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This paper used dynamic image analysis (DIA) to analyze the grain size and shape data of beach surface sediments in Bao'ding Bay, eastern Hainan Island, China, and explored the effects of sediment transport modes and beach morphology on the grain size–shape trend curves. This paper adopted a method of combining grain size cumulative frequency curves and grain size–shape trend curves to identify three sediment transport modes: suspension, saltation, and traction, and analyzed the characteristics of the grain size–shape trend curves under different beach morphologies (reflective, intermediate, and dissipative). This paper found that the grain size–shape trend curves can effectively indicate the sediment transport modes and improve the accuracy of subpopulation division; the grain size–shape trend curves showed different distribution characteristics in the cross-shore and longshore directions, which are closely related to the beach's morphology and sediment transport direction. This paper provides a new method and idea for studying beach sediment transport and sedimentary environment using sediment grain size and shape data. [ABSTRACT FROM AUTHOR]

The size of snow grains is an important parameter in cryosphere studies. It is the main parameter affecting snow albedo and can have a feedback effect on regional climate change, the water cycle and ecological security. Larger snow grains increase the likelihood of light absorption and are important for passive microwave remote sensing, snow physics and hydrological modelling. Snow models would benefit from more observations of surface grain size. This paper uses an asymptotic radiative transfer model (ART model) based on MOD09GA ground reflectance data. A simulation of snow grain size (SGS) in northeast China from 2001 to 2019 was carried out using a two-channel algorithm. We verified the accuracy of the inversion results by using ground-based observations to obtain stratified snow grain sizes at 48 collection sites in northeastern China. Furthermore, we analysed the spatial and temporal trends of snow grain size in Northeastern China. The results show that the ART model has good accuracy in inverting snow grain size, with an RMSD of 65 μm, which showed a non-significant increasing trend from 2001 to 2019 in northeast China. The annual average SGS distribution ranged from 430.83 to 452.38 μm in northeast China, 2001–2019. The mean value was 441.78 μm, with an annual increase of 0.26 μm/a, showing a non-significant increasing trend and a coefficient of variation of 0.014. The simulations show that there is also intermonth variation in SGS, with December having the largest snow grain size with a mean value of 453.92 μm, followed by January and February with 450.77 μm and 417.78 μm, respectively. The overall spatial distribution of SGS in the northeastern region shows the characteristics of being high in the north and low in the south, with values ranging from 380.248 μm to 497.141 μm. Overall, we clarified the size and distribution of snow grains over a long time series in the northeast. The results are key to an accurate evaluation of their effect on snow–ice albedo and their radiative forcing effect. [ABSTRACT FROM AUTHOR]

As one of the main interfaces of the Earth system, estuaries show the strongest land–sea interaction in the carbon cycle, which links terrestrial ecosystems to the marginal sea. Furthermore, estuaries are considered as one of the most active intermediate reservoirs for both terrestrial and marine matter due to complex hydrodynamic processes regulated by the river runoff, wave and tide. Processing of organic matter (OM) in tidal estuaries modifies its transfer and transformation from the river to the sea, so studies of on the source and distributions of estuarine OM can help us understand the behavior of production, exchange, transport and burial of diverse OM within this transition zone before entering the marginal sea. In this paper, we took the Minjiang River Estuary (MRE) as a typical system in which there is strong influence of the tide. The source, composition and spatial distribution of OM in surface sediments of MRE were deciphered based on multiple organic geochemical properties for source-specific biomarkers (n-alkanes, n-alkanols, sterols) and bulk OM. Results show that sedimentary organic components were negatively correlated with sediment grain size, which indicates fine particles such as silt and clay are the major carriers of the OM signals in tidal estuaries. Source-specific biomarker proxies indicate that in terms of source diversity the sedimentary OM in the MRE shows mixed signals of terrestrial and marine sources, and the proportion of terrestrial OM decreases with the increase in distance from the land. The fractional contributions of OM from the riverine (i.e., terrestrial), marine and deltaic sources were quantitatively estimated using a Monte Carlo (MC) three-end-member mixing model based on C/N and δ13C values, and the average contributions of the three sources are 40 ± 10%, 48 ± 10% and 12 ± 4%, respectively, with little contribution from deltaic sources. The dispersion of sedimentary OM from different sources in the MRE is primarily controlled by the depositional environment determined by dynamic conditions and tidal processes play a significant role in the redistribution of sedimentary OM dispersion patterns. Compared with other large estuaries in southeast China, the OM accumulation contribution in the tide dominated small and medium-sized estuaries such as the MRE which is largely dependent on riverine and marine deliveries. The MRE has a high potential for both terrestrial and marine organic carbon (OC) burial, with an accumulation rate of 3.39 ± 1.83 mg cm−2 yr−1 for terrestrial OC, and an accumulation rate of 3.18 ± 0.68 mg cm−2 yr−1 for marine OC in muddy sediment, making it an important contributor to the sedimentary carbon sink of the marginal sea. [ABSTRACT FROM AUTHOR]

The North Yellow Sea, located at the intersection of the Eurasian continent and North Pacific Ocean at mid-latitudes, is a sensitive area subjected to the joint actions of the ocean, land, and monsoons. On its southern shore, loess and paleosol sedimentary sequences were widely developed during the last interglacial period, which is of great significance for revealing patterns of climate change and dynamic conditions. In this paper, we focus on the Zhifu section (ZFS) on Zhifu Island within the Shandong Province of China. The optically stimulated luminescence (OSL) dating method was used to construct our chronological framework. Grain size and its endmember (EM) components were then analyzed; EM1 is a clay component EM, which represents a weak dynamic environment and strong weathering pedogenesis, while EM2 and EM3 are silt and very fine sand component EMs, respectively, representing a strong dynamic environment and weak weathering pedogenesis. Maximum EM1, mean grain size, clay content, and pH values occur in the paleosol layers (ZF4, ZF6, and ZF8), with minimum values in the loess layers (ZF5 and ZF7); EM3 values show the opposite pattern. This indicates that the ZF4, ZF6, and ZF8 layers represent warm and humid environments with abundant precipitation, where the East Asian summer monsoon (EASM) was enhanced, corresponding to Marine Isotope Stages (MIS) 5a, 5c, and 5e. In contrast, ZF5 and ZF7 represent sub-warm and humid environments with less precipitation, where the EASM was weakened, corresponding to MIS 5b and 5d. Among these stages, MIS5e is the warmest and wettest. These climatic events reveal the pattern of climate fluctuation over a ten-thousand-year timescale; they are synchronous with climate changes recorded in other geological repositories, such as cave stalagmites in southern China and sea-level fluctuations in the Yellow-Bohai Sea, which result from changes in global solar radiation. [ABSTRACT FROM AUTHOR]

Grain size is the basic property of intertidal zone sediment. Grain size acts as an indicator of sedimentary processes and geomorphological evolution under human and nature interactions. The remote sensing technique provides an alternative for sediment grain-size parameter monitoring with the advantages of wide coverage and real-time surveying. This paper attempted to map the distributions of three sediment grain size contents and the mean grain size with multitemporal Landsat images along the southwestern coast of Laizhou Bay, China, from 1989 to 2015. Considering the low correlations between the measured reflectance and grain-size parameters, we used a support vector machine (SVM) to develop a nonlinear calibration model by taking several band indices as input variables. Then, the performance of the back propagation neural network (BPNN) was determined and discussed with that of the SVM. The SVM performed better than the BPNN in calibrating the four grain-size parameters based on a comparison of R2 and the root-mean-square error (RMSE). Moreover, an atmospheric correction algorithm originally proposed for case II water enabled the TM\ETM+ images to be precisely atmospherically corrected in this study. The SVM-mapped spatial-temporal grain-size variation showed a coarsening trend, which agreed with that obtained during in situ measurements in a former study. The changes in Yellow River discharge and precipitation associated with the coarsening trend were further analyzed. The yielded results showed that the coarsening trend and reduction in tidal flat area might be aggravated with overutilization. More reasonable planning would be necessary in this case. [ABSTRACT FROM AUTHOR]

Mass movement deposit grain‐size distributions (GSDs) record initiation, transport and deposition mechanisms, and contribute to the rate at which sediment is exported from hillslopes to channels. Defining the GSD of a mass movement deposit is a significant challenge because they are often difficult to access, are heterogeneous in planform and with depth, contain grain sizes from clay (<63 μm) to boulders (>1 m), and require considerable time to calculate accurately. There are numerous methods used to measure mass movement GSDs, but no single method alone can measure the entire range of grain sizes. This paper compares five common methods for determining mass movement deposit GSDs to assess how their accuracy may affect their applicability to different research areas. We applied an automated wavelet analysis (pyDGS), Wolman pebble counts, survey tape counts, manual photo counts and sieving to three different mass movement deposits (two debris flows, one rockslide) in Tredegar, Wales and the Longmen Shan, China. We found that pyDGS and survey tape counts produced comparable GSDs to sieving over a single order of magnitude. PyDGS required calibration to achieve accurate results, limiting its use for many applications. In Tredegar, Wolman pebble counts over‐estimated grain sizes in the lower 80% of the distribution relative to the other four methods used. We demonstrate that method choice can introduce significant uncertainties, particularly at the edges of the distributions, such that D16 values differ by up to a factor of five. These methodological uncertainties limit GSD comparisons across studies, particularly where these are used to infer processes within deposits. To minimize these challenges, the methods chosen should be both carefully reported and consistent with the research question. [ABSTRACT FROM AUTHOR]

This paper outlines a model for the domestication of Panicum miliaceum (broomcorn millet) in Northern China. Data from 43 archaeological sites indicate a continuous increase in average grain size between 6000 and 3300 bc. After this date there is a divergence, with grain size continuing to increase in some populations, while others show no further size increase. The initial increase in grain size is attributed to selection during domestication, while later divergence after 3300 bc is interpreted as resulting from post-domestication selection. Measurements of grains from two archaeological populations of P. ruderale, showed grains were longer in length by 3300 bc than the earliest grains of P. miliaceum. This suggests this sub-species includes many feral, weedy and/or introgressed forms of P. miliaceum and therefore is probably not entirely representative of the true wild ancestor. It is argued that changes from shattering to non-shattering are contemporary with increasing grain size and the commencement of cultivation. The window of P. miliaceum domestication is therefore likely to lie between 7000 and 3300 bc. However, it is probable that a lengthy period of millet harvesting and small-scale management preceded its domestication. [ABSTRACT FROM AUTHOR]

This paper presents a detailed field characterization of boudinage in a high- strain zone several kilometers wide in Northern China to establish relationships between boudin types and rheological contrasts between different parts of migmatites during the migmatization process. This zone contains nearly all types of boudins: foliation boudins, block- torn boudins, pinch- and- swell structures, tapering boudins, object boudins, and modified boudins. These boudinage structures record the different stages of meltinvolved and solid- state deformation. The boudinage of migmatites is significantly controlled by the evolving rheological contrasts between the leucosome and melanosome. During the melting stage, the deformation and boudinage of rocks are controlled by the melt fraction. Migmatite strength progressively decreases with increasing melt fraction. The occurrence of melt- filled foliation boudins and melanosome block boudins suggests that the residuum and melanosome are more competent than the leucosome. During solid- state deformation after crystallization, the existence of recrystallized solid- state leucosomes and the intrusion of pegmatites cause the migmatite strength to increase. The relationship is reversed: the leucosome is much more competent than the melanosome. The type and geometry of boudins and pinch- and- swell structures are correlated to the fraction of leucosome in the migmatites. The mechanical strength and strain localization of migmatites after crystallization depend on the presence and volume fraction of the different mineral phases, as well as the mineral grain size. The type and geometry of boudins suggest that the effective viscosity of migmatite can be ranked, from high to low, as: quartz veins; coarse- grained, thick pegmatite; coarse- grained, diatexite migmatite; medium- grained leucosome; and fine- grained melanosome. While experiencing partial melting and migmatization, a rheologically homogeneous protolith is turned into two dominant lithologic domains: a competent diatexite migmatite domain and an incompetent melanosome migmatite domain. Spatially, with the increasing leucosome fraction in migmatites, the migmatite rheology of rock changes from homogeneous to heterogeneous and anisotropic, and then back to homogeneous. The strain distribution likewise changes from uniform to partitioned, and then back to uniform. This evolutionary process of strength and rheological properties of rocks during migmatization may promote strain localization at mid- crustal conditions. [ABSTRACT FROM AUTHOR]

Aluminum–lithium alloys have been extensively used in the aviation and aerospace field. Now it is one of the critical materials for the production of large aircraft in China. Thermoplastic deformation is one of the key methods to solve the difficulty in the precise deformation of Al–Li alloy parts. The thermoplastic deforming behavior of the Al–Li alloys is characterized by a phenomenological model. The effects of deforming temperature, strain rate, and combining with strain are applied to fit and predict the flow stress in the model. However, the model does not explicitly explain the deformation mechanism. The physical constitutive model takes into account the physical parameters and the microstructure evolution of the material during deformation,such as dislocation density, grain size, and dynamic recrystallization, which is the development trend of the thermoplastic deforming constitutive relationship of Al–Li alloy. In this paper, the researches on the phenomenological constitutive models and physical constitutive models summarized commonly are adopted to characterize the thermoplastic deformation of Al–Li alloys. Besides, the characterization tendency is forecasted. [ABSTRACT FROM AUTHOR]

Quantifying landscape heterogeneity and its organization at different scales is essential for understanding ecosystems and landscapes. Among hundreds of landscape metrics, entropy-related index represents an efficient tool to quantify and characterize landscape patterns. A recent development is Spatial Entropy index (Hs), and it has been validated as flexible and effective in landscape pattern analysis. However, the effects of changing spatial scale on Hs has not been quantified. This paper applies the fractal method to measure the spatial scale (grain size) sensitivity of Hs. Using the initial land-use data of Yanhe watershed, which is located in northwest of China, eleven different spatial scales were created in order to investigate the scale effects on Hs. A linear log–log regression model was then constructed based on the power law to calculate the coefficient of determination (COD) of the model and the fractal dimension (FD) of Hs. The result indicates that Spatial Entropy index shows a robust fractal feature, and it decreases as the spatial scale (or grain size) becomes lager in a moderate degree. In total, we believe that this study will help us to get a better understanding of Hs, and to facilitate further applications of this entropy-related index. [ABSTRACT FROM AUTHOR]

This research delves into the intricate nexus of particle size, mineralogical composition, surface attributes, elemental mapping, and rare earth element (REE) adsorption mechanisms within an ion-adsorption clay sample from South America. The investigation entails the fractionation of the ion-adsorption clay into three size categories: S1 (< 0.25 mm), S2 (0.25–0.5 mm), and S3 (0.5–2 mm). Each fraction undergoes meticulous characterization to unveil its elemental composition, mineralogical composition, surface area, morphological characteristics, elemental mapping, and the mechanisms governing REE incorporation. The results indicate that S1 has 31% physiosorbed, 8% chemisorbed, and 61% mineralized REEs, while S2 has 40% physiosorbed, 5% chemisorbed, and 55% mineralized REEs, and S3 has 24% physiosorbed, 5% chemisorbed, and 71% mineralized REEs. The physisorbed REEs are attributed to the presence of kaolinite, conducive to mostly physisorption. In terms of grain size and REE content/type relationship, the results show that REE content decreases with increasing grain size; however, there is not a clear trend in terms of REE occurrence modes with grain size. Heavy rare earth elements (HREEs) are discernibly favored in adsorption over light rare earth elements (LREEs). This preference is underpinned by the weathering processes that led to the formation of ion-adsorption clay, which facilitated the transport and accumulation of HREEs. Notably, the ion-adsorption clay encompasses a substantial content of mineralized REEs, necessitating more demanding extraction methodologies, such as acid baking followed by water leaching if complete extraction of all REEs is desired. Among the desorbable REEs, physisorption dominates, encompassing over 80% of the total. Chemisorbed REEs exhibit versatility in association with various minerals, encompassing kaolinite, quartz, and goethite. In essence, this study unveils the intricate interplay between particle dimensions, mineralogical constitution, surface attributes, and REE adsorption modes within this ion-adsorption clay sample. The ion-adsorption clay in this study contains a significant portion of mineralized REEs that cannot be extracted using the mild conditions typically employed for the desorption process. Additionally, the REE concentration in this ion-adsorption clay is notably higher than the average found in clay deposits worldwide, reaching levels comparable to those of regolith deposits in China, which are a major global source of REEs. This remarkable concentration of REEs, along with the unique modes of their occurrence in this deposit, presents a significant interest to the scientific community. [ABSTRACT FROM AUTHOR]

Grain size is commonly used as a proxy to reconstruct past lake hydrology; however, published research rarely links grain size with modern processes, and uncertainties exist for interpretation. In this paper, we decompose the grain size frequency distributions (GSFD) for 196 lake surface sediments from 61 lakes and 9 reservoirs across the Inner Mongolia Plateau and adjacent areas and divide them into five GSFD components. We statistically analyze the relationship between the GSFD components and influencing variables to determine the taphonomic dynamics and their environmental implications. Within individual lakes, we found that GSFD component 4 (74.00–209.30 μm) and GSFD component 5 (209.30–592.00 μm) dominate near the lake margin and reduce toward the lake center in proportions. By contrast, GSFD component 2 (2.75–15.56 μm) increases toward the lake center. Therefore, the proportions of GSFD component 2, 4, and 5 reflect the relative distance to the lakeshore and allow inferences about lake area changes. We apply this large modern dataset to a sediment core obtained from Lake Wulanhushao (WLHS) on the Inner Mongolia Plateau and link the lake surface sediment-based GSFD components to BEMMA end-members of grain size records to define their environmental implications over the last 18.59 cal. kyrs BP. We found that the Lake WLHS has responded to the orbital and suborbital climate changes since the last deglaciation. Specifically, maximum lake transgression prevailed during the early to middle Holocene (11.70–7.10 cal. kyr BP), medium lake transgression dominated during 17.05–15.80 cal. kyr BP, and weak transgression developed during 14.60–12.90 cal. kyr BP. Maximum lake regressions prevailed before 17.05 cal. kyr BP, during 15.80–14.60 cal. kyr BP and 12.90–11.70 cal. kyr BP. Our reconstructed early Holocene maximum lake area is consistent with regional abiotic proxy-based moisture records, but contrasts with the regional biotic proxy-based moisture records, which reconstruct increasing moisture conditions. Our new method to determine lake area changes will provide valuable data to understand the climate dynamics of northern China. • We numerically revealed the environmental implications of grain size components of lake surface sediment. • Linking lake surface sediment grain size component to core end members provide basis for interpretations. • Maximum lake transgression prevailed during the early Holocene in northern China. • Abiotic proxies-based early Holocene lake transgression is distinct with biotic proxies' reconstructions. [ABSTRACT FROM AUTHOR]

China's need for energy resources is growing every day. Future energy demands will be partly met by low-temperature pyrolysis of oil-rich coal, which is a form of coal-to-oil technology. Under the existing fully-mechanized coal mining technology, oil-rich coal is mechanically broken into different particle sizes by a shearer and used in different industrial utilization directions. However, due to differences in particle size and material composition, the pyrolysis products of oil-rich coal with different natural particle sizes are different, which affect the pyrolysis efficiency of oil-rich coal with different particle sizes. In order to explore the differences and influencing factors of pyrolysis products of oil-rich coal with different particle sizes, and taking Jurassic oil-rich coal in northern Shaanxi as the research object, the differences and causes of pyrolysis production of oil and gas from nine kinds of oil-rich coal with different natural particle sizes under existing coal mining conditions are discussed according to particle size characteristics, pore structure, heat transfer velocity and molecular structure. The findings demonstrate that the pyrolysis characteristics of coal do not show a single trend with change in particle size. With decrease in particle size, the ash and sulfur contents were relatively high, and the tar yield increased first and then decreased. In contrast, the light fraction decreased overall, and the heavy fraction decreased. The tar yield of 0.125–0.25 mm was the highest, and the tar content was 1.996 g. For the gas components produced by pyrolysis, the contents of CH4, CO and H2 first increased and then decreased with decrease in particle size, while the contents of CO2 and CnHm showed the opposite trend. Larger particles (about 30 mm) affect the escape efficiency of pyrolysis products and the amount of carbon deposition due to the difference in porosity (interparticle resistance) of the inner surface and pyrolysis bed, resulting in secondary reactions of the products escaped from a primary reaction, thus affecting the differences in pyrolysis products. The heat transfer process of coal was affected by particle size, and the thermal conductivity increased gradually with decrease in particle size, which is consistent with the change of tar yield with particle size. The maceral components and molecular structure functional groups in coal with different particle sizes were also different, which resulted in the differences in tar yield. Studies have shown that smaller particle sizes have longer alkyl side chains, and pyrolysis accompanied by rising temperature causes different changes in the aliphatic hydrocarbon content in coal coke after pyrolysis. The aliphatic hydrocarbon content decreased the most when the particle size was 0.125 mm, which is more beneficial to the improvement of tar yield. In addition, vitrinite is a good carrier of tar yield, and the granular coal vitrinite after crushing is enriched to smaller particles. [ABSTRACT FROM AUTHOR]

The ancient Loulan kingdom in northwest China was a key transportation hub along the ancient Silk Road. What determined the burial practice in Loulan is a mystery as many of the tombs were constructed atop approximately 20-m-high yardangs in the north of the ancient city of Loulan. This paper includes the first attempt to provide a geoarchaeological perspective on this problem. A representative section (3.8 m) from the tomb area was investigated using optically stimulated luminescence (OSL) dating and grain size analyses to reconstruct environmental changes. Results show that the section was formed during Loulan's early development stage (approximately from the second century BC to the first century AD) in the wake of lacustrine-fluvial hydrology fluctuation. Radiocarbon dating suggests that the tombs were also constructed during the period. Therefore, our reconstruction indicates that the landscape of the burial area was dominated by extensive island-like yardangs within a lake or wetland. We argue that the burial practice was influenced by the yardang's location high above the wetland/flooded area. People would generally prefer cemeteries in the area to avoid disturbance to the bodies from the fluctuating water table. [ABSTRACT FROM AUTHOR]

Research on the evolution and driving mechanisms of East Asian monsoon (EAM) precipitation during the past millennium has received considerable attention. Previous studies have focused on comparisons between relative mean dry/wet conditions and those linked to the Pacific sea surface temperature (SST) anomalies during the Medieval Warm Period (MWP) and the Little Ice Age (LIA); however, uncertainties remain regarding the relationship between precipitation changes and Pacific SST anomalies under sub-cool internal conditions within the LIA. Herein, we present a composite high-resolution monsoon precipitation record (from 1400 CE to the present) based on chroma and median grain size data from Lake Nvshan sediments in the Jiang-Huai (JH) region, central eastern China. The results indicate that more (less) precipitation in the JH region could be associated with the warm (cold) Pacific Decadal Oscillation (PDO) phase on inter-decadal scales. We also observed an enhanced modulating effect of the PDO on JH precipitation during the late LIA. These changes in the modulating effect were likely a response to enhanced PDO amplitudes induced by increased effective radiative forcing. [ABSTRACT FROM AUTHOR]

The Qinling Mountains (QLM) form the climatic boundary between the temperate north and subtropical south of China. Many important Paleolithic archaeological sites located on fluvial terraces in this area have been reported in recent decades. Abundant artifacts have been excavated in silt layers overlying fluvial gravels and coarse sands. These silt layers have thus far been interpreted as aeolian deposits. However, in principle they could also represent (in part) fluvial (floodplain) deposits, especially near the base of fine-grained sequences. Reconstruction of fluvial terrace formation is crucial for the correct interpretation of the environment of hominin occupation. In this paper, two sediment sequences from two Paleolithic sites, located on different terrace levels of the Hanjiang River in the Hanzhong basin, are studied mainly using grain-size and grain-shape analyses. In addition, grain-size distributions have been unraveled by applying end-member modelling to distinguish different sedimentary environments. The results show that three different units can be discriminated in each section. The lower unit, consisting of gravelly sand mixed with fine silt, is interpreted as shallow-channel-fill sediment deposited during the start of the transition from a channel to a floodplain environment. The middle unit comprises a fine-grained, gradually fining-upward sequence, representative a floodplain environment. At its base, it reflects a high-energy floodplain situation; at its top, the sequence is interpreted as a low-energy floodplain environment with aeolian input (settling in static water). The third, uppermost unit consists of aeolian loess interbedded with paleosol(s) and sediments that are interpreted as the results of episodic surface runoff. The gradual transition between the 3 units and the gradual fining upward trend of the middle unit indicates that there is no considerable age gap (no hiatus) between the fluvial- and aeolian sedimentary environments. Stone artifacts have been found in all 3 units, with difference abundance, indicating that both the aeolian and floodplain depositional environments provided favorable living conditions. For the floodplain environment, the resources of water and raw materials (fluvial gravels) for tool making may have offered fundamental resources for hominin settlement. • The depositional environments of the artifact-bearing sediment have been determined. • Both aeolian dust deposit on terrace surface and floodplain environment were occupied by hominins in central China. • The transition from fluvial to aeolian sedimentary environment during incision is gradual. • Combined grain size and grain shape analysis allows for the distinction of aeolian and fluvial sedimentary environments. [ABSTRACT FROM AUTHOR]

The arid regions of northwestern China are dominated by extensive areas of mobile sand dunes. These features cause environmental problems and exert global climatic impacts; however, due to the lack of systematically-applied indicators of aeolian activity, direct evidence of past changes in aeolian activity is unreliable, especially for aeolian sand source regions. In this paper, we analyze the end-member (EM) distributions of various types of surface soil across the Tengger Desert in northwestern China, and devise a sensitive proxy for aeolian activity using a spatio-temporal substitution approach. This proxy is then used to evaluate a Quaternary aeolian succession and to understand the response of aeolian activity to regional climate change. Our results suggest that gradual increases in the coarse-grained EM components 3–5 reflect enhanced dune mobility and reduced vegetation coverage, which are a direct function of the intensity of regional aeolian activity. In the aeolian section, coarse- and medium-grained sand layers resemble modern semi-mobile and mobile dunes, whereas fine-grained sand layers are analogous to vegetated fixed/semi-fixed or semi-mobile dunes. Combining this record with independent multi-proxy evidence from the same section leads us to conclude that strong aeolian activity coincided with a dry climate, sparse vegetation cover, and strong surface winds during the Last Glacial Maximum, and that these conditions gradually attenuated at the beginning of the Last Deglacial. These inferences are in accord with independent paleoclimate records from this region, confirming that the intensity of aeolian activity in the southeastern Tengger Desert is closely associated with large-scale climate change. Our findings show that our EM proxy can be used to infer the intensity of aeolian activity and to reliably reconstruct the evolution of deserts in northwestern China. [Display omitted] • Coarse grain-size End-members (EM) 3–5 are a proxy of the strength of aeolian activity. • This proxy is applied to a palaeo-aeolian sequence to reconstruct the history of desert evolution. • Aeolian activity was closely associated with large-scale climate change. [ABSTRACT FROM AUTHOR]

This paper investigates sediment settling process during summer seasons based on in-situ observation and sediment analysis at the east tip of the Shandong Peninsula, which is a pathway for sediments from the Bohai Sea and the North Yellow Sea to enter the South Yellow Sea in China. Bottom-tethered sediment traps, together with platforms equipped with current profilers/meters and temperature/salinity and turbidity sensors, were deployed for approximately 10 days in August 2017 over an elongated deposit off the coast of the Shandong Peninsula. A computed tomography (CT) scan and grain size and 210Pb analyses of trap sediment were carried out to determine the settling process of suspensions at the study site. Twenty-three couplets were found in the CT images of the trap, the time series of which was established using intervalometer disks. Quantitative characterization of rhythmites using a hounsfield unit indicates that the period of couplets is approximately quarter-diurnal, and the settling process could be divided into three stages during Aug. 21st – 27th. Current, wave, wind, and SSC data illustrate that the diversion of the bottom current leads to the formation of couplets, and the thickness of the couplet is controlled by the vertical current velocity and wind direction. Northerly winds enhance the difference in settlement between flood and ebb tides, whereas southerly winds smoothen the difference. The gale event inhibited the settlement of the suspended matter, and the source of the suspensions was converted from local to remote after the event, as evidenced by 210Pb data. No evident erosion can be detected in the sediment traps. The results are of significance to better understand the sedimentary dynamics near the Shandong clinoform and inspire the practical efficiency of bottom-tethered sediment traps in the settling process in coastal areas. • Quarter-diurnal couplet were found by CT scan of sediment in the Anderson-type sediment trap. • Flood and ebb tides lead to the formation of couplets, and the thickness of the which is controlled by vertical velocity and wind direction. • Gale events could inhibit the settling of suspensions at the clinoform off the Shandong Peninsula. [ABSTRACT FROM AUTHOR]

Reservoir heterogeneity is an important factor in oil and gas exploration and development. It has guiding significance for favourable target optimization because it helps clarify the formation and development characteristics of laminae: thin, alternating layers of sediment deposited in a repeating pattern in Cretaceous sandstone reservoirs. Reservoir heterogeneity is higher when laminae are densely distributed. For example, laminae have a significant influence on reservoir properties in the Kelasu structural belt in the Bozi–Dabei area, Tarim Basin, China, where oil and gas wells have very low productivity. Hence, this study attempts to develop a classification scheme based on laminae to identify how they influence reservoir properties. Based on an analysis of cores, thin section and logging imaging data, laminae in this area can be classified into three types: magnetite-enriched, iron-stained argillaceous-enriched, and grain-size change. Results show that magnetite-enriched and iron-stained argillaceous-enriched laminae are well-developed in the BZ1 and DB10 well areas in northern Bozi. They have much lower porosity compared to a non-laminae reservoir and their lateral permeability is greater than vertical permeability. Grain-size change laminae are well-developed in the southern Bozi region. For the laminated reservoirs, increasing the length of the perforation interval and the perforation density using sand or acid fracturing is an effective method for communicating with the vertical reservoir layers, improving permeability, and increasing single-well production. [ABSTRACT FROM AUTHOR]

This article studies the sedimentary characteristics and models of the delta and gravity flow system of the third member of the Shahejie Formation in the Niuzhuang Sag area. Through seismic, logging, and core observation methods, a thorough investigation is conducted to examine the lithologic characteristics, grain size characteristics, sedimentary structure characteristics, and sedimentary facies distribution characteristics of this region. The results show that the third middle member of the Shahejie Formation in the Niuzhuang Sag can be classified into four sedimentary types: sliding, collapse, clastic flow, and turbidity flow. This article aimed to establish the distribution characteristics and depositional models of the deltaic and gravity flow depositional systems within the study area. The findings reveal that slip deposition primarily occurs near the delta front, while collapse and clastic flow depositions are concentrated near the far slope. Moreover, turbidity flow deposition is found near the far slope. This study significantly contributes to our understanding of the sedimentary characteristics and models associated with deltas and gravity flow systems in faulted lacustrine basins. Furthermore, it enriches existing theories related to gravity flow and provides a valuable reference for the investigation of deep-water sedimentation in continental faulted lacustrine basins. [ABSTRACT FROM AUTHOR]

Groundwater is susceptible to arsenic contamination by sediment with high arsenic content, which is the primary culprit of regional arsenic pollution and poisoning. To explore the influence of the change in hydrodynamic conditions caused by changes in the sedimentary environment over time on arsenic content in sediments during the Quaternary, the hydrodynamic characteristics and arsenic content enrichment of borehole sediments were studied in typical high-arsenic groundwater areas of the Jianghan–Dongting Basin, China. The regional hydrodynamic conditions represented by each borehole location were analyzed, the correlation between the variation in groundwater dynamics characteristics and arsenic content in different hydrodynamic periods was analyzed, and the relationship between arsenic content and grain size distribution was quantitatively investigated using grain size parameter calculation, elemental analysis, and statistical estimates of arsenic content in borehole sediments. We observed that the relationship between arsenic content and hydrodynamic conditions differed between sedimentary periods. Furthermore, arsenic content in the sediments from the borehole at Xinfei Village was significantly and positively correlated with a grain size of 127.0–240.0 μm. For the borehole at Wuai Village, arsenic content was significantly and positively correlated with a grain size of 1.38–9.82 μm size (at 0.05 level of significance). However, arsenic content was inversely correlated with grain sizes of 110.99–716.87 and 133.75–282.07 μm at p values of 0.05 and 0.01, respectively. For the borehole at Fuxing Water Works, arsenic content was significantly and positively correlated with a grain size of 409.6–655.0 μm size (at 0.05 level of significance). Arsenic tended to be enriched in transitional and turbidity facies sediments with normal corresponding hydrodynamic strength but poor sorting. Furthermore, continuous and stable sedimentary sequences were conducive to arsenic enrichment. Fine-grain sediments provided abundant potential adsorption sites for high-arsenic sediments, but finer particle size was not correlated with higher arsenic levels. [ABSTRACT FROM AUTHOR]

Dust storm disasters have emerged as a significant environmental challenge in East Asia. However, relying on a single monitoring method to track dust storms presents limitations and can be variable. Therefore, it is necessary to use a combination of ground and remote sensing monitoring methods to explore the source and impact range of dust storms in order to fully characterize them. To achieve this, we examined the sources and impact ranges of dust storms in East Asia from 1980 to 2020 using both ground station data and remote sensing data. In addition, we focused on three specific dust storm events in the region. Our results indicate that the central source areas of dust storms are located in southern Mongolia and the Taklamakan Desert in China. Dust storms are mainly transported and spread in the northwestern region, while they are relatively rare in the southeastern region. The HYSPLIT model simulations reveal that the primary source directions of dust storms in East Asia are northwest, west, and north, the region involved includes Kazakhstan, southern Mongolia, and the Taklimakan Desert in China. The vertical structure of the dust storm layer depends on the source of the dust storm and the intensity of the dust storm event. Dust grain stratification probably occurs due to differences in dust storm sources, grain size, and regularity. These findings demonstrate that a combination of ground-based and remote sensing monitoring methods is an effective approach to fully characterize dust storms and can provide more comprehensive information for dust storm studies. [ABSTRACT FROM AUTHOR]

Highway constructions in southern China have revealed a massive distribution of carbonaceous mudstone. However, this mudstone is seldomly used as embankment fillers because of its significant disintegration upon wetting. Compared to bulk carbonaceous mudstone, small disintegrated carbonaceous mudstone (DCM) grains show less disintegration potential and may be applied to fill embankments in some regions. The purpose of this study is to reveal the mechanism behind the further disintegration of primarily DCM and investigate the swelling–consolidation characteristics of the DCM, scanning electron microscopy (SEM) was used to observe the difference for the compacted DCM specimens before and after wetting, and the microstructural change and the disintegration mechanism of the wetted DCM were analyzed accordingly. The saturated free swelling tests and saturated consolidation tests were conducted to elucidate the influences of dry density and grain size range on the swelling and consolidation characteristics of the DCM. The results show that the disintegration of the DCM is greatly affected by the swelling of hydrophilic clay minerals and softening and dissolving of inter-particle cementation. The free swelling deformation of the DCM increases with increasing dry density and decreasing grain size upon wetting. The DCM shows an increasing compression index as the consolidation pressure increases, which is related to its disintegrating nature. The settlement and compression index of the DCM reduce as an increase in dry density or the grain size. Therefore, relatively large grain sizes and compacted at a higher dry density for DCM is recommended in filling highway embankments. [ABSTRACT FROM AUTHOR]

Thick Quaternary alluvial and floodplain sediments in north Hebei Plain provide important information for understanding local paleoenvironmental and paleoclimatic variations. A 120.8 m drilled core (SHBZK-1) was recovered to determine the late Pleistocene climatic fluctuations, sedimentary environment and their coevolutionary relationship. Laboratory analysis, including grain size distribution, magnetic susceptibility, and optical stimulated luminescence dating, was carried out. Lithofacies and grain size showed that the sediments are of fluvial origin and contain two subfaces: river sand bar and flood plain. The good correlation between magnetic susceptibility and grain size show that climate change is the main factor controlling the variation of sedimentary environment in Hebei Plain, rather than tectonic factors. Furthermore, variations of the magnetic susceptibility and lithofacies reflect the intensity and fluctuations of Asian monsoons and couple well with glacial-interglacial cycles, suggesting that the variation of ice volume in the Northern Hemisphere drives climate change in the Hebei Plain, which, in turn, regulates the variation of the sedimentary environment and facies through controlling precipitation changes, as well as the input amount of magnetic minerals. This research provides a useful continental archive for understanding the late Pleistocene environmental and climatic variation and suggests the prevalence of climate-driven environmental change. [ABSTRACT FROM AUTHOR]

At the end of the Palaeozoic Era, most species on Earth disappeared completely and the global sedimentary environment and biology changed dramatically. The Permian–Triassic boundary (PTB) was studied in three sections of the middle Upper Yangtze Platform, SW China: Xingwen well and Zhijin and Shangsi sections. These sections are characterized by carbonate-platform, toe-of-slope and basin facies, respectively. Detailed analysis of 100 closely spaced thin-sections revealed a total of 24 microfacies and 11 microfacies associations based on the dominant carbonate grain size and the skeletal material (type and proportion). Six bioassemblages are documented for the first time, spanning c.  1 Ma across the boundary succession, including normal, resurrected and miniaturized Permian biota, and cyanobacteria-dominated, survival post-crisis and neonatal Triassic biota. The Xingwen well indicated sedimentary evolution from a rimmed carbonate platform to a homoclinal carbonate ramp, as well as a sharp fall in sea level just prior to the PTB in the study area. The Zhijin section revealed a slope setting, in which toe-of-slope and middle-ramp microfacies are identified. The Shangsi section showed a complete evolution of basin and outer-ramp microfacies and bioassemblages. Fossil evidence showed that the Permian biota (trilobites, gastropods and phylloid algae) occurred in the uppermost Changhsingian stage and was overlain by biomicrites with miniaturized ostracods (< 0.2 mm in size). This indicated that the major extinction horizon is located up to 14 cm below the PTB, which lies in the middle–lower segments of the miniaturized ostracod layer. [ABSTRACT FROM AUTHOR]

The distribution of sediment grain size can record past environmental conditions and human activity. In this study, radioisotope of 210Pb and 137Cs and a grain size of a 41 cm core in Hulun Lake were applied to reconstruct the high-resolution sedimentation history. The profiles of the grain size of the lake sediments show that silt (4–63 µm) was the largest contribution with an average content of 84.05%, and the second largest contribution was sand (>63 µm) with an average content of 15.68%. The median grain size and the mean grain size in the whole sediment core was 22.39 μm and 36.85 μm, respectively. Correlations of the sedimentological variables with instrumental measurements were also analyzed. The peak–trough value of the mean grain size of the sediments in Hulun Lake can reflect the magnitude of rainfall intensity and river discharge. The clay and silt contents at a depth of approximately 32–38 cm was different from other depths throughout the core, which showed continuous maxima with an average content of 0.35% and 94.08%. These changes in grain size correspond to the period of dam construction in 1963–1970. Therefore, the sediment grain size of Hulun Lake effectively recorded the dam-building activity. [ABSTRACT FROM AUTHOR]

In this paper, the distribution, degree of pollution and sources of Cu, Pb, Zn, Cd, Cr, As, Co, Ni and Hg in the surface sediment of Sanmen Bay were studied. The average concentrations of the identified potentially toxic elements (PTEs) were in the following order: Zn > Ni > Cr > Cu > Pb > Co > As>Cd > Hg. Almost all PTEs had a significant positive correlation with TOC, clay and Al; Cr had no significant correlations. Apart from Hg, the contamination levels of 8 PTEs were at those considered to be low-to-no pollution. Comparatively, the contamination level of Hg was much higher than the background value, which indicated moderate pollution. The source of this pollution may have included industrialization, urbanization and/or transport of industrial waste materials. Both geoaccumulation index (I geo) and potential ecological risk (RI) values suggested that Hg was the major contributor to the ecological risk posed by the selected PTEs. • The pollution of PTEs in Sanmen Bay of China was evaluated. • The concentration of PTEs in sediment descended Zn>Ni>Cr>Cu>Pb> Co>As>Cd>Hg. • Grain size and TOC were the factors controlling the distribution of most PTEs. • Hg was a non-negligible toxic element which posed a moderate ecological risk. [ABSTRACT FROM AUTHOR]

A series of flume experiments were conducted to study the hydraulic characteristics, sediment siltation mechanisms against different layouts of flexible mattresses that are gaining prominence over the traditional mattresses that are rigid and anti-scouring. The optimal layout pattern of interlacement and spacing 15 cm was found with an ecological effect of a comfortable hydraulic environment (water resistance rate of near bottom of 63%) and a proper deposition thickness (relative siltation thickness of 0.06). The ecological cavity mattress was successfully applied to the lower reach of Yangtze River in China. A stable and effective deposited layer (grain size of 25.21– 48.29 μm) was formed, which was exactly coincident to the laboratory experiment results, and where were found some organic matters (organic matter content of 1.77% ~ 3.68%) and a few of benthic fauna (abundance of 85ind./m2 and biomass of 0.62 g/m2 in flood season). A comfortable hydraulic environment was created in the inner structure in both the flood and drought seasons, just as the flume experiment presented. The sediment constituent and organic matter quantity in the inner structure were also relatively stable. Obviously, the new ecological cavity mattress exerts a positive ecological effect in the river ecosystem rehabilitation, which can be put into extensive use. In addition, design concept and optimization procedure of the new structure in this paper could also provide some reference for other relevant studies. [ABSTRACT FROM AUTHOR]

The movement of aeolian materials and dynamics of dune landforms are results of the transportation and accumulation of sandy sediments under the influence of climate, in which the processes that gave birth to sand dune formations are complex as the arid area has experienced different periods of humidity and aridity. These dynamics are still not well understood at present, especially at the inter‐decadal time scale. Based on a comprehensive analysis of geomorphological, sedimentological, geochemical, and ecohydrological data, this study discussed the dynamical changes of different dune landforms during the past half‐century and their formation mechanism in the Hexi Corridor, northern China. The results show that on the inter‐annual and inter‐decadal scales, the crescent‐shaped dunes move the fastest among different dune types. Dunes in Minqin move the fastest (at 6.2 ± 0.5 m yr−1) and dunes in Dunhuang move the slowest (at 0.8 ± 0.2 m yr−1). The dune sands are mainly medium sand (21.7%–57.4%) and fine sand (23.2%–53.0%) with an average grain size of 0.07 ± 0.01 mm ~0.24 ± 0.06 mm, similar to the world's average particle size of sand dunes. Annual precipitation and spring precipitation, annual average wind speed, and number of annual strong wind days are the main factors affecting the dynamic changes of dunes in the Corridor, indicating a major influence of climatic factors. STC (sufficient transport capacity) is evidenced for both the western and eastern Hexi Corridor, however, SSS (sufficient sand supply) and SA (sand availability) are the favourable factor for dune formation in the east part but is the limiting factor for the west. In the past half‐century, although the vulnerability of land degradation is a function of climate change, geomorphological processes, and anthropogenic pressure in the Hexi Corridor, water resource limitations have been more important. [ABSTRACT FROM AUTHOR]

In order to study the dominant seepage channel of the third member of Weizhou formation (Ew3) in Weizhou 12-X oilfield, Weixinan Sag, Beibu Gulf Basin, and tap the potential of remaining oil. The distribution and causes of the anomalously high permeability zones in Weizhou Formation were studied by using conventional core physical property analysis, scanning electron microscope, laser particle size analysis, X-ray diffraction and thin section microscopic identification. As the results show, vertically,there are three anomalously high permeability zones in the A11, A12 and A21 micro-stage of the middle diagenetic stage, with the depth range of 2300 m ~ 2400 m, 2400 m ~ 2600 m, 2600 m ~ 2900 m respectively. Grain size, sorting, dissolution and early emplacement of hydrocarbons are the main causes of anomalously high permeability zones. Although both grain size and sorting affect porosity and permeability, the effect of grain size on permeability is stronger than sorting, and sorting has a stronger effect on porosity than grain size. Magmatic hydrothermal and organic acid promote dissolution and concomitant porosity and permeability increase by dissolving unstable minerals. The early emplacement of hydrocarbons retard the cementation and accompanying porosity and permeability reduction by reducing the water-rock ratio. Finally, sandstone reservoirs in the Ew3 are characterized by anomalously high permeability zones. [ABSTRACT FROM AUTHOR]

Peatlands are one of the most significant carbon reservoirs in the terrestrial ecosystem. Understanding past peatland carbon accumulation processes and their responses to varying external and internal forcing factors would help reveal the general development patterns of peatland ecosystems and provide useful insights into projecting the fate of carbon reservoirs into the future. In this paper, the basal ages of 17 peat cores were used to explore the lateral expansion processes of the Laolike peatland, northeast China. Two cores were selected to calculate carbon accumulation rates (CAR) and reconstruct moisture/precipitation records based on δ13C and grain size analyses. The basal ages show that the peatland was initiated at 12.1 cal kyr BP, then laterally expanded with its fastest rate occurring during the early Holocene, and reached its largest area around 6 cal kyr BP. The time-weighted mean CAR in the Laolike peatland ranged from 31.1 to 52.9 g C/m2/yr (with an average of 42 g C/m2/yr) during the Holocene. The peatland experienced a high CAR of 52.5 g C/m2/yr from 11.7 to 5 cal kyr BP, followed by a low CAR of 35.1 g C/m2/yr after 5 cal kyr BP. Both lateral expansion and vertical accretion are consistent with the summer insolation, climate seasonality, and the strength of the East Asia summer monsoon (EASM) over multi-millennium timescales, where the CAR correlated well with δ13C and grain size, implying moisture/precipitation might be the primary factors controlling carbon accumulation over millennium timescales. Local conditions, such as topography and hydrology, also played an important role in the process of peatland initiation and lateral expansion, as well as the discrepant CAR within the peatland. This study reveals the roles of climate and local conditions in peatland initiation, expansion, and CAR during the Holocene. In addition, we provide a window for a better understanding of the driving factors of peatland development in the temperate zones of the Northern Hemisphere. • Climate conditions are the primary control on the lateral expansion and vertical accretion of Laolike peatland over multi-millennium timescales. • Moisture/precipitation affects carbon accumulation of Laolike peatland over millennium timescales. • Local conditions play an important role in the lateral expansion and the internal differences of carbon accumulation rate. [ABSTRACT FROM AUTHOR]

Plant leaves can accumulate particulate matter (PM) from the air, thus mitigating air pollution. Nine plant species from the central part of Shanxi Province, China, were investigated to characterize differences in their PM retention capacity and the grain sizes of the collected PM. Styphnolobium japonicum, Syringa oblata, and Cerasus serrulata demonstrated strong retention capacity for PM particles of diverse size fractions. Philadelphus incanus, Viburnum opulus, and Yulania biondii had relatively weak retention capacity for overall and fine PM. Generally, species with smaller leaves and roughness surfaces, waxy leaves, or leaves with hair had strong PM retention capacity. Leaves with suitable groove widths better retained fine PM. Foliar dust observed on leaves presented multimodal distribution curves, including bimodal, trimodal, and four-peak distributions, which differed from the trimodal distribution of natural dustfall. The different PM retention capacities of the nine investigated species and the differing grain sizes between foliar dust and atmospheric dustfall indicated that plant leaves could selectively retain PM. The results of this study provide a scientific basis for the use of the plant to mitigate particulate air pollution. [ABSTRACT FROM AUTHOR]

Understanding the multiple biotic and abiotic controls of aboveground biomass (AGB) is important for projecting the consequences of global change and to effectively manage carbon storage. Although large-scale studies have identified the major environmental and biological controls of AGB, drivers of local-scale variation are less well known. Additionally, involvement of multiple causal paths and scale dependence in effect sizes potentially confounds comparisons among studies differing in methodology and sampling grain. We tested for scale dependence in evidence supporting selection, complementarity and environmental factors as the main determinants of AGB variation over a 50 ha study extent in subtropical China, modelling this at four sampling grains (0.01, 0.04, 0.25 and 1 ha). At each grain, we used piecewise structural equation models to quantify the direct and indirect effects of environmental (topographic and edaphic properties) and forest attributes (structure, diversity and functional traits) on AGB, while controlling for spatial autocorrelation. Direct scale-invariant effects on AGB were evident for structure and community-mean traits, supporting dominance of selection effects. However, diversity had strong indirect effects on AGB via forest structure, particularly at larger sampling grains (≥ 0.25 ha), while direct effects only emerged at the smallest grain size (0.01 ha). The direct and indirect effects of edaphic and topographic factors were also important for explaining both forest attributes and AGB across all scales. Although selection effects appeared to be more influential on ecosystem function, ignoring indirect causal pathways for diversity via structural attributes risks overlooking the importance of complementarity on ecosystem functioning, particularly as sampling grain increases. [ABSTRACT FROM AUTHOR]

The optimal development of hot dry rock (HDR) geothermal is deep HDR geothermal. Because of different diagenesis environments, the mineral composition and micro-structure of deep granite are quite different than those of shallow granite. To reveal the characteristics of deep granite and guide HDR geothermal development, the difference in thermal and mechanical properties between the granite in Luya Mountain, Shanxi Province, China (coarse-grained granite) and the granite in Shandong Province, China (fine-grained granite) under high-temperature (100–400 ℃) triaxial stress was studied. The results show that the thermal expansion coefficient of the coarse-grained granite increases linearly with increasing temperature, and the thermal expansion coefficient of the coarse-grained granite is 1.52 times that of the fine-grained granite on average, and the difference reaches a maximum at 400 ℃. The elastic modulus of the coarse-grained granite increases slowly first and then decreases sharply with increasing temperature, and its threshold temperature varies with temperature at approximately 300 ℃. The elastic modulus of the fine-grained granite is 1.4–2.6 times that of the coarse-grained granite, and the difference increases with increasing temperature and confining pressure. According to the failure test under triaxial stress (confining pressure (σc) = 25 MPa) and at 400 ℃, for the coarse-grained granite, the peak strength, elastic modulus and its threshold temperature change with temperature are smaller, the peak strain is larger and the elasto-plastic transition occurs easier than those for the fine-grained granite. Micro-observation shows that the larger crystal particles and the extreme heterogeneity of the coarse-grained granite lead to larger thermal deformation and greater deterioration of the mechanical properties, compared with those of the fine-grained granite, further leading to higher permeability of the coarse-grained granite under high temperature and high pressure. The existence of coarse-grained granite provides a good geological foundation for high-efficiency, low-cost and large-scale construction of artificial reservoirs in the process of HDR geothermal development. [ABSTRACT FROM AUTHOR]

Microplastic pollution is considered to be a major coastal environmental issue worldwide, and studies have confirmed the ubiquitous nature of microplastics on many beaches. To best of our knowledge, no previous study on microplastic pollution has been conducted in the present study area to date. This study examined the microplastic abundance, polymer type, size, shape and color in the sediments of Liuqinghewan Bathing Beach and the fishing port beach of Qingdao, China. Microplastics (1–0.5, 0.5–0.25 and 0.25–0.125 mm) were extracted from beach sediments using a density separation method. Fourier transform infrared (FTIR) spectroscopy was used to determine the chemical composition of the plastics while physical characteristics (size, shape, and color) of microplastics were observed using a stereomicroscope. The average microplastic abundance values with the grain size ranges from 1 to 0.125 mm at Liuqinghewan Bathing Beach and at the fishing port beach were approximately 208 ± 3.5 and 299 ± 5.7 microplastics per kg of dry sand, respectively. The number of microplastic particles with the grain size from 0.25 to 0.125 mm was significantly higher than for the other grain sizes. Microplastics were mainly multicolor fibers in all samples making up a large proportion that exceeded 97%. On the basis of FTIR analysis, the microplastics were shown to be composed of polypropylene and polystyrene at both sites. Microplastic characteristics used to identify their origin revealed high development and industrialization predict the non-point source of microplastics related to their hydrodynamic and geographical conditions. Assessing the distribution and characterization of microplastics on sandy beaches of some regions is not novel but a rather common study. However, the outcomes of current study furnish valuable and novel data for the evaluation of microplastic concentrations in beach sediments, environmental risks in China, and a baseline for future analysis. [ABSTRACT FROM AUTHOR]

Salt and drought-induced RING finger1 (SDIR1) is a RING-type E3 ubiquitin ligase that plays a key role in ABA-mediated responses to salinity and drought stress via the ubiquitination pathway in some plant species. However, its function in wheat (Triticum aestivum) is unknown. Here, we isolated a SDIR1 member in wheat, TaSDIR1-4A , and characterized its E3 ubiquitin ligase activity. DNA polymorphism assays showed the presence of two nucleotide variation sites in the promoter region of TaSDIR1-4A , leading to the detection of the haplotypes Hap-4A-1 and Hap-4A-2 in wheat populations. Association analysis showed that TaSDIR1-4A haplotypes were associated with 1000-grain weight (TGW) across a variety of different environments, including well-watered and heat-stress conditions. Genotypes with Hap-4A-2 had higher TGW than those with Hap-4A-1. Phenotypes in both gene-silenced wheat and transgenic Arabidopsis showed that TaSDIR1-4A was a negative regulator of grain size. Gene expression assays indicated that TaSDIR1-4A was most highly expressed in flag leaves, and expression was higher in Hap-4A-1 accessions than in Hap-4A-2 accessions. The difference might be attributable to the fact that TaERF3 (ethylene response factor) can act as a transcriptional repressor of TaSDIR1-4A in Hap-4A-2 but not in Hap-4A-1. Examination of modern wheat varieties shows that the favorable haplotype has been positively selected in breeding programs in China. The functional marker for TaSDIR1-4A developed in this study should be helpful for future wheat breeding. [ABSTRACT FROM AUTHOR]

The Ti‐in‐zircon (TIZ) and Zr‐in‐rutile (ZIR) geothermometers record metamorphic temperatures. In theory, their results should be consistent when zircon and rutile equilibrate as they form. However, we show that these geothermometers were decoupled during ultrahigh temperature (UHT) metamorphism of the Dabie Orogen, China. The TIZ geothermometer records a peak temperature of 927 ± 38°C for the granulite‐facies metamorphism. Rutile occurs as inclusions in UHT metamorphic zircon domains, and they were syn‐crystallised. Rutile records ZIR temperatures of 783 to 798°C. We infer that diffusion of Ti and Zr between zircon and rutile is the main cause of decoupling between the TIZ and ZIR geothermometers. Diffusion of Zr in rutiles is closely related to the distribution of elements, the duration of UHT metamorphism, and rutile grain size. [ABSTRACT FROM AUTHOR]

Alluvial fan exhibits various modal distribution of pore-throat size, which effectively control the oil displacement efficiency and fluid movement. However, the genetic mechanism of the modal distribution of the pore-throat size and its macroscopic distribution within alluvial fan is poorly understood. Based on core analysis, this paper, which take the sandy conglomerate reservoir within the alluvial fan in Junggar Basin as an example, aims to study the variations in modal distribution of pore-throat size and controlling mechanisms. The results reveal that (1) The modal distribution types of the pore-throat size are complicated, and can be classified into six subtypes, including unimodal type Ⅰ (Uni-Ⅰ), unimodal type Ⅱ (Uni-Ⅱ), unimodal type Ⅲ (Uni-Ⅲ), bimodal type Ⅰ (Bi-Ⅰ), bimodal type Ⅱ (Bi-Ⅱ) and multimodal type (Multi). Uni-Ⅰ, Uni-Ⅱ, and Uni-Ⅲ is dominated by intergranular pores, intragranular dissolved pores and micropores, respectively. Bi-Ⅰ, Bi-Ⅱ and Multi are characterized by the combination of several pore types. (2) Diagenesis, including compaction, cementation and dissolution, rock composition (the mudstone fragment content) and rock texture (the clay content) control the volume of each pore-throat type, which significantly influences the modal distribution of the pore-throat size. Lithofacies with low mudstone fragment and clay content and great grain sorting tend to have experienced weak compaction, thereby retaining a large volume of intergranular pores, and have been subjected to strong dissolution when adequate acidic ions occur in the porewater, resulting in a large volume of intragranular dissolved pores. Strong dissolution reduced the rock compressive strength, and further enhanced the degree of mechanical compaction during the burial process. Cementation occurred later than compaction and dissolution, and its intensity is controlled by the supply of CO 2 and Ca2+ and compaction intensity, thus reducing the volume of intergranular pores. The content of mudstone fragment and clay varies among different lithofacies of different origins. For traction current deposits, lithofacies with smaller median grain size contain fewer mudstone fragments, resulting in fewer micropores. The clay content decreased first and then increased with decreasing median grain size, and lithofacies with lower clay content cause less volume of micropores. (3) Lithofacies types, combined with porewater condition for dissolution and lithofacies location, affect the diagenetic intensity, rock composition and rock texture variations, thus resulting in various modal distribution of pore-throat size within the alluvial fan. Moreover, the rock texture, especially grain sorting, is very important for compaction, and facilitates percolation of meteoric water and dissolution. • The modal distribution of pore-throat size of the sandy conglomerates within alluvial fan is complicated. • Lithofacies types, combined with porewater condition for dissolution and lithofacies location, affect the diagenetic intensity, rock composition and rock texture variations, thus resulting in various modal distribution of pore-throat size within the alluvial fan depositional system. [ABSTRACT FROM AUTHOR]

Deep‐water deposits in marine basins have recently received considerable research attention. However, the controls of sediment transported to deep‐lacustrine environments are comparatively understudied. In this study, we utilize field‐based outcrop data to investigate the variability of sediment distribution and its controlling factors in the Lower Cretaceous synrift Xiguayuan Formation in the Luanping Basin. Two fan‐delta systems with variability dominate the measured outcrop sections. At the lithological scale, the ratio of conglomerate to strata in the Xiyuan fan‐delta system is 87%, and the average thickness of individual coarse‐grained layers is ~1 m; the corresponding values in the Caoying fan‐delta system are 52% and 0.4 m. In addition, sand‐rich gravity‐flow deposits are developed in front of the Xiyuan fan delta, whereas mud‐rich mass transport deposits (i.e., sliding block and slumping debris) are found in front of the Caoying fan delta. At the stratigraphical scale, a delta succession in the Xiyuan section characterized by sand‐rich facies from proximal to distal parts is developed in a relatively steep slope setting. In the Caoying section, however, a delta succession characterized by sand‐rich facies in the proximal to middle parts is found in addition to a mud‐rich distal part developed in a gentle slope setting. Differential sediment supply resulted in significant variation in the sediment distribution pattern. In particular, the grain size of the fan‐delta front controls that of the deep‐lacustrine gravity‐flow deposits fed by them. This study highlights the variability of sediment supply and their control on sediment partitioning in continental rift and marine basins. [ABSTRACT FROM AUTHOR]

Fine-grained sediment (grain size under 2,000 µm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 µm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode betweenmixed suspended bed load transport and suspensiondominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities. [ABSTRACT FROM AUTHOR]

Hydroclimatic variations over the eastern Central Asia are highly sensitive to changes in hemispheric-scale atmospheric circulation systems. To fully understand the long-term variability and relationship between hydroclimate and atmospheric circulation system, we present a high-resolution lascustrine record of late Holocene hydroclimate from Lake Sayram, Central Tianshan Mountains, China, based on the total organic carbon, total nitrogen, and carbonate contents, carbon/nitrogen ratios, and grain size. Our results reveal four periods of substantially increased precipitation at the interval of 4000–3780, 3590–3210, 2800–2160, and 890–280 cal yr BP, and one period of slightly increased precipitation from 1700–1370 cal yr BP. These wetter periods broadly coincide with those identified in other records from the mid-latitude Westerlies-dominated eastern Central Asia, including the northern Tibetan Plateau. As such, a similar hydroclimatic pattern existed over this entire region during the late Holocene. Based on a close similarity of our record with reconstruction of North Atlantic Oscillation indices and solar irradiance, we propose that decreased solar irradiance and southern migration of the entire circum-North Atlantic circulation system, particularly the main pathway of the mid-latitude Westerlies, significantly influenced hydroclimate in eastern Central Asia during the late Holocene. Finally, the inferred precipitation at Lake Sayram has increased markedly over the past 100 years, although this potential future changes in hydroclimate in Central Asia need for further investigation. [ABSTRACT FROM AUTHOR]

There have been few high‐resolution investigations covering the last glacial and Holocene from Sichuan, Yunnan, or south Asia area in the south‐west monsoon domain region. High‐resolution analyses of lake sediments retrieved from Qionghai Lake, Sichuan Province, were conducted using a combination of variables including total organic carbon (TOC) and total nitrogen (TN) concentration, low frequency magnetic susceptibility (χLF), particle size, carbonate content, and δ13C value of organic matter (δ13Corg), to provide a new perspective on the detailed paleoclimate history of south‐west China spanning the past 30 cal ka BP. Our findings suggest that organic matter in the Qionghai Lake was mainly derived from microorganisms, aquatic macrophytes, and terrestrial C3 plants. From 29.1 to 23.2 cal ka BP, low carbonate contents, high median grain size (Md values), and χLF values indicated a warm and wet climate. During the period 23.2 to 15.4 cal ka BP, low χLF, Md values, and high carbonate contents suggested a decrease in temperature and humidity. The cold and dry Last Glacial Maximum (LGM) and Heinrich 1 event (H1) were captured between 21.6 and 19.4 cal ka BP and 17.6 and 15.8 cal ka BP, respectively. During the interval 15.4 to 9.7 cal ka BP, low level of χLF values and Md values, together with relatively high carbonates, demonstrated that a dry climate prevailed in this period. Since 9.7 cal ka BP, the climate was warm and humid in the early to mid‐Holocene and shifted towards cold and dry condition in the late Holocene. A cold and dry period at 8.5 to 8.1 cal ka BP and warm and wet interval at 6.6 to 4.6 cal ka BP were identified, corresponding to the 8.2‐ka cold event and Holocene climatic optimum (HCO), respectively. These climate changes may reflect variations of the intensity of the south‐west summer monsoon, primarily in response to the Northern Hemisphere solar insolation on a millennial scale induced by orbital forcing. The position of the Intertropical Convergence Zone (ITCZ) may add a complementary effect on the evolution of the monsoon strength in the Holocene. [ABSTRACT FROM AUTHOR]

The nature and dynamics of climate change in central Asia since the late Pleistocene are controversial. Moreover, most of the published studies focus mainly on the evolution of moisture conditions, and there have been few attempts to address changes in seasonality. In this study, records of δ13Corg, TOC, TN, C/N and grain size were obtained from lacustrine sediments at Yili Basin, Xinjiang, NW China. Our aim was to reconstruct the trend in seasonality of precipitation from the last glaciation to the Holocene. The organic matter content of the sediments is derived predominantly from terrestrial plants. The δ13Corg values vary from -19.4% to -24.8%, indicating that the vegetation was dominated by C3 plants. Winter-spring precipitation is identified as the factor determining the relative proportions of C3 and C4 plants in the region. A negative trend in δ13Corg corresponding to an increase in the relative abundance of C3 plants indicate a trend of increasing winter-spring precipitation from the last glaciation to the Holocene. The increased incidence of wintertime storms in the interior of Asia is suggested to result in the increase of winterspring precipitation in the Holocene. [ABSTRACT FROM AUTHOR]

Lawsonite eclogites are crucial to decipher material recycling along a cold geotherm into the deep Earth and orogenic geodynamics at convergent margins. However, their tectono‐metamorphic role and record especially at ultrahigh‐pressure (UHP) conditions are poorly known due to rare exposure in orogenic belts. In a ~4 km long cross‐section in Muzhaerte, China, at the western termination of the HP‐UHP metamorphic belt of western Tianshan, metabasite blocks contain omphacite and lawsonite inclusions in porphyroblastic garnet, although matrix assemblages have been significantly affected by overprinting at shallower structural levels. Two types of lawsonite eclogites occur in different parts of the section and are distinguished based on inclusion assemblages in garnet: Type 1 (UHP) with the peak equilibrium assemblage garnet+omphacite±jadeite+lawsonite+rutile+coesite±chlorite±glaucophane and Type 2 (HP) with the assemblage garnet+omphacite±diopside+lawsonite+titanite+quartz±actinolite±chlorite+glaucophane. Pristine coesite and lawsonite and their pseudomorphs in Type 1 are present in the mantle domains of zoned garnet, indicative of a coesite‐lawsonite eclogite facies. Regardless of grain size and zoning profiles, garnet with Type 1 inclusions systematically shows higher Mg and lower Ca contents than Type 2 (prp4–25grs13–24 and prp1–8grs20–45 respectively). Phase equilibria modelling indicates that the low‐Ca garnet core and mantle of Type 1 formed at UHP conditions and that there was a major difference in peak pressures (i.e., maximum return depth) between the two types (2.8–3.2 GPa at 480–590°C and 1.3–1.85 GPa at 390–500°C respectively). Scattered exposures of Type 1 lawsonite eclogite is scatteredly exposed in the north of the Muzhaerte section with a structural thickness of ~1 km, whereas Type 2 occurs throughout the rest of the section. We conclude from this regular distribution that they were derived from two contrasting units that formed along two different geothermal systems (150–200°C/GPa for the northern UHP unit and 200–300°C/GPa for the southern HP unit), with subsequent stacking of UHP and HP slices at a kilometre scale. [ABSTRACT FROM AUTHOR]

In recent years, enriched hydrocarbon reservoirs have been largely founded in the Lower Triassic Baikouquan Formation, in the Mahu Depression of Junggar basin, northwestern China. Accordingly, the sedimentologic complexity of associated deposits has been extensively studied, though most of them focused on local oil‐producing fields separately. In this research, a detailed sedimentary study of the entire Mahu Depression has been conducted, which include several aspects of sedimentary characteristics, sediment provenance, evolution, and controls of the coarse‐grained fan‐delta system. According to facies features recognized from cores, thin sections, well logs, and seismic data, three sedimentary facies associations were identified: upper fan‐delta plain, lower fan‐delta plain, and fan‐delta front. Furthermore, four depositional systems (Xiazijie, Haungyangquan, Karamay, and Xiayan fan‐delta) around the Mahu Depression were recognized by the distribution of heavy mineral assemblages and change of ZTR index (percentage of Zircon, Tourmaline, and Rutile in the total transparent heavy mineral assemblage). Based on the analysis of facies and sediment provenance, the temporal and spatial distribution of the fan‐delta system were reconstructed associated with the variation of net/gross ratio. As characterized by decreasing‐upward of net/gross ratios and fining‐upward trend of grain size, the evolution of the fan‐delta succession showed an overall retreating pattern which was mainly controlled by lake level rising and rapid tectonic subsidence. Within the retreating pattern, hydrocarbons were trapped in the middle deposits with reservoir space produced by fan‐delta front and lower fan‐delta plain, which were encased between the top transgressive lacustrine mudstones and the bottom debris‐flow deposits produced by upper fan‐delta plain. These findings of the research throw light on the phenomena that the stratigraphy trap for hydrocarbon accumulation could be constructed by retreating, coarse‐grained fan‐delta systems. [ABSTRACT FROM AUTHOR]

In this study, field investigation and numerical modeling using Particle Flow Code (PFC) were conducted to investigate deposit characteristics and their implications for the fragmentation mechanisms of the 2009 Jiweishan rock avalanche in Wulong, China. The results show that average grain-size distribution of the debris diminishes both from the proximal to the distal end and from the surface to the bottom of the deposit. A carapace of large boulders was formed at the surface and passively carried by the underlying finely fragmented debris during runout. Stratigraphic preservation, directly aligned boulders on the surface, and jigsaw fracture patterns exclude fragmentation mechanisms involving collision. Fragmentation induced by normal stress also cannot explain the progressive reduction in grain size of the deposit from the proximal to the distal end. Loose soil on the transport path was bulldozed to the very front and pushed passively by the rock debris, rather than remaining at the bottom and reducing frictional resistance between the debris and the ground. Thus, the undrained-loading hypothesis widely used to explain the long-runout of rock avalanches is not applicable. Shear-induced fragmentation is the most probable mechanism that can adequately explain the characteristics of the rock avalanche deposit. [ABSTRACT FROM AUTHOR]

Xu, M.; Meng, K.; Zhao, Y., and Zhao, L., 2019. Sedimentary environment evolution in East China's coastal tidal flats: The North Jiangsu radial sand ridges. Journal of Coastal Research, 35(3), 524–533. Coconut Creek (Florida), ISSN 0749-0208. The North Jiangsu radial sand ridges (NJRSR) are a unique sedimentary system comprising the largest silt and mud coastal tidal flat in China. Many factors influence its tidal geomorphology sensitivity when responding to the marine environment and human activities. In this study, three typical core samples were collected from sampling points near Xinyang Gang (XYG), Chuandong Gang (CDG), and Xiaoyangkou Gang (XYK). 210Pb and 137Cs radionuclide dating was used to estimate the sedimentation rate of the tidal flat. On the basis of combined sediment grain size and reclamation history over the last 50 years, the evolution of the NJRSR coastal tidal flat sedimentary environment under the impact of human activities and the changing coastal environment was examine. The result indicated that the predominant type of sedimentary deposition is sandy silt; however, sediment composition varies because of coastal reclamation activities extending into the sea and with changes in sediment source and depositional forces. Average sedimentation rates of the three core samples were 1.27, 1.85, and 2.43–3.3 cm/y, respectively, reflecting increasing sedimentation rates from north to south. However, sedimentation rates over the past century have gradually declined in core XYG because of a reduced supply of materials from northern sources. Moreover, sand content has increased in the north since the 1980s, and grain size has become coarser. In the middle sample, a sudden change in sediment composition occurred in the 1950s–60s, exhibited by a significant reduction in sand content but an increase in silt content and finer grain sizes. In the south, grain size coarsened initially before becoming finer, likely because of a reduction of eroded material from the Yellow River in the north, increased coastal reclamation activities, and changes in sedimentary dynamics. [ABSTRACT FROM AUTHOR]

Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-term records of paleofloods in arid regions are scarce, thus preventing a thorough understanding of such events. In this study, a reconstruction of paleofloods over the past 300 years was conducted through an analysis of grain sizes from the sediments of Kanas Lake in the Altay Mountains of northwestern China. Results showed that grain parameters and frequency distributions can be used to infer possible abrupt environmental events within the lake sedimentary sequence, and two extreme flood events corresponding to ca. 1736-1765 AD and ca. 1890 AD were further identified based on canonical discriminant analysis (CDA) and coarse percentile versus median grain size (C-M) pattern analysis, both of which occurred during warmer and wetter climate conditions by referring to tree-ring records. These two flood events are also evidenced by lake sedimentary records in the Altay and Tianshan mountains. Furthermore, through a comparison with other records, the flood event from ca. 1736-1765 AD in the study region seems to have occurred in both the arid central Asia and the Alps in Europe, and thus may have been associated with changes in the North Atlantic Oscillation (NAO) index. [ABSTRACT FROM AUTHOR]

Grain size and concentrations of organic carbon (Corg) and particulate metals (PMs) As, Cd, Cr, Cu, Hg, Pb, Zn, Al, Fe, and Mn of 373 surface sediment samples, salinities in 67 surface water samples, were analyzed in various environments, including the upper delta plain wetlands (UDPW), its adjacent shallow sea wetland (SSW) in the Liaodong Bay, and river channels that are running through the Liaohe Delta, to evaluate the spatial distribution, transportation environmental dynamics of metals, and the provenance of metal pollution and assess the filtration functions of wetlands. The concentrations of PMs for UDPW were generally higher by a factor of ~ 10–22% compared with its analogues in SSW, suggesting the accumulation of PMs within the UDPW indicates that the UDPW systems are efficiently physical and chemical traps for PMs of anthropogenic sources by retaining and storing pollutants flowing into the sea. However, there was sever sewage irrigation-induced Cd pollution with a geo-accumulation index of 0.62–3.11 in an area of ~ 86 km2 of the adjacent shallow sea wetland, where large amount wetlands were historically moved for agriculture in the UDPW. Remarkably, the distributions of PMs were controlled by salinity-induced desorption and re-adsorption mechanisms and significantly dispersed the contamination coverage by the three-dimensional hydrodynamic and sedimentation processes that dominated by inputs of freshwater and ocean dynamics including NE-SW tidal currents and NE-E longshore drifts in the SSW of the Liaodong Bay. A high agreement between the UDPW and the SSW datasets in principal component analysis essentially reflects that the characteristics of PM sources in the SSW were actually inherited from that in the UDPW, with a much closer relationship among metals, organic matter, and fine particulates in SSW than that of UDPW, which was judged by their correlation coefficient range of 0.406–0.919 in SSW against those of 0.042–0.654 in UDPW. [ABSTRACT FROM AUTHOR]

Material components and geochemical behaviour of desert deposits are closely related with the level and degree of the desertification. In this research, we systematically carried out a grain size and geochemical study of the surface sediments from fixed, semi-fixed, semi-mobile and mobile sand dunes and discussed their link with the desertification in the Mu Us Desert, northern China. Grain size results indicated that the main components of the different sandy sediments were predominantly 200-300-µm coarse grain size. Along with the stronger desertification, the fine material content (clay and silt) and mean grain size (Φ) became lessened, while the coarse particle is remarkably increased due to the repeated wind sorting during that process. These sandy deposits were mainly transported by saltation and creep; the increased creep and decreased saltation and suspended components were probably a response to the lessened fixation degree of the dunes. Geochemical analysis demonstrated that the surface sandy deposits were mainly composed of SiO2, Al2O3 and Na2O, which was very similar to the geochemical constituents of the other deserts in northern China. These sandy surface sediments, with their relatively high Ca and Na content, incur little or no geochemical weathering, which is probably attributable to the arid conditions and the lack of effective weathering. Additionally, an A-CNK-FM diagram indicated that decreased Fe and Mg contents were possibly related to the stronger abrasion and sorting during the desertification process. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]