Eclogites discovered in the eastern part of the East Kunlun Mountains, Western China, are primarily composed of garnet+omphacite+quartz+rutile. The garnets show end-member components of 48–55% ...almandine, 1–2% spessartine, 19–29% grossularite and 16–29% pyrope, and the omphacite has a jadeite content of 21–63%. The peak-metamorphic assemblage of eclogites records a P–T condition of >1.6GPa and 590°C–650°C. Zircon U–Pb dating of the inherited magmatic zircons from fine-grained eclogite reveals a Neoproterozoic age of 934Ma, representing the protolith age of the eclogite. Zircons from the coarse-grained eclogite contain inclusions of garnet, omphacite and rutile, and yield a weighted mean age of 428Ma, indicating the metamorphic age of eclogite. The eclogites, together with the Late Cambrian (508Ma) high-pressure granulite to the west, constitute an Early Paleozoic high-pressure metamorphic belt in the East Kunlun.
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► Discovery of eclogite in the East Kunlun orogen. ► Estimated P-T conditions of eclogite formation at 590°C–650°C and >1.6GPa. ► Gabbro-diorite protolith formed at 934Ma and eclogite metamorphism at 428Ma. ► Early Paleozoic HP metamorphic zone identified in Central East Kunlun Fault.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Heishan mafic–ultramafic complex in the Qimantag Mountains of the Eastern Kunlun Orogen, consists of olivine pyroxenites, pyroxenites, gabbros, and massive basalts. Zircons from the gabbros have ...magmatic sector zoning, with Th/U ratios of 0.5–2.3, and yield a SHRIMP age of 486±6Ma (MSWD=0.31), which is taken as the time of magma crystallization. Spinel, pyroxene, and plagioclase mineral compositions indicate that the rocks formed in an island arc environment. The cumulates have low (La/Yb)N ratios (0.6–0.8) and depleted LREE patterns, high abundances of Cr (3031–1185ppm), Co (119–50ppm), and Ni (953–291ppm), and εNd(t) values of about +8.0. The massive basalts have somewhat higher contents of TiO2 (1.0%–1.3%), Na2O (2.6%–2.8%), total REE and Mg#s (55–63) than those of the cumulates. The (La/Yb)N ratios of the basalts range from 0.8 to 1.2 and the chondrite-normalized REE patterns are flat. εNd(t) values of the basalts range from +7.7 to +9.4. The compositions of the cumulates and volcanic rocks, especially their similar Nd isotopes, suggest that the rocks were derived from similar depleted mantle sources. The primary magmas were probably generated in an initial arc environment. We conclude that the Heishan mafic–ultramafic complex in the Qimantag area preserves a record of Proto-Tethyan oceanic lithosphere formed in the early Paleozoic. It possibly marks a suture between the Qaidam and North Kunlun terranes in the western segment of the Eastern Kunlun Orogen.
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•The Heishan mafic-ultramafic complex consists of cumulates and massive basalts.•The εNd (t) values of the mafic-ultramafic complex vary from +7.7 to +9.4.•The mafic magma crystallized at 486±6Ma.•This complex represents relict of incipient island arc.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Although deep carbon recycling plays an important role in the atmospheric CO2 budget and climate changes through geological time, the precise mechanisms remain poorly understood. Since recycled ...sedimentary carbonate through plate subduction is the main light-δ26Mg reservoir within deep-Earth, Mg isotope variation in mantle-derived melts provides a novel perspective when investigating deep carbon cycling. Here, we show that the Late Cretaceous and Cenozoic continental basalts from 13 regions covering the whole of eastern China have low δ26Mg isotopic compositions, while the Early Cretaceous basalts from the same area and the island arc basalts from circum-Pacific subduction zones have mantle-like or heavy Mg isotopic characteristics. Thus, a large-scale mantle low 8 26Mg anomaly in eastern China has been delineated, suggesting the contribution of sedimentary carbonates recycled into the upper mantle, but limited into the lower mantle. This large-scale spatial and temporal variation of Mg isotopes in the mantle places severe constraints on deep carbon recycling via oceanic subduction.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The metamorphism and dynamic processes of the Early Paleozoic continental margin arc in the East Kunlun orogen are still unclear. This study investigated the metasedimentary rocks with granulite ...facies in the Qingshuiquan area in the eastern section of the East Kunlun orogen. The kyanite is not found in the pelitic granulite. The phase equilibrium modeling indicates a middle-pressure type with metamorphic conditions of 0.7 to 0.8 GPa and 800 to 840°Cfor pelitic granulite. UPb dating of zircons from metasedimentary rocks yielded metamorphic ages of 490-480 Ma and detrital zircons ages of 1700-1500 Ma. REE patterns of the metasedimentary rocks are enriched LREEs and distinct negative Eu anomalies, the εNd values vary from −1 to −16. These results imply that the Precambrian supracrustal rocks were buried into the middle-lower crust level and granulite facies metamorphism occurred in Late Cambrian-Early Ordovician.
Synchronous (520-480 Ma) magmatic rocks in Qingshuiquan and adjacent areas indicate that subduction of the Proto-Tethyan oceanic crust led to the formation of arc magmatic rocks. Meanwhile, it induced some sedimentary rocks to underthrust or return flows into the middle-lower crust of the upper plate and underwent granulite facies metamorphism.
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•Granulite facies metasedimentary rocks formed at 490-480 Ma.•Estimated peak conditions are 0.7–0.8 GPa at 800–840 °C.•Supracrustal rocks were underthrust into the middle-lower crust.•Qingshuiquan slice represents a root of continental arc.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Eclogites in the garnet-peridotite unit were formed from troctolite and gabbro.•The troctolite-gabbrowas formed in a rift setting at around 495 Ma.•The eclogite facies metamorphism ...occurred at 370–360 Ma.•The eclogites were products of oceanic basin closed and continental crust subducted.
Knowing the protoliths of eclogites is important to understanding the nature and process of orogeny. It has been debated whether the eclogites of the Marun-Keu complex, Russian Polar Urals represent a fragment of metamorphosed oceanic crust or a fragment of metamorphosed continental crust. Here, we focus on eclogites from the garnet- peridotite-eclogite unit in the complex at the Mica Hill. The eclogites have high MgO contents (mostly greater than 8 wt%) and Mg# (Mg/Mg + Fe2+ = 0.7–0.8), their Al2O3 contents vary from 16 wt% to 26 wt%, and CaO contents vary from 10 wt% to 15 wt%, respectively. TiO2 contents less than 0.5 wt% and a large variation of chromium concentrations (282–1745 ppm). The eclogites are enriched in the light rare earths (LREE), have positive Eu anomalies (δEu = 1.0–2.3), and varying εNd (t) from −3 to +2. Such geochemical features are evidence that the protoliths of these eclogites are troctolite and gabbro, which may have formed in a rift environment of a continental margin. Using the SHRIMP method to date zircons two groups of ages were obtained: 500–490 Ma and 370–360 Ma, respectively. The older population is interpreted as protolith formation age while the later population is interpreted as the metamorphic age of the eclogite facies.
So the eclogites are likely the result of high pressure metamorphism due to subduction of the newly formed Eastern European continental margin under the Syum-Keu intra-oceanic arc, and not metamorphosed ophiolite (Paleo-Urals oceanic crust).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ophiolitic chromitites in the eastern sector of the Alpine-Himalayan and Polar Ural orogenic belts preserve evidence of formation under ultra-high-pressure (UHP), deep mantle conditions. The textural ...and compositional characteristics of microscopic and submicroscopic inclusions in magnesiochromite from the Ray-Iz ophiolites are considered as clues of their complex evolutionary history. Bulk-rock platinum-group-element (PGE) compositions of refractory and metallurgical chromitite ores (102–309 ppb) with generally IPGE>PPGE are consistent with supra-subduction zone (SSZ) metasomatism. The abundant unusual UHP phases (e.g., micro-diamonds, moissanite, coesite…etc.), together with clinopyroxene lamellae, and globular silicate inclusions in the Cr-spinel are seen as indications of deep mantle recycling of the mantle section of the Ray-Iz ophiolites. The calculated fO2 values for dunite and chromitite (+1.17 to +4.16, generally above the FMQ buffer) are in line with interaction of mid-ocean ridge (MOR) or back-arc ophiolites with oxidized, Mg-rich silicic (boninitic) melts in a SSZ environment.
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•New EPMA data of olivine, pyroxene and Cr-spinel in Ray-Iz ophiolites are presented.•The Ray-Iz chromitites have noticeably IPGE > PPGE, consistent with the SSZ setting.•UHP inclusions in Ray-Iz chromitite provide in-situ clues of deep mantle recycling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mobile laser scanning (MLS) systems are often used to efficiently acquire reference data covering a large-scale scene. The terrestrial laser scanner (TLS) can easily collect high point density data ...of local scene. Localization of static TLS scans in mobile mapping point clouds can afford detailed geographic information for many specific tasks especially in autonomous driving and robotics. However, large-scale MLS reference data often have a huge amount of data and many similar scene data; significant differences may exist between MLS and TLS data. To overcome these challenges, this paper presents a novel deep neural network-based localization method in urban environment, divided by place recognition and pose refinement. Firstly, simple, reliable primitives, cylinder-like features were extracted to describe the global features of a local urban scene. Then, a probabilistic framework is applied to estimate a similarity between TLS and MLS data, under a stable decision-making strategy. Based on the results of a place recognition, we design a patch-based convolution neural network (CNN) (point-based CNN is used as kernel) for pose refinement. The input data unit is the batch consisting of several patches. One patch goes through three main blocks: feature extraction block (FEB), the patch correspondence search block and the pose estimation block. Finally, a global refinement was proposed to tune the predicted transformation parameters to realize localization. The research aim is to find the most similar scene of MLS reference data compared with the local TLS scan, and accurately estimate the transformation matrix between them. To evaluate the performance, comprehensive experiments were carried out. The experiments demonstrate that the proposed method has good performance in terms of efficiency, i.e., the runtime of processing a million points is 5 s, robustness, i.e., the success rate of place recognition is 100% in the experiments, accuracy, i.e., the mean rotation and translation error is (0.24 deg, 0.88 m) and (0.03 deg, 0.06 m) on TU Delft campus and Shanghai urban datasets, respectively, and outperformed some commonly used methods (e.g., iterative closest point (ICP), coherent point drift (CPD), random sample consensus (RANSAC)-based method).
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The effects of brewers’ spent grain (BSG) diets on the fatty liver deposition and the cecal microbial community were investigated in a total of 320 healthy 5-day-old Landes geese. These geese were ...randomly and evenly divided into 4 groups each containing 8 replicates and 10 geese per replicate. These four groups of geese were fed from the rearing stage (days 5–60) to the overfeeding stage (days 61–90). The Landes geese in group C (control) were fed with basal diet (days 5–90); group B fed first with basal diet in the rearing stage and then basal diet + 4% BSG in the overfeeding stage; group F first with basal diet + 4% BSG during the rearing stage and then basal diet in the overfeeding stage; and group W with basal diet + 4% BSG (days 5–90). The results showed that during the rearing stage, the body weight (BW) and the average daily gain (ADG) of Landes geese were significantly increased in groups F and W, while during the overfeeding stage, the liver weights of groups W and B were significantly higher than that of group C. The taxonomic structure of the intestinal microbiota revealed that during the overfeeding period, the relative abundance of
Bacteroides
in group W was increased compared to group C, while the relative abundances of
Escherichia–Shigella
and
prevotellaceae_Ga6A1_group
were decreased. Results of the transcriptomics analysis showed that addition of BSG to Landes geese diets altered the expression of genes involved in PI3K-Akt signaling pathway and sphingolipid metabolism in the liver. Our study provided novel experimental evidence based on the cecal microbiota to support the application of BSG in the regulation of fatty liver deposition by modulating the gut microbiota in Landes geese.
Heritage documentation is implemented by digitally recording historical artifacts for the conservation and protection of these cultural heritage objects. As efficient spatial data acquisition tools, ...laser scanners have been widely used to collect highly accurate three-dimensional (3D) point clouds without damaging the original structure and the environment. To ensure the integrity and quality of the collected data, field inspection (i.e., on-spot checking the data quality) should be carried out to determine the need for additional measurements (i.e., extra laser scanning for areas with quality issues such as data missing and quality degradation). To facilitate inspection of all collected point clouds, especially checking the quality issues in overlaps between adjacent scans, all scans should be registered together. Thus, a point cloud registration method that is able to register scans fast and robustly is required. To fulfill the aim, this study proposes an efficient probabilistic registration for free-form cultural heritage objects by integrating the proposed principal direction descriptor and curve constraints. We developed a novel shape descriptor based on a local frame of principal directions. Within the frame, its density and distance feature images were generated to describe the shape of the local surface. We then embedded the descriptor into a probabilistic framework to reject ambiguous matches. Spatial curves were integrated as constraints to delimit the solution space. Finally, a multi-view registration was used to refine the position and orientation of each scan for the field inspection. Comprehensive experiments show that the proposed method was able to perform well in terms of rotation error, translation error, robustness, and runtime and outperformed some commonly used approaches.
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