Fault and fracture patterns around a strike-slip influenced salt wall

Alsop, G. Ian; Weinberger, R.; Marco, Shmuel; Levi, T.

doi:10.1016/j.jsg.2017.10.010

Cited by 24 publications

(12 citation statements)

References 82 publications

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“…Moreover, the general settings differ in that BPS associated with seismic shaking is recorded above the Sedom salt Formation and is bound to the east by the Sedom salt wall (e.g. Weinberger et al, 2006;Alsop et al, 2018b). Such a setting may amplify seismicity (Jacoby et al, 2015 ) compared to the Miflat case study area, which has the deepest part of the basin to the east and is therefore unconstrained.…”

Section: Bps Created By Co-seismic Shakingmentioning

confidence: 99%

Bed-parallel slip: Identifying missing displacement in mass transport deposits

Alsop

Weinberger

Marco

et al. 2020

Journal of Structural Geology

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Bed-parallel slip (BPS), where neighbouring beds slide past one another along bedding planes, is notoriously difficult to identify without reference to pre-existing features such as steep faults or dykes that act as markers to record BPS offset. While BPS is intuitively thought to operate during downslope sliding of mass transport deposits (MTDs) in sedimentary basins, there is a conspicuous lack of supporting outcrop or seismic data to corroborate this and BPS displacement may therefore have remained unaccounted for. This study addresses this gap in knowledge by investigating late-Pleistocene MTDs developed around the Dead Sea Basin and provides the first detailed analysis of BPS that pervades a gravity-driven setting. In particular, we examine the role of BPS that crosscuts earlier normal and reverse faults that act as markers to allow metre-scale patterns of horizontal displacement to be identified in MTDs. The studied BPS always forms with a consistent top-to-the east sense of offset that corresponds with gravity-driven downslope movement towards the depo-centre of the basin. BPS frequently develops adjacent to competent detrital-rich beds and forms discrete glide planes with little or no visible deformation in sediments on either margin, although detachment folds are occasionally developed above the slip plane and confirm directions of easterly movement. Early downslope-dipping normal faults that are cut by later BPS planes results in older over younger stratigraphic relationships across the BPS surface, together with 'sawtooth' patterns where multiple BPS planes have developed. Conversely, early upslope-dipping normal faults that are cut by BPS create younger over older stratigraphic relationships combined with missing section and 'staircase' patterns where multiple BPS planes exist. As BPS in subhorizontal sequences does not have a vertical component of displacement, it may be examined in terms of horizontal 'heave'. BPS increases heave in upslope-dipping normal faults, whereas it reduces heave in downslope-dipping normal faults and may even become negative where sections are repeated across sawtooth profiles. In addition, BPS increases heave in upslope-dipping reverse/thrust faults and reduces heave across downslope dipping 'backthrusts'. Although individual BPS planes may have limited displacement, the net consequence of multiple planes of BPS that form in the shallow-subsurface is to distort patterns and estimates of extension and contraction across fault zones in MTDs.

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Section: Bps Created By Co-seismic Shakingmentioning

confidence: 99%

Bed-parallel slip: Identifying missing displacement in mass transport deposits

Alsop

Weinberger

Marco

et al. 2020

Journal of Structural Geology

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“…In the example of the Flieth salt pillow, the Bockenberg and Weiler clusters seem to follow the shape of the salt structure (Figure 10-1), similar to the Thomsdorf cluster (Triepkendorf salt pillow; regions (Alsop et al, 2018). Furthermore, the occurrence of the cracks may also be influenced by pre-existing structures and lithological variations underground.…”

Section: Discussionmentioning

confidence: 81%

“…The cracks mostly occur only on one side of the structure and do not surround the structure in a radial pattern, as might be expected. However, as revealed by structural analyses of fracture patterns in the overburden around a salt wall in the Dead Sea region, radial patterns do not necessarily develop in tectonically active regions (Alsop et al, 2018). Furthermore, the occurrence of the cracks may also be influenced by pre‐existing structures and lithological variations underground.…”

Section: Discussionmentioning

confidence: 99%

Surface cracks—geomorphological indicators for late Quaternary halotectonic movements in Northern Germany

Hardt

Norden

Bauer

et al. 2021

Earth Surf Processes Landf

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Loading and unloading effects of the Scandinavian Ice Sheet triggered halotectonic movements in Northern Germany. We present newly detected geomorphological features-termed surface cracks-which indicate a relation between ice sheetinduced salt movement and surface processes. As a part of the Central European Basin System, numerous Zechstein salt structures are abundant in the North German Basin. On the basis of high-resolution digital terrain data, more than 160 surface cracks were mapped in Northern Germany, which were grouped into 30 clusters. Almost all of the surface cracks occur above the top regions of Zechstein salt structures. The surface cracks can be several kilometres long, up to more than 20 m deep and more than 100 m wide. The comparison of the shape of the salt structures and the orientation of the cracks reveals a geometric dependency, indicating that the cracks preferably occur near the crest margins of the salt structures. Furthermore, 3D seismic data from two sites show that subsurface faults originating from salt movement exist beneath the surface cracks. We interpret the cracks as surface ruptures due to ice sheet-induced halotectonic movements. The cracks occur in a variety of Quaternary sediments and landforms. This indicates that widespread halokinetic movements occurred in the region after the last (Weichselian) deglaciation and likely before the thawing of the permafrost, possibly in a time frame from c. 30-20 ka until c. 15 ka.

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“…The Sedom salt wall is one of the few places on Earth where thick intrasalt beds and adjacent salt are exposed at the surface. The large‐scale setting of these beds was previously determined by means of field mapping (Zak, ), stratigraphy (Zak et al, ), paleomagnetism (Weinberger et al, , ), and mesoscale analysis (Alsop et al, , ). In this study, we provide further insights from the results of magnetic fabric analysis, which was recently shown to be a promising tool for assessing deformation within exposed salt bodies (Santolaria et al, ; Soto et al, ) (see section ).…”

Section: Introductionmentioning

confidence: 99%