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[Objective] The Shanxi Graben System has become an important area of Late Cenozoic deformation research in eastern China for its unique tectonic location. However, due to the limitations of the outcrop profile, complete sedimentary environment evolution of the basins in the graben system is rarely reported, which hinders our understanding of its evolution process. [Methods] The depositional environments and provenance were analyzed using the detailed sedimentary record from the ZK01 borehole in the Taiyuan Basin. [Results and Conclusions] The analysis of the sedimentary environment shows that the Taiyuan Basin underwent a fluvial-delta/lake-river sedimentary environment evolution process. Two mega transgressions generated basin-wide lakes, one at ca. 5.8-4.4 and the other at ca. 2.2-1.6 Ma. Provenance analysis shows that the provenance was mainly the Jurassic quartz sandstones of the Taihang Mountain before 5.8 Ma. After 5.8 Ma, the provenance changed to the Triassic feldspathic sandstones, Meanwhile, the debris of metamorphic and volcanic rocks from the northern part of the Lvliang Mountain began to enter the basin, indicating the development of Fen River in the Taiyuan Basin. Asynchronous processes between paleoclimatic variations and transgressions illustrate the lakes' spreading processes as mainly influenced by tectonic subsidence, being a structural-geomorphic response to the eastward spreading of the Qinghai-Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The Shanxi Graben System (SGS) is one of the first‐order Cenozoic tectonic features in North China. Understanding the kinematics of this tectonic system is crucial for deciphering the mechanism of continental rifting and the deformation pattern across North China. Although the SGS has long been thought to be a right‐lateral, transtensional shear zone, the geologic and geomorphologic evidence for dextral strike‐slip along its internal faults was slim and even controversial. Field investigations, interpretations of satellite imagery, and construction of decimeter‐scale digital elevation models from unmanned aerial vehicle surveys were used in this work to investigate the tectonic geomorphology of the eastern segment of the North Liulengshan Fault (NLSF) in the northern SGS. Although this fault segment was previously thought to be a pure normal fault, the presence of geomorphic features such as right‐laterally offset terrace risers and gullies, along with an analysis of fault‐slip data, suggests a component of right‐lateral strike‐slip displacement. Combined with optically stimulated luminescence dating of offset fluvial terraces, the late Quaternary right‐lateral strike‐slip and vertical slip rates of this fault segment are both estimated to be ∼0.2–0.3 mm/yr. The discovery of dextral strike‐slip along the NLSF provides compelling direct evidence for determining the dextral transtensional kinematics of the SGS. This puts new constraints on our knowledge that the evolution of the SGS is primarily driven by the outward expansion and growth of the Tibetan Plateau and supports the "bookshelf" rotation kinematic model for North China. Plain Language Summary: It has long been believed that many right‐lateral strike‐slip faults may exist in the Shanxi Graben System (SGS) in central North China, but exactly which ones are not fully understood. Here, we report on a newly discovered dextral strike‐slip fault—the North Liulengshan Fault in the northern SGS, based on interpretations of historical satellite images and field investigations. The dextral strike‐slip motion along the eastern segment of that fault is evidenced by geomorphic features like right‐laterally offset terrace risers and gullies and fault striations preserved on exposed fault planes. Combining our displacement measurements and geochronology data yields both right‐lateral strike‐slip and vertical slip rates of ∼0.2–0.3 mm/yr for the fault. This discovery provides key geologic and geomorphic evidence for determining the kinematics of the SGS, which is of great significance for better understanding the geodynamics of the SGS and the deformation pattern of North China. Key Points: We present direct and compelling evidence for the dextral shearing of the Shanxi Graben SystemDextral strike‐slip along the eastern segment of the North Liulengshan Fault (NLSF) is significant in addition to normal faultingLate Quaternary dextral strike‐slip and vertical slip rates along the eastern segment of the NLSF are both ∼0.2–0.3 mm/yr [ABSTRACT FROM AUTHOR]

Yuncheng Basin, the southernmost basin in the Shanxi Graben System, is considered to be one of the earliest formed in this region. However, due to the insufficient study on the strata and the lack of drilling data, the initial time of the Yuncheng Basin has not been accurately constrained, which heavily restricts our understanding about the formation and evolution of the Shanxi Graben System. In this study, borehole SG‐1, which penetrated through the entire Late Cenozoic sediments and reached the basement bedrock, was obtained in the northern part of the Yuncheng Basin, and a detailed magnetostratigraphic study has been carried out on the samples selected from the borehole SG‐1. Results show that the borehole SG‐1 records 17 normal (N1–N17) and 16 reversed (R1–R16) polarity zones which can correspond to the chron C1n‐C4An.1n of the global geomagnetic polarity timescale (GPTS). The bottom of the borehole SG‐1 is within chron C4An, and the age of the bottom can be extrapolated to 9.1 Ma according to the sediment accumulation rates calculated by two lowermost major polarity transition boundaries. This age provides precise limitation for the initiation of the Yuncheng Basin and the formation of the Shanxi Graben System. The sediment accumulation rates of the Borehole SG‐1 was calculated by major polarity boundaries of chrons and subchrons in the borehole SG‐1 and showed significant changes at 9.1, 3.6, and 1.2 Ma. Unlike other basins around the Ordos Block which formed much earlier under the influence of western subduction of the Pacific Ocean, the initiation and evolution of the Shanxi Graben system were mainly controlled by the uplift and outward expansion of the Tibetan Plateau after the Late Miocene. The initiation of the Shanxi Graben System indicates that the far‐field effect of the uplift and outward expansion of the Tibetan Plateau reached the central North China Craton by at the latest 9.1 Ma. The effect posed a persistent impact on the evolution of the Yuncheng Basin since 9.1 Ma and led to significant changes of the sediment accumulation rates and sedimentary facies at 9.1, 3.6, and 1.2 Ma in the Yuncheng Basin which correspond well to the prologue of the Qingzang Movement, phase A of the Qingzang Movement, and Kunhuang Movement. [ABSTRACT FROM AUTHOR]

The North Liuleng Shan Fault (NLSF) is one of the major active faults in the northern Shanxi Graben System (SGS) in North China. Although the fault has been investigated extensively in terms of late Quaternary activity, its active deformation pattern is still poorly characterized. In this study, we conducted a morphometric analysis of the fault using various geomorphic indices to assess the along-strike relative uplift rates, which include basin relief, slope, mountain front sinuosity (S mf), hypsometric integral (HI) and curves, valley floor width-to-height ratio (V f), asymmetry factor (A f), basin elongation ratio (R e), and normalized channel steepness indices (k sn). Our findings indicate that the central portion of the fault has experienced higher relative uplift rates than the southwestern and northeastern portions, as demonstrated by higher basin-averaged slopes and k sn values, and lower V f , R e , and S mf values. This spatial distribution pattern of relative uplift rates appears to correlate well with along-strike changes in the fault geometry and kinematics of the NLSF. We interpret the EW-striking, central portion of the NLSF as a releasing bend formed by the NE-striking, right-stepping, en-echelon southwestern and northeastern portions of the fault system, which are characterized by right-lateral oblique slip. Furthermore, the northeastward increase in HI values along with the regional basin evolution history suggest that the NLSF likely propagated from southwest to northeast. We propose that the southwestern portion of the fault most probably initiated earlier and that the central and northeastern portions formed later as extensional structures at the termini of the fault zone. Our findings contribute to a better understanding of the tectonics and genesis of the basin-and-range geomorphology in the northern SGS. • The relative uplift rate is highest in the central portion of the North Liuleng Shan Fault. • Oblique-slip releasing bend model explains the deformation along the North Liuleng Shan Fault. • The North Liuleng Shan Fault propagated gradually from southwest to northeast. [ABSTRACT FROM AUTHOR]

Previous numerical–analytical approaches have suggested that the main range divide prefers to migrate towards the high uplift flank in the asymmetric tectonic uplift pattern. However, natural examples recording these processes and further verifying the numerical simulations results, are still lacking. In this study, the landscape features, and the probable drainage evolution history of the Zhongtiao Shan, a roughly west-east trending, half-horst block on the southernmost tip of the Shanxi Graben System, were investigated through the geomorphic analyses (i.e., slope and steepness distributions, and the Gilbert and χ metrics). The topographic slope and steepness results indicate that the Zhongtiao Shan, controlled by the north Zhongtiao Shan normal fault, experiences asymmetric uplift and erosion patterns, with higher uplift and erosion on the north range. In addition, the Gilbert and χ metrics suggest that the western part of the main divide is currently stable, while the eastern divide is moving southward. According to the drainage divide stability criteria, we suggest that the uplift and erosion, on the fault side, balance each other well on the western part of the range, while on the eastern part, the uplift is outpaced by the erosion. In addition, a dynamic divide migration model in the asymmetric uplift condition is proposed, indicating that the interaction between uplift and erosion controls the migration and/or stability of the main divide. Deducing through this dynamic model, we suggested that the eastern segment of the north Zhongtiaoshan Fault must have experienced higher activities in the geological history, and the western fault may remain its activity along with the mountain relief generation. This gives a case that specific information on asymmetric neotectonic history and landscape evolution in an orogenic mountain can be uncovered by the proposed dynamic model.

A numerical formation age for the Tangxian planation surface (TXPS) in North China is still controversial. The TXPS, beveled across paleoarchean basement rocks, is overlain by late Cenozoic conglomerate, aeolian red clay, and loess. The magnetostratigraphy of two late Cenozoic deposition sections is established, and two other sections are recorded and measured in this work. The magnetostratigraphy indicates six normal magnetozones (N1 to N6) and six reverse magnetozones (R1 to R6). These magnetozones are correlated to chron C1n through C2An.1r, indicating that the TXPS was formed at 3.12–3.03 Ma. The characteristics of the Zhongtiao Shan tectonic uplift and its relationship with the Tibetan Plateau and Ordos Block are discussed in terms of tectonic uplift. The TXPS formation and accumulation of the late Cenozoic sediments are mainly controlled by tectonic activities. The formation and uplift of the TXPS with a lag in the Shanxi Graben System is consistent with the activities of the Tibetan Plateau and Ordos Block, implying that the NE extension of the Tibetan Plateau epeirogenic uplift advances successively. [ABSTRACT FROM AUTHOR]

The late Pleistocene and Holocene sediment along the North Zhongtiaoshan Faults (NZF) in Shanxi Province north China provided excellent records of events and displacing rate of the Holocene paleoearthquakes. We conducted a paleoseismological study with the geomorphological mapping and trenching along the 137-km normal faults trending NE–NEE. Identified from the results of trenching along the NZF, the first rupturing event in the Holocene was between 10,420±145 and 11,245±55CalaBP, the second event was between 7860±80 and 8100±90CalaBP, the third event was between 4540±110 and 4695±125CalaBP and the fourth event was between 465±45 and 675±45CalaBP. The average interval of the four events interpreted was 3370yr. The trending of the vertical displacements of four events and of the estimated magnitudes of the paleoearthquakes shows a decelerating faulting pattern of the NZF in the Holocene. The paleoseismic events went stronger from the northeast segment to the southwest segment along the NZF and the most active faulting around 465±45CalaBP was in the Hanyang Segment. [ABSTRACT FROM AUTHOR]

The Huoshan Fault, being of NEN strike, is one of the most important faults in the Shanxi Graben System of North China; it is the location of the 1303 A.D. Hongtong earthquake (MS = 8.0). The late Pleistocene and Holocene offset of some gullies that cross the fault and some fault scratches have proved its right lateral movement during the late Quaternary; however, until now, geological evidence to support the movement in the Neogene and early Quaternary was scarce. Our work provides further crucial evidence that supports both its movement in the late Cenozoic and the total right-lateral displacement since the Pliocene. The difference in the outcrop heights of the Pliocene sediment along the fault, the difference in the geomorphological development along the fault, the inconsistency in the lithological composition of the Pliocene proluvial gravels with the rock types within the catchments of the current upper stream, and the offset of the Pliocene alluvial gravels all completely indicate that the fault has always moved right-laterally since the Pliocene. Additionally, this evidence indicates that the accumulative displacement is up to 12.5 km. Based on the horizontal and vertical displacement of the fault since the Pliocene, the time-averaged horizontal slip rate of the fault is estimated to be about 3.5 mm/a, while the ratio of the horizontal to vertical offsets is about 3.8; these data are roughly close to the results that were acquired from the Holocene and the present movement of the fault. This similarity in the tectonic movement parameters may imply that the intensity as well as the configuration of the regional stress field has remained constant, and that no significant changes have taken place since the Pliocene. [ABSTRACT FROM AUTHOR]

By comprehension of earthquake focal mechanism solutions and the data of in-situ stress measurements, the tectonic stress field in Shanxi region has been summarized, which indicate that the stress state in this region is different from that of its eastern surrounding regions. The next, by fitting the measured data, the boundary forces that influenced the distribution of the stress field in this region has been studied using inversion method. The inversion results showed the following messages: the effect of the boundary force between the blocks is the main determinative factor for the recent tectonic stress field in Shanxi and the regional material and its property is a secondary factor; the horizontal main stress of tectonic stress field in Shanxi region is consistent with the stretch of fault basins. [ABSTRACT FROM AUTHOR]

Previous numerical–analytical approaches have suggested that the main range divide prefers to migrate towards the high uplift flank in the asymmetric tectonic uplift pattern. However, natural examples recording these processes and further verifying the numerical simulations results, are still lacking. In this study, the landscape features, and the probable drainage evolution history of the Zhongtiao Shan, a roughly west-east trending, half-horst block on the southernmost tip of the Shanxi Graben System, were investigated through the geomorphic analyses (i.e., slope and steepness distributions, and the Gilbert and χ metrics). The topographic slope and steepness results indicate that the Zhongtiao Shan, controlled by the north Zhongtiao Shan normal fault, experiences asymmetric uplift and erosion patterns, with higher uplift and erosion on the north range. In addition, the Gilbert and χ metrics suggest that the western part of the main divide is currently stable, while the eastern divide is moving southward. According to the drainage divide stability criteria, we suggest that the uplift and erosion, on the fault side, balance each other well on the western part of the range, while on the eastern part, the uplift is outpaced by the erosion. In addition, a dynamic divide migration model in the asymmetric uplift condition is proposed, indicating that the interaction between uplift and erosion controls the migration and/or stability of the main divide. Deducing through this dynamic model, we suggested that the eastern segment of the north Zhongtiaoshan Fault must have experienced higher activities in the geological history, and the western fault may remain its activity along with the mountain relief generation. This gives a case that specific information on asymmetric neotectonic history and landscape evolution in an orogenic mountain can be uncovered by the proposed dynamic model. [ABSTRACT FROM AUTHOR]