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Palaeo-uplifts often exist in fold-and-thrust belts. However, their effects on the deformational process have not yet been well understood. To evaluate such effects, six analogue models were systematically run based on geological features of the Wupoer fold-and-thrust belt (FTB), NE Pamir, where the Wulagen palaeo-uplift with overlying gypsum bed has been clearly identified. Our analogue results demonstrated that the palaeo-uplift (its location and inhomogenous distribution), accompanied with overlying gypsum bed that serves as ductile décollement, plays a critical role in localizing the front thrust fault and shaping it into arc form. The results indicate that the front thrust fault slides along the ductile décollement (gypsum bed), and breaks through onto the surface at the region where the palaeo-uplift develops, forming a piggy-back basin in the hanging wall. It suggests that the palaeo-uplift with consequent topographic variation of the overlying ductile décollement localizes the breakthrough point of the front thrust fault. In addition, the results indicate that the front thrust fault (Pamir Front Thrust, PFT) initially broke through in the location where it develops the Wulagen palaeo-uplift and propagated aside. This resulted in the distance between the PFT and the basement-involved fault (Main Pamir Thrust, MPT) to decrease from the region with palaeo-uplift to the areas aside without palaeo-uplift, thereby forming the arc-shaped PFT in map view. The results of this study also provide a revised geological model, which emphasizes the effect of décollement layer on absorbing the slip along the PFT. Our results provide a new mechanical interpretation of the deformation of Wupoer FTB, NE Pamir. [ABSTRACT FROM AUTHOR]

Abstract: Late Cretaceous inversion structures, which are significant for oil and gas accumulation, are widely distributed throughout the Jiuquan Basin. These structures are primarily made up of inverted faults and fault-related folds. Most of the axial planes of folds are parallel to inverted faults trending north-east, indicating that the principal stress direction was north-west–south-east in the Late Cretaceous. The average inversion ratios of faults in the four sags that were investigated are 0.39, 0.29, 0.38, 0.32. The average inversion ratio in the Jiuquan Basin is 0.34 and the degree of inversion is moderate to strong. As moderate inversion is suitable for forming excellent hydrocarbon traps, there is considered to be significant potential in the basin for the presence of structural traps. [Copyright &y& Elsevier]

The geology of Tian Shan provides an excellent example for understanding the intracontinental orogeny in the context of Indian–Eurasian convergence. Previous studies leave much space in basinfill deposition process to be assessed in the regions west to the Talas–Fergana fault (TFF). We improve the understanding by conducting new investigations on sedimentology and magnetostratigraphy in the Tierekesazi section of the foreland region of south West Tian Shan. Four lithofacies have been identified, (i) marine lithofacies from the Aertashi to Bashibulake Formations, (ii) lacustrine to fluvial (plain) lithofacies from the Keziluoyi to the middle Pakabulake Formations, (iii) alluvial sand–gravel sheet lithofacies in the upper Pakabulake Formation, and (iv) conglomerate lithofacies from the Atushi to Xiyu Formations. Magnetostratigraphic analysis, accompanied with biostratigraphic correlation, indicates that four lithofacies cover age intervals of ca. 65 Ma to 34 Ma, ca. 22.1 Ma to 12 Ma, 12 Ma to 5.2 Ma, and 5.2 Ma to approximately present (?), with the sediment accumulation rates increasing from ca. 2.4/3.3–3.5 (compacted/decompacted) cm/ka in the lithofacies (i), to 12.3/16–17 cm/ka in the lithofacies (ii), to 16.3/19.5–20.6 cm/ka in the lithofacies (iii), and finally to > 22.8/> 22.8 cm/ka in the lithofacies (iv). These results suggest three episodes of sedimentary events. Combined with previous results, these episodes of sedimentary events are attributed to tectonic activities that are widespread along south Tian Shan. We speculate that the Oligo-Miocene boundary event more directly and likely marks the initial underthrusting of the Tarim block beneath the south Tian Shan. The mid-Miocene and Mio-Pliocene boundary events, although approximately synchronous between the regions east and west to the TFF, have different structural expressions in the two regions. Such difference is proposed to cause the dextral slipping of the TFF, and more fundamentally, likely be driven by the northward indentation of the Pamir at this time. [ABSTRACT FROM AUTHOR]

The amount of fault slip and timing of fault activation are two fundamental elements of quantitatively structural analysis. Currently, these two parameters are mainly determined by the geometry of fault-related folds and the growth strata over the fault ramp. In this study, we propose a new type of growth strata that directly constrain both the amount of fault slip and the timing of fault activity at the fault flat based on interpretations of seismic reflection profiles and related numerical modeling of the Manan Structure along the southern Tarim Basin. The seismic sections show a rootless synform beyond the north limb of the Manan Anticline with the hinge dipping toward north. Numerical modeling suggests that this synform is a result of northward migration of the growth strata along with the slip of the underlying detachment thrust with a bulge at the fault surface. We define this type of growth strata 'migrating growth strata (MGS)'. The dipping direction of the hinge of the synform marks the slip direction, the projecting distance of the hinge on the fault surface measures the slip amount, and the timing of the MGS represent the timing of the activity of the underlying detachment thrust. Analyses of the Manan MGS along the southern Tarim Basin suggest ∼13–22 km of northward fault slip passed by the Manan Structure along the basal Cenozoic detachment and was finally absorbed by the Mazatagh Belt, which confirms a ∼230-km-long detachment thrust along the southern Tarim Basin and provide key evidence to establish a kinematic linkage between the Hotan and Mazatagh Belts. Two-segment style of the hinge of the synform indicates that the Manan Structure has undergone two-stage evolution related to the lower Cambrian and the basal Cenozoic detachments, respectively. These results imply that detachments in difference depths and their sequential activities are key in transmitting strain from the Tibetan Plateau into the Eurasian continental interiors. • Seismic sections show a rootless synform in Manan Structure, southern Tarim Basin. • The synform was produced by growth strata migrating with the detachment thrust. • Such a structure was defined as 'migrating growth strata (MGS)'. • MGS provide a new tool for quantitatively analyzing the fold-thrust belts. • The results demonstrate a ∼230-km-long detachment thrust in southern Tarim Basin. [ABSTRACT FROM AUTHOR]

Paleo-uplift is one of the main controlling factors that influence the style of deformation in salt-bearing fold-and-thrust belt (FTB). Whereas, how paleo-uplift amplitude influences salt-related deformations in FTB remains unclear. Here we designed four series of experimental models that contain a basal brittle décollement and a shallow ductile décollement. Our studies show that the presence of paleo-uplift in the ductile décollement has a profound impact on deformation propagation in the supra-salt overburden during the contraction, which localizes shortening strain in the proximal and central parts of the models and deters rapid deformation propagation towards the distal part. As the amplitude of the paleo-uplift increases, its influence on deformation propagation becomes stronger, resulting in out-of-sequence deformation towards the hinterland. The increase of paleo-uplift amplitude also controls the distribution and migration of rock salt during the contraction. Particularly, when the paleo-uplift height equals or exceeds the thickness of salt layer, the position of salt pinch-out or welding point localizes shortening strain and thereby initiates folding and thrusting deformation over the salt-base high. This process leads to salt fed into the fold and fault belt over the paleo-high and the uplift of the supra-salt layers. Our modeling results are highly comparable with natural examples of Kuqa FTB and provide insights to the salt-influenced deformations in the Qiulitage structural belt. • The presence of paleo-uplift has a profound impact on deformation propagation in the supra-salt overburden. • The increase of paleo-uplift amplitude controls the distribution and migration of rock salt during the contraction. • Higher amplitude paleo-uplift results in localized deformation and salt thickening. [ABSTRACT FROM AUTHOR]

Transverse drainages are prominent landscape features in active foreland thrust-and-fold belts. Understanding their response to folding processes is pivotal for comprehending landscape evolution and erosion-deformation interactions within the foreland. Here, we focus on the extensively developed transverse drainages across the Tugerming anticline in the southern Tian Shan foreland. Based on fold topography, drainage patterns, and various morphometric indices, we conducted a detailed geomorphological analysis of the Tugerming anticline. Our results suggest that the Tugerming fold laterally grows towards both ends, exhibiting notable segmentation along its strike. The westward lateral fold growth is characterized by interactions between the Tugerming anticline and two adjacent anticlines (Yiqikelike and Tuziluoke). At its eastern termination, lacking nearby folds, the Tugerming anticline laterally propagates without other adjacent folds, resulting in an elongated, gentle termination. Additionally, the hinterland catchment controls sediment and water flux of foreland transverse rivers, and its size has a significant influence on both channel morphology and river-fold interactions of the Tugerming anticline. Among the transverse rivers studied, those with large hinterland catchments (>80 km2) were dominated by braided river channels. In these cases, rivers respond to changes in channel gradient due to fold growth primarily through aggradation and degradation processes. Conversely, rivers with limited hinterland catchments (<80 km2) or originating within the fold, show a prevalence of incised meander channels. Moreover, channels accommodate gradient changes induced by the growing fold, primarily altering channel morphology, including channel sinuosity, slope, and width-to-height ratio. Our study reveals the significance of considering the hinterland catchment size in interpreting river-fold interactions and associated channel morphology within foreland transverse drainages. • We study transverse drainages in the Tugerming anticline in South Tian Shan foreland. • Geomorphic indices suggest lateral growth of the Tugerming fold towards both ends. • The lateral fold growth exhibits significant along-strike segmentation characters. • Hinterland catchment sizes affect channel morphology and river-fold interaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Onset time of the basin was the late Miocene to early Pliocene (∼5.8–4.6 Ma). • Multiple depocenters existed in the basin and intergraded to one in the Quaternary. • Eastward migration of the depocenter records the collision between the Pamir and South Tian Shan. The Pamir salient is the preeminent example of an intracontinental collision and defines the western end of the Himalayan-Tibetan orogen. Previous work has paid much attention to reveal the internal evolution of the Plateau. However, the structural growth and expansion of the Northern Pamir still have several unknowns. To address this process of the indentation, we describe the architecture of the Wupoer Piggyback Basin (WPB), the westernmost tip of the Tarim Basin, in between the northeastern Main Pamir Thrust (MPT), and the Pamir Frontal Thrust (PFT). The geometry of the WPB growth strata and its relationship with the compressive structures were explored through six seismic sections, five cutting the WPB along dip and one along strike. According to the sense prevailing in the literature, we define the onset of a piggyback basin with the first evidence of tectonic deformation within the basin fill. Interpreted from the seismic sections and field work, an unconformity between the Atushi Fm. and the underlying strata marks the base of the WPB, dated the onset of the basin at the latest Miocene to early Pliocene (∼5.8–4.5 Ma). The growth strata were separated into 6 units above the unconformity (G1-G6). The relative isopach maps reveal the existence of three main depocenters, evolving to a single one in the Quaternary. The structural interpretation documents the PFT is significantly segmented by transfer faults and lateral ramps. The eastward migration of the depocenter since the Quaternary points to the oblique collision between the Pamir and the South Tian Shan and gradual encroachment of deformation towards the east. [ABSTRACT FROM AUTHOR]

Abstract: The Cenozoic evolution of the Liupan Shan, situated at the northeast of the Tibetan Plateau, will provide constraints to test the models and mechanisms of the evolution of the plateau. In this contribution, the Sikouzi section, at the east of the Liupan Shan, has been selected to study Liupan Shan’s uplift history. At around 9.5Ma, constrained by the magnetostratigraphy, the sediment and depositing architecture characteristics obviously changed. Synchronously, flow direction changed from E→W to W→E, and accumulation rate increased to more than double. All these evidences suggest that the Liupan Shan initiated uplifting at around 9.5Ma. Subsequently, a stage of intense uplift happened during 8.2–7.3Ma, indicated by the apatite fission-track (AFT) data across the Liupan Shan. Regional comparison indicates that this stage of uplift is not only with local but also regional significance. The Miocene uplift of the Tibetan Plateau triggered the intensification of the East Asian Monsoon and Asian intercontinental aridity, which has been implied by the pollen results of the Sikouzi section. [Copyright &y& Elsevier]

In northeastern China, Cenozoic ‘reverse faults’ can be found in most basins. It was proposed that these faults were the products of inversion tectonics during a Cenozoic regional compressional event. This explanation is inconsistent with regional structures that are dominated by normal faults on seismic profile. As a typical example, the Rongxintun fault in northeastern Liaohe basin is systemically analyzed on the basis of deformation style, sedimentary character, and systemic mapping using seismic data. We conclude that the Rongxintun fault was related to right-lateral strike slipping of the Yannan main fault during the late Paleogene when the Dongying deposition occurred, and it was a secondary right-lateral/reverse fault (P Plane Fault) of the Yannan strike-slip fault system. The fold was a fault related fold formed as a result of movement along the Rongxintun fault. According to this analysis of the Rongxintun fault, we conclude that the Cenozoic ‘reverse fault’ in northeastern China was a secondary right-lateral/reverse fault of a strike-slip fault system and did not represent a compressional event. This kind of mechanism of ‘reverse faulting’ is consistent with the fact that there was large-scale strike-slip faulting in northeastern China during the Cenozoic. [Copyright &y& Elsevier]

• Cona rift is the easternmost rift in the Himalayas. • Multi-thermochronometers suggest 3.0–2.3 Ma rift initiation. • Initiation of Himalayan rifts youngs monotonically eastward. • Lithospheric flow driven by asynchronous GPE gradients caused E–W extension. Several competing hypotheses have been proposed to explain east-west extension observed across the Himalayan orogen, based primarily on observations from the western and central Himalaya. They make predictions for the temporal and spatial patterns of deformation in the eastern Himalaya. These tectonic models include radial spreading or oroclinal bending of the Himalayan arc, oblique convergence of the Indian continent, tearing or lateral detachment of the Indian slab and eastward flow of lithosphere. Here, for the first time we constrain the activity history of the Cona rift, the only north-trending rift currently recognized in the eastern Himalaya, based on biotite and K-feldspar 40Ar/39Ar and zircon and apatite (U–Th)/He thermochronology, to evaluate these proposed rifting mechanisms. Low-temperature thermochronological results suggest that the Cona rift is the youngest rift system in the Himalayas: after a slow phase of exhumation since ∼14 Ma (∼0.2–0.13 mm/yr), normal faulting initiated here at ∼3.0–2.3 Ma with a fault slip rate of ∼3.8–1.6 mm/yr and a horizontal extension magnitude of ∼2–5 km. Analysis of rifting across the Himalayas shows that rift initiation ages young eastward, which is matched by eastward decreasing rift-extension magnitudes. Monotonically eastward younging rift development is consistent with the tectonic model involving eastward lithospheric flow driven by Indian slab dynamics and coupled asynchronous gravitational potential energy gradients. [ABSTRACT FROM AUTHOR]