Dunhuang Basin Research Articles

The Distribution and Evolution of Groundwater Level Depths and Groundwater Sustainability in the Hexi Corridor over the Last Five Years

Groundwater overexploitation for agricultural irrigation is prone to lead to numerous ecological concerns. This study delved into the present distribution and recent trend of groundwater levels in the plain areas of the Hexi Corridor in Northwest China according to the groundwater level depth (GWD) data from 264 monitoring wells in the Shiyang River Basin (SYB) and 107 in the Shule River Basin (SLB), recorded annually in April from 2019 to 2023. The key findings include the following: (1) Over the five-year span, the SYB’s GWD experienced change rates (CRs) ranging from −12.17 to 9.11 m/a (average: −0.13 m/a), with the number of monitoring wells showing increased and decreased GWDs accounting for 50% and 50%, respectively. By contrast, the SLB’s GWD exhibited CRs ranging from −1.87 to 2.06 m/a (average: 0.01 m/a), with the number of monitoring wells showing increased and decreased GWDs accounting for 52% and 48%, respectively; (2) the Wuwei (CR = 0.09 m/a) and Changning (0.58 m/a) basins in the SYB and the Yumen (0.06 m/a), Guazhou (0.05 m/a), and Huahai (0.03 m/a) basins in the SLB, witnessed rising groundwater levels. In contrast, the Minqin Basin (0.09 m/a) in the SYB and the southern Dunhuang Basin (0.04 m/a) in the SLB witnessed declines in the groundwater levels; (3) The groundwater sustainability assessment showed that the groundwater is still extremely unsustainable. This study’s insights are instrumental in targeted treatment, as well as the preparation and adjustment of sustainable groundwater protection strategies.

Jurassic sedimentary migration characteristics and their geodynamic implications in the Dunhuang Basin and adjacent regions, Northwestern China

The Dunhuang Basin, situated in western China along the Altyn Tagh Fault (ATF) zone, intersects the Tethys and Paleo‐Asian Ocean tectonic domains. Influenced by both the ATF system and the far‐field effects of the Qiangtang‐Lhasa‐Eurasia collision during the Mesozoic, the mechanism of the Jurassic sedimentary migration of the basin in response to tectonic movements is unclear so far. The paper uses a comprehensive approach, including field geological surveys, lithologic and lithofacies discern, stratigraphic relationships analysis and 2D seismic profile interpretation, to examine the distribution of Jurassic residual strata in the basin. The comprehensive results of our study suggest that the Dunhuang Basin exists as an isolated block with unique tectonic and sedimentary evolution characteristics. In the Early Jurassic, the Dunhuang Basin underwent initial rifting, leading to the formation of small segmented intermontane sags. This phase was marked by the coarse particle sedimentary system of alluvial fans and braided rivers, represented the near source rapid deposition in the initial formation period of the basin. Stratigraphic distribution was primarily influenced by pre‐Jurassic basement topography and was not significantly constrained by faulting during this period. The formation of these isolated discontinuous small intermontane sags indicates the segmented activities of the ATF in the Early Jurassic period. In the Middle Jurassic period, influenced by the ATF dextral strike‐slip faulting, sedimentation extended eastward and the depocenter migrated clockwise compared with the distribution of the Middle Jurassic strata within the Dunhuang Basin. This period witnessed the development of coal measure strata at the basin's margins and lacustrine fine‐grained clastic deposition in the centre. The segmented fracture of the ATF gradually initiated a unified dextral strike‐slip tectonic movement. In the Late Jurassic period, sedimentary strata were locally present in the Wanyao Sag but absent in other sags. The depocenter migrated counterclockwise compared with the distribution of Middle Jurassic strata within the Dunhuang Basin, due to regional uplift accompanied by the ATF sinistral strike‐slip faulting caused by the collision between the Lhasa Block and the Eurasia Plate. The depocenter migration of the Dunhuang Basin constrained within the ATF system from the Early to Middle and Late Jurassic can be attributed to the transition of the ATF strike‐slip faulting in context of the stress relaxation and compression between the collision of the Qiangtang and Lhasa blocks to the Eurasia Plate, respectively.

Quaternary evolution of the Dunhuang paleolake and its controlling factors in the northeastern Tibetan Plateau

Complex interactions between neotectonics, surface uplift, and climatic oscillations have been affecting the landscape and environmental evolution of the northeastern Tibetan Plateau since the late Cenozoic. The Dunhuang Basin, located at the northeastern frontier of the plateau, has undergone intensive deformation and desertification during the Quaternary, recording the coupling between the plateau's northward growth and associated environmental changes. Here we conduct an integrative study on the Quaternary fine-grained lacustrine deposits of the Dunhuang Basin including sedimentary observations, chronological determination, and climatic and provenance analyses. Our results reveal the existence of basin-scale paleolakes with two phases in the Dunhuang Basin during the Quaternary: (1) the paleo-South Lake, with sedimentary ages ranging from ∼1.16 to 0.41 Ma, is mainly exposed to the south of the Sanwei Shan and north of the Altyn Tagh Fault (ATF), and may have a further northward extension across the Sanwei Shan to the Bei Shan; (2) the paleo-West Lake developed later, with sedimentary ages of ∼18–9 ka, is situated to the north of the Sanwei Shan and south of the Bei Shan, and likely continued westwards to Lop Nur. Combining our new data with previous studies, we propose a model of propagating foreland basins to reveal the Quaternary evolution of the Dunhuang paleolake in the context of plateau growth. In this model, the Quaternary transpression of the ATF formed a foreland basin, which controlled the formation of the paleo-South Lake since ∼1.16 Ma. Subsequently, the plateau propagated from the ATF to the Sanwei Shan Fault (SWSF). The northward-thrusting SWSF caused the uplift of its southern wall, which forced the paleo-South Lake to migrate northwards, resulting in its drying up and the formation of the paleo-West Lake since ∼0.41 Ma. Finally, the combination of tectonic uplift and climate caused the drying up of the paleo-West Lake and the formation of the present-day desert landscape after ∼9 ka.

Late Quaternary hydroclimatic variations in the hyper-arid Dunhuang Basin, northwestern China

The changes in paleoclimate and their driving mechanisms in northwestern (NW) China since the Late Quaternary remain unclear and controversial. This is due to the scarcity of relatively continuous sedimentary records with high-resolution chronological controls in this hyper-arid region. To address this gap, a new sedimentary record was drilled from Yitang Lake in the Dunhuang Basin of NW China, and used to reconstruct the long history of regional hydroclimatic changes since the Late Pleistocene. A comprehensive high-resolution geochronology of the upper part of the drilling core indicates a significant sedimentary hiatus between approximately 100 ka and 23 ka, likely due to the dry and harsh environmental conditions during the Last Glacial period (MIS 4 to MIS 2). Since then, the study area has experienced a relatively dry Late Glacial period (∼23–11 ka), gradually wetter early Holocene (∼11–8 ka), and moist mid-Holocene (∼8–5 ka), followed by a drying trend after approximately 5 ka. Hydrological variations in this area since the Late Quaternary were mainly controlled by changes in precipitation and glacier meltwater from the northeastern Tibetan Plateau. These alterations were ultimately regulated by shifts in atmospheric circulation patterns, as well as the dynamic interplay between the westerlies and the East Asian summer monsoon at both orbital and suborbital scales.

Influence of Acid Treatment on Pore Structure and Fractal Characterization of a Tight Sandstone: A Case Study from Wudun Sag, Dunhuang Basin

AbstractIn this study, X‐ray diffraction, N2 adsorption (N2A), and mercury intrusion (MI) experiments were used to investigate the influence of acid treatment on pore structure and fractal characterization of tight sandstones. The results showed that acid treatment generated a certain number of ink‐bottle pores in fine sandstone, aggravated the ink‐bottle effect in the sandy mudstone, and transformed some smaller pores into larger ones. After the acid treatment, both the pore volume in the range of 2–11 nm and 0.271–8 μm for the fine sandstone and the entire pore size range for the sandy mudstone significantly increased. The dissolution of sandstone cement causes the fine sandstone particles to fall off and fill the pores; the porosity increased at first but then decreased with acid treatment time. The fractal dimension obtained using the Frenkel‐Halsey‐Hill model was positively correlated with acid treatment time. However, the total fractal dimensions obtained by MI tests showed different changes with acid treatment time in fine sandstone and sandy mudstone. These results provide good guiding significance for reservoir acidification stimulation.

Jurassic Evolution of the Dunhuang Basin and Its Implications for the Early History of the Altyn Tagh Fault, Northeast Tibet Plateau

AbstractBasin evolution along the northeastern Tibetan Plateau related to the Altyn Tagh Fault (ATF) has significant implications for deciphering the formation of the Tibetan Plateau. However, the Mesozoic history of the ATF is still not well understood. In this contribution, we present a comprehensive sedimentologic and provenance analysis of the Jurassic Dunhuang Basin (DHB) to reconstruct the basin prototype and evolution and to discuss the early history of the ATF. The basin infill consists of late‐Early through Late Jurassic sediments interbedded with basalt, which were deposited in alluvial to lacustrine environments during the Early to Middle Jurassic, and in fluvial to fan delta environments during the Late Jurassic. The analyses of gravel component, paleocurrent and detrital zircon U‒Pb geochronology indicate that the clastic sediments were mainly derived from peripheral areas of the Bei Shan (north), Altyn Tagh—Qilian Shan (south), and the internal Sanwei Shan. Combined with seismic reflection data interpretations, our results suggest that rifting started by the activation of bilateral boundary faults during the Early Jurassic. This was followed by extension and associated magmatism due to subcrustal ductile necking and increased heat flux during the Middle Jurassic, and by final transformation into subsidence sag related to boundary fault die‐out or weakening during the Late Jurassic. We conclude that the DHB formed in an extensional setting generated by the far‐field effects of the Bangong‐Nujiang Ocean closure during the Jurassic, and that the ATF consisted of three subordinate normal faults rather than a sinistral strike‐slip fault during the Jurassic.

Northward Growth of the Northeastern Tibetan Plateau and Paleolake Evolution in the Dunhuang Basin During the Quaternary

Northward Growth of the Northeastern Tibetan Plateau and Paleolake Evolution in the Dunhuang Basin During the Quaternary

Element Geochemical Characteristics and Provenance Conditions of the 1st Member of Jurassic Zhongjiangou Formation in Wudun Sag, Dunhuang Basin

In order to clarify the provenance of the 1st member of the Zhongjiangou formation in Wudun sag, Dunhuang basin, the structural attributes, weathering and sedimentary characteristics of the provenance area were analyzed by means of element geochemistry, so as to determine the differences of sediment sources in different well areas. The results show that the higher the Al2O3 and K2O contents, the higher the enrichment of large ion lithophile elements and high field strength elements, while the iron and magnesium elements are relatively deficient, and there are characteristics of medium degree differentiation of light and heavy rare earth elements in Well XC1 and Well D2. The lower the Al2O3 content and the higher the SiO2 content, a loss of large ion lithophile elements and high field strength elements are observed, while the ferrophilic magnesium elements show serious loss, as shown in the characteristics of the high degree of differentiation of light and heavy rare earth elements in Well D1. In the UCC-normalized element spidergrams, the trend of Well XC1 and Well D2 is similar, which is different from that of well D1, indicating that the sediments of Well XC1 and Well D2 come from the same provenance area, while the sediment of Well D1 comes from a different provenance area. The provenance area of Well XC1 and Well D2 shows strong tectonic activity and strong weathering, while the provenance area of well D1 exhibits relatively weak tectonic activity and weathering. Combined with previous research results, Wudun sag is mainly characterized by a faulted lacustrine basin controlled by the southern boundary fault in the Jurassic layer. Therefore, the sediments of Well XC1 and Well D2 mainly come from the southern Sanweishan uplift provenance area, with strong tectonic activity; the sediments of Well D1 mainly come from the northern Beishan provenance area, with relatively weak tectonic activity.

Drainage Development in the Dunhuang Basin, NE Tibet, Controlled by Multi-Segment Fault Growth

The Dongbatu Shan (DBTS, also known as the Nanjie Shan), which interrupts the northern Tibetan foreland in the Dunhuang basin, is an active anticline. It has accommodated the northwestern growth of the eastern Altyn Tagh fault system (ATF). Although several thrust faults have been identified around the DBTS, their evolution history and influence on regional landscape have received little attention during the late-Quaternary. In this study, several geomorphic methods are used to investigate the interaction between drainage development and tectonic movement around DBTS. Based on high-resolution satellite images, field investigation, and cosmogenic nuclide 10Be dating method, the fluvial landform sequences around DBTS were constructed. Using quantitative geomorphology methods including landscape relief profile, asymmetry factor (AF), and transverse topographic symmetry factor (T), we hypothesize that drainage deflection is controlled by multi-segment fault growth. Combining the results of the above-mentioned methods, we propose that Yulin He, flowing across the DBTS, had gone through several abandonments since the late mid-Pleistocene due to the lateral propagation of DBTS. Affected by the discharge of channel and multi-segment fault growth, our research confirms that the direction of river abandonment may have decoupled with the mountain range propagation trend. Based on the chronology dating, the DBTS has gone through two severe uplifts since ∼208 ka and the shortening rate across the central DBTS is constrained to be ∼1.47 mm/yr since ∼83 ka. Given the fact that thrust faults are widely developed around DBTS, we propose that the flower-like structure formed by the northward growth of the eastern ATF could better explain the development of the secondary subparallel faults.

Jurassic sequence framework and sedimentary system distribution in the Wudun Sag, Dunhuang Basin

Jurassic sequence framework and sedimentary system distribution in the Wudun Sag, Dunhuang Basin

Early Pleistocene uplift of the northeastern Tibetan Plateau: Evidence from the Dunhuang Basin, NW China

The Cenozoic uplift of the Tibetan Plateau plays an important role in global climate change, basin-mountain geomorphology formation and desertification in western China. As an important component, the Early Pleistocene uplift process and its influence on the northeastern Tibetan Plateau has been controversial for many years. Quaternary synorogenic sediments within the Dunhuang Basin on the northeastern Tibetan Plateau record the details of plateau uplift. Detailed grain size analysis, rock magnetic properties, mudstone 36Cl dating and 40Ar/39Ar detrital mica dating were conducted on the Quaternary alluvial-fluvial-lacustrine-aeolian sediments of the Dunhuang Basin. The Aksay section in the southern Dunhuang Basin is dominated by conglomerate, sandstone, siltstone and mudstone. Detrital mica 40Ar/39Ar ages show major age populations of 200–160 Ma, 400–200 Ma and 510–430 Ma from the northeastern Altyn Mountains. The results of 36Cl ages and rock magnetic properties show that the Altyn Mountains rapidly uplifted at 1.16 Ma. From 1.16 to 0.80 Ma, the sedimentary environment was stable with two small-scale uplift pulses at ca. 1.03 Ma and 0.98 Ma. After 0.80 Ma, the climate became arid, and the Kumtag Desert formed in the Dunhuang Basin. These multistage uplifts are also widely found in the northeastern Tibetan Plateau. The Early Pleistocene uplift of the Altyn Mountains, corresponding to the Kunhuang Movement, resulted in the northeastern margin of the Tibetan Plateau reaching its present height and climate changeing towards drought in this region.

Impacts of water resource planning on regional water consumption pattern: A case study in Dunhuang Oasis, China

Water resources are critical for the existence and development of oases in endorheic basins. Thus, to enable sustainable development, it is fundamentally important to understand how to allocate and use these resources in a reasonable way. We therefore simulated and analyzed changes in water consumption pattern within the Dunhuang Oasis of China under three scenarios using a system dynamic model that corresponds to different water consumption pattern. This was done to assess the impacts of regional water resource planning (comprehensive planning of the rational use of water resource and protection of ecosystem services in the Dunhuang Basin) on water consumption pattern within the Dunhuang Oasis. The first of these, Scenario 1, is a baseline in which the status quo is maintained, while Scenario 2 incorporates the comprehensive effects of agricultural water-saving irrigation measures with an inter-basin water diversion project, and Scenario 3 focuses on ecological rehabilitation. In the baseline Scenario 1, the total water consumption within the Dunhuang Oasis increased progressively while agricultural water consumption remained extremely high and threatened overall ecological security. In contrast, Scenario 2 would decrease agricultural water consumption by almost 5.30×107 m3 following the implementation of water-saving practices. The additional water allocated from an inter-basin water diversion project would play an important role in alleviating ecological strain on the oasis. Finally, in Scenario 3, the total irrigated land must be decreased to 20.6×103 hm2 by 2025 assuming that water supply for ecosystem restoration would be at least 50% of the total consumption. Although water resource planning plays a very important role in alleviating the ecological water crisis within the oasis, it is necessary to consider the suitable scale of oasis with regard to current water consumption pattern.

Study on geological structure of the Dunhuang Basin based on gravity and electric data

Study on geological structure of the Dunhuang Basin based on gravity and electric data

Next-generation sequencing yields a nearly complete mitochondrial genome of the Variegated Racerunner (Eremias Vermiculata) from Dunhuang Basin

The Variegated Racerunner, Eremias vermiculata, is widespread in Northwest China, southern Mongolia, and Zaisan Basin of Kazakhstan. In this study, a nearly complete mitochondrial genome (17,972 bp in length) of E. vermiculata from the Dunhuang Basin in Northwest China was determined by next-generation sequencing. Similar to the typical mtDNA of vertebrates, it contained two ribosomal RNA genes, 13 protein-coding genes (PCGs), 22 transfer RNA genes, and one control region (CR). With exception to the CR, all of the 37 genes were completely recovered. The concatenated PCGs were used to conduct Bayesian phylogenetic analyses together with mitogenome data of lacertids in GenBank. The resulting phylogenetic tree confirmed the monophyly of genus Eremias and its viviparous species as well as E. vermiculata, respectively. The mitogenome presented here will contribute to the examination of phylogeographic structure for E. vermiculata and understanding of mitochondrial DNA evolution in Eremias.

Groundwater sustainability and groundwater/surface-water interaction in arid Dunhuang Basin, northwest China

The Dunhuang Basin, a typical inland basin in northwestern China, suffers a net loss of groundwater and the occasional disappearance of the Crescent Lake. Within this region, the groundwater/surface-water interactions are important for the sustainability of the groundwater resources. A three-dimensional transient groundwater flow model was established and calibrated using MODFLOW 2000, which was used to predict changes to these interactions once a water diversion project is completed. The simulated results indicate that introducing water from outside of the basin into the Shule and Danghe rivers could reverse the negative groundwater balance in the Basin. River-water/groundwater interactions control the groundwater hydrology, where river leakage to the groundwater in the Basin will increase from 3,114 × 104 m3/year in 2017 to 11,875 × 104 m3/year in 2021, and to 17,039 × 104 m3/year in 2036. In comparison, groundwater discharge to the rivers will decrease from 3277 × 104 m3/year in 2017 to 1857 × 104 m3/year in 2021, and to 510 × 104 m3/year by 2036; thus, the hydrology will switch from groundwater discharge to groundwater recharge after implementing the water diversion project. The simulation indicates that the increased net river infiltration due to the water diversion project will raise the water table and then effectively increasing the water level of the Crescent Lake, as the lake level is contiguous with the water table. However, the regional phreatic evaporation will be enhanced, which may intensify soil salinization in the Dunhuang Basin. These results can guide the water allocation scheme for the water diversion project to alleviate groundwater depletion and mitigate geo-environmental problem.

敦煌盆地侏罗系露头沉积特征差异性分析

敦煌盆地侏罗系露头沉积特征差异性分析

Three source rocks discovered in the Mid-Lower Jurassic, Dunhuang Basin in China

Three source rocks discovered in the Mid-Lower Jurassic, Dunhuang Basin in China

Effects of RapidEye imagery’s red-edge band and vegetation indices on land cover classification in an arid region

Land cover classification (LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidEye images was effective for vegetation identification and could improve LCC accuracy. However, there has been no investigation of the effects of RapidEye images’ red-edge band and vegetation indices on LCC in arid regions where there are spectrally similar land covers mixed with very high or low vegetation coverage information and bare land. This study focused on a typical inland arid desert region located in Dunhuang Basin of northwestern China. First, five feature sets including or excluding the red-edge band and vegetation indices were constructed. Then, a land cover classification system involving plant communities was developed. Finally, random forest algorithm-based models with different feature sets were utilized for LCC. The conclusions drawn were as follows: 1) the red-edge band showed slight contribution to LCC accuracy; 2) vegetation indices had a significant positive effect on LCC; 3) simultaneous addition of the red-edge band and vegetation indices achieved a significant overall accuracy improvement (3.46% from 86.67%). In general, vegetation indices had larger effect than the red-edge band, and simultaneous addition of them significantly increased the accuracy of LCC in arid regions.

Comparison and integration of feature reduction methods for land cover classification with RapidEye imagery

Feature reduction (FR) methods can effectively reduce the feature set and improve the accuracy for land cover classification (LCC) using high resolution remote sensing data with high dimensional or strongly correlated feature sets. However, FR methods have rarely been applied for LCC in arid regions with complex geographic environments, especially for the integration of feature selection (FS) and feature extraction (FE) methods. This study investigated the comparison and integration of FR methods for LCC in part of Dunhuang Basin, northwestern China, which is a typical inland arid region and groundwater-dependent ecosystems. Five spectral bands and 9 vegetation indices features that derived from RapidEye satellite imagery were used with support vector machines algorithm. Two wrapper FS methods, based on random forest algorithm (varSelRF and Boruta packages in R software), were used. Three FE methods (principal component analysis, PCA; independent component analysis, ICA; and minimum noise fraction transformation, MNF), were employed to extract a reduced number of reconstructed new features. Integration of varSelRF and PCA methods (varSelRF-PCA) was attempted. All 14 features were relevant, indicated by Boruta method; only 6 features, including the red-edge band selected by the varSelRF module, had higher importance. All the five FR methods could improve classification accuracy, but only varSelRF achieved significant improvement. The varSelRF outperformed the FE methods, followed by MNF, PCA, and ICA. The proposed varSelRF-PCA model significantly improved classification accuracy and outperformed all the FS or FE methods.

敦煌盆地东部侏罗纪原型盆地探讨

敦煌盆地东部侏罗纪原型盆地探讨