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Lithium is one of the important strategic energy metals, which is in short supply in China. There are three major types of lithium deposits: brine and salt lake type, highly differentiated granite or pegmatite type, and carbonate-clay type. In recent years, some new types of lithium deposits have also begun to receive great attention and subject recent research. There are many crypto-explosive breccia pipe type deposits in the world, including copper, gold, lead, zinc, tungsten and tin deposits, but little is known about this type of lithium deposit. This paper introduces the latest research results of the Weilasituo Sn−Li−Rb polymetallic deposit in Inner Mongolia (NE China), which occurs in the middle-southern section of the Great Xing'an Range metallogenic belt. A remarkable feature of this deposit is the coexistence of various mineralization types, including granite type Rb and Sn−Zn, hydrothermal crypto-explosive breccia pipe type Li−Rb, quartz vein type Sn−Zn and sulfide vein type Pb−Zn−Ag mineralization. Among them, hydrothermal crypto-explosive breccia pipe type Li-Rb deposit is currently very rare at home and abroad, which is likely a new type of rare metal deposit that worthy of our attention. This paper systematically summarizes the geology, alteration and mineralization, geochemistry, isotopes and geochronology of the Weilasituo deposit, and establishes a new petrogenic and metallogenic model. [ABSTRACT FROM AUTHOR]

The Langshan Group is an important constituent of the Precambrian metamorphic rocks in the Langshan area. The accurate determination of its metamorphic age is of great scientific significance for the further study of the Precambrian geological evolution in the region. Disputes remain regarding the metamorphism and deformation overprinting of the Langshan Group. This paper presents a detailed study comprising a field geological investigation, petrological observations, and zircon U-Pb aging of garnet-bearing mica quartz schists in the BangBang District. The result of detrital zircon U-Pb dating from the metamorphosed volcanic sedimentary rock series and geological investigation of the garnet-bearing mica quartz schists suggest the strata formed in the Neoproterozoic. The results from cathodoluminescence (CL) image analysis and U-Pb dating of zircons indicate a large number of metamorphic zircons exist in the garnet-bearing mica quartz schists. The metamorphic overgrowth rims of zircon from two samples were analyzed by LA-ICP-MS. The 206Pb/238U weighted average age of ca. 244 Ma of the zircon metamorphism rims represents the timing of Indosinian greenschist-amphibolite facies metamorphism in the Langshan area, which may be in response to the collision-type orogeny of the North China and Siberian plates in the Late Paleozoic. Acid-intermediate magmatic intrusive activities occurred in the Langshan area, and metamorphic events developed at the same time or at a later stage during the closure of the Paleo-Asian Ocean. [ABSTRACT FROM AUTHOR]

Plant carbon (C) input via litter decomposition is essential for forming soil organic C (SOC). Previous studies have investigated the fate of litter C through one-time litter addition, while litter input could be recurrent, e.g., gradual litter input from above-ground plant material in diverse ecosystems. This paper investigates how litter input's frequency (single vs. repeated) and amount (low vs. high) affect the SOC formation and the associated microbial community composition and activity in a controlled microcosm experiment. After incubating the 13C-labeled litter (Stipa krilovii) for 80 days with the fresh field soil collected from a semi-arid steppe in Inner Mongolia, China, we measured newly formed SOC, microbial biomass C (MBC), and microbial phospholipid fatty acid (PLFA) indicated by 13C-labeling. The repeated litter addition resulted in 19.92% greater and 12.45% more efficient SOC formation than the single addition. Repeated litter addition also increased C use efficiency (CUE, + 76.71%), indicating more substrate C allocated for microbial growth than respiration. It also enhanced the fungi to bacteria ratio by 47.40% (based on 13C-PLFA) and maintained relatively stable microbial assimilation of litter C (based on 13C-MBC). These findings were consistent regardless of litter amounts. Our results indicate that the uninterrupted litter input to the soil in natural ecosystems benefits SOC formation and highlights soil fungi's critical role in promoting SOC formation. This study suggests that incorporating plant C input frequency into SOC dynamic models may improve the predictions of C cycling. [ABSTRACT FROM AUTHOR]

Tamusu mudstone, located in Inner Mongolia, is being recognized to be the potential host formation in deep HLW disposal across China. This paper describes diverse laboratory experiments performed using the fractured Tamusu mudstone, with concern to the study of the combined mechanical and thermal effects on its hydraulic properties, as well as its self-sealing effect. A single rough fracture is generated down the sample diameter direction before the sample's installation. Considering a heating-cooling cycle, the evolution of the samples' hydraulic properties under different stress conditions has been monitored. The hydraulic conductivity is proved to be not only related to the temperature-induced water viscosity and density variation but also the change of stress state. At the same thermal conditions, the increase of confining pressure (or deviatoric stress) may weaken the flow capacity of the fractures and thus reduce the permeability. The non-coincidence for the curve of permeability versus temperature at the heating and cooling stage indicates that the permeability alterations in the fractures are irreversible. Fracture zone changes were observed by X-ray computer tomography (CT) before and after the tests. The self-sealing behavior, which may be beneficial from high confining pressure, was detected for fractured Tamusu mudstone. Morphologies of fracture surfaces were detected by the 3D scanning technique, which shows that the fracture surface roughness, due to the alteration of asperity contacts and void spaces under high stress, may take an important part of the responsibility to the change of permeability. [ABSTRACT FROM AUTHOR]

Many orogenic belts in the world exhibit accretionary and collisional orogenic phases to varying extents. How accretion evolves into collision of the Central Asian Orogenic Belt (CAOB), the largest Phanerozoic accretionary orogenic belt, is an intriguing question. In this paper, we present new U-Pb age, geochemical and isotopic data for Permian-Triassic granitoids from middle Inner Mongolia, Northern China in the southeastern CAOB, and delineate the magmatic transition from subduction to (soft) collision. The magmatic record of soft collision is identified and characterized by thickened lower crust-derived high Sr/Y granitoids with a sub-linear distribution along the Solonker suture zone. Granitoids from Early Permian to Late Permian became more enriched in whole-rock Nd and zircon Hf isotopic compositions (εNd(t) values from 2.4 to −19.5, εHf(t) values from 11.6 to −33.7), indicating increasing incorporation of old crust. The change in peak timing of magmatism from west (ca. 264 Ma) to east (ca. 251 Ma) along the Solonker suture zone implies "scissor-like" closure of the Paleo-Asian Ocean. Integrated with previous studies, a three-stage tectonic model from the Permian to Triassic by accretion leading to collision on the south-eastern margin of CAOB is proposed. (1) Early Permian (> ca. 285 Ma): Juvenile magmatism on an active continental margin with double-sided subduction of the Paleo-Asian Ocean; (2) Middle Permian to Middle Triassic (ca. 285–235 Ma): Magma source transition from juvenile to old crust induced by a tectonic switch from arc to "scissor-like" closure and subsequent intra-continental orogenic contraction; (3) Late Triassic (< ca. 235 Ma): A-type and alkaline magmatism in response to post-collisional extension. [ABSTRACT FROM AUTHOR]

Fault identification in vegetated area (e.g., grassland) is a major challenge compared to that in outcrop areas. To identify concealed faults in a grassland covered area, a hybrid method combining the temperature vegetation dryness index (TVDI) and the singularity index was proposed in this paper to extract TVDI anomalies associated with concealed fractures in the Sonid Left Banner Grassland, Inner Mongolia, North China. In the triangle space of LST/NDVI (land surface temperature/normalized difference vegetation index), scattered points were concentrated in the areas of partial and full cover, while few data points were in the areas of bare soil with low values of NDVI and high values of LST; this result is consistent with the semiarid grassland landscape of the study area. Although TVDI imaging shows an obvious linear pattern with an NE-NNE trend, which indicates the existence of concealed faults, the surrounding background weakened and reduced the significance of the anomalies. To better delineate the concealed faults, the singularity index was employed to remove the influence of the background and enhance the TVDI anomalies associated with the concealed faults. The TVDI imaging and singularity index mapping showed NNE and NE orientations; this finding is consistent with the regional tectonic framework. Geological mapping footprints showed that the hybrid method is useful to identify concealed faults in covered areas of grassland. [ABSTRACT FROM AUTHOR]

Since the typical destructive methods for measuring aboveground biomass (AGB) have many limitations, a variety of non-destructive techniques have been developed. In this paper, the potential of ground-based hyperspectral remote-sensed data for non-destructive assessment of semi-arid pasture AGB at the peak productive period was investigated. The reflectance spectrometric and AGB data were sampled at the end of the growing season (almost peak biomass) over two locations at pastures in the southern Horqin sandy land, eastern Inner Mongolia, China. All combinations (two-band and three-band) of narrow bands in the forms of simple ratio vegetation index (SRVI), normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI) and enhanced vegetation index (EVI) were used in a linear regression analysis against AGB. The predictive performance of the stepwise multiple linear regression (SMLR) using 4 best VIs as input variables was compared with the performance of multivariate partial least squares regression (PLSR) using all reflectance bands as input variables to estimate AGB. It was observed that the relationship between AGB and single band spectral reflectance was low, while the estimation performance of the best VIs based on all available wavebands was improved considerably. In addition, the best VIs based on all available wavebands had considerably better fitting performance than those based on traditionally used wavebands for estimating AGB. In comparison to PLSR using the full individual reflectance as input variables, SMLR using the best VIs as input variables performed much better, with the maximum decrease in RMSECV of 37% and the relative mean absolute errors always below 12.5%. The study demonstrated the high potential to estimate pasture AGB, which is a proxy for pasture forage yield, at the peak productive period using a hyperspectral technique. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of roof strata conditions, shield pressure, and ground surface subsidence above Panel 42105 of the Buertai Coal Mine in Inner Mongolia, China. A 3D geological model and a 2D numerical simulation model are established to examine the roof strata structures with varying strata conditions. Numerical simulation results demonstrate that the hard rock 1 and 2 roof layers are, on average, likely to break 20 m and 57 m behind the coal face, respectively. It is concluded that when the immediate roof is relatively thin, a cantilever beam is formed, whereas a Voussoir beam is formed when the immediate roof is relatively thick. The patterns of shield pressure and surface subsidence under different roof conditions are also examined. The shield working pressure under the Voussoir beam structure appears to be lower than that under the cantilever beam structure. The average horizontal distance behind the working coal face at which the maximum surface subsidence occurs is 92.1 m. On-site monitoring data are used to explain the causes of the unusual shield pressure and its relation to surface subsidence. Finally, guidelines to predict the shield pressure under similar conditions are provided. [ABSTRACT FROM AUTHOR]

On the basis of climate zones classified by the number of days of the daily average temperature ≥ 10 °C (DT10) over China, the performance of the 9 CMIP5 climate models is evaluated in this paper. The results indicate that the CMCC-CMS and MPI-ESM-MR show higher skill than the other 7 models in simulating spatial pattern and its decadal change of climate zones over China. The simulation results for FGOALS-g2 and INM-CM4 both show relatively lower skill than the other 7 models. Meanwhile, the performance of multi-model ensemble in simulating climate zones over China is obviously better than the simulated result of any single model. So, it is a good way to simulate climate zones by multi-model ensemble to reduce some uncertainty of climate models. However, it is crucial to select appropriate ensemble members. Compared with 1960-2005, the climatic zones in China have an obvious trend of northward shift in 2021-2100. The range of southern sub-tropical belt expands to the most areas in the south of Yangtze River under RCP4.5 emission scenarios, and further extends to the north areas of Yangtze River with a maximum of 2-6° of latitude under RCP8.5 emission scenarios. Middle sub-tropical belt shifts gradually to the areas between Yellow River and north areas of the middle and lower reaches of the Yangtze River. Northern sub-tropical belt shifts northward to southeastern North China. Warm extra-tropical belt extends to the most of Northeast China, most of central Inner Mongolia, and northern Xinjiang under RCP8.5 emission scenarios. [ABSTRACT FROM AUTHOR]

Three-North Shelterbelt Forest (TSF) program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region is important for understanding the overall function of carbon sequestration of the forest and other terrestrial ecosystems in China. This study investigated the distribution area of shrubland in the TSF region based on remote sensing images in 1978 and 2008, and calculated the carbon density of shrubland in combination with the field investigation and previous data from published papers. The carbon sequestration quantity and rate from 1978 to 2008 was analyzed for four sub-regions and different types of shrubs in the TSF region. The results revealed that: 1) The area of shrubland in the study area and its four sub-regions increased during the past thirty years. The area of shrubland for the whole region in 2008 was 1.2 × 10 ha, 72.8% larger than that in 1978. The Inner Mongolia-Xinjiang Sub-region was the largest shrubland distribution area, while the highest coverage rate was found in the North China Sub-region. 2) In decreasing order of their carbon sequestration, the four types of shrubs considered in this study were Hippophae rhamnoides, Caragana spp., Haloxylon ammodendron and Vitex negundo var. heterophylla. The carbon sequestration of H. rhamnoides, with a maximum mean carbon density of 16.5 Mg C/ha, was significantly higher than that of the other three species. 3) The total carbon sequestration of shrubland in the study region was 4.5 × 10 Mg C with a mean annual carbon sequestration of 1.5 × 10 Mg C. The carbon density in the four sub-regions decreased in the following order: the Loess Plateau Sub-region, the North China Sub-region, the Northeast China Sub-region and the Inner Mongolia-Xinjiang Sub-region. The paucity of studies and data availability on the large-scale carbon sequestration of shrub species suggests this study provides a baseline reference for future research in this area. [ABSTRACT FROM AUTHOR]