Sediment creep on slopes in pelagic limestones: Upper Jurassic of Northern Calcareous Alps, Austria

Ortner, Hugo; Kilian, Sinah

doi:10.1016/j.sedgeo.2016.03.013

Cited by 29 publications

(13 citation statements)

References 40 publications

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“…Regarding the lithological formations, the tectonic status of the study area has led to diverse and heterogeneous outcrops that add up to 15 lithological formations, among which ultra-basic rocks, pillow-shaped rock mounds, and pelagic limestone, Mesozoic in age, had the highest rate of landslide density. Mainly, unmetamorphosed pelagic limestone by featuring a chaotic assemblage of clayey-marly sequences with an increase in shale thickness towards upper strata exhibits high susceptibility to different types of landslides, which has been previously reported in different studies such as Ortner and Kilian (2016) and Carabella et al (2019). Similar results on landslide-prone limestones are also reported by Lau (2018), Pham et al (2019).…”

Section: Expected Resultssupporting

confidence: 52%

Landslide susceptibility assessment and mapping using statistical and data mining models in Iran

Hanifinia

Nazarnejad

Najafi

et al. 2021

Preprint

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This study applied to evaluate landslide susceptibility using four data mining models including, “Generalized Linear Model (GLM)”, “Maximum Entropy (ME)”, “Artificial Neural Network (ANN)”, and “Support Vector Machine (SVM)” in Cherikabad Watershed in Urmia City, Iran. In particular, Shannon entropy was used to assess the intercomparison of factors’ classes. Eleven factors including, elevation, slope angle, slope aspect, geological formation, annual mean rainfall, land use/ land cover, distance to the village, distance to faults, distance to roads, distance to streams, and NDVI used in the current study. Landslide inventory map was identified using Google Earth imagery, extensive field surveys, and scrutinizing archived data. The produced landslide susceptibility maps were evaluated by the AUROC index. The results of performance metrics revealed that the Shannon entropy with an AUROC of 0.879 proved highly reliable and so is the intercomparison analysis of factors’ classes derived from it. Additionally, the goodness-of-fit of the GLM, ME, ANN, and SVM models were 0.763, 0.740, 0.926, and 0.924, while their predictive powers were 0.751, 0.727, 0.917, and 0.935, respectively. Hence, the results indicated that the SVM model can be introduced as the superior model for the study area based on which the most critical factors affecting landslides were found to be elevation, annual mean rainfall, and distance to the village. The results of this work are of great use for land use planning in landslide-prone areas with similar geo-topological, geomorphological, and climatic conditions.

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Section: Expected Resultssupporting

confidence: 52%

Landslide susceptibility assessment and mapping using statistical and data mining models in Iran

Hanifinia

Nazarnejad

Najafi

et al. 2021

Preprint

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“…6g, h) may therefore encourage harmonic folding. Ortner & Kilian (2016) also recognised fold styles that vary between Class 1B and Class 3 in adjacent layers within unlithified carbonates undergoing downslope-directed creep. Ramsay (1974) realised that if competent layers were thicker than the average in the multilayer, then accommodation structures must develop around this thicker layer, with adjacent layers displaying 'keel-like' hinges (Price & Cosgrove 1990, p.320).…”

Section: What Range Of Fold Styles Are Created During Slumping?mentioning

confidence: 99%

“…It is generally assumed that slump folds generated during soft-sediment deformation (SSD) within mass transport deposits (MTDs) bear a close resemblance to tectonic folds created during hard rock deformation (HRD) (see discussions in Elliot & Williams 1988;Maltman 1994;Alsop et al 2019a). However, there has in reality been very little systematic analysis of fold styles created during soft-sediment deformation, with some notable exceptions including Woodcock (1976aWoodcock ( , b, 1979, Farrell & Eaton (1987), Waldron & Gagnon (2011) and Ortner & Kilian (2016). Hudleston (1986, p.238) noted that "shape alone cannot be used to distinguish soft-sediment folds from tectonic folds" (see also Woodcock 1976b).…”

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confidence: 99%

Folding during soft-sediment deformation

Alsop

Weinberger

Marco

et al. 2019

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The detailed analysis of folding in rocks was in part pioneered by John Ramsay, and resulted in a range of techniques and criteria to define folds. Although folding of unlithified or ‘soft’ sediments is typically assumed to produce similar geometries to those in ‘hard rocks’, there has to date been little detailed analysis of such folds. The aim of this paper is therefore to investigate folds developed during soft-sediment deformation (SSD) by applying techniques established for the analysis of tectonic folds during hard-rock deformation (HRD). We use the Late Pleistocene Lisan Formation exposed around the Dead Sea as our case study, as the laminated lake sediments record intricacies of fold detail generated during seismically triggered slumping of mass transport deposits (MTDs) towards the depocentre of the basin. While it is frequently assumed that folds created during SSD are chaotic and form disharmonic structures, we provide analyses that show harmonic fold trains may form during slumping, although larger upright folds cannot be traced for significant distances and are more typically disharmonic. Our analysis also reveals a range of fold styles, with more competent detrital-rich layers displaying buckles (Class 1B), as well as upright Class 1A folds marked by thickened limbs. Class 1A buckle folds are generally considered to be created by flattening that overprints folds with an original Class 1B geometry. As thickened fold limbs are truncated by overlying erosive surfaces, the vertical flattening is considered to have occurred during the slump event. Different fold shapes may partially reflect variable flattening, depending on the original orientation of upright or recumbent folds, together with continued downslope-directed simple-shear deformation that modifies the fold geometry. Analysis of fold wavelength, amplitude and bed thickness allows us to plot strain contour maps, and indicates that beds defining slump folds display viscosity contrasts in the range of 50–250, which are similar to values estimated from folds created during HRD in metamorphic rocks. A range of refold patterns, similar to those established by John Ramsay in metamorphic rocks, are observed within slumps, and are truncated by the overlying sediments, indicating that they formed during a single progressive slump event rather than distinct ‘episodes’ of superimposed deformation. This study confirms that techniques developed for the analysis of folds created during HRD are equally applicable to those formed during SSD, and that resulting folds are generally indistinguishable from one another. Extreme caution should therefore be exercised when interpreting the origin of folds in the rock record where the palaeogeographical and tectonic contexts become increasingly uncertain, thereby leading to potential misidentification of folds created during SSD.

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“…1) in the Karwendel thrust sheet includes both the Oberalm Fm. (Nagel et al, 1976;Ortner and Kilian, 2016), and up to 150 m thick Lower Cretaceous, Aptian-Albian sandstones in the eastern Thiersee syncline (Wilmers, 1971) comparable to the Roßfeld Fm. Therefore, the Karwendel thrust sheet belongs to the Tirolic thrust sheets (compare Mandl et al, 2017).…”

Section: Tectonic Subdivision Of the Nca In The Study Areamentioning

confidence: 99%

Structural evidence of in-sequence and out-of-sequence thrusting in the Karwendel mountains and the tectonic subdivision of the western Northern Calcareous Alps

Kilian

Ortner

2019

Austrian Journal of Earth Sciences

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We present the results of a field study in the Karwendel mountains in the western Northern Calcareous Alps, where we analysed the boundary between two major thrust sheets in detail in a key outcrop where nappe tectonics had been recognized already at the beginning of the 20th century. We use the macroscopic structural record of thrust sheet transport in the footwall and hanging wall of this boundary, such as folds, foliation and faults. In the footwall, competent stratigraphic units tend to preserve a full record of deformation while incompetent units get pervasively overprinted and only document the youngest deformation.Transport across the thrust persisted throughout the deformation history of the Northern Calcareous Alps from the late Early Cretaceous to the Miocene. As a consequence of transtensive, S-block down strike-slip tectonics, postdating folding of the major thrust, new out-of-sequence thrusts formed that climbed across the step, and ultimately placed units belonging to the footwall of the initial thrust onto its hanging wall.One of these out-of-sequence thrusts had been used to delimit the uppermost large thrust sheet (Inntal thrust sheet) of the western Northern Calcareous against the next, tectonically deeper, (Lechtal) thrust sheet. Based on the structural geometry of the folded thrust and the age of the youngest sediments below the thrust, we redefine the thrust sheets, and name the combined former Inntal- and part of the Lechtal thrust sheet as the new Karwendel thrust sheet and the former Allgäu- and part of the Lechtal thrust sheet as the new Tannheim thrust sheet.

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Sediment creep on slopes in pelagic limestones: Upper Jurassic of Northern Calcareous Alps, Austria

Cited by 29 publications

References 40 publications

Landslide susceptibility assessment and mapping using statistical and data mining models in Iran

Landslide susceptibility assessment and mapping using statistical and data mining models in Iran

Folding during soft-sediment deformation

Structural evidence of in-sequence and out-of-sequence thrusting in the Karwendel mountains and the tectonic subdivision of the western Northern Calcareous Alps

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