Tacheng Basin Research Articles

Spatio-temporal variation of species richness and phylogenetic diversity patterns for spring ephemeral plants in northern China

Understanding the spatiotemporal distribution of species diversity in response to climatic change is essential for the conservation and management of species resources. Spring ephemeral plants (SEs) have played a crucial role in sustaining the desert and woodland ecosystems of northern China. However, our knowledge regarding the spatiotemporal variation of species diversity in SEs is limited. In this study, we employed occurrence and phylogenetic data for 200 SEs, alongside 19 environmental variables, to model their geographical distribution during the Last Glacial Maximum (LGM), Current, and the year 2070 (considering two representative concentration pathway scenarios, SSP2–4.5 and SSP5–8.5). We also visualized the phylogenetic diversity patterns in the Current. Our findings revealed that more than half of the SEs notably expanded their range and continuously shifted northeastward from LGM to 2070. From LGM to Current and from Current to SSP2–4.5_2070, 64% and 54% of SEs shifted from higher to lower elevations, and 53% of them will slightly shift to higher elevations from Current to SSP5–8.5_2070. We identified three distinct bioregions corresponding to the core ranges of desert SEs and understory SE ecotypes. The Ili Valley, Tacheng Basin, northern and southern Junggar Basin, and Changbai Mountains were identified as hotspots for species richness, phylogenetic diversity, and endemism for the two SE ecotypes. Notably, these hotspots had limited overlap with existing nature reserves. Additionally, the suitable habitat of desert SEs was primarily determined by precipitation seasonality and precipitation of driest month, whereas the distribution of forest understory SEs was mainly influenced by annual precipitation and temperature seasonality. This study significantly contributes to a comprehensive understanding of the modern diversity distribution patterns and conservation priorities for SEs within a species distribution and phylogenetic framework.

A Fossil Paleozoic Subduction-Dominated Trench-Arc-Basin System Revealed by Airborne Magnetic-Gravity Imaging in West Junggar, NW China

A Carboniferous trench-arc-basin system related to oceanic slab subduction has been thoroughly imaged by various geophysical probing approaches and proposed for the formation of West Junggar, Northwest China, located in the southwest of the Central Asian Orogenic Belt. However, debate on the origin of West Junggar still continues. Here, we present an integrated aeronautic magnetic–gravity observation to further identify the trench-arc-basin system and constrain the subduction mode. By deploying an integrated aerial magnetic–gravity survey consisting of 66,000 survey-line kilometers from August 3, 2015 to April 22, 2016, we determine the magnetic and gravitational anomaly across the study region by using geophysical potential-field processing. Our results reveal curial crust-scale variations in magnetic and gravitational structures beneath West Junggar and that a prominent Bouguer gravity high is located between the Darbut and Karamay–Urho faults, likely corresponding to a trapped oceanic slab. Notably, the Tacheng Basin is characterized by high-frequency magnetic signal and gravity highs, as well as the Carboniferous rifting–related sedimentary cover, which could be reasonably interpreted to be a back-arc basin. Integrated with these comprehensive geological and geophysical observations across West Junggar, the previous model of West Junggar trench-arc-basin system related to a fossil intra-oceanic subduction during the Late Paleozoic is further renewed.

Habitat suitability assessment for the Great Bustard Otis tarda tarda in Tacheng Basin, western China

The Great Bustard is afforded the highest category of protection in China. This species has disappeared from much of its former range, and identification of factors influencing habitat suitability can play a key role in development of conservation plans. We used distance sampling and interviews to census Great Bustards in the Tacheng Basin of western China in October from 2014 to 2016, and obtained 210 occurrence points. We then used high-resolution species distribution models to explore the role of 16 environmental variables, including a novel high-resolution contemporary climate dataset, in habitat suitability. Our ensemble model classifies approximately 3,885 km 2 , or 9.9% of our study area in the most suitable and moderately suitable categories. These suitable areas are distributed primarily in the north of our study area, in farmlands along the southern slope of Talbahetai Mountain, and to a lesser degree along the eastern slope of Balluk Mountain. The variables which contributed most significantly to habitat suitability include distance to county highway, elevation, distance to field edge, and mean summer temperature. We propose reducing disturbance associated with roads by conducting awareness campaigns among local residents and creating campaigns and policies to promote responsible bird photography. Given the important role of farmlands to Great Bustards, we recommend planting compatible crops and establishing a Great Bustard protection demonstration area to implement and inform others about measures to improve farmland habitat for Great Bustards.

Distribution characteristics and enrichment mechanism of fluoride in the shallow aquifer of the Tacheng Basin

Distribution characteristics and enrichment mechanism of fluoride in the shallow aquifer of the Tacheng Basin

East Tacheng (Qoqek) Fault Zone: Late Quaternary Tectonics and Slip Rate of a Left‐Lateral Strike‐Slip Fault Zone North of the Tian Shan

AbstractAlthough the Tacheng Basin may play an important role in accommodating crustal shortening north of the Tian Shan and west of the Junggar Basin based on observations of several conspicuous surface ruptures in satellite imagery, little is known about its late Quaternary tectonic activity. We analyze the tectonic geomorphology of the East Tacheng fault zone, including the subparallel NE‐SW trending East Tacheng and Wuerkashier faults, using field observations, interpretations of satellite imagery, and construction of decimeter‐scale digital elevation models from unmanned aerial vehicle surveys. Geomorphological features such as displaced stream channels and terrace risers, negligible vertical offset, opposite facing directions of a single fault scarp, and linear fault traces suggest that the East Tacheng fault is a nearly pure left‐lateral subvertical strike‐slip fault. The late Quaternary horizontal slip rate is estimated to be 0.4–2.0 mm/year, likely ∼0.7 mm/year. Paleoearthquake studies in trenches reveal that the most recent earthquake occurred between 3.1 and 0.5 ka. The Wuerkashier fault, which shows pristine surface ruptures along a total length of ∼67 km, is also a nearly pure left‐lateral strike‐slip fault. The most recent earthquake along this fault is dated to be 7.9–0.5 ka. Combining GPS velocity and active fault kinematics in the northern Tian Shan and western Junggar, we suggest that the western Junggar is controlled by regional N‐S crustal shortening related to the India‐Eurasia collision, and the reactivated Paleozoic fault zones in the western Junggar play a key role in transferring deformation northeastward into the Altai and Mongolia.

Late Quaternary activity characteristics of the strike-slip Dongbielieke Fault in West Junggar, China

The Dongbielieke Fault, an active fault that originated during the Holocene, is located at a key position in the West Junggar orogenic belt. The total length of NE-striking the fault is 120 km. Since the Late Quaternary, continuous activity on the Dongbielieke Fault has caused clear left-lateral dislocations at all morphological units along it, and a continuous linear steep ridge has formed on the eastern side of the Tacheng Basin. Using high-resolution UAV images and differential GPS to depict and measure the strike-slip dislocations at each river terrace level, it was found that the maximum left-lateral dislocations in the T5, T4, and T2 terraces are 30.7 m, 12.0 m, and 8.7 m, respectively. In addition, based on the geomorphic ages from optically stimulated luminescence analyses, we have limited the sliding rate of different terraces on the Dongbielieke Fault. The average left-lateral strike-slip rate since the late Quaternary of the Dongbielieke Fault is 0.91 ± 0.18 mm/a. Combining the GPS rates for North Tianshan with those for the Tacheng Basin, it is believed that the three large NE-trending strike-slip faults (Daerbute, Tuoli, and Dongbielieke faults) absorb a large amount of residual deformation in the area. This would allow the faults to maintain a higher left-lateral slip rate. In summary, analysis of surface faulting, Quaternary geology, seismicity, and measurements of Holocene morphology suggests that the Dongbielieke Fault is an active strike-slip fault with high seismic risk. However, it is unlikely that this fault could generate an earthquake of magnitude greater than 7.5. Our data do not allow for discussion of a more complex seismic cycle.

Spatial Utilization Coordination Features and Development Potential on Ecology-Agriculture-Urban Space of Key Ecological Function Areas: A Case Study of Tacheng Basin, China

Spatial Utilization Coordination Features and Development Potential on Ecology-Agriculture-Urban Space of Key Ecological Function Areas: A Case Study of Tacheng Basin, China

Chemical Evolution of Groundwater in the Tacheng Basin of Xinjiang in the Process of Urbanization

With the development of the local economy, the volume of groundwater production has increased continuously in the past decades in the Tacheng Basin of the Xinjiang Uygur Automous Region. Previous studies have not provided a clear pattern of the chemical composition evolution of groundwater and its driving force in this basin, which makes the future development and utilization of groundwater riskier. This study carried out systematic sampling and analysis of groundwater chemistry in this basin, and the chemical evolution of groundwater in the basin was analyzed by comparison with historical hydrochemical data. The results show that Ca2+ and Na+ are the main cations in the groundwater, HCO3-, SO42- are the main anions in the groundwater, and freshwater is widely distributed. The chemical types of groundwater changed from HCO3-Ca and HCO3·SO4-Ca·Mg in the source zone in front of the mountains to SO4·HCO3-Na·Ca type in the plain area. In comparison with the hydrochemical data of 1979, HCO3 and SO4·HCO3 type groundwater increased significantly. SO4 and Cl type groundwater with high total dissolved solids decreased significantly. However, the Cl- and SO42- concentration and total hardness in the groundwater around the cities and towns increased. Aquifer material and the change of flowing field are the two controlling factors of groundwater chemical change, but the leakage of waste water from city drainage channels also affects the groundwater chemistry drastically.

2018年冬季塔城盆地两次致灾暴风雪天气对比分析

2018年冬季塔城盆地两次致灾暴风雪天气对比分析

Three Types of Spatial Function Zoning in Key Ecological Function Areas Based on Ecological and Economic Coordinated Development: A Case Study of Tacheng Basin, China

Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development. For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that: 1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space, which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones, ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.

Pronounced changes in paleo-wind direction and dust sources during MIS3b recorded in the Tacheng loess, northwest China

Central Asia loess deposits can yield detailed records of aridification across the Asian interior, as well as the atmospheric circulation. In this study, we presented grain size, heavy mineral assemblage, rock magnetism and anisotropy of magnetic susceptibility of a loess section in the Tacheng Basin in Xinjiang region, NW China. The results of anisotropy of magnetic susceptibility indicated that a near-surface SE wind prevailed in the Tacheng area since Marine Isotope Stage (MIS) 3, while a near-surface SW prevailing wind developed during MIS3b. We inferred that the change of wind direction was due to glacial advance during MIS3b. Combining the result of anisotropy of magnetic susceptibility with grain size, heavy mineral assemblage data and previously published low-field mass susceptibility revealed that dust transported by the near-surface SW wind had a greater ability to enhance magnetic susceptibility and higher amphibole/epidote ratio. Additionally, a strong Siberian High during Heinrich Event (H)5 at ca. 48 ka blocked the advection of moisture into the region via mid-latitude westerlies, causing glacial recession and the weakening of the prevailing SW wind. Our study has implications for identifying changes in paleo-wind direction and dust source, which can aid understanding of the influence of westerlies and the Siberian High on dust accumulation, as well as their interactions.

Orbital and millennial northern mid-latitude westerlies over the last glacial period

The northern mid-latitude westerlies play an important role in the climate interactions between the low and high latitudes. Our understanding of the factors that control the latitudinal displacement of the westerlies remains incomplete due to insufficient climatic proxy. Here we present a latitudinal-shift record of the westerlies in the eastern Central Asia over the past 70,000 years, on the basis of the grain size of the loess sequence from the Tacheng basin. On millennial timescale, the variation of the reconstructed westerlies resembles that of the Greenland temperature and the Atlantic meridional overturning circulation (AMOC), indicating the role of the AMOC on the westerlies. On orbital time scale, their variation is controlled by precession and insolation. Our analyses of the LOVECLIM and CCSM3 models’ results show that the impact of insolation and AMOC on the latitudinal shift of the westerlies is through changing the latitudinal temperature and pressure gradients.

On the Orographically Generated Low-Level Easterly Jet and Severe Downslope Storms of March 2006 over the Tacheng Basin of Northwest China

A high-latitude low-level easterly jet (LLEJ) and downslope winds, causing severe dust storms over the Tacheng basin of northwestern China in March 2006 when the dust source regions were previously covered by snow with frozen soil, are studied in order to understand the associated meteorological conditions and the impact of complex topography on the generation of the LLEJ. Observational analyses show the development of a large-scale, geostrophically balanced, easterly flow associated with a northeastern high pressure and a southeastern low pressure system, accompanied by a westward-moving cold front with an intense inversion layer near the altitudes of mountain ridges. A high-resolution model simulation shows the generation of an LLEJ of near-typhoon strength, which peaked at about 500 m above the ground, as well as downslope windstorms with marked wave breakings and subsidence warming in the leeside surface layer, as the large-scale cold easterly flow moves through a constricting saddle pass and across a higher mountain ridge followed by a lower parallel ridge, respectively. The two different airstreams are merged to form an intense LLEJ of cold air, driven mostly by zonal pressure gradient force, and then the LLEJ moves along a zonally oriented mountain range to the north. Results indicate the importance of the lower ridge in enhancing the downslope winds associated with the higher ridge and the importance of the saddle pass in generating the LLEJ. We conclude that the intense downslope winds account for melting snow, warming and drying soils, and raising dust into the air that is then transported by the LLEJ, generated mostly through the saddle pass, into the far west of the basin.

Paleomagnetic study of Late Paleozoic rocks in the Tacheng Basin of West Junggar (NW China): Implications for the tectonic evolution of the western Altaids

To better understand the tectonic evolution of West Junggar in the western Altaids, we have conducted a combined paleomagnetic and geochronological study on Late Devonian (D3), Late Carboniferous (C2) and Early Permian (P1) successions from the Tacheng Basin, northwest of China. Both primary and secondary characteristic remanent magnetization components have been successfully isolated and yield three reliable paleomagnetic poles of C2 and Late Permian (P2) ages. The C2 and P2 poles reveal a significant clockwise rotation of 35.6°±10.4° which is comparable to the rotation deduced in the western part of the Chingiz Range during the time interval C2 to P2. Similar rotation patterns for the two units suggest that the Chingiz–West Junggar has remained as a quasi-rigid block by the P2 time and constituted the northeast limb of the Kazakhstan Orocline. The differential rotation of ca. 25° to 30° deduced between the northeast and middle limbs of the Kazakhstan Orocline further suggests that at least a part of the curvature of the Balkhash Arc was acquired during the C2 to P2 interval and was a continuation of the middle Paleozoic oroclinal bending. Moreover, the C2 poles for West Junggar and the Junggar Block are significantly different while the P2 ones almost overlap supporting the view that final closure of the Balkhash–Junggar Ocean occurred during the C2 to P2 interval. On the other hand, a large-scale counterclockwise rotation of ca. 80° to 90° is observed in West Junggar and Junggar relative to the western part of the Chingiz Range since the P2 time, and this rotation probably represents an important intra-continental deformation within the western part of the Altaids. A reconstruction of the Paleo-Asian Ocean has been proposed in which the Kazakhstan Orocline was emphasized by using the paleomagnetic results and geological evidence.

How was the Carboniferous Balkhash–West Junggar remnant ocean filled and closed? Insights from the Well Tacan-1 strata in the Tacheng Basin, NW China

The Balkhash–West Junggar remnant ocean is a conspicuous tectonic feature that had an important effect on the Paleozoic tectonic evolution of the Central Asian Orogenic Belt. How the Carboniferous Balkhash–West Junggar remnant ocean was filled and closed is poorly understood. In this study, we focus on the integrated tectonic–sedimentary evolution of the Tacheng Basin, which is located in the eastern part of the Balkhash–West Junggar remnant ocean, using high-resolution seismic reflection, well-line, geochronological and geochemical data to establish the filling of the basin by sediments and its evolution. The Carboniferous Balkhash–West Junggar remnant ocean basin was filled with Early Carboniferous deep marine mudstone and interbedded sandstone with minor andesite, basalt and tuff, and Late Carboniferous basalt, andesite, breccia and tuff and shallow marine mudstone and sandstone. The Carboniferous igneous assemblage mainly consists of basalt with high Nb content and (Nb/La)PM values and concomitant magnesian andesites with adakite geochemical characteristics of high Sr and low Y and Yb, suggesting a subduction-related tectonic setting. Zircons in the tuff that underlies the basalts and magnesian andesites were dated to ca. 315Ma by LA–ICP–MS U–Pb. The identified unconformity between the Carboniferous and Lower Permian from seismic reflection profile in Well Tacan-1 subdivided the Carboniferous–Early Permian strata into two tectonostratigraphic units. The Lower Permian sequences overlap the Carboniferous strata and the facies transition from the submarine Carboniferous to the terrigenous Lower Permian indicates that the Balkhash–West Junggar remnant ocean closed during the Early Permian. These new data suggest that the sedimentary filling of the basin was in response to subduction and accretionary processes and that oceanic subduction was an important mechanism that led to the shrinking, filling and closure of the Balkhash–West Junggar remnant ocean because of compression. Therefore, lateral crust growth through subduction–accretionary processes still played an important role in the Carboniferous construction of western Junggar.

Spatial distribution of the extreme hydrological events in Xinjiang, north-west of China

We examined spatial distribution characteristics of extreme hydrological events in Xinjiang, China, using district data from 1901 to 2010. Frequency distribution showed a general symmetry along the Tianshan Mountains, with even distribution in Junggar Basin and Tarim Basin. Frequency was more in the north-west than in the south-east. The maximum incidence was in west Tianshan Mountains and generally decreased south-eastward. There were significant regional variations in type distribution. Rainstorm floods were more common in central Xinjiang. Hailstorms mainly occurred in the central Junggar Basin, the southern slope of the western Tianshan Mountains and north-west of Tarim Basin. Debris flow was mainly distributed in Ili Valley and the central northern Tianshan Mountains. Glacier lake outburst floods were more common in the Karakorum Mountains and southern slopes of the western Tianshan Mountains. Ice floods were mainly distributed in the western Tianshan Mountains. Snow hazards were mainly distributed in the wide northern areas, especially the Altai Mountains and Hamilton Basin. Snowmelt floods were mainly distributed in the Tacheng Basin and Ili Valley. The incidence of extreme hydrological events was greatly affected by weather systems and terrain features.

Structural characteristics of the basement and the prospective of favorable oil and gas blocks in the Tacheng basin

The Tacheng basin has been identified as a Carboniferous basement with a central uplift, surrounded by orogenic belts. This identification was based on the comprehensive analysis of field outcrops, regional magnetic and gravimetric data, skeleton seismic profiles, magnetotelluric profiles and drilling data. Here, we present gravimetric and magnetic data analyses of the basement structures of the Tacheng basin and its base formation. We also provide a magnetotelluric profile analysis of the structural features and tectonic framework of basin-mountain patterns. We use local geology, drilling data, and other comprehensive information to document the tectonic framework of the basement of the basin. Small-scale nappe structures are found in the northern basin, whereas stronger and more pronounced thrusting structures are found to the south and east of the basin. The basin is divided into four first-order tectonic units: a central uplift, a northern depression, a southeastern depression and a western depression. In addition, the Emin sag is suggested as a possible reservoir for oil and gas.

Invasion of Colorado potato beetle, Leptinotarsa decemlineata, in China: dispersal, occurrence, and economic impact

AbstractColorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), is a global destructive pest of potato, Solanum tuberosum L. (Solanaceae). It is also an important quarantine pest in China, but its dispersal history, occurrence, and economic impact in China have not yet been reported. We determined the current distribution of CPB and reconstructed its dispersal routes. We also investigated the density of CPB in China in 2006, 2007, 2009, and 2010, and estimated the economic impact of CPB in China. In 1993, CPB was first detected in Xinjiang and subsequently spread eastward. The CPB entered China at three distinct points in Xinjiang: in Huocheng County, Tacheng City, and Habahe County. As of 2010, CPB had invaded 38 counties and cities in China, with a distribution area of 277 000 km2, between 42°40′–48°28′N and 80°15′–90°41′E. The distribution area could be divided into four zones (from south to north): Ili River Valley, northern slope of the Tianshan Mountains, Tacheng Basin, and Altay. The average annual dispersal rates in the four zones were 18, 45, 12, and 24 km year−1, respectively. In China, CPB seriously damages potato, impacts eggplant, Solanum melongena L., and occasionally harms tomato, Solanum lycopersicum L. The current annual economic loss caused by CPB in China is estimated to be 3.2 million USD. The potential annual economic losses after completion of its invasion in China is estimated to be 235 million USD. Future invasion pathways, factors affecting CPB dispersal, and control measures were discussed.