Neotectonics of the Bailongjiang and Hanan faults: New insights into late Cenozoic deformation along the eastern margin of the Tibetan Plateau

Abstract The way that far-field stresses and deformation propagated eastward in response to the growth and extrusion of the northeastern Tibetan Plateau remains a crucial scientific issue. This paper focuses on the Bailongjiang and Hanan faults, which are the easternmost part of the East Kunlun fault in northeast Tibet. Based on new field geological investigations, structural data, satellite imagery interpretation, and optically stimulated luminescence and 14C dating results, this paper presents the structural geometry and neotectonic activities of the two faults. The ∼200-km-long Bailongjiang fault, bounding the Bayan Har block in northeast Tibet, consists of two segments. Along the western segment, late Pleistocene lacustrine-facies deposits and Holocene activities were discovered in a great fault scarp. The left-slip rate of the fault is estimated to be ∼1.73–2.61 mm/yr, with an elapsed time of ∼2205 yr after a catastrophic paleoseismic event greater than M 7.2 ruptured the fault. The eastern segment splits into two branches and shows a positive flower structure where a pull-apart basin developed, filled with ∼200-m-thick mudstone and argillaceous siltstone, which record the mid-late Miocene deformation of the Bailongjiang fault. The Hanan fault features reverse faulting caused by NNW-SSE compression in the late Cenozoic. The two faults, together with the Maqên-Maqu-Tazang fault, confine the area of a strip block, the eastward extrusion of which was accommodated by thrusting due to the resistance of the stable Bikou massif since the late Cenozoic, which led to decreasing slip rates along the easternmost part of the Kunlun fault.

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Effects of Erosion and Deposition on Constraining Vertical Slip Rates of Thrust Faults: A Case Study of the Minle–Damaying Fault in the North Qilian Shan, NE Tibetan Plateau

Frontiers in Earth Science ◽

10.3389/feart.2021.635702 ◽

2021 ◽

Vol 9 ◽

Author(s):

Qingri Liu ◽

Huiping Zhang ◽

Youli Li ◽

Feipeng Huang ◽

Xudong Zhao ◽

...

Keyword(s):

Tibetan Plateau ◽

Slip Rate ◽

Simulation Method ◽

The Tibetan Plateau ◽

Stratigraphic Sequence ◽

Erosion And Deposition ◽

Slip Rates ◽

The North ◽

Vertical Fault ◽

Fault Displacement

The height of a thrust-fault scarp on a fluvial terrace would be modified due to erosion and deposition, and these surface processes can also influence the dating of terraces. Under such circumstances, the vertical slip rate of a fault can be misestimated due to the inaccurate displacement and/or abandonment age of the terrace. In this contribution, considering the effect of erosion and deposition on fault scarps, we re-constrained the vertical slip rate of the west end of the Minle–Damaying Fault (MDF), one of the thrusts in the north margin of the Qilian Shan that marks the northeastern edge of the Tibetan Plateau. In addition, we tried to explore a more reliable method for obtaining the vertical fault displacement and the abandonment age of terraces with AMS 14C dating. The heights of the surface scarps and the displacements of the fluvial gravel layers exposed on the Yudai River terraces were precisely measured with the Structure from Motion (SfM) photogrammetry and the real-time kinematic (RTK) GPS. The Monte Carlo simulation method was used to estimate the uncertainties of fault displacements and vertical slip rates. Based on comparative analysis, the dating sample from the fluvial sand layer underlying the thickest loess in the footwall was suggested to best represent the abandonment age of the terrace, and the fluvial gravel layer could better preserve the original vertical fault displacement compared with the surface layer. Using the most reliable ages and vertical offsets, the vertical slip rate of the MDF was estimated to be 0.25–0.28 mm/a since 42.3 ± 0.5 ka (T10) and 0.14–0.24 mm/a since 16.1 ± 0.2 ka (T7). The difference between the wrong vertical slip rate and the right one can even reach an order of magnitude. We also suggest that if the built measuring profile is long enough, the uncertainties in the height of a surface scarp would be better constrained and the result can also be taken as the vertical fault displacement. Furthermore, the consistency of chronology with stratigraphic sequence or with terrace sequence are also key to constraining the abandonment ages of terraces. The fault activity at the study site is weaker than that in the middle and east segments of the MDF, which is likely due to its end position.

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OSL dating of the late Quaternary slip rate on the Gyaring co Fault in central Tibet

Geochronometria ◽

10.1515/geochr-2015-0040 ◽

2016 ◽

Vol 43 (1) ◽

pp. 162-173 ◽

Cited By ~ 1

Author(s):

Duo Wang ◽

Gong-Ming Yin ◽

Xu-Long Wang ◽

Chun-Ru Liu ◽

Fei Han ◽

...

Keyword(s):

Tibetan Plateau ◽

Late Quaternary ◽

Slip Rate ◽

Strike Slip ◽

Alluvial Fan ◽

Osl Dating ◽

The Tibetan Plateau ◽

Slip Rates ◽

Absolute Age ◽

Central Tibet

Abstract The Gyaring Co Fault (GCF) is an active right-lateral strike-slip fault in central Tibet that accommodates convergence between India and Asia in the interior of the Tibetan Plateau. The average long-term slip rate of the fault remains controversial, given the absence of absolute age data of faulted geomorphic features. We have applied optically stimulated luminescence (OSL) dating to the northern segment of the GCF, revealing that the GCF has displaced alluvial fans at Aerqingsang by 500 ± 100 m since their deposition at ~109 ka, yielding a slip rate of 4.6 ± 1.0 mm/yr. A slip rate of 3.4 ± 0.4 mm/yr is inferred from analysis of an alluvial fan with an offset of 65 ± 5 m (~19 ka) at Quba site 1. The Holocene slip rate is estimated to be 1.9 ± 0.3 mm/yr, as inferred from the basal age (~8.3 ka) of terrace T1 that has a gully displacement of 16 ± 2 m at Quba site 2. These slip rates are generally lower early estimates (10–20 mm/yr), but are consistent with more recent results (2.2–4.5 mm/yr) and GPS data for other strike-slip faults in this region, indicating that deformation may be distributed across the entire Tibetan Plateau. Moreover, we suggest that the slip rate along the GCF may have decreased slightly during the late Quaternary.

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New constraints on Quaternary slip partitioning near the eastern termination of the Altyn Tagh Fault

10.5194/egusphere-egu21-12517 ◽

2021 ◽

Author(s):

Nimrod Wieler ◽

Amit Mushkin ◽

Eitan Shelef ◽

Huiping Zhang ◽

Amir Sagy ◽

...

Keyword(s):

Tibetan Plateau ◽

Late Quaternary ◽

Slip Rate ◽

Alluvial Fan ◽

Luminescence Dating ◽

The Tibetan Plateau ◽

Altyn Tagh Fault ◽

Slip Rates ◽

Altyn Tagh ◽

Slip Partitioning

Slip partitioning along the northern boundary of the Tibetan Plateau is essential for understanding regional deformation and the seismic potential of the different faults that accommodate it. Within this framework the Altyn Tagh Fault (ATF) is commonly viewed as the primary structure that separates the Tibetan Plateau from the stable Gobi-Alashan block to the north. Late Quaternary sinistral slip rates of 8-12 mm/yr across the central ATF between 86&#176; and 93&#176;E decrease eastwards to zero as the fault approaches its mid-continental termination at ~97&#176;E. To better understand how late Quaternary slip is partitioned along the ATF&#8217;s eastern termination we obtained new slip-rate measurements&#160; for the ~200-km-long left-lateral ENE striking Sanweishan Fault (SSF) located ~60 km north of the ATF between 94&#176;-96&#176;E near the town of Dunhuang.Multiple sinistral offsets ranging up to 600 m were identified by linking the clast assemblage of offset alluvial fan remnants with their provenance upstream of the fault. &#160;Luminescence dating revealed depositional ages ranging from 100 - 200 ka for the offset features and time-invariant minimum sinistral slip of 2.5&#177;1 mm/yr during the last ~200 ka, which is approximately an order of magnitude higher than previously reported slip-rates for the SSF. Our results indicate that the SSF and the eastern segment of the ATF accommodate comparable magnitudes of late Quaternary slip. Considering this substantial transfer of lateral slip as far as 60 km north of the eastern ATF we propose that the SSF may represent juvenile northeastward expansion of the Tibetan Plateau into previously stable parts of the Gobi-Alashan block.

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Holocene slip rate of the frontal thrust in the western Qilian Shan, NE Tibetan Plateau

Geophysical Journal International ◽

10.1093/gji/ggz325 ◽

2019 ◽

Vol 219 (2) ◽

pp. 853-865

Author(s):

Xingwang Liu ◽

Daoyang Yuan ◽

Wenjun Zheng ◽

Yanxiu Shao ◽

Bingxu Liu ◽

...

Keyword(s):

Tibetan Plateau ◽

Slip Rate ◽

Slip Rates ◽

Northern Margin ◽

Field Investigations ◽

Western Segment ◽

Aerial Vehicle ◽

High Resolution Satellite Imagery ◽

Fault Scarps ◽

Geomorphic Surfaces

SUMMARY The activities of frontal thrusts in the northern Qilian Shan are critical for understanding the deformation of the Qilian Shan and the northeastern Tibetan Plateau. In this study, we estimate the slip rate of the active Fodongmiao–Hongyazi thrust along the northern margin of the Qilian Shan. High-resolution satellite imagery interpretations and detailed field investigations suggest that the fault displaced late Pleistocene terraces and formed fresh prominent north-facing fault scarps. To quantify the slip rate of the fault, we measured the displacements along the fault scarps using an unmanned aerial vehicle system and dated the displaced geomorphic surfaces using optically stimulated luminescence (OSL) and 14C methods. The vertical slip rate of the fault is estimated at 1.0 ± 0.3 mm yr−1 for the western segment. The slip rates for two branches in the eastern segment are 0.3 ± 0.1 and 0.6 ± 0.1 mm yr−1. Using a fault dip of 40 ± 10°, we constrain the corresponding shortening rates to 1.4 ± 0.5 and 1.2 ± 0.4 mm yr−1, respectively. The rates are consistent with values over different timescales, which suggests steady rock uplift and northeastward growth of the western Qilian Shan. Crustal shortening occurs mainly on the range-bounding frontal thrust.

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Late Cenozoic geological evolution of the foreland basin bordering the West Kunlun range in Pulu area: Constraints on timing of uplift of northern margin of the Tibetan Plateau

Journal of Geophysical Research Atmospheres ◽

10.1029/2002jb001877 ◽

2003 ◽

Vol 108 (B8) ◽

Cited By ~ 62

Author(s):

Erchie Wang

Keyword(s):

Tibetan Plateau ◽

Foreland Basin ◽

The Tibetan Plateau ◽

Late Cenozoic ◽

The West ◽

Northern Margin ◽

Geological Evolution ◽

West Kunlun

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Late Cenozoic Denudation and Topographic Evolution History of the Lhasa River Drainage in Southern Tibetan Plateau: Insights From Inverse Thermal History Modeling

Frontiers in Earth Science ◽

10.3389/feart.2021.636459 ◽

2021 ◽

Vol 9 ◽

Author(s):

Dongxu Cai ◽

Xianyan Wang ◽

Guangwei Li ◽

Wenbin Zhu ◽

Huayu Lu

Keyword(s):

Tibetan Plateau ◽

Surface Erosion ◽

The Tibetan Plateau ◽

Monsoon Precipitation ◽

Late Cenozoic ◽

River Drainage ◽

History Of ◽

Southern Tibetan Plateau ◽

Lhasa River ◽

Topographic Evolution

The interaction of surface erosion (e.g., fluvial incision) and tectonic uplift shapes the landform in the Tibetan Plateau. The Lhasa River flows toward the southwest across the central Gangdese Mountains in the southern Tibetan Plateau, characterized by a low-relief and high-elevation landscape. However, the evolution of low-relief topography and the establishment of the Lhasa River remain highly under debate. Here, we collected thermochronological ages reported in the Lhasa River drainage, using a 3D thermokinematic model to invert both late Cenozoic denudation and relief history of the Lhasa River drainage. Our results show that the Lhasa River drainage underwent four-phase denudation history, including two-stage rapid denudation at ∼25–16 Ma (with a rate of ∼0.42 km/Ma) and ∼16–12 Ma (with a rate of ∼0.72 km/Ma). In the latest Oligocene–early Miocene, uplift of the Gangdese Mountains triggered the rapid denudation and the formation of the current main drainage of the Lhasa River. In the middle Miocene, the second stage of the rapid denudation and the high relief were associated with intense incision of the Lhasa River, which is probably due to the enhanced Asian summer monsoon precipitation. This later rapid episode was consistent with the records of regional main drainage systems. After ∼12 Ma, the denudation rate decreases rapidly, and the relief of topography in the central Gangdese region was gradually subdued. This indicates that the fluvial erosion resulting from Asian monsoon precipitation increase significantly impacts on the topographic evolution in the central Gangdese region.

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Initiation and Development of the Late Cenozoic Uplift of Daluo Mts, Northeastern Margin of the Tibetan Plateau

Acta Geologica Sinica - English Edition ◽

10.1111/1755-6724.14891 ◽

2022 ◽

Author(s):

Linlin KOU ◽

Xiaopeng DONG ◽

Zhenhong LI ◽

Jiawei CUI ◽

Zhaoying MA ◽

...

Keyword(s):

Tibetan Plateau ◽

The Tibetan Plateau ◽

Late Cenozoic

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Paleoearthquakes on the Húsavík-Flatey Fault in northern Iceland: Where are the large earthquakes?

10.5194/egusphere-egu21-13998 ◽

2021 ◽

Author(s):

Remi Matrau ◽

Yann Klinger ◽

Jonathan Harrington ◽

Ulas Avsar ◽

Esther R. Gudmundsdottir ◽

...

Keyword(s):

Slip Rate ◽

Late Glacial ◽

Fault Scarp ◽

Alluvial Fan ◽

Tectonic Deformation ◽

Birch Wood ◽

Alluvial Deposits ◽

Slip Rates ◽

Tephra Layers ◽

Large Earthquakes

Paleoseismology is key to study earthquake recurrence and fault slip rates during the Late Pleistocene-Holocene. The H&#250;sav&#237;k-Flatey Fault (HFF) in northern Iceland is a 100 km-long right-lateral transform fault connecting the onshore Northern Volcanic Zone to the offshore Kolbeinsey Ridge and accommodating, together with the Gr&#237;msey Oblique Rift (GOR), ~18 mm/yr of relative motion between the Eurasian and North American plates. Significant earthquakes occurred on the HFF in 1755, 1838 and 1872 with estimated magnitudes of 6.5-7. However, historical information on past earthquakes prior to 1755 is very limited in both timing and size.We excavated five trenches in a small basin (Vestari Krubbssk&#225;l) located 5.5 km southeast of the town of H&#250;sav&#237;k and at 300 m.a.s.l. and one trench in an alluvial fan (Tra&#240;arger&#240;i) located 0.5 km north of H&#250;sav&#237;k and at 50 m.a.s.l. In a cold and wet environment, such as in coastal parts of Iceland, one has to take into account periglacial processes affecting the topsoil to discriminate tectonic from non-tectonic deformation. We used tephra layers in the Vestari Krubbssk&#225;l and Tra&#240;arger&#240;i trenches as well as birch wood samples in Tra&#240;arger&#240;i to constrain the timing of past earthquakes. Tephra layers Hekla-3 (2971 BP) and Hekla-4 (4331&#177;20 BP) are visible in the top half of all the trenches. In addition, a few younger tephra layers are visible in the top part of the trenches. In Tra&#240;arger&#240;i several dark layers rich in organic matter are found, including birch wood-rich layers from the Earlier Birch Period (9000-7000 BP) and the Later Birch Period (5000-2500 BP). In Vestari Krubbssk&#225;l the lower halves of the trenches display mostly lacustrine deposits whereas in Tra&#240;arger&#240;i the lower half of the trench shows alluvial deposits overlaying coarser deposits (gravels/pebbles) most likely of late-glacial or early post-glacial origins. In addition, early Holocene tephra layers are observed in some of the trenches at both sites and may correspond to Askja-S (10800 BP), Saksunarvatn (10300 BP) and Vedde (12100 BP). These observations provide good age constraints and suggest that both the Vestari Krubbssk&#225;l and Tra&#240;arger&#240;i trenches cover the entire Holocene.Trenches at both sites show significant normal deformation in addition to strike-slip, well correlated with their larger scale topographies (pull-apart basin in Vestari Krubbssk&#225;l and 45 m-high fault scarp in Tra&#240;arger&#240;i). We mapped layers, cracks and faults on all trench walls to build a catalogue of Holocene earthquakes. We identified events based on the upward terminations of the cracks and retrodeformation. Our results yield fewer major earthquakes than expected, suggesting that large earthquakes (around magnitude 7) are probably rare and the more typical HFF earthquakes of magnitude 6-6.5 likely produce limited topsoil deformation.[yk1]&#160; Our interpretation also suggests that the Holocene slip rate [yk2]&#160;for the fault section we are studying may be slower than the estimated geodetic slip rate (6 to 9 mm/yr)[yk3]&#160; for the entire onshore HFF, although secondary onshore sub-parallel fault strands could accommodate part of the deformation.

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