Soft sediment deformation structures in the Lixian lacustrine sediments, eastern Tibetan Plateau and implications for postglacial seismic activity

Jiang, Hanchao; Zhong, Ning; Li, Yanhao; Xu, Hongyan; Yang, Haijun; Peng, Xiaoping

doi:10.1016/j.sedgeo.2016.06.011

Cited by 40 publications

(40 citation statements)

References 82 publications

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“…The liquefaction/fluidification process, typical at the mesoscale, causes the formation of (i) intrusions of fluidized sands in fractures crosscutting undeformed strata (clastic dikes; e.g., Montenat et al, ) and (ii) sand volcanoes and blows along planar fissures (e.g., Rodríguez‐Pascua et al, ; Tuttle & Barstow, ). Other seismically induced soft‐sediment deformations (SSDs) are load structures and slumps frequently hosting minor thrust and normal faults, mainly recorded in coastal, deltaic, and turbidite settings and also in flat‐lying layers such as lacustrine sediments (Alsop & Marco, ; García‐Tortosa et al, ; Jiang et al, ; Moretti & Ronchi, ; Moretti & Sabato, ; Rodríguez‐Pascua et al, ; Uner, ). Although seismically induced sand dikes and slumps are commonly observed within the geological record, examples of paleosand volcanoes are very limited (e.g., Caputo et al, ; Loope et al, ).…”

Section: Introductionmentioning

confidence: 99%

Seismically Induced Soft‐Sediment Deformation Phenomena During the Volcano‐Tectonic Activity of Campi Flegrei Caldera (Southern Italy) in the Last 15 kyr

et al. 2019

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We report, for the first time, evidence of seismically induced soft‐sediment deformations in the central area of the active Campi Flegrei caldera (southern Italy). We analyzed the marine‐transitional and continental sequences located along the coastal La Starza cliffs and several stratigraphic logs exposed during the excavation of a 1‐km‐long tunnel in the Pozzuoli area. The successions host several soft‐sediment structures including sand dikes and sand volcanoes, which are largely dated within the 4.55‐ to 4.28‐kyr BP interval. The volcano‐sedimentary sequence, deposited within the Campi Flegrei caldera in the last 15 kyr, is schematically formed by the superposition of three layers with different rheological behaviors; from the base progressing upward we recognize (1) a massive tuff, (2) marine‐transitional sands of the La Starza unit, and (3) a dominance of continental volcanoclastics. We envisage that during unrest episodes of the volcano, which included ground deformation and seismic activity, the whole volcano‐sedimentary pile was deformed through brittle mechanisms with the formation of normal faults. However, the intermediate layer, when subject to seismic shaking, behaved locally as a viscous material facilitating liquefaction processes and lateral spreading deformation. Furthermore, new geophysical, stratigraphic, and structural surveys allowed us to model the deformation evolution of this area over the last 15 kyr. The evidence of seismically induced soft‐sediment deformation within the volcano‐sedimentary record suggests that moderate earthquakes could occur during future volcano‐seismic unrests. Consequently, liquefaction and related gravitational mass movements must be considered as a hazard during these unrest and volcanic crises.

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Section: Introductionmentioning

confidence: 99%

Seismically Induced Soft‐Sediment Deformation Phenomena During the Volcano‐Tectonic Activity of Campi Flegrei Caldera (Southern Italy) in the Last 15 kyr

et al. 2019

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“…The structure under study was found in the Cretaceous Gyeokpori Formation, which is ex-posed along the western coast of South Korea. The formation consists of lacustrine sediments that accumulated on the slope of a subaqueous fan-delta system, a position that is commonly considered most suitable to inducing and preserving SSDS (Gibert et al, 2005;Moretti & Sabato, 2007;Tanner & Lucas, 2007;Gladkov et al, 2016;Jiang et al, 2016;Ko et al, 2017). Indeed, the formation contains numerous slump-related SSDS (Martinsen, 1989;Porębski & Steel, 2003) in addition to the one under study.…”

Section: Introductionmentioning

confidence: 99%

A new type of slumping-induced soft-sediment deformation structure: the envelope structure

et al. 2019

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The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled. A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure.

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“…Soft-sediment deformation (SSD) structures related to liquefaction and/or fluidization processes are commonly used to identify paleoseismic events 6 , 8 , 9 , 11 . Recently, various SSD structures have been found on the eastern Tibetan Plateau (TP), including clastic dykes, ball-and-pillow structures, flame structures, clastic gravels, micro-faults, and slump folds 8 , 9 , 11 . Data on earthquake intensity and the effects of seismicity on sediments suggest that liquefaction is generally induced at magnitudes greater than Ms~5.0/5.5 12 , 13 .…”

Section: Introductionmentioning

confidence: 99%

A continuous 13.3-ka record of seismogenic dust events in lacustrine sediments in the eastern Tibetan Plateau

Jiang

Zhong

et al. 2017

Sci Rep

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Lacustrine sediments on the eastern Tibetan Plateau (TP) contain a wealth of information on local and regional tectonic activity. High-resolution grain-size and magnetic susceptibility measurements were conducted on the 23.4-m-thick Lixian lacustrine sedimentary sequence spanning from 19.3 to 6.0 ka, revealing 70 prehistoric seismic events on the eastern TP. The seismic events caused intermittent increases in source materials that endowed the samples of an individual event layer with a gradual fining trend along the C = M line on a C (one percentile)-M (median diameter) plot. Grain-size distribution and end-member modeling imply that dust particles of <20 μm in size were transported primarily by long-term suspension, while medium to coarse silt and sand were transported primarily by short-term suspension, such as aeolian transport constrained by local topography. Provenance analysis based on U-Pb zircon ages indicates that dust particles generated by earthquakes at Lixian had no effect on dust deposition at Xinmocun and Diaolin, and vice versa. These prehistoric seismic events, revealed by variations in grain size and magnetic susceptibility, thus provide invaluable information on the long-term behavior of local seismic activity.

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Soft sediment deformation structures in the Lixian lacustrine sediments, eastern Tibetan Plateau and implications for postglacial seismic activity

Cited by 40 publications

References 82 publications

Seismically Induced Soft‐Sediment Deformation Phenomena During the Volcano‐Tectonic Activity of Campi Flegrei Caldera (Southern Italy) in the Last 15 kyr

Seismically Induced Soft‐Sediment Deformation Phenomena During the Volcano‐Tectonic Activity of Campi Flegrei Caldera (Southern Italy) in the Last 15 kyr

A new type of slumping-induced soft-sediment deformation structure: the envelope structure

A continuous 13.3-ka record of seismogenic dust events in lacustrine sediments in the eastern Tibetan Plateau

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