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Granulites and eclogites are useful for revealing the thermal and tectonic evolution of orogens. Early Palaeozoic granulites and associated eclogites in the East Kunlun Orogenic Belt (EKOB) display contrasting metamorphic age. Such asynchronous granulite–eclogite associations have rarely been reported, and the geological significance of their existence remains to be further explored. In this study, petrological and geochronological techniques were used to investigate two felsic and two mafic granulites collected from the Qingshuiquan area in the eastern section of the EKOB. These rocks record similar P–T paths, which are characterized by a peak stage within suprasolidus and high‐pressure (HP) granulite facies conditions (750–832°C and 10.1–12.0 kbar), followed by an initial decompression and cooling stage to subsolidus conditions (600–748°C and 6.5–8.6 kbar), and then a stage of further retrogression under greenschist facies conditions. The protoliths to these granulites are of volcanic and sedimentary origin and suggested to be a component of the continental basement unit. Metamorphic P–T paths indicate that these rocks experienced peak metamorphism at a depth of ~40 km, then cooling and uplift to a depth of ~25 km, and eventually experienced low‐grade retrogression at shallow crustal levels. Cathodoluminescence images and compositional data demonstrate that the zircons in these rocks are of metamorphic origin and they crystallized at or near peak conditions. SIMS U–Pb dating of representative zircon grains yield concordant metamorphic ages of c. 490–520 Ma, with a peak value of 505 Ma on the probability density curve. These ages are similar to other 480–530 Ma ages typically retrieved from EKOB granulites and associated rocks, and are markedly older than the 400–450 Ma ages retrieved from eclogites and their host rocks. The HP granulites and eclogites of the EKOB do not show overprinting relationships. Such asynchronous characteristics imply that the two rock types formed in distinct tectonic settings and at different stages of a protracted subduction–collision process. The studied granulites are suggested to have formed in the root of a continental arc during a stage of Proto‐Tethys Ocean subduction. The formation of the eclogites could be attributed to subsequent deep continental subduction. [ABSTRACT FROM AUTHOR]

The experiment was to find a green and effective method to separate flavonoids from Eucommia ulmoides leaves. Ultrasonic-assisted choline tryptophan ionic liquid was used to extract flavonoids from Eucommia ulmoides leaves. Response surface methodology was used to optimize the extraction of total flavonoids. Aqueous two-phase combined with antisolvent precipitation was used to separate and extract flavonoids, and the components of flavonoids extracts were analyzed by liquid chromatography. The results showed that the optimum parameters of response surface optimization were ultrasonic time 54.76 min, ultrasonic power 504.8 W and liquid-material ratio 23.5 mL/g, and the predicted extraction rate of total flavonoids was 2.66%. Under the optimized conditions of ultrasonic time 55 min, ultrasonic power 505 W and liquid-material ratio 24 mL/g, the extraction rate of total flavonoids from Eucommia ulmoides leaves was 2.53%. The content of rutin and quercetin in flavonoids extract was 50.88% and 1.26%, respectively. The study indicates that the process used in the experiment is green and environmentally friendly, and can be used as an efficient method for separating and extracting flavonoids from Eucommia ulmoides leaves. [ABSTRACT FROM AUTHOR]

Olivine and orthopyroxene (Opx) are the most abundant minerals in lherzolitic to harzburgitic peridotites, and their compositions represent an important—and sometimes only—source of information for the origin and physicochemical evolution of the subcontinental lithospheric mantle (SCLM). We report a high‐quality in situ trace element data set for Opx and olivine of well‐characterized spinel‐peridotite xenoliths, including eight lherzolites and four harzburgites, which were entrained in the Cenozoic basalts from Jiaohe, NE China. While the lherzolites and harzburgites show contrasting evolution involving various metasomatic agents, reflected in different trace element relationships, both experienced early cooling followed by recent (pre‐entrainment) heating, as unraveled by a combination of mineral thermometers with inherently different diffusion rates. The sampling depth of spinel‐facies peridotites is obtained by olivine‐spinel thermobarometry, taking into account post‐melting subsolidus processes and pre‐emplacement thermal disturbance, using an empirical correction for the Ca content in olivine, which yields a pressure range of 1.1–2.0 GPa. The V contents (92–116 μg/g) and V/Sc ratios (5.7–6.4) in lherzolitic Opx are higher than those in harzburgitic Opx (V: 56–76 μg/g; V/Sc: 3.4–5.9), qualitatively reflecting the reducing and oxidizing effect, respectively of refertilization versus metasomatic interaction with a small‐volume melt. Thus, comparative thermobarometry, together with trace element systematics of Opx and olivine can be effective tools to reveal the architecture, chemical, thermal, and redox evolution of the shallow SCLM, as sampled by spinel peridotite xenoliths. Plain Language Summary: Peridotite xenoliths entrained in basalts are direct samples of the subcontinental lithospheric mantle, archiving a wealth of information on the genesis, structure, and evolution of this long‐lived terrestrial reservoir. Orthopyroxene and olivine constitute the only rock‐forming minerals in some mantle rocks, such as harzburgites and dunites from which petrogenetic information may be gained. However, until relatively recently, trace element abundances in these minerals have been under‐utilized due to their low abundances and analytical challenges. Moreover, pressure (i.e., depth) estimates for spinel‐facies peridotites have been hampered by the lack of accurate and precise geobarometers. In this study, we determined trace element abundances in orthopyroxene and olivine of well‐characterized spinel lherzolite and harzburgite xenoliths from Jiaohe, NE China by in situ high‐precision analyses. We demonstrate their utility to obtain the xenoliths' depth of origin, and to illuminate the chemical, thermal, and redox evolution of the shallow continental lithosphere, providing a new approach, perspective and impetus to comprehensively study this reservoir. Key Points: Trace element compositions of all minerals are used to unravel the petrogenesis of peridotitesEmpirical correction for Ca in olivine applied for quantitative olivine‐spinel thermobarometryUse of multiple thermometers reveals short‐term perturbations superposed on long‐term continental thermal trends globally [ABSTRACT FROM AUTHOR]

Oxygen fugacity controls the behaviour of multivalent elements and compositions of C-O-H fluids in Earth's mantle, which further affects the cycling of materials between the deep interior and surface of Earth. The redox state of the mantle lithosphere of typical stable cratons has been well documented, but how oxygen fugacity had varied during craton destruction remains unclear. This study estimates the oxygen fugacity of peridotite xenoliths entrained in Mesozoic and Cenozoic basalts on North China Craton (NCC), a typical destroyed craton. The oxygen fugacity vs. Mg# of olivine reveals that the mantle lithosphere beneath the NCC experienced three stages of evolution in terms of oxygen fugacity. First, the refractory and oxidized peridotite xenoliths indicate that the lithospheric mantle experienced a high degree of melt extraction and later long-term and complicated metasomatism before craton destruction. Then, the variations of olivine Mg-number in peridotites and oxygen fugacity reveal significant metasomatism by melts originated from the shallow asthenosphere during the destruction of the NCC since the Mesozoic. The third stage may have occurred when mantle peridotites interacted with silica-undersaturated melts or fluids stemmed from the mantle transition zone where the stagnant Pacific slab underlies. This study further verifies that the asthenospheric convection induced by the roll-back of the subducted paleo-Pacific slab played a crucial role in the destruction of the NCC and helps understand the oxygen fugacity variability during the later life of the craton. [ABSTRACT FROM AUTHOR]

Subduction of the Pacific slab has been widely credited for the destruction of the eastern North China Craton (NCC). However, the nature of the subcontinental lithospheric mantle (SCLM) beneath the central and western NCC is less well constrained, which has hindered the understanding of cratonic responses to repeated Phanerozoic circum-craton subductions. Here, we report the in situ major- and trace-element contents and Sr isotopic compositions of minerals from 27 peridotite xenoliths obtained from Cenozoic basalts from Xiyang‒Pingding, central NCC, to gain new insights into how plate subduction affected the Archean lithospheric keel. On the basis of olivine major-element and clinopyroxene trace-element contents, as well as clinopyroxene Sr isotopic compositions, we divide the xenoliths into four types. The high-Mg# types 1 and 2 peridotites show high olivine forsterite (Fo) contents, convex-upward rare-earth element patterns, and high 87Sr/86Sr (0.7053‒0.7062) in clinopyroxene, and they could be relicts of an old cratonic root. The high-Mg# type 3 peridotites exhibit high (La/Yb)N and low Ti/Eu and 87Sr/86Sr (0.7038‒0.7044), and they are interpreted as reaction products of Archean SCLM and carbonatitic melts from the asthenosphere with a contribution of recycled oceanic components. The low-Mg# type 4 peridotites display low 87Sr/86Sr (0.7029‒0.7033) and represent fragments of modified SCLM that has been recently refertilized by asthenospheric melts. Complex architectures of the SCLM underneath Xiyang‒Pingding reflect multistage overprinting of mantle metasomatism. Recent influxes of asthenospheric melts played a critical role in transforming refractory SCLM to fertile SCLM. Combined with previous studies, our findings suggest that the SCLM beneath the central NCC became progressively more refertilized from the center toward both the northern and southern margins, a spatial pattern that was likely generated by N‒S-trending subductions of the circum-craton plates. [ABSTRACT FROM AUTHOR]

Olivine grains from Songshugou mylonitized peridotite massif record δ18O both lower and higher than in pristine mantle samples in North Qinling Orogen, Central China. Olivines from dunites exhibit large variations in δ18O (4.03–7.07‰), and some porphyroclasts display negative correlations between δ18O and forsterite content {Fo; [100×Mg/(Mg+Fe2+)]}. The porphyroclast cores have low-δ18O values, indicating that they formed in the oceanic lithospheric mantle prior to subduction. We attribute low-δ18O values to seawater-peridotite interaction under high-temperature conditions. The porphyroclast rims and small olivines exhibit high-δ18O values. These features suggest that high-δ18O olivines formed during mylonitization in the exhumation process. Olivines reacted with 18O-rich melt/fluids released from subducted altered oceanic basalts and continental sediments at low temperature (<610–680 °C). The 18O-rich melt/fluids selectively affected porphyroclast rims and small olivine grains. Unlike the olivines in the dunites, the olivines and orthopyroxenes in the harzburgites show limited variations in δ18O (4.21–5.45‰ and 5.5–5.8‰, respectively), due to orthopyroxene exchange with melt/fluid at a slower rate than the coexisting olivine. The preservation of the low-δ18O signature in olivines indicates a short residence time (<20 Ma) for subducting peridotites to mantle depths. [ABSTRACT FROM AUTHOR]

We report Lithium (Li) concentrations and isotopic compositions for co-existing olivine, orthopyroxene (opx), and clinopyroxene (cpx) mineral separates from depleted and metasomatised peridotite xenoliths hosted by basaltic lavas from northwestern Ethiopian plateau (Gundeweyn area). The peridotites contain five lherzolites and one harzburgite and are variably depleted and enriched in LREE relative to HREE. In both depleted and enriched lherzolites, Li is preferentially incorporated into olivine (2.4-3.3 ppm) compared to opx (1.4-2.1 ppm) and cpx (1.4-2.0 ppm) whereas the Li contents of olivines (5.4 ppm) from an enriched harzburgiteare higher than those of lherzolites. Olivines from the samples show higher Li abundances than normal mantle olivines (1.6-1.9 ppm) indicating the occurrence of Li enrichments through melt-preroditite interaction. The average δ Li values range from +2.2 to +6.0‰ in olivine, from -0.1 to +2.0‰ in opx and from -4.4 to -0.9‰ in cpx from the lherzolites. The Li isotopic composition (3.5‰) of olivines from harzburgite fall within the range of olivine from lherzolites but the opxs show low in δLi (-2.0‰). Overall Li isotopic compositions of olivines from the peridotites fall within the range of normal mantle olivine, δLi values of ~+4±2‰ within uncertainty, reflecting metasomatism (enrichment) of the peridotites by isotopically heavy Li-rich asthenospheric melt. Li isotope zonation is also observed in most peridotite minerals. Majority of olivine grains display isotopically heavy cores and light rims and the reverse case is observed for some olivine grains. Orthopyroxene and clinopyroxene grains show irregular distribution in δLi. These features of Li isotopic compositions within and between grains in the samples reflect the effect of diffusion-driven isotopic fractionation during meltperidotite interaction and cooling processes. [ABSTRACT FROM AUTHOR]

Lithium (Li) elemental and isotopic compositions for mineral separates of coexisting olivine, orthopyroxene and clinopyroxene of mantle xenoliths from the Quaternary volcanic rocks of southern Ethiopian rift (Dillo and Megado) reveal the influence of late stage melt-peridotite interaction on the early depleted and variably metasomatized lithospheric mantle. Two types of lherzolites are reported (LREE-depleted La/Sm = 0.11-0.37 × Cl and LREE-enriched, La/Sm = 1.88-15.72 × Cl). The depleted lherzolites have variable range in Li concentration (olivine: 2.1-5.4 ppm; opx: 1.1-2.3 ppm; cpx: 1.0-1.8 ppm) and in Li isotopic composition (δLi in olivine: −9.4 to 1.5‰; in opx: −4.5 to 3.6‰; in cpx: −17.0 to 4.8‰), indicating strong disequilibrium in Li partitioning and Li isotope fractionation between samples. The enriched lherzolites have limited range in both Li abundances (olivine: 2.7-3.0 ppm; opx: 1.1-3.1 ppm; cpx: 1.1-2.3 ppm) and Li isotopic compositions (δLi in olivine: −1.3 to +1.3‰; in opx: −2.0 to +5.0‰; in cpx: −7.5 to +4.8‰), suggest that the earlier metasomatic event which lead to LREE enrichment could also homogenize the Li contents and its isotopes. The enriched harzburgite and clinopyroxenite minerals show limited variation in Li abundances and variable Li isotopic compositions. The Li enrichments of olivine and clinopyroxene correlate neither with the incompatible trace element enrichment nor with the Sr-Nd isotopic compositions of clinopyroxene. These observations indicate that the metasomatic events which are responsible for the LREE enrichment and for the Li addition are distinct, whereby the LREE-enrichment pre-dates the influx of Li. The presence of large Li isotopic disequilibria within and between minerals of depleted and enriched peridotites suggest that the lithospheric mantle beneath the southern Ethiopian rift has experienced recent melt-peridotite interaction. Thus, the Li data set reported in this study offer new additional evidence for the existence of late stage metasomatism, which probably occurred at shallow depth briefly before and/or during entrainment and ascent of mantle xenoliths to the surface. [ABSTRACT FROM AUTHOR]

Due to their small size, zinc oxide (ZnO) nanoparticles (NPs) are readily absorbed and easily cross biological barriers, which make them promising candidates as diet additives. However, some studies have reported that ZnO NPs cause toxicity; therefore, their safety and potency as diet additives for farm animals should be established. This study was the first to fully evaluate the effects of ZnO NPs on the homeostasis of eight elements in seven organs/tissues. The regulation of element homeostasis was found to be organ specific with no influence on oxidation status, anti-oxidation capability, or organ damage. ZnO NPs may specifically regulate the homeostasis of mineral elements and affect the following correlations: (1) between the element content in each organ and the concentration of Zn used in ZnSO or ZnO NP treatments; (2) between ZnO NP and ZnSO treatments for the same element in each organ; and (3) between elements (in each organ in ZnSO or ZnO NP treatments) in layers' organs/tissues. The use of ZnO NPs as diet additives for animals should be implemented cautiously because, among other uncertainties, they may affect mineral element content. [ABSTRACT FROM AUTHOR]

Mantle xenoliths hosted in Quaternary basaltic lavas from the Dillo and Megado areas of the southern Ethiopian rift are investigated to understand the geochemical composition and associated processes occurring in the lithospheric mantle beneath the region. The xenoliths are comprised of predominantly spinel lherzolite with subordinate harzburgite and clinopyroxenite. Fo content of olivine and Cr# of spinel for peridotites from both localities positively correlate and suggest the occurrence of variable degrees of partial melting and melt extraction. The clinopyroxene from lherzolites is both LREE depleted (La/Sm = 0.11-0.37 × Cl) and LREE enriched (La/Sm = 1.88-15.72 × Cl) with flat HREEs (Dy/Lu = 0.96-1.31 × Cl). All clinopyroxene from the harzburgites and clinopyroxenites exhibits LREE-enriched (La/Sm = 2.92-27.63.1 × Cl and, 0.45 and 1.38 × Cl, respectively) patterns with slight fractionation of HREE. The Nd/Nd and Hf/Hf ratios of clinopyroxene from lherzolite range from 0.51291 to 0.51370 and 0.28289 to 0.28385, respectively. Most of the samples define ages of 900 and 500 Ma on Sm-Nd and Lu-Hf reference isochrons, within the age range of Pan-African crustal formation. The initial Nd and Hf isotopic ratios were calculated at 1, 1.5, 2 and 2.5 Ga plot away from the trends defined by MORB, DMM and E-DMM which were determined from southern Ethiopian peridotites, thus indicating that the Dillo and Megado xenoliths could have been produced by melt extraction from the asthenosphere during the Pan-African orogenic event. There is no significant difference in Sr/Sr ratios between the depleted and enriched clinopyroxene. This suggests that the melts that caused the enrichment of the clinopyroxene are mainly derived from the depleted asthenospheric mantle from which the xenoliths are extracted. Largely, the mineralogical and isotopic compositions of the xenoliths show heterogeneity of the CLM that could have been produced from various degrees of melt extraction, followed by metasomatism. [ABSTRACT FROM AUTHOR]

New O and Sr isotope compositions of minerals from well-characterized and variably metasomatized mantle xenoliths in Cenozoic basalts from the northwestern plateau (Gundeweyn area) and southern rift zone (Dillo and Megado areas) of Ethiopia were acquired to further evaluate the nature and effects of metasomatic processes affecting the lithospheric mantle beneath the East African Rift System (EARS), where a transition from plume impingement to rifting is recorded. The studied samples are dominantly fresh spinel lherzolites with subordinate spinel harzburgites and clinopyroxenites. The in situ δ18O composition of olivine is largely homogeneous, with average values of 5.31‰ for Gundeweyn, 5.22‰ for Dillo, and 5.25‰ for Megado xenoliths. The values are within the range of normal mantle olivine (δ18O = 5.1‰–5.4‰), and there is no systematic variation of δ18O values with petrographic characteristics, elemental compositions, Sr isotopic ratios, or tectonic setting (i.e., plateau [Gundeweyn] vs. rift [Dillo and Megado]). This suggests the absence of major tectonic controls on the δ18O ratios of lithospheric mantle beneath the EARS and indicates buffering of mantle oxygen with respect to metasomatic fluids or melts. The average in situ 87Sr/86Sr ratios of clinopyroxenes vary from 0.70300 to 0.70371 for Gundeweyn, 0.70254 to 0.70327 for Dillo, and 0.70288 to 0.70330 for Megado mantle xenoliths. In contrast to O isotopes, radiogenic Sr isotope compositions combined with light rare earth element enrichment in clinopyroxenes in both tectonomagmatic settings betray interaction with metasomatic melts or fluids that may be related to the Afar plume, and neither precludes nor requires influence of a Pan-African subduction component to the continental lithospheric mantle beneath the area. However, slightly higher 87Sr/86Sr and a higher abundance of enriched peridotite types in the plateau xenolith suite suggest a stronger contribution from plume or aged metasomatized lithospheric mantle sources than in the rift peridotites. [ABSTRACT FROM AUTHOR]

The vortex-induced vibration is one of the most important factors to make the engineering failure in wind engineering. This paper focuses on the suppression method of vortex-induced vibration that occurs on a circular cylinder fitted with vortex generators, based on the wind tunnel experiment. The effect of the vortex generators is presented with comparisons including the bare cylinder. The experimental results reveal that the vortex generators can efficiently suppress vortex-induced vibration of the circular cylinder. Vortex generator control can make the boundary layer profile fuller and hence more resistant to separation. The selections of skew angles and the angular position have a significant influence on the vortex generator control effect. By correlation analysis, it can be concluded that the vortex generators can inhibit the communication between the two shear layers and produce streamwise vortices to generate a disturbance in the spanwise direction. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanoparticles (NPs) have been applied in numerous industrial products and personal care products like sunscreens and cosmetics. The released ZnO NPs from consumer and household products into the environment might pose potential health issues for animals and humans. In this study the expression of microRNAs and the correlations of microRNAs and their targeted genes in ZnO NPs treated chicken ovarian granulosa cells were investigated. ZnSO4 was used as the sole Zn2+ provider to differentiate the effects of NPs from Zn2+. It was found that ZnO-NP-5 μg/ml specifically regulated the expression of microRNAs involved in embryonic development although ZnO-NP-5 μg/ml and ZnSO4-10 μg/ml treatments produced the same intracellular Zn concentrations and resulted in similar cell growth inhibition. And ZnO-NP-5 μg/ml also specifically regulated the correlations of microRNAs and their targeted genes. This is the first investigation that intact NPs in ZnO-NP-5 μg/ml treatment specifically regulated the expression of microRNAs, and the correlations of microRNAs and their targeted genes compared to that by Zn2+. This expands our knowledge for biological effects of ZnO NPs and at the same time it raises the health concerns that ZnO NPs might adversely affect our biological systems, even the reproductive systems through regulation of specific signaling pathways. [ABSTRACT FROM AUTHOR]

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To investigate the effects of melt-rock interaction on Li isotope fractionation, we report in situ Li concentrations and δ7Li of olivine (Ol), orthopyroxene (Opx), and clinopyroxene (Cpx) for six peridotite xenoliths from the eastern North China Craton. These xenoliths contain two lherzolites, two Cpx-rich lherzolites, and two wehrlites and are variably metasomatized. Lithium isotope zonation is observed in most peridotite minerals. The majority of Cpx grains display isotopically light cores with lower Li concentrations than the heavy rims. However, the Opx grains show a different style of zonation from Cpx, where higher Li concentrations in the cores are associated with much lighter δ7Li. Olivines in most peridotites have a restricted range of Li concentration and δ7Li within individual grains, whereas the olivines in a lherzolite show isotopically light cores (210.3) with high Li concentrations (2.3 ppm) and heavy rims (5.5) with low Li concentrations (1.7 ppm). These Li isotopic variations in mineral phases may reflect the combined effects of diffusion driven kinetic fractionation of Li isotopes during melt/fluid-peridotite interactions and slow cooling. Intersample heterogeneity of Li isotopes is also apparent. Olivine with forsterite (Fo) content of 91.3 in one lherzolite sample has "normal" mantle-like Li concentrations (1.1~2.4 ppm) and light δ7Li (210.3~5.5), while Ol with Fo content of 89.7 in another lherzolite has slightly high Li concentrations (2.0~3.0 ppm) but similar δ7Li (1.6~6.4) relative to normal mantle. Olivines in Cpx-rich lherzolites have lower Fo contents (83.8-87.5), higher Li concentrations (1.4~4.5 ppm), and heavier δ7Li (5.0~22.0) than those in lherzolites and normal mantle. The δ7LiOl value correlates positively with Li concentration and negatively with Fo from lherzolites to Cpx-rich lherzolites, indicating a reaction between lherzolites and melts with isotopically heavy Li- and Fe-rich signatures. By contrast, olivines in wehrlites have extremely lower Fo contents (82.2~83.2) and higher Li concentrations (2.4~4.2 ppm) than those in normal mantle, while their δ7Li values are within the range of normal mantle, reflecting metasomatism of the peridotites by asthenospheric melt. Overall, the large intragrain and intersample variations in Li concentrations and isotopic compositions reflect kinetic isotope fractionation during multiple metasomatisms. [ABSTRACT FROM AUTHOR]

Screening of zearalenone (ZEN)-producing species and monitoring of ZEN in feed were performed by using anti-zearalenone monoclonal antibodies. ELISA recoveries of ZEN from corn distillers dried grains with solubles (DDGS) feed, corn feed, rice bran, soybean meal, wheat bran and rapeseed dregs were between 78.6% and 88.6%. ZEN recovery from culture media was 96.3% at the spiked level of 500 µg/kg. Eighty-three samples of DDGS feed, corn feed and other fee ingredients were collected from 11 provinces of China and analysed for ZEN. Average ZEN levels were 563.4 µg/kg for DDGS feed, 393.1 µg/kg for corn feed and 65.7 µg/kg for other feed ingredients. EighteenFusariumspecies such asFusarium graminearumwhich could produce ZEN were isolated from corn feed and other feed ingredients. [ABSTRACT FROM AUTHOR]

Experimental studies on the partial melting of eclogite and peridotite provide important clues on mantle metasomatism. Here, we review results from some of the recent experiments and show that melting of carbonated eclogite and peridotite can produce carbonatitic to carbonated silicate melt, in which carbonates melt preferentially before Ti oxides and silicates. Low-degree melting results in carbonatitic melt coexisting with Ti oxides and silicates. This process also leads to the fractionation between some high-field strength elements (Nb, Ta, Zr, Hf, and HREE) and highly incompatible elements (U and Th) in the melt. When Ti oxides are nearly exhausted in eclogite, extremely high TiO2 contents (e.g. 19 wt.%) are present in the melt with marked concentration of Nb and Ta. These results help to explain the features of carbonatitic metasomatism and the Nb–Ta spike in oceanic island basalts as identified in experimental studies. These studies also explain the reducing conditions that stabilize diamond in the deep mantle (>150 km) as well as the occurrence of diamond at different depths reported in various studies. Melting in such a reduced mantle can happen through redox reaction between diamond, pyroxene, and olivine, in which the initial liquid is a carbonated silicate melt. However, the theoretical oxygen fugacity (fO2) in the asthenosphere is much lower than that predicted by the reaction and requires elevated fO2, which can be caused by the addition of relatively oxidized materials from the lower mantle, deep asthenospheric material, and various recycled components. A combination of these processes generates locally oxidized domains in the deep mantle. [ABSTRACT FROM AUTHOR]

Major and trace element compositions of constituent minerals, partly decomposed rims of orthopyroxenes (DRO), 'closed' melt pockets (CMP) and open melt pockets (OMP) in some Western Qinling peridotite xenoliths were obtained by LA-ICP-MS. Systematic core-to-rim compositional variations of garnet, clinopyroxene and orthopyroxene demonstrate that these minerals underwent variable degrees of subsolidus breakdown or partial melting. Both DROs and CMPs consist of similar mineral assemblages and are characterized by high TiO, CaO + NaO and low MgO contents; they are enriched in LREE and LILE compositions, have positive anomalies in Pb, Sr and particularly Ti, negative Th and U, and variable Zr and Hf anomalies. These chemical features are distinct and reflect reactions involving the orthopyroxenes. Compared to the CMPs, the OMPs, which are composed of a complex assemblage of minerals, display lower FeO and MgO contents, larger ranges in SiO and NaO, higher TiO, AlO, CaO and trace element concentrations, slightly negative Zr and Hf anomalies, and apparently negative Ti anomalies. Modeling calculations of partial fusion of orthopyroxenes and clinopyroxenes suggest that the CMPs most likely originated from the breakdown of orthopyroxenes with variably minor contribution of external melts from the melting of clinopyroxenes, whereas the OMPs were probably formed from the modification of the CMPs through the interaction with large amount of external melts. [ABSTRACT FROM AUTHOR]

Elemental and Li-Sr-Nd isotopic data of minerals in spinel peridotites hosted by Cenozoic basalts allow us to refine the existing models for Li isotopic fractionation in mantle peridotites and constrain the melt/fluid-peridotite interaction in the lithospheric mantle beneath the North China Craton. Highly elevated Li concentrations in cpx (up to 24 ppm) relative to coexisting opx and olivine (<4 ppm) indicate that the peridotites experienced metasomatism by mafic silicate melts and/or fluids. The mineral δLi vary greatly, with olivine (+0.7 to +5.4‰) being isotopically heavier than coexisting opx (−4.4 to −25.9‰) and cpx (−3.3 to −21.4‰) in most samples. The δLi in pyroxenes are considerably lower than the normal mantle values and show negative correlation with their Li abundances, likely due to recent Li ingress attended by diffusive fractionation of Li isotopes. Two exceptional samples have olivine δLi of −3.0 and −7.9‰, indicating the existence of low δLi domains in the mantle, which could be transient and generated by meter-scale diffusion of Li during melt/fluid-peridotite interaction. The Nd/Nd (0.5123-0.5139) and Sr/Sr (0.7018-0.7062) in the pyroxenes also show a large variation, in which the cpx are apparently lower in Sr/Sr and slightly higher in Nd/Nd than coexisting opx, implying an intermineral Sr-Nd isotopic disequilibrium. This is observed more apparently in peridotites having low Sr/Sr and high Nd/Nd ratios than in those with high Sr/Sr and low Nd/Nd, suggesting that a relatively recent interaction existed between an ancient metasomatized lithospheric mantle and asthenospheric melt, which transformed the refractory peridotites with highly radiogenic Sr and unradiogenic Nd isotopic compositions to the fertile lherzolites with unradiogenic Sr and radiogenic Nd isotopic compositions. Therefore, we argue that the lithospheric mantle represented by the peridotites has been heterogeneously refertilized by multistage melt/fluid-peridotite interactions. [ABSTRACT FROM AUTHOR]

Spongy textures are observed in mantle peridotite xenoliths hosted in Cenozoic kamafugites from the Western Qinling, central China. These textures are mainly developed in clinopyroxenes and spinels, and occur as spongy rims consisting of low-Na clinopyroxene, ilmenite, and bubbles, enclosing nonspongy cores. The ilmenites and bubbles exhibit shapes and sizes that vary with the width of the spongy rims. The spongy-textured minerals preserve primary shapes and well-defined grain boundaries and do not show apparent interaction with contact minerals or observed melts except the subsequent melts forming melt pockets. The xenocrysts display reactive zoning textures with host magmas rather than spongy textures. Compositionally, the spongy rims are enriched in Ca, Ti, and most trace elements, have high Cr#, and are depleted in Na, Al, Fe, Al, and Al/Al compared with the cores. These observations suggest that melts/host magmas did not play any significant role in the formation of the spongy textures. We therefore propose that spongy-textured clinopyroxenes and spinels in Western Qinling peridotite xenoliths developed from a decompression-induced partial melting event prior to formation of melt pockets and xenolith entrainment in host magmas. [ABSTRACT FROM AUTHOR]

Lithium isotope geochemistry is increasingly being used to trace deep-earth processes, reflecting the observed large variation of Li isotope ratios in mantle-derived rocks, including peridotite xenoliths associated with ancient continents. We briefly review the Li isotopic compositions of major geochemical reservoirs, the assumed mechanisms of Li isotopic fractionation, and, in particular, the origins of isotopically light Li in mantle-derived rocks based on the latest developments in Li isotope geochemistry. Comparison of Li isotope data with existing Sr-Nd isotope ratios reflects the subduction-recycling of ancient oceanic crust and the reappearance of Li in volcanic rocks. This circulation may play an important role in generating the isotopically light-Li component in the mantle - perhaps the enriched mantle end member defined by the Sr-Nd isotopic compositions of oceanic basalts. [ABSTRACT FROM AUTHOR]

A number of emerging studies suggest that air pollutants such as hydrogen sulfide (H2S) and ammonia (NH3) may cause a decline in spermatozoa motility. The impact and underlying mechanisms are currently unknown. Boar spermatozoa (in vitro) and peripubertal male mice (in vivo) were exposed to H2S and/or NH3 to evaluate the impact on spermatozoa motility. Na2S and/or NH4Cl reduced the motility of boar spermatozoa in vitro. Na2S and/or NH4Cl disrupted multiple signaling pathways including decreasing Na+/K+ ATPase activity and protein kinase B (AKT) levels, activating Adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) and phosphatase and tensin homolog deleted on chromosome ten (PTEN), and increasing reactive oxygen species (ROS) to diminish boar spermatozoa motility. The increase in ROS might have activated PTEN, which in turn diminished AKT activation. The ATP deficiency (indicated by reduction in Na+/K+ ATPase activity), transforming growth factor (TGFβ) activated kinase-1 (TAK1) activation, and AKT deactivation stimulated AMPK, which caused a decline in boar spermatozoa motility. Simultaneously, the deactivation of AKT might play some role in the reduction of boar spermatozoa motility. Furthermore, Na2S and/or NH4Cl declined the motility of mouse spermatozoa without affecting mouse body weight gain in vivo. Findings of the present study suggest that H2S and/or NH3 are adversely associated with spermatozoa motility. [ABSTRACT FROM AUTHOR]