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3D modeling structures of Qaidam basin, and the data unit is elevation depth (meter). (a): The base of the Pleistocene (Q).(b): The base of the upper Miocene (N22). $(\rm N_2^2 ).$ (c): The base of the upper Eocene (E32). $(\rm E_3^2 ).$ (d): The base of the Paleocene (E1+2). The magenta surface indicates the site of the Altyn Tagh fault, and the Qaidam basin is bounded by the southwest-directed Kunlun thrust belt in the west and the northeast-directed Qilian mountain thrust belt in the east. The green arrow indicates north direction
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The Qaidam basin, bounded by the Altyn Tagh fault in the north, is located in the northeast of the Tibet plateau, and it has important implications for understanding the history and mechanism of Tibetan plateau formation during the Cenozoic Indo-Eurasia collision. In this study, we constructed the main geological structures and surfaces in three di...
Citations
... We estimated divergence times based on the earliest fossil evidence for Schizothoracini (e.g., Paleoschizothorax qaidamensis; [54], as gauged in the Qaidam Basin [55]). This placed initial divergence at the onset of the Oligocene (33 Ma) (see also [56]). ...
... We estimated divergence times based on the earliest fossil evidence for Schizothoracini (e.g., Paleoschizothorax qaidamensis; [54], as gauged in the Qaidam Basin [55]). This placed initial divergence for Schizothoracini at the onset of the Oligocene (~33 Ma) (see also [56]). ...
Global biodiversity hotspots are often remote, tectonically active areas undergoing climatic fluctuations, such as the Himalaya Mountains and neighboring Qinghai-Tibetan Plateau (QTP). They provide biogeographic templates upon which endemic biodiversity can be mapped to infer diversification scenarios. Yet, this process can be somewhat opaque for the Himalaya, given substantial data gaps separating eastern and western regions. To help clarify, we evaluated phylogeographic and phylogenetic hypotheses for a widespread fish (Snowtrout: Cyprininae; Schizothorax ) by sequencing 1,140 base pair of mtDNA cytochrome-b ( cytb ) from Central Himalaya samples (Nepal: N = 53; Bhutan: N = 19), augmented with 68 GenBank sequences (N = 60 Schizothorax /N = 8 outgroups). Genealogical relationships (N = 132) were analyzed via maximum likelihood (ML), Bayesian (BA), and haplotype network clustering, with clade divergence estimated via TimeTree . Snowtrout seemingly originated in Central Asia, dispersed across the QTP, then into Bhutan via southward-flowing tributaries of the east-flowing Yarlung-Tsangpo River (YLTR). Headwaters of five large Asian rivers provided dispersal corridors from Central into eastern/southeastern Asia. South of the Himalaya, the YLTR transitions into the Brahmaputra River, facilitating successive westward colonization of Himalayan drainages first in Bhutan, then Nepal, followed by far-western drainages subsequently captured by the (now) westward-flowing Indus River. Two distinct Bhutanese phylogenetic groups were recovered: Bhutan-1 (with three subclades) seemingly represents southward dispersal from the QTP; Bhutan-2 apparently illustrates northward colonization from the Lower Brahmaputra. The close phylogenetic/phylogeographic relationships between the Indus River (Pakistan) and western tributaries of the Upper Ganges (India/Nepal) potentially implicate an historic, now disjunct connection. Greater species-divergences occurred across rather than within-basins, suggesting vicariance as a driver. The Himalaya is a component of the Earth’s largest glacial reservoir (i.e., the “third-pole”) separate from the Arctic/Antarctic. Its unique aquatic biodiversity must be defined and conserved through broad, trans-national collaborations. Our study provides an initial baseline for this process.
... Many species occurred in both areas such as I. qaidamensis, I. pseudomanasensis, C. gasiensis, C. subgasiensis, C. eboliangensis, E. concinna qaidamensis, P. lenghuensis, Z. membranae, C. qiulingensis, C. ordinata, L. tropis, L. gongheensis (Table 1). The Cenozoic strata in the Qaidam Basin are over 15 km in total thickness, mainly with a continuous sequence of lacustrine, fluvial, alluvial and aeolian sediments (Guo et al. 2017). These strata are further divided into the Palaeocene to the early Eocene Lulehe Formation (65-49 Ma), the middle Eocene to the early Oligocene lower Ganchaigou Formation (49-28.5 Ma), the late Oligocene upper Ganchaigou Formation (28.5-23.8 ...
... Specifically, four thrust belts control the evolution of the basin squeezing it to a narrow irregular shaped structure: the Kunlun fault to the south, the Altyn Tagh fault to the northwest, the Kunlun Mountains thrust belt on the southern margin, and the Qilian Mountain thrust belt to the northeast of the basin (Fig. 2). The Altyn Tagh fault is the major boundary fault, leading to stronger deformation in the north (Guo et al. 2017;Zheng et al., 2013;Yin et al., 2008;Wang et al., 2006;Yang et al., 2001;Zhang et al., 2001;Cowgill, 2001). The left slip on the Altyn Tagh fault zone is related to and absorbed by crustal shortening within the Qilian Mountains, the Qaidam basin, and other convergent structures south of the fault zone. ...
... The left slip on the Altyn Tagh fault zone is related to and absorbed by crustal shortening within the Qilian Mountains, the Qaidam basin, and other convergent structures south of the fault zone. The deformation history of the Qaidam basin shows that the basin experienced continuous compression with a total shortening of over 25 km since the beginning of Cenozoic (Guo et al., 2017;Meng & Fang, 2008;Zhou et al., 2006;Wang et al., 2006). In later Eocene and Quaternary, the basin had two relatively fast shortening phases. ...
... In later Eocene and Quaternary, the basin had two relatively fast shortening phases. The Cenozoic sedimentary center is located in the central basin with about 15 km deposition (Guo, et al. 2017). Generally, the salt lakes lie within the main areas of late Pleistocene subsidence (Chen & Bowler, 1986). ...
The Qaidam basin in W China is an immense hyperarid intramontane basin with flat vast playas and salt lakes on the Qinghai-Tibet Plateau. The central basin is about 2800–2900 m a.s.l. elevation and enclosed by mountain ranges reaching > 5800 m in the Qilian Mountains and > 6200 m in the eastern Kunlun Mountains. The extensive playas of the basin are covered by gypsum or halite with very subordinate additional solids. In this contribution we report on the chemical composition of salt lakes and inflows to the Qaidam basin (analysis of 30 water samples collected in the summer of 2008 and 2009) together with the composition of 22 salt samples. Salt lakes and small salt ponds formed at topographic depressions. Some of the lakes cover > 300 km ² surface but are very shallow (1–2 m deep). Most salt lakes and salt ponds are NaCl dominated and contain typically 250–300 g kg ⁻¹ total dissolved solids (TDS). Some lakes are industrially used and produce KCl fertilizer, LiCl, and boron or are strongly modified by deep water produced in oil fields. Lakes along the borders to the high mountains are typically not fully saturated with halite. However, also these lakes lost most Ca and are drastically enriched in Mg and some lakes also in B and Li. The chemical development of the most natural salt lakes follows a path producing Ca-deficient water that ultimately precipitate Mg-bearing carbonates and chlorites in addition to halite upon evaporation. The salt lakes form by continuous and drastic evaporation of the waters supplied by the inflows to the lakes in the basin. All inflows carry considerable amounts of Cl and are characterized by very high Cl/Br ratios. These chemical characteristics suggest that the salt load of the inflows originates mostly from re-dissolved windblown halite deposited together with sand up to high altitudes in the bordering mountain ranges. Also, thermal waters ascending along deep faults along the Qilian Mountains carry considerable amounts of chloride. Their low Cl/Br ratio however suggests that most of the dissolved Na is derived from minerals of the basement rocks by fluid-rock interaction at T > 130 °C. The thermal fluids also carry considerable amounts of boron, indicating that co-precipitated borax in the salt lakes ultimately also derives from minerals in the basement rocks (tourmaline). Consequently, the presented data improve the understanding how the brines and salt lake waters develop from a wide range of chemically distinct low-TDS inflows and how the sequences of minerals precipitated upon evaporation in the Qaidam basin formed.
... Geophysical and geological data are the basic information for building high-precision 3D geological models. The structure and formation characteristics of geological objects are essential factors underlying the production of hydrocarbons (Mehmood et al., 2016;Guo et al., 2017). One of the key challenges in reservoir modeling is the accurate representation of reservoir geometry, including the structural framework (i.e., horizons/major depositional surfaces, and fault surfaces) and detailed stratigraphic layers. ...
Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir characteristics play important roles in assessment of hydrocarbon potential. Here, an approach that integrates digital elevation modelling, seismic interpretation, seismic attributes, three-dimensional (3D) geological structural modeling predicated on seismic data interpretation, and petrophysical analysis is presented to visualize and analyze reservoir structural trends and determine residual hydrocarbon potential. The digital elevation model is utilized to provide verifiable predictions of the Dhulian surface structure. Seismic interpretation of synthetic seismograms use two-way time and depth contour models to perform a representative 3D reservoir geological structure evaluation. Based on Petrel structural modeling efficiency, reservoir development indexes, such as the true 3D structural trends, slope, geometry type, depth, and possibility of hydrocarbon prospects, were calculated for the Eocene limestone Chorgali, upper Paleocene limestone Lockhart, early Permian arkosic sandstone Warcha, and Precambrian Salt Range formations. Trace envelope, instantaneous frequency, and average energy attribute analyses were utilized to resolve the spatial predictions of the subsurface structure, formation extrusion, and reflector continuity. We evaluated the average porosity, permeability, net to gross ratio, water saturation, and hydrocarbon saturation of early Eocene limestone and upper Paleocene limestone based on the qualitative interpretation of well log data. In summary, this integrated study validates 3D stratigraphic structural trends and fault networks, facilitates the residual hydrocarbon potential estimates, and reveals that the Dhulian area has a NE to SW (fold axis) thrust-bounded salt cored anticline structure, which substantiates the presence of tectonic compression. The thrust faults have fold axes trending from ENE to WSW, and the petrophysical analysis shows that the mapped reservoir is of good quality and has essential hydrocarbon potential, which can be exploited economically.
... The Qaidam Basin is a typical petroliferous basin that is located on the northern margin of the Tibetan Plateau ( Figure 1) [14][15][16]. The basin covers an area of approximately 1.2 × 10 5 km 2 and has elevations of 2,500-3,000 m [17,18] [19]. The deformation of major faults and the Cenozoic strata within the basin provides a record of the effect of compression from the uplift of the Tibetan Plateau. ...
... The basin model was divided into two parts: the cover and the basement. A 2D model was constructed for each part using identical boundary conditions by 3D modeling structures of the Qaidam Basin which was proposed by Jianming et al. [19]. The main difference between the cover and basement of the basin was lithology and fracture development. ...
... The fault extended from the basement to the cover, and the main controlling area of fracture development was the basement. To analyze the particularity of cover and base, the cover to be a homogeneous elastic plate and the basement to be an elastic plate with six faults [19] were assumed. Since the stress state of the model being static was discussed, the relative slip between fractures could be ignored. ...
This article analyzes the stress fields in the Qaidam Basin since the entire Cenozoic using finite element numerical simulations. The stress fields are investigated by analyzing tectonic joints and the GPS velocity field in the basin. The relationship between the stress field patterns and the tectonic activity of the basin was discussed. Based on previous research on the uplift of the Tibetan Plateau, five stages of the tectonic evolution of the Qaidam Basin are modeled. The simulation results show that the stress trajectories in the Oligocence and the Pliocene–Quaternary were similar. In the Oligocence, the stress trajectories in the basin changed significantly and were mainly controlled by the compressional stress on the southern boundary in the initial stage. As the compressional stress on the northern boundary of the basin gradually increased, the compressional stress on the southern and northern boundaries had equal effects in the intermediate stage, and the compressional stress on the northern boundary mainly controlled the stress trajectories in the late stage. During the uplift of the Tibetan Plateau, the stress trajectories in the Qaidam Basin experienced an apparent reversal. The stress trajectories of the internal basin rotated clockwise from NE–SW to NW–SE in the Oligocence and which gradually changed to counterclockwise from NW–SE to NE–SW in the Miocene and recovered to clockwise from NE–SW to NW–SE in the Pliocene–Quaternary.
... Schizothoracini (e.g., Oligocene: Paleoschizothorax qaidamensis; [84]). This Qaidam Basin fossil was estimated from its stratigraphic formation as being Eocene-to-Oligocene [85], and given 528 this, we chose an Oligocene initiation (33Ma) as our divergence time. (which was not certified by peer review) is the author/funder. ...
The Himalayan uplift, a tectonic event of global importance, seemingly disseminated aquatic biodiversity broadly across Asia. But surprisingly, this hypothesis has yet to be tested. We do so herein by sequencing 1,140 base-pair of mtDNA cytochrome-b for 72 tetraploid Nepalese/Bhutanese Snowtrout ( Schizothorax spp. ), combining those data with 67 GENBANK ® sequences (59 ingroup/8 outgroup), then reconstructing phylogenetic relationships using maximum likelihood/ Bayesian analyses. Results indicate Snowtrout originated in Central Asia, dispersed across the Qinghai-Tibetan Plateau (QTP), then into Bhutan via south-flowing tributaries of the east-flowing Yarlung-Tsangpo River (YLTR). The headwaters of five large Asian rivers provided dispersal corridors into southeast Asia. South of the Himalaya, the YLTR transitions into a westward-flowing Brahmaputra River that facilitated successive colonization of Himalayan drainages: First Bhutan, then Nepal, followed by far-western drainages subsequently captured by the Indus River. We found greater species-divergences across rather than within-basins, implicating vicariant evolution as a driver. The Himalaya is a component of the “third-pole” [Earth’s largest (but rapidly shrinking) glacial reservoir outside the Arctic/Antarctic]. Its unique aquatic biodiversity must not only be recognized (as herein) but also conserved through broad, trans-national collaborations. Our results effectively contrast phylogeography with taxonomy as a necessary first step in this process.
The Himalaya is the most extensive and recently evolved mountain system on Earth (length=2400km; width=240km; elevation=75-8800m), with a global significance underscored by its large-scale lithospheric, cryospheric, and atmospheric interactions [1]. These have not only driven global climate, but also defined the cultural and biological endemism of the region [2]. Massive, tectonically derived mountain chains such as the Alps and the Himalaya are hypothesized as being fundamental to the formation of global biodiversity gradients via vicariance and local adaptation, with a significantly stronger signal in terrestrial rather than aquatic systems [3]. Here we test how orogeny (the deformation and folding of Earth’s crust by lateral compression) has contributed to the diversification of freshwater fishes broadly across Asia. We do so by evaluating the phylogeography of an endemic high-elevation fish, the Snowtrout ( Schizothorax : Cyprinidae).
To investigate the differences in east-west lithospheric deformation in the Qaidam Basin, we present thermo-rheological models of two profiles across the western Qaidam Basin (WQB) and eastern Qaidam Basin (EQB). The differences in east-west geodynamic deformation styles are also described, involving GPS motions, focal mechanisms (P axes), seismic anisotropy (SKS-wave splitting), and low-velocity zones (LVZs). The WQB is characterized by a warm destabilized cratonic basin with a weak lower crust, and the rheological structure changes from a rather weak crème brûlée-1 regime into a strong jelly sandwich-1 regime, from the Altyn-Qaidam boundary to the northeastern corner of the WQB. Combined with the limited distribution of the LVZs and the strong crust-mantle decoupling revealed by the unmatched pattern between P axes (N20ºE) and SKS-wave splitting (N110°E), the crust-mantle mixing related to the under-thrusting of the Tarim Basin along the Altyn Tagh Fault is suggested as the primary tectonic dynamic inducement of the destabilized WQB craton, which weakens the lithospheric strength greatly and contributes to the shallow brittle deformation. However, the EQB performs as a typical cold and rigid cratonic basin characterized by a jelly sandwich-2 rheological regime, which is sufficiently strong to maintain crust-mantle coupling. The LVZs beneath the EQB revealed by recent wide-angle seismic profiles have only a small effect on the lithospheric strength drop. The EQB could be regarded as a solid basin, anchored in the NE Tibetan Plateau, which shows a strong resistance to NE extrusion of the weak plateau material, leading to clockwise rotation.
