Seismic origin of the soft‐sediment deformation structures in the upper Palaeo‐Mesoproterozoic Semri Group, Vindhyan Supergroup, Central India

2020 ◽  
Vol 55 (11) ◽  
pp. 7474-7488
Author(s):  
Birendra Pratap Singh ◽  
Krishna Mondal ◽  
Akanksha Singh ◽  
Preeti Mittal ◽  
Rohit Kumar Singh ◽  
...  

Geologos ◽  
2014 ◽  
Vol 20 (2) ◽  
pp. 89-103 ◽  
Author(s):  
Subir Sarkar ◽  
Adrita Choudhuri ◽  
Santanu Banerjee ◽  
A.J. (Tom) Van Loon ◽  
Pradip K Bose

Abstract Numerous soft-sediment deformation structures occur within the Proterozoic Bhander Limestone of an intracratonic sag basin in a 750 m long section along the Thomas River, near Maihar, central India. Part of these deformation structures have most probably a non-seismic origin, but other structures are interpreted as resulting from earthquake-induced shocks. These seismic structures are concentrated in a 60 cm thick interval, which is interpreted as three stacked seismi-tes. These three seismites are traceable over the entire length of the section. They divide the sedimentary succession in a lower part (including the seismites) deposited in a hypersaline lagoon, and an upper open-marine (shelf) part. Most of the soft-sediment deformations outside the seismite interval occur in a lagoonal intraclastic and muddy facies association. The SSDS within the seismite interval show a lateral continuity. They record simultaneous fluidisation and liquefaction. The bases of each of the three composing seismite bands are defined by small-scale shear folds, probably recording an earthquake and aftershocks. The presence of the three seismite bands at the boundary between the lagoonal and the overlying open-marine oolitic facies association suggests that the seismic event also triggered basin subsidence.



Terra Nova ◽  
1997 ◽  
Vol 9 (5) ◽  
pp. 208-212 ◽  
Author(s):  
P.G. Silva ◽  
J.C. Canaveras ◽  
S. Sanchez-Moral ◽  
J. Lario ◽  
E. Sanz


2000 ◽  
Vol 49 (4) ◽  
pp. 197-214 ◽  
Author(s):  
Dan Bowman ◽  
Dorit Banet-Davidovich ◽  
Hendrik J. Bruins ◽  
Johannes Van der Plicht




Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 721
Author(s):  
Ukhwan Byun ◽  
A.J. (Tom) van Loon ◽  
Kyoungtae Ko

The Gyeokpori Formation in the Buan volcanic area primarily contains siliciclastic rocks interbedded with volcanoclastics. These sediments are characterized by a variety of soft-sediment deformation structures (SSDS). The SSDS in the Gyeokpori Formation are embedded in poorly sorted conglomerates; slump folds are also present in the formation. The deformation mechanisms and triggers causing the deformation are not yet clear. In the present study, the trigger of the SSDS in the Gyeokpori Formation was investigated using facies analysis. This included evaluation of the reworking process of both cohesive and non-cohesive sediments. The analysis indicates that the SSDS are directly or indirectly associated with the alternation of conglomerates and mud layers with clasts. These layers underwent non-cohesive and cohesive deformation, respectively, which promoted SSDS formation. The slump folds were controlled by the extent of cohesive and non-cohesive deformation experienced by the sediment layers in the slope environment. The SSDS deformation style and morphology differ, particularly in the case of reworking by slump activity. This study contributes to the understanding of lacustrine slope-related soft-sediment deformation structures.



Fractals ◽  
2018 ◽  
Vol 26 (01) ◽  
pp. 1850018 ◽  
Author(s):  
YOSHITO NAKASHIMA ◽  
JUNKO KOMATSUBARA

Unconsolidated soft sediments deform and mix complexly by seismically induced fluidization. Such geological soft-sediment deformation structures (SSDSs) recorded in boring cores were imaged by X-ray computed tomography (CT), which enables visualization of the inhomogeneous spatial distribution of iron-bearing mineral grains as strong X-ray absorbers in the deformed strata. Multifractal analysis was applied to the two-dimensional (2D) CT images with various degrees of deformation and mixing. The results show that the distribution of the iron-bearing mineral grains is multifractal for less deformed/mixed strata and almost monofractal for fully mixed (i.e. almost homogenized) strata. Computer simulations of deformation of real and synthetic digital images were performed using the egg-beater flow model. The simulations successfully reproduced the transformation from the multifractal spectra into almost monofractal spectra (i.e. almost convergence on a single point) with an increase in deformation/mixing intensity. The present study demonstrates that multifractal analysis coupled with X-ray CT and the mixing flow model is useful to quantify the complexity of seismically induced SSDSs, standing as a novel method for the evaluation of cores for seismic risk assessment.



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