Gobi Research Articles

Characterization of dust activation and their prevailing transport over East Asia based on multi-satellite observations

Mineral dust from the deserts and arid areas in East Asia plays a critical role in regional climate and air quality. Based on integrated satellite observations and MERRA-2 reanalysis, we provide an observational insight into dust activities governing spatial patterns of dust aerosols over East Asia. With Moderate resolution Imaging Spectroradiometer Aerosol Optical Depth (AOD) and Ozone Monitoring Ultraviolet Aerosol Index (UVAI), fixed dust-active areas with distinct spatial-temporal differences are revealed. Besides the few dust storms mostly in spring, unnoticeable but frequent dust plumes are found to be the predominant sources of prevailing dust particles over East Asia. Compared with the active dust sources in Taklimakan Desert throughout the year, dust activities in Gobi deserts are at a much lower frequency. The elevated dust plumes are concentrated within 2–6 km over the deserts with large seasonal variations, and can be transported downstream to eastern China and Sichuan Basin within 3–5 days. Moreover, owing to the lack of enough strong winds, these dust plumes tend to be concentrated above the haze layers near surface in eastern China. The intense temperature inversion during winter and early spring can delay the mixing of dust-pollution. Despite a generally reasonable performance in dust AOD, MERRA-2 reanalysis exhibits some uncertainties in reproducing spatial locations of dust hotspots, dust concentration, and transport process. Our results emphasize significant role of the inapparent but prevalent dust plumes in air quality and in climate effects of East Asia.

Nowhere to Call Home: A Study of Sanmenxia-Reservoir Resettlement From Henan To Gansu, 1956–1965

AbstractIn the late 1950s, the creation of a large reservoir for the Sanmenxia hydropower project required the displacement of tens of thousands of households along the Yellow River. Simultaneously, the state commenced a land-reclamation project, sending people from populated areas to the frontiers. Under the supervision of county and provincial authorities, more than 7,000 reservoir inhabitants from Henan were mobilized to migrate to Dunhuang, an oasis surrounded by the Gobi Desert in the northwest. The socialist state's pursuit of irrigation and hydroelectricity benefits not only altered the waterscape of the Yellow River; it also impacted nearby rural communities as well as those a thousand miles away. From the high-modernist perspective, the state-sponsored demographic engineering and the Yellow River engineering seemed to complement each other well. Yet, with the massive flight of resettlers, the state-envisioned integration of reservoir displacement and frontier reclamation ultimately failed.

A new partial skeleton of Kryptobaatar from the Upper Cretaceous of Bayan Mandahu (Inner Mongolia, China) relaunch the question about variability in djadochtatherioid multituberculate mammals

A new well-preserved partial skeleton of the djadochtatheriid multituberculate Kryptobaatar is here described from the Campanian Bayan Mandahu Formation of the southern Gobi Basin in Inner Mongolia, China. We refer to it as Kryptobaatar sp. because it presents characters that are specific to Kryptobaatar dashzevegi and others specific to Kryptobaatar mandahuensis, as well as characters of its own. When those taxa are incorporated into a phylogenetic analysis of the Djadochtatherioidea, the Kryptobaatar species appear to be paraphyletic. This raises again questions about the high intraspecific variability in some multituberculates. Based on a comparison with the published specimens, we conclude that K. mandahuensis is a valid species, close to but distinct from K. dashzevegi. Our results also suggest that endemism alone in the Gobi Basin is not the cause of the high variability observed in the genus Kryptobaatar. But the impact of a possible difference in age or paleoenvironment between the different Kryptobaatar-bearing sites of the Gobi Desert is, for the moment, not possible to test in the current state of knowledge.

Geographical drivers of geochemical and mineralogical evolution of Motianling peatland (Northeast China) exposed to different sources of rare earth elements and Pb, Nd, and Sr isotopes

Geochemical shifts triggered by surface runoff and atmospheric fallout in a Chinese peatland were investigated by using Pb, Sr, and Nd, REE and by SEM mineralogical analysis. Motianling peatland (Northeast China) is located at 1670 m a.s.l., near the China–Mongolia border. Based on division of profile into two phases of different trophy, the total ∑REE value determined for the minerotrophic part of the profile (from 62 to 46 cm) varied from 67 to 31 mg·kg−1 and mineralogical analysis revealed the occurrence of weathered volcanic rocks, supported by a high εNd value (−3.26). After the transition from minerotrophic to more ombrotrophic conditions, the peatland became independent of the local bedrock weathering, which was manifested by a much lower concentration of REE (7–20 mg·kg−1) and lower εNd values (−7.37; −8.11). Moreover, PAAS-normalized pattern of REE distribution in the bottom part revealed the highest Eu/Eu* value (1.24), as well as a slight enrichment in Eu. The anthropogenic effect was visible from 1964, during which period the spheroidal aluminosilicate particles (SAP), produced by coal-fired power-plant activity, appeared for the first time, followed by an abrupt decrease in 206Pb/207Pb isotopic signature to 1.167. The dimensions of SAP (~1.5 μm), as well as the time of first appearance, indicated long-range transport. The REE ratios obtained in this study are characteristic of the eolian deposition signature, which is like the Gobi and northern Chinese deserts. The anthropogenic activity was manifested by a slight enrichment in Gd during reduced delivery of natural dust. Both, North Chinese and Asian part of the Russian industry supply anthropogenic dust. Topography, wind direction, and patterns of precipitation, as well as the initial phases of Asian industrial development, are the most important drivers promoting the deposition of chemical elements.

Characteristics of the severe March 2021 Gobi Desert dust storm and its impact on air pollution in China

A dust storm that formed in the north of China and the southeastern part of Mongolia in March 2021 significantly deteriorated air quality over a large area of East Asia. According to the synoptic pattern, the cause of the dust storm was a cyclone with a significant drop in pressure leading to high winds and dry components of the soil over parts of the Gobi Desert becoming airborne. Data obtained from ground-based air quality monitoring stations show that the observed hourly PM10 concentration greatly exceeded the recommended maximum of 150 μg/m3 with readings above 1500 μg/m3 in the cities of Tianjin, Baoding, Zhengzhou, Luoyang, Zhoukou. In Shijiazhuang, Taiyuan, Jinnan, Xining, Baotou, and Jining. In Handan, it was over 2000 μg/m3. Cities where PM10 concentration exceeded 3900 μg/m3 included Lanzhou, Hohhot, Changzhou, Alashan, Yan'an, Yulin, Hami, Jiuquan, Heze, Hotan, and Baiyin. Concentrations exceeded 7000 μg/m3 on March 15th over parts of the provinces of Inner Mongolia, Gansu and Ningxia, in the cities of Ordos, Jinchang, Wuwei and Zhongwei. According to satellite data, the area of dust covered approximately 450,000 km2. MODIS and TROPOMI data demonstrated high aerosol optical depth (AOD) (more than 1) with a high ultraviolet aerosol index (UVAI) (more than 2), confirming the predominance of dust particles during the storm. Data from CALIPSO show the presence of a dense layer of dust extending from the earth's surface to a height of about 8 km. The Dust Regional Atmospheric Model (BSC-DREAM8b) demonstrates high synchrony with the satellite's surface dust concentration data, ranging from 640 to 1280 μg/m3, and exceeding 2650 μg/m3 in some areas. The purpose of this study is to analyze data from ground-based sensors, satellites, and atmospheric models to better understand the March 2021 dust storm event. The results may be useful for the implementation of protective and preventive measures for both the environment and human health, including air quality control.

Global dust optical depth climatology derived from CALIOP and MODIS aerosol retrievals on decadal timescales: regional and interannual variability

Abstract. We derived two observation-based global monthly mean dust aerosol optical depth (DAOD) climatological datasets from 2007 to 2019 with a 2∘ (latitude) × 5∘ (longitude) spatial resolution, one based on Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and the other on Moderate Resolution Imaging Spectroradiometer (MODIS) observations. In addition, the CALIOP climatological dataset also includes dust vertical extinction profiles. Dust is distinguished from non-dust aerosols based on particle shape information (e.g., lidar depolarization ratio) for CALIOP and on dust size and absorption information (e.g., fine-mode fraction, Ångström exponent, and single-scattering albedo) for MODIS, respectively. The two datasets compare reasonably well with the results reported in previous studies and the collocated Aerosol Robotic Network (AERONET) coarse-mode AOD. Based on these two datasets, we carried out a comprehensive comparative study of the spatial and temporal climatology of dust. On a multi-year average basis, the global (60∘ S–60∘ N) annual mean DAOD is 0.032 and 0.067 according to CALIOP and MODIS retrievals, respectively. In most dust-active regions, CALIOP DAOD generally correlates well (correlation coefficient R>0.6) with the MODIS DAOD, although the CALIOP value is significantly smaller. The CALIOP DAOD is 18 %, 34 %, 54 %, and 31 % smaller than MODIS DAOD over the Sahara, the tropical Atlantic Ocean, the Caribbean Sea, and the Arabian Sea, respectively. Applying a regional specific lidar ratio (LR) of 58 sr instead of the 44 sr used in the CALIOP operational retrieval reduces the difference from 18 % to 8 % over the Sahara and from 34 % to 12 % over the tropical Atlantic Ocean. However, over eastern Asia and the northwestern Pacific Ocean (NWP), the two datasets show weak correlation. Despite these discrepancies, CALIOP and MODIS show similar seasonal and interannual variations in regional DAOD. For dust aerosol over the NWP, both CALIOP and MODIS show a declining trend of DAOD at a rate of about 2 % yr−1. This decreasing trend is consistent with the observed declining trend of DAOD in the southern Gobi Desert at a rate of 3 % yr−1 and 5 % yr−1 according to CALIOP and MODIS, respectively. The decreasing trend of DAOD in the southern Gobi Desert is in turn found to be significantly correlated with increasing vegetation and decreasing surface wind speed in the area.

Prediction of Biome-Specific Potential Evapotranspiration in Mongolia under a Scarcity of Weather Data

We propose practical guidelines to predict biome-specific potential evapotranspiration (ETp) from the knowledge of grass-reference evapotranspiration (ET0) and a crop coefficient (Kc) in Mongolia. A paucity of land-based weather data hampers use of the Penman–Monteith equation (FAO-56 PM) based on the Food and Agriculture Organization (FAO) guidelines to predict daily ET0. We found that the application of the Hargreaves equation provides ET0 estimates very similar to those from the FAO-56 PM approach. The Kc value is tabulated only for crops in the FAO-56 guidelines but is unavailable for steppe grasslands. Therefore, we proposed a new crop coefficient, Kc adj defined by (a) net solar radiation in the Gobi Desert (Kc adjD) or (b) leaf area index in the steppe region (Kc adjS) in Mongolia. The mean annual ETp obtained using our approach was compared to that obtained by FAO-56 guidelines for forages (not steppe) based on tabulated Kc values in 41 locations in Mongolia. We found the differences are acceptable (RMSE of 0.40 mm d−1) in northern Mongolia under high vegetation cover but rather high (RMSE of 1.69 and 2.65 mm d−1) in central and southern Mongolia. The FAO aridity index (AI) is empirically related to the ETp/ET0 ratio. Approximately 80% and 54% reduction of ET0 was reported in the Gobi Desert and in the steppe locations, respectively. Our proposed Kc adj can be further improved by considering local weather data and plant phenological characteristics.

Sand, Water, and Stars: Chinese Mapping of the Gobi and Taklamakan Deserts

Abstract Many Chinese maps from the mid-sixteenth century onwards mark the Gobi Desert as a prominent strip visually separating China from what lies beyond. Even before that time, the Gobi, as well as the Taklamakan Desert appeared on maps. Influenced by statements from the early classic “Yugong,” Chinese scholars and Han literati during late imperial China’s history had perceived the deserts as some kind of boundary, while with the integration of these regions into Qing territory, the imperial Manchu view shifted away from the desert being a boundary. The terms for the desert as well as the graphical depiction on maps link the desert to water and to some extent also to celestial phenomena. This article explores the history and cultural significance of the desert from the Song to the mid-Qing period based on maps in relation with relevant texts and draws connections to the origins and changes of these depictions.

Mineralogical similarities and differences of dust storm particles at Beijing from deserts in the north and northwest

Dust storm particles have been one of the important contributors to global aerosol loading, affecting human health and climate system. Beijing, a megapolitan city, experienced two severe dust storms in spring of 2015, with maximum hourly-mean PM10 mass concentrations exceeding 1000 μg/m3. The first dust storm (Dust 1) was from east area of Gobi Desert about 850 km in the north of Beijing and the second (Dust 2) was from west area of Gobi Desert about 1500 km in the northwest of Beijing. Morphologies and elemental compositions of dust particles were identified using high-resolution electron microscopy. The statistical analysis showed that the number fractions of mineral dust particles during the two dust storm episodes were 85.3% and 95.4%, respectively. Clay minerals were the most abundant among mineral particles, with a number fraction larger than 50%, followed by quartz particles (17.3% and 14.8%) and feldspar. Feldspar and carbonate particles accounted for 14.8% and 3.4% of mineral particles in Dust 1, and 9.9% and 13.6% in Dust 2, with the difference due to the different source areas. When the dust storms directly migrated to Beijing, the occurrence of S-containing mineral particles and the relative weight ratio of S in individual mineral particles were extremely low, indicating limited production of sulfate on the dust-storm particles in the atmosphere, regardless of the differences of source areas, migration paths, and mineralogical components. After the peaks of dust storms passed, the occurrence of S on the mineral particles were much higher, although the relative weight ratios of S in the mineral particles was still very small. This result suggests that most of the mineral particles underwent heterogeneous reactions, but the reaction rates were low.

Retrievals of dust-related particle mass and ice-nucleating particle concentration profiles with ground-based polarization lidar and sun photometer over a megacity in central China

Abstract. The POLIPHON (polarization lidar photometer networking) method is a powerful pathway to retrieve the height profiles of dust-related particle mass and ice-nucleating particle (INP) concentrations. The conversion factors fitted from the sun photometer observation data are the major part of the POLIPHON computations, which can convert the polarization-lidar-derived dust extinction coefficients into dust-related particle mass and INP concentrations. For the central Chinese megacity of Wuhan (30.5∘ N, 114.4∘ E), located at the downstream area several thousands of kilometers far away from the source regions of Asian dust, dust particles always mix with other aerosols from local emissions. Therefore, very few dust case data sets can be available when using the column-integrated Ångström exponent (for 440–870 nm) <0.3 and aerosol optical depth (at 532 nm) >0.1 recorded by a sun photometer as the filtering criteria. Instead, we present another dust case data set screening scheme that applies the simultaneous polarization lidar observation to verify the occurrence of dust. Based on the 33 dust-intrusion days identified during 2011–2013, the extinction-to-volume (cv,d) and extinction-to-large particle (with radius >250 nm) number concentration (c250,d) conversion factors are determined to be (0.52±0.12)×10-12Mmm3m-3 and 0.19±0.05 Mm cm−3, respectively. The c250,d for Wuhan is 27 % larger than that observed at Lanzhou SACOL (36.0∘ N, 104.1∘ E), a site closer to the Gobi Desert, and tends to be closer to those observed in North Africa and the Middle East, indicating dust aerosols from these two sources are also possibly involved in the dust events observed over Wuhan. As a comparison, the conversion factor c290,c of 0.11±0.02Mmcm-3 for continental aerosol is much smaller than c250,d, indicating that there is no significant influence of urban aerosols on the retrievals of dust-related conversion factor over Wuhan. The conversion factors are applied in a dust event in Wuhan to reveal the typical dust-related immersion-mode INP concentration over East Asian cities. The proposed dust case data set screening scheme may potentially be extended to the other polluted city sites that are more influenced by mixed dust.

Metallographic Cooling Rate and Petrogenesis of the Recently Found Huoyanshan Iron Meteorite Shower

AbstractThe Huoyanshan iron meteorite shower, recently found in the Gobi Desert of Hami, Xinjiang, China, has very high Ni (21.1 wt%) content and low Au (2.0 ppm), Ir (0.02 ppm), Ge (1.7 ppm), and Ga (1.1 ppm) contents, and was classified into IAB‐sLH subgroup. The iron has a finest octahedrite structure of Widmanstätten pattern (the intergrowth of kamacite [α] and taenite [γ]) with plessite matrix, and euhedral schreibersite (Sch) crystals exclusively enclosed in kamacite bands. The textural features suggest the following formation process: γ→γ + Sch→γ + Sch + α, and then γ→α2 + γ. The metallographic cooling rate of Huoyanshan iron was determined to be 3–50°C/Myr using both the taenite Ni profile‐matching and taenite central Ni content methods, with the bandwidths corrected for crystallographic orientation by electron backscatter diffraction (EBSD). The cooling rate of Huoyanshan is consistent with other sLH irons and confirms the slow cooling history of the IAB low‐Au subgroups. These slow cooling rates require immediate re‐accretion with a thick brecciated fragments layer in the parent body after the impact melting event. The depleted but unfractionated Re, Os, Ir, Ru, and Pt and the enriched Pd and Au abundances of Huoyanshan iron and other sLH subgroup irons show complementary feature to that of refractory metal nuggets in Ca‐, Al‐rich inclusions (CAIs), which could be explained by extracting the metallic Fe‐Ni with HSE predominantly remained in CAIs from a CAI‐bearing asteroid. The very high Ni content of sLH subgroup and its Mo isotope evidence (Worsham et al., 2017, https://doi.org/10.1016/j.epsl.2017.02.044) suggest it has an oxidized parent body with non‐carbonaceous chondrite‐like precursor composition. We propose that the sLH subgroup was produced by impact melting of a LL like and CAI‐bearing asteroid, followed by fast burying of thick and porous silicate breccia.

Impact of massive topography on the dust cycle surrounding the Tibetan Plateau

The Tibetan Plateau (TP), the most massive topographic feature in the world, is located at the crossroads of the Asian dust cycle and plays an important role in dust transport via topography. However, the difference in the Tibetan Plateau's topographical effect on and mechanism of dust transport from the northern and southern TP are not clear. Here, through the Tibetan topography experiments by a model, we propose a mechanism for the differential impact of the TP on the dust cycle sourced from northern and southern deserts neighboring the TP. Dust emitted from the southwestern Taklimakan Desert (TD), which is located on the north side of the TP, is mainly transported by the strong upslope winds caused by Tibetan topography to the upper layers. Consequently, it results in less dust suspended in low layers but more dust suspended in upper layers. In addition, the “narrow pipe effect” caused by massive Tibetan topography in the Hexi Corridor induces stronger dust activity in the Gobi Desert. In addition, on the southern side of the TP, more intensive dust emissions in the Great Indian Desert (GID) are induced by Tibetan topography; simultaneously, whole layers are lifted to the upper troposphere through the “heat pump effect” of the TP where the Tibetan topography acts as a “ladder”. Essentially, the existence of Tibetan topography can change the near-surface wind speeds by adjusting the atmospheric circulations, which changes the dust emission location in the TD and strengthens dust emissions in GID and Gobi Desert. This study can provide clues for a better understanding of the impact of TP topography on the dust cycle.

Avian-power line interactions in the Gobi Desert of Mongolia: are mitigation actions effective?

BackgroundElectrocution and collisions on power lines are among the leading causes of non-natural mortality for birds. Power lines are exponentially increasing, particularly in developing countries, but mitigation strategies to prevent bird mortality are questionable. Mongolia combines a recently increased power line network, an abundant raptor population, a dangerous crossarm configuration and a habitat with no natural perches, producing many bird-power line interactions. Our aim is to assess the bird mortality caused by power lines in the Gobi Desert of Mongolia, to determine the factors increasing the risk of bird electrocution, and to evaluate the effectiveness of used retrofitting measures.MethodsIn July 2019 we covered 132.9 km of 15 kV power lines checking 1092 poles. We also conducted bird transects to record raptor and corvid richness and abundance, to assess species vulnerability to electrocution.ResultsWe recorded 76 electrocuted birds of 7 species. Electrocution rate was 6.96 birds/100 poles. The most affected species were Common Raven (Corvus corax) and Upland Buzzard (Buteo hemilasius), highlighting the electrocution of 5 endangered Saker Falcons (Falco cherrug). By contrast, we only recorded 8 individuals of 5 species colliding with wires, the most affected being Pallas’s Sandgrouse (Syrrhaptes paradoxus). About 76.1% of sampled poles had some mitigation measure. Of these, 96.6% were brush perch deflectors and 3.4% rotating-mirrors perch deterrents. We found differences in electrocution rates among crossarm configurations, with the strain insulator with one jumper being the most lethal. Additionally, we found no correlation between bird abundance and electrocution rates, suggesting that some species are more sensitive to electrocution. Although no differences in total bird electrocution rates were detected between poles with and without perch deterrents, when bird size is considered, deterrents reduced the mortality rate of small birds, while they were ineffective for medium-sized birds.ConclusionsDespite the widespread use of perch deterrents in the Mongolian power line network, there is still an alarming electrocution rate. This strategy is ineffective and some mechanisms, such as brush perch deflectors, may increase the electrocution rate for some medium-sized birds. Finally, we propose strategies to minimize the avian electrocution rate in the Gobi Desert.

A re-appraisal of Parvicursor remotus from the Late Cretaceous of Mongolia: implications for the phylogeny and taxonomy of alvarezsaurid theropod dinosaurs

Parvicursor remotus Karhu & Rautian, 1996, based on a fragmentary skeleton from the Campanian Barungoyot Formation at Khulsan, in the Gobi Desert of Mongolia, is re-described in detail. Contrary to the original description, we find no evidence that the last dorsal vertebra is opisthocoelous. A biconvex last dorsal vertebra could be present in Parvicursor as in other parvicursorines. The transversely compressed sacral centrum with a sharp ventral keel is the last sacral, not the first sacral as originally alleged. The pelvic bones are not fused at the acetabulum. The holotype of P. remotus, the smallest known alvarezsaurid specimen, is a juvenile individual far from skeletal maturity. New morphological details of Parvicursor that are revealed include a ventral ridge on the posterior dorsal vertebrae; a horizontal supraacetabular crest of the ilium whose anterior end is placed anterior to the most ventrally projecting part of the pubic peduncle; the possible presence of a pubic obturator foramen; an entocondylar tuber on the femur; internal flexor flanges on metatarsals II and IV; a lateral flexor ridge on metatarsal IV; and a proximoventral notch on pedal phalanx IV-1. The Tugriken Shireh alvarezsaurid is not referable to Parvicursor because of its much larger ungual phalanx on the second pedal digit. Kol ghuva is excluded from Alzarezsauridae. The two successive sister taxa for Parvicursor are Ceratonykus and Linhenykus. Ceratonykus differs little from Parvicursor and might be a synonym of the latter. Linhenykus is very similar to Parvicursor in all overlapping skeletal elements. The Parvicursorinae includes all Asian Late Cretaceous alvarezsaurids except Qiupanykus and Nemegtonykus.

Genesis and fluid evolution of the Huangtan Au-Cu deposit in the Kalatag district, Eastern Tianshan, NW China: Constraints from geology, geochronology, fluid inclusions, and H-O-S-Pb isotope geochemistry

The newly discovered Huangtan Au-Cu deposit is located in the central Dananhu - Tousuquan arc of Eastern Tianshan, southern Central Asian Orogenic Belt (CAOB). It is the first Au-dominated volcanogenic massive sulfide (VMS) polymetallic deposit in the Eastern Tianshan. Veinlet-disseminated and massive orebodies are hosted within Early Silurian pyritic phyllic tuff and volcanic breccia and controlled by a secondary fracture zone of the Kalatag fault with extensive hydrothermal alteration. Four primary alteration/mineralization stages have been recognized as follows: (1) Early ore stage (S1), forming mainly ore-barren fine quartz veins with minor gold-bearing sulfides; (2) main ore stage (S2), forming mainly thick quartz veins with abundant coarse-grained subhedral pyrite (S2-1), and plentiful chalcopyrite, sphalerite, barite and Au-bearing sulfide veins (S2-2); (3) late ore stage (S3), which is characterized by plenty of barren quartz–calcite veins with few sulfides; and (4) supergene stage (S4), accompanied by abundant oxide mineralization, including malachite, jarosite and other supergene minerals. From S1 to S3, microthermometric data of fluid inclusions show homogenization temperatures of 263–379 °C (mean = 308 °C), 188-292 °C (mean = 240 °C), and 118-198 °C (mean = 158 °C), respectively, and salinities of 5.3–14.2 (mean = 10.8) wt.% NaCl equiv., 2.8–10.7 (mean = 7.6) wt.% NaCl equiv., and 0.3–14.1 (mean = 2.6) wt.% NaCl equiv., respectively. The ore-forming fluids are characterized by middle-low temperature, low salinity, relatively reduced condition, and an H2O-NaCl ± CO2 ± CH4 system.The δ34S values (−5.25‰ to 0.50‰) and Pb isotopic ratios (206Pb/204Pb = 17.868–19.495, 207Pb/204Pb = 15.446–15.575, and 208Pb/204Pb = 37.350–38.491) suggest that the ore-forming materials came predominantly from a deep-seated magma source with a minor contribution of lower continental crust. The δ18OH2O and δDV-SMOW values of fluid inclusions in each metallogenic stage range from −6.1 to 5.6‰ and −66.8 to −53.9‰, respectively, suggesting the dominant role of magmatic water mixed with convectively circulating heated seawater during fluid evolution. Fluid cooling dilution, local boiling, and fluid mixing were considered as the main mechanisms of metal precipitation. The 40Ar-39Ar plateau age of hydrothermal muscovite from the late ore stage (S3) is 414.4 ± 0.4 Ma, which represents the upper limit age of shallow hydrothermal alteration and Au-Cu mineralization. It is also consistent with the Early Silurian polymetallic metallogenic event in the Kalatag district. The auriferous Huangtan and adjacent Cu-Zn-rich Huangtupo VMS deposits show obvious ore-forming element differences, and constitute a unique VMS metallogenic system in the Eastern Tianshan Orogenic Belt (ETOB), which provides an important research object and new insight for ore prospecting in the peripheral Gobi Desert area.

Long‐term monitoring using DNA sampling reveals the dire demographic status of the critically endangered Gobi bear

AbstractInformation about population demography is crucial for developing and implementing conservation measures. The brown bear in the Gobi desert of southwestern Mongolia (referred to as the Gobi bear) is one of the smallest and most isolated brown bear populations in the world. We conducted genetic sampling (n = 2660 samples collected) using hair corrals around feeding sites at 13 water sources during 2009, 2013, and 2017 to evaluate population size, survival, and population trend. Bears were identified using 13 microsatellite loci and one sex marker. We detected 51 unique individuals (15F and 36M) from our targeted surveys in 2009, 2013, and 2017. Based on capture–mark–recapture robust design, population estimates were 23 (95% CI: 21–32) in 2009, 28 (95% CI: 25–35) in 2013, and 31 (95% CI: 29‐38) individuals in 2017. Spatial capture–recapture analysis suggested abundance was very low ( = 27; 95% CI: 22–35), and there was no significant change from 2009 to 2017. The population density was 0.93 bears/1000 km2 (95% CI: 0.74–1.17). Our population estimates suggested a stable population trend. However, the population is still very small, and the sex ratio is skewed toward males, raising concerns for future persistence. Annual survival based on Robust design CMR was 0.85. Low abundance and apparent survival for both sexes in this unhunted population coupled with a skewed sex ratio highlight the need for on‐the‐ground conservation action to conserve this isolated population of bears.

Formation and evolution of mountainous aeolian sediments in the northern Tibet Plateau and their links to the Asian winter monsoon and westerlies since the Last Glacial Maximum

The production, transport, and deposition of dust has profound impacts and feedbacks on the regional and global environments. In parallel, the Tibet Plateau (TP) plays an important role in East Asian and global climate systems. Previous studies have shown that the dust can reach the plateau by long-distance transport from the westerlies and by short-distance transport from regional weathering. Here we present three new datasets in the Qilian Mountains of the northern TP, including two mountainous aeolian sedimentary sequences and a surface sample dataset. Proxies include grain size, magnetic susceptibility, mineral composition, total organic carbon, and total nitrogen. Data from surface samples indicate spatial gradient effects in altitude (from low to high) and latitude (from north to south), suggesting dust transport from the Gobi Desert to the plateau. The synthetic analysis of two aeolian sedimentary sequences and paleoclimate simulation data reveals that the northern TP can be a dust transport channel controlled mainly by the Asian winter monsoon and less influenced by the westerlies.

A partial oviraptorosaur skeleton suggests low caenagnathid diversity in the Late Cretaceous Nemegt Formation of Mongolia.

The Nemegt Formation of the Gobi Desert of Mongolia has produced one of the most abundant and diverse oviraptorosaur records globally. However, the caenagnathid component of this fauna remains poorly known. Two caenagnathid taxa are currently recognized from the Nemegt Formation: Elmisaurus rarus and Nomingia gobiensis. Because these taxa are known from mostly non-overlapping material, there are concerns that they could represent the same animal. A partial, weathered caenagnathid skeleton discovered adjacent to the holotype quarry of Nomingia gobiensis is referable to Elmisaurus rarus, revealing more of the morphology of the cranium, mandible, pectoral girdle, and pubis. Despite metatarsals clearly exhibiting autapomorphies of Elmisaurus rarus, overlapping elements are identical to those of Nomingia gobiensis, and add to a growing body of evidence that these taxa represent a single morphotype. In the absence of any positive evidence for two caenagnathid taxa in the Nemegt Formation, Nomingia gobiensis is best regarded as a junior synonym of Elmisaurus rarus. Low caenagnathid diversity in the Nemegt Formation may reflect broader coexistence patterns with other oviraptorosaur families, particularly oviraptorids. In contrast to North America, competition with the exceptionally diverse oviraptorids may have restricted caenagnathids to marginal roles in Late Cretaceous Asian ecosystems.

Estimation of dry vegetation cover and mass from MODIS data: Verification by roughness length and sand saltation threshold

Monitoring of dry vegetation in arid and semi-arid regions is crucial in environmental investigations such as assessments of wind erosion risk, livestock forage, and fire risk. However, there has been little research into estimating the coverage and mass of dry (non-photosynthetic) vegetation. In our study area at Tsogt-Ovoo (TsO) in the northern Gobi Desert, Mongolia, we used MODIS data to compare observed dry vegetation cover (VCd_obs) and mass (Md_obs) with values estimated from the Normalized Difference Vegetation Index (NDVI) and six other potential Short Wavelength InfraRed (SWIR) dry vegetation indices. Of the seven vegetation indices, the Soil Tillage Index (STI) and Normalized Difference Tillage Index (NDTI), both of which are calculated from SWIR bands 6 and 7, provided good estimates of VCd_obs and Md_obs. Our comparisons of observed roughness length (z0) and threshold friction velocity (u*t) for sand saltation at stony and non-stony sites with dry vegetation cover determined from STI verified its suitability for estimating VCd(STI). At both sites, the observed z0and u*tincreased with increasing estimated VCd(STI). Based on their relationships with STI, we predicted values of z0and u*tin the absence of dry vegetation that were in accordance with published data. The threshold wind speeds at 10 m height derived from u*tat both the stony and non-stony sites were reasonably close to the value that is commonly used in dust models. Thus, we verified that STI is a suitable index for estimating the amount of dry vegetation in the Gobi Desert and, potentially, in other arid and semi-arid regions. Although the relationships of z0and u*twith STI require further validation, it appears that the use of STI can improve future wind erosion risk assessments in arid and semi-arid environments.

The complete mitogenome of Sokolov’s Dwarf Hamster (Cricetulus sokolovi) and implication of phylogenetic status

There is still an obvious lack of information on Sokolov's Dwarf Hamster (Cricetulus sokolovi) which belongs to subfamily Cricetinae because the species is only rarely found in Gobi desert. In this study, we obtained the complete mitochondrial genome sequences of C. sokolovi. The genome is 16,292bp in length and has a base composition of 33.5% A, 30.5% T, 22.9% C, and 13.1% G. The mitogenome structure, consisting of 13 protein-coding genes, two rRNA genes (12S rRNA and 16S rRNA), 22 tRNA genes, and one control region, is similar to that of typical vertebrate mitochondrial genomes of other rodents. We restructured a Bayesian phylogenetic tree by using 12 species belonging to subfamily Cricetinae. As indicated by the phylogenetic tree, genus Cricetulus is polyphyletic group, and C. Sokolovi is the closest relative of Cricetulus griseus. The mitochondrial genome can provide basic data for further study on the phylogenetic relationship of subfamily Cricetinae.