modification. Zircon U–Pb dating yields middle Neoproterozoic ages of 751±27 to 779±25Ma for protolith crystallization and Triassic ages of 214±10 to 241±33Ma for metamorphic resetting. However, no metamorphic modification occurs in zircon REE patterns that only indicate magmatic recrystallization and hydrothermal alteration, respectively. Thus, the negative δ18O zircons are interpreted as crystallizing from negative δ18O magmas due to melting of meteoric-hydrothermally altered negative δ18O rocks in an active rift setting at about 780Ma. The variation in zircon δ18O values indicates considerable O isotope heterogeneity in its granitic protolith. Zircon Lu–Hf isotope analyses give positive ε Hf(t) values of 1.6–4.1 and Hf model ages of 1.18–1.30Ga. This suggests that the granitic protolith was derived from the mid-Neoproterozoic reworking of late Mesoproterozoic juvenile crust. The metagranites at Zaobuzhen and Qinglongshan, about 450km apart, are two known occurrences of the unusually low δ18O zircons below −6‰ so far reported in the Sulu orogen. They are similar to each other in both protolith and metamorphic ages, so that they share the same nature of both Neoproterozoic protolith and Triassic metamorphism. Therefore, the locally negative δ18O zircons may register centers of low δ18O magmatism during the supercontinental rifting. [Copyright &y& Elsevier]

The LA-ICP-MS U-Pb dating of hundreds of detrital zircon grains from the Sinian sandstones of Liantuo formation and tillites of Nantuo formation at Sanxia area in Yichang identified 3319–3508 Ma zircon grains. Their 207pb/206pb and 206pb/238U ages show excellent agreement (concordia degree 99%–100%). Their CL images exhibit well-developed oscillatory zoning and the Th/U ratios are within 0.46–0.76, implying that they are igneous zircons which formed during middle-early Archean. These zircons are the oldest ones discovered in Yangtze craton until now. However, the detrital zircons with ages older than 3.3 Ga in the metamorphic rocks of Kongling group were not found by further investigation, which suggests the presence of crust older than high-grade metamorphic Kongling terrain in Yangtze craton. [ABSTRACT FROM AUTHOR]

• The stratigraphic Mg isotopic profiles and the depositional cycles are coupled in the massive dolostone succession. • Mg isotope could be used to sequence the dolomitization events. • Massive dolostone could be generated by the temporal and spatial stacking of multiple dolomitization events. • Sea level fluctuation results in the stacking of multiple dolomitization events. The origin of ancient massive dolostones, i.e. continuous dolostone sequence with a thickness >100 m and a platform-wide distribution, is the key issue of the 'Dolomite Problem' that cannot be clearly demonstrated by any existing dolomitization model individually or sequentially. It has been proposed that the massive dolostone could be generated by the stacking of multistage dolomitization events linked to the sea-level fluctuation, which results in repeatedly occurring of limestone precipitation-dolomitization cycles. However, the sequence of dolomitization events cannot be differentiated by any sedimentological or traditional geochemical techniques. Here we report Mg isotopic compositions of the massive dolostone (δ 26 Mg dol) from the middle Cambrian Qinjiamiao Formation (QJM) in the Yangtze Platform, South China, which consists of cyclic depositions of shoaling upward sequences. The stratigraphic variation of δ 26 Mg dol is coincident with the depositional cycles, suggesting the dolomitization might be periodic and be coupled with the sea-level oscillation. As dolomitization fluids experience changes in δ 26 Mg values during dolomitization processes, the intra-cycle stratigraphic δ 26 Mg dol profile reflects the processes of dolomitization. Our study indicates that the massive dolostone could be generated by the temporal and spatial stacking of multiple dolomitization events that are associated with sea-level fluctuation. If this model can be verified by other massive dolostone successions, the origin of massive dolostone may be resolved. [ABSTRACT FROM AUTHOR]

The numerical and experimental data of the helically coiled-twisted trilobal tube (HCTTT) heat exchanger are compared, the results present that, due to more intense secondary flow of the HCTTT caused by the superposition of overall twist and self-twist, region near the center of the HCTTT has higher turbulent kinetic energy, and the region near the wall of the HCTTT is with the better Field synergy Angle. Two evaluation criteria, Performance Evaluation Criteria (PEC) and Filed synergy number (Fc) are introduced to comprehensively evaluate comprehensive performance, the results present that the HCTTT performs better in the Hydrodynamic and thermal performance than that of the helically coiled elliptical tube (HCET), helically coiled plain tube (HCPT) and trilobal tube (HCTT). In addition, compared to the HCPT, the increment ratio on Nusselt number of HCTTT is more than 19%–31%, while the augmentation ratio of flow resistance is up to 24%–38%. The novel correlations proposed in the HCTTT heat exchanger are consistent with the simulation data. [ABSTRACT FROM AUTHOR]

To enhance the degradation of wheat straw (WS) and corn straw (CS) in rumen fermentation, characterization of degradation and ruminal microorganisms of monosubstrate (WS/CS) groups and a cosubstrate strategy with food waste (FW) group was performed. The cellulose, hemicellulose, and lignin degradation efficiency of WS and CS; soluble chemical oxygen demand; volatile fatty acid yields; and activity of ligninolytic, cellulolytic, and hemicellulolytic enzymes for the cosubstrate group were improved compared with those for the corresponding monosubstrate groups. An accurate and a good of fit of the Weibull kinetic model, decreased crystallinity index values, and characteristic absorbance bands in the Fourier transform-infrared spectra further confirmed that cosubstrate addition with FW decreased the resistance of cellulose and hemicellulose to biodegradation. High-throughput sequencing results suggested that the bacterial diversity in CS rumen fermentation and fungal diversity and richness in WS rumen fermentation were promoted with FW as a cosubstrate. The cosubstrate addition with FW significantly affected the composition of the ruminal bacteria and fungi in rumen fermentation. The relative abundances (RAs) of rumen bacteria were increased in the cosubstrate CS/WS and FW fermentation conditions, and the enhancement of CS degradation with FW supplementation was stronger than that of WS rumen fermentation with FW supplementation. The RAs of the ruminal fungal genera Ustilago and Fusarium were promoted in CS and WS fermentation with FW, respectively. Moreover, the fermentation properties and rumen flora in the FW rumen fermentation also provided some evidence to suggest an enhancement of the cosubstrate strategy compared with the monosubstrate strategy. Image 1 • Food waste (FW) increased alkalinity and improved VFAs yield in rumen fermentation. • Wheat/corn straw (WS/CS) rumen degradation was enhanced by cosubstrate with FW. • Lignocellulases and bacterial diversity in CS and FW fermentation were improved. • Fungal diversity and richness in WS fermentation were promoted with FW addition. [ABSTRACT FROM AUTHOR]

Rumen fermentation is known to be effective for lignocellulosic-wastes biodegradation to certain extent but it is still unclear if there exists a termination of the microorganisms' action to further degrade the bio-refractory fractions. In order to illuminate the related microbiological characteristics, experiments were conducted in a prolonged duration of rumen fermentation of mechanically ruptured wheat straw, with inoculation of cow rumen microorganisms in vitro. Although the organic wastes could not be biodegraded quickly, continuous conversion of the lignocellulosic contents to volatile fatty acids and biogas proceeded in the duration of more than three months, resulting in 96–97% cellulose and hemicellulose decomposition, and 42% lignin decomposition. X-ray diffraction and Fourier transform infrared spectroscopy further demonstrated the characteristics of lignocellulosic structure decomposition. Under the actions of cow rumen microorganisms, stable pH was maintained in the fermentation liquid, along with a steady NH 4 +-N, volatile fatty acids accumulation, and a large buffering ability. It was identified by enzyme analysis and Illumina MiSeq sequencing that the rich core lignocellulolytic enzymes secreted by the abundant and diverse rumen bacteria and fungi contributed to the persistent degradation of lignocellulosic wastes. Members of the Clostridiales order and Basidiomycota phylum were found to be the dominant lignocellulolytic bacteria and fungi, respectively. It could thus be inferred that the main lignocellulose degradation processes were a series of catalytic reactions under the actions of lignocellulolytic enzymes secreted from bacteria and fungi. The dominant hydrogenotrophic methanogens (Methanomassiliicoccus , Methanobrevibacter , Methanosphaera , and Methanoculleus) in the rumen could also assist CH 4 production if the rumen fermentation was followed with anaerobic digestion. Unlabelled Image • High WS decomposition was achieved by the persistent action of cow rumen microflora. • Degradation characteristics of raw WS subject to rumen fermentation were analysed. • Rich core lignocellulolytic enzymes were secreted by the rumen bacteria and fungi. • Firmicutes and Basidiomycota were the dominant lignocellulolytic bacteria and fungi. • Degradation mechanisms for the in vitro rumen fermentation of WS were elucidated. [ABSTRACT FROM AUTHOR]

Cow manure (CM) was added to a dynamic membrane bioreactor (DMBR) operated under anaerobic condition for enhancing food waste (FW) digestion for over 300 days with stepwise increase of organic loading rates (OLRs) from 1.07 to 11.9 g COD/L/day. At a FW/CM ratio of 3.5:1 (based on volatile solids), the mixed liquor pH was always above 8.0 and no apparent volatile fatty acids (VFAs) accumulation occurred even at the highest OLR of 11.9 g COD/L/day (hydraulic retention time as 10 days and solid retention time as 15.5 days, correspondingly), indicating a very stable operation condition which resulted in an average CH 4 yield as high as 250 mL/g COD and CH 4 production as high as 2.71 L CH 4 /L/day. The hardly biodegradable organic components, such as cellulose, hemicellulose, and lignin, were effectively degraded by 78.3%, 58.8%, and 47.5%, respectively. Significantly high anaerobic digestion reaction ratios, especially the hydrolysis ratio which is usually the limiting factor, were calculated based on experimental results. Furthermore, the high lignocellulase contents and coenzyme F 420 levels, along with the decrease of cellulose crystallinity from 72.6% to 16.4% in the feedstock, provided strong evidence of an enhanced biological activity by CM addition. By high-throughput sequencing analysis, more abundant and diverse bacterial, archaeal, and fungal genera were identified from the DMBR sludge. With CM addition, the biodegradation of lignocellulose might have produced sufficient H 2 and CO 2 for the hydrogenotrophic methanogens such as Methanoculleus , Methanomassiliicoccus , and Methanobacterium , which were highly tolerant to ammonium inhibition, and then the elevated ammonium level would have provided high buffering capacity in the DMBR thus ensuring a stable condition for high rate FW digestion and CH 4 production. Image 1 • Long-term operation of a DMBR was conducted for FW digestion with CM as additive. • Steady pH and low VFA level were maintained with increasing OLR to 11.9 g COD/L/day. • CH 4 production continuously increased with increasing OLR up to 2.71 L/L/day. • More abundant and diverse bacteria, archaea and fungi were detected with CM addition. [ABSTRACT FROM AUTHOR]