Trace element compositions of garnet, omphacite and apatite in ultrahigh-pressure eclogites from the main hole of the Chinese Continental Scientific Drilling (CCSD) project were in situ analyzed by the LA-ICP-MS method. Although both garnet and omphacite have homogeneous major element compositions, their trace elements show zonations from core to rim in rare earth elements. In particular, middle rare earth elements in the garnet, heavy rare earth elements in the apatite and all rare earth elements in the omphacite increase from core to rim, respectively. Based on dependence of partition coefficients on temperature and pressure in these minerals, we suggest that the trace elemental zonations in these minerals may record a short-lived heating event during exhumation. eclogite, in situ analysis, trace element, mineral zoningThe Sulu ultrahigh pressure (UHP) metamorphic belt is an important part of the Qinling-Dabie Central Orogenic Belt in China. The main hole of the Chinese Continental Scientific Drilling (CCSD) is located at Donghai County, the southwestern part of the Sulu UHP terrain. Rocks drilled through by CCSD ever resided in the deep level of mantle beneath the convergent plate boundary, which is the best area to study the continental subduction and geodynamics [1,2] . Recent studies reveal that the eastmost Sulu UHP rocks suffered partial melting during exhumation [3] , and some eclogites in the eastern Shandong were overprinted by granulite-facies metamorphism [4][5][6][7] . Then, one important question is what causes the partial melting. To answer this question, decompression, increasing temperature and adding volatile were ever suggested. Yao et al. [7] attributed overprinting of granulite-facies metamorphism on eclogites to fluid infiltration during the exhumation. However, P-T path of coesite eclogite to granulite indicates that the overprinting of granulite-facies metamorphism was associated with heating, and the extent of temperature increasing was ~40℃ [4] . O'Brien and Vrána [8] suggested that a short-lived heating event during exhumation resulted in overprinting of granulite-facies metamorphism on the UHP eclogites in the Moldanubian Zone. The presence of corundumbearing mafic and ultramafic rock is an indicator of ultrahigh temperature [9][10][11][12] . In the Sulu UHP belt, corundum is found in eclogite enclosed in ultramafic rocks [13] and garnetite in garnet peridotite [14] . Especially, we recently found a unique mineral assemblage (garnet + corundum + spinel + quartz + feldspar) indicating (ultra-) high temperature nearby the CCSD. These observations imply that the eclogites in some parts of the Sulu UHP terrane could suffer a short-lived high-T stage during the exhumation.The thermodynamic theory of trace element partitioning between metamorphic minerals indicates that compared with major elements, trace elements are potentially more sensitive to chemical and thermobaromet-
Beijing-you chicken (BJY) is a classic chicken breed originating from the Beijing area. BJY is popular among the local people and faces the risk of counterfeiting in the market. In this study, hyperspectral imaging in tandem with multivariate analyses were employed to identify and authenticate BJY among four common chicken breeds.
The Cenozoic basalts from eastern China show commonly high Fe/Mn ratios (average = 68.6 ± 11.5) coupled with OIB-type trace element signature. The Cenozoic basalts form the northern margin and the southern margin of the North China Craton are studied in detail. Model calculations point out that the coupling feature of high Fe/Mn ratio with OIB-type trace element signature of these basalts cannot be produced by neither pyroxene/olivine crystallization nor remelting of previously melted mantle, but require partial melting of a garnet pyroxenite-rich mantle source. Combining these features of the Cenozoic basalts with the Phanerozoic lithospheric evolution of the eastern China, we suggest that the Cenozoic basalts were derived from a garnet pyroxenite-rich mantle source associated with continental crust delamination or oceanic crust subduction.Cenozoic basalts, High Fe/Mn ratios, OIB-type signature, Lithospheric recycling
Curved texturing is an effective technique to improve the skid-resistance performance of concrete pavements, which relies on the suitable combination of the groove parameters. This study aims to optimize these parameters with the consideration of skid-resistance performance and driving stability. A pressure film was adopted to obtain the contact stress distribution at the tire–pavement interface. The evaluated indicator of the stress concentration coefficient was established, and the calculation method for the stationary steering resistance torque was optimized based on actual tire–pavement contact characteristics. Test samples with various groove parameters were prepared use self-design molds to evaluate the influence degree of each groove parameter at different levels on the skid-resistance performance through orthogonal and abrasion resistance tests. The results showed that the groove depth and groove spacing had the most significant influence on the stress concentration coefficient and stationary steering resistance torque, respectively, with the groove depth having the most significant influence on the texture depth. Moreover, the driving stability and durability of the skid-resistance performance could be balanced by optimizing the width of the groove group. After analyzing and comprehensively comparing the influences of various parameters, it was found the parameter combination with width, depth, spacing, and the groove group width, respectively, in 8 mm, 3 mm, 15 mm, and 50 mm can balance the skid-resistance performance and driving stability. The actual engineering results showed that the R2 of the fitting between the stress concentration coefficient and SFC (measured at 60 km/h) was 0.871, which proved the effectiveness of the evaluation index proposed in this paper.
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