Non-seismic soft-sediment deformation structures from Late Pleistocene lacustrine deposits of Lake Van (Eastern Turkey): Storm and overloading effect

Journal of Great Lakes Research 45 (2019) 664–671

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Non-seismic soft-sediment deformation structures from Late Pleistocene lacustrine deposits of Lake Van (Eastern Turkey): Storm and overloading effect Serkan Üner a,⁎, Azad Sağlam Selçuk a, Erman Özsayın b a b

Van Yüzüncü Yıl University, Department of Geological Engineering, 65040 Van, Turkey Hacettepe University, Department of Geological Engineering, 06100 Ankara, Turkey

a r t i c l e

i n f o

Article history: Received 10 January 2019 Accepted 15 March 2019 Available online 21 March 2019 Communicated by Harvey Thorleifson Keywords: Soft-sediment deformation structures Triggering mechanism Lacustrine deposits Late Pleistocene Eastern Turkey

a b s t r a c t Soft-sediment deformation structures of different types and sizes are frequently observed in the lacustrine deposits of Lake Van. According to sedimentary features and regional factors, these structures are categorized as non-seismic originated and seismically-induced, soft-sediment deformation structures. Well-preserved nonseismic originated, soft-sediment deformation structures were observed in fine-grained sandy and silty deposits at three locations (Çatakdibi, Yumrutepe, and Yukarıışıklı), and occur at different stratigraphic horizons, exhibiting morphological variability as they consist of load, flame, and slump structures. The formation mechanisms of these structures are determined by the characteristics of their sedimentary facies and environmental conditions. Overloading, caused by rapid coarse sediment deposition or underwater landslides, and storm waves are identified as triggering mechanisms, while rapid sediment accumulation and underwater mass movements caused by volcanogenic shakes are the conditions responsible for the formation of non-seismic softsediment deformation structures, in terms of regional geodynamics. © 2019 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.

Introduction Soft-sediment deformation structures (SSDS) are common in unconsolidated, loosely packed and saturated sands and silts, and have been observed in many ancient and modern sedimentary environments such as lacustrine, fluvial, transitional, and marine environments (Seilacher, 1969; Seed and Idriss, 1982; Obermeier et al., 1989; Ringrose, 1989; Owen, 1996; Koç Taşgın, 2011). Inner basins and lakes are the most suitable environments for the formation of SSDS (Sims, 1975). Liquefaction and fluidization are the main processes that cause a temporary change in the behaviour of sand and silt from solid to liquid (Allen, 1982). These processes can be enhanced by overloading, waveinduced cyclical and/or impulsive stresses, sudden changes in the groundwater level, and earthquakes (Owen, 1987). Identifying the triggering mechanism/s, specifically whether deformation is generated by seismic shaking or is of non-seismic origin, is the main challenge for understanding SSDS (Owen and Moretti, 2008; Sarkar et al., 2014). Interpreting the trigger mechanism for SSDS can only be reliable when analyzing their SSDS morphology, deformation mechanism, facies of

⁎ Corresponding author. E-mail address: [email protected] (S. Üner).

the sediments that are involved in the deformation, and regional/local tectonics (Moretti et al., 2016). SSDS of different types and sizes are frequently observed in the lacustrine deposits of Lake Van particularly in the northern and eastern regions. Numerous seismically induced SSDS (seismites) detected in these lacustrine deposits were identified, dated, and associated with active faults (Üner et al., 2010; Üner, 2014). In this study, we aimed to; (1) identify non-seismic SSDS; (2) determine the triggering mechanisms of these non-seismic SSDS; and (3) discuss the effect of regional dynamics on triggers. Regional geology Lake Van Basin The Eastern Anatolian Plateau emerges from the collision between the Eurasian and Arabian plates in the eastern Mediterranean region (Şengör and Yılmaz, 1981) (Fig. 1a). Several basins have been formed by this compressional tectonism, including the Pasinler, Muş, and Lake Van basins (Şaroğlu and Güner, 1979). In the Lake Van Basin the N-Soriented compressional/contractional neotectonic period, located in the southern part of the Eastern Anatolian Plateau, began in the Late Pliocene (Koçyiğit et al., 2001), and is characterized by E-W-trending reverse faults, NW-SE-trending dextral and NE-SW-trending sinistral

https://doi.org/10.1016/j.jglr.2019.03.007 0380-1330/© 2019 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.

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Fig. 1. Location maps of the study area showing: (a) the tectonic setting of eastern Turkey (NAF: North Anatolian Fault; EAF: East Anatolian Fault; BZCZ: Bitlis Zagros Suture Zone; CF: Çaldıran Fault); (b) geological, morphological and structural features of the Lake Van Basin (modified from Şenel, 2001; Koçyiğit, 2013). The red stars indicate the locations of the SSDS.

strike-slip faults, and N-S-trending extensional structures (Şaroğlu and Yılmaz, 1986; Özkaymak et al., 2011; Koçyiğit, 2013). Quaternary volcanic activity related to plate tectonics is another characteristic feature of the region (Degens et al., 1984) (Fig. 1b). Lake Van was formed 600 ka ago (Stockhecke et al., 2014), and is the largest sodic lake in the world, with a surface area of 3570 km2, volume of 607 km3, and maximum depth of 451 m (Kempe et al., 1978). The water level of Lake Van has undergone significant fluctuations since its formation. Ancient lacustrine deposits are also presented in the east and north of the lake, indicating that it previously covered a larger area than it currently does (Degens et al., 1978; Kuzucuoğlu et al., 2010).

Stratigraphy The basement of the Lake Van Basin consists of metamorphic rocks (Bitlis metamorphics), Upper Cretaceous ophiolites (Yüksekova mélange), and Tertiary turbidites. Bitlis metamorphics are primarily composed of Paleozoic–Mesozoic schists, gneisses, and meta-basic rocks (Oberhänslı et al., 2010), while the ophiolitic rocks correspond to mafic-ultramafic tectonites and cumulate (Acarlar et al., 1991). Shallow- to deep-marine turbidites consist of fine- to coarse-grained alternating sandstone-marl with gravelly layers. Basement rocks are unconformably overlain by Quaternary volcanics and coeval lacustrine deposits from Lake Van (Fig. 2).

The lacustrine sequences of Lake Van chiefly consist of horizontally bedded clays, silts, and fine- to coarse-grained sandy shallow lacustrine and gravelly shore deposits. Varve-like facies characterize the depocentral environments and largest areas during common lakedeepening episodes, while the sandy and gravelly layers exhibit wave ripples and cross-bedding in the shallow lacustrine environment. Dreissena sp. shells are the most abundant fossils in the different levels of the lacustrine deposits. Volcanic rocks are present in the northwestern part of the basin (Fig. 1b), including basalts and pyroclastics, derived from the Nemrut and Süphan Volcanoes (Karaoğlu et al., 2005; Özdemir et al., 2011). Pyroclastic layers alternate with lacustrine deposits owing to coeval activity. Late Pleistocene travertines and alluvium are the youngest lithologies in the basin (Aksoy, 1988; Acarlar et al., 1991) (Fig. 2). Materials and methods Various sedimentary sequences are located in different parts of Lake Van which are the result of variations in the depositional processes and/ or environmental conditions. The composition, size, geometry, and top and bottom contacts of the deformation structures were measured, along with their relationship with other units. The geological properties of these structures and the paleoenvironmental setting under which the deformations occurred are identified for each sequence. These sequences were evaluated to elucidate the trigger mechanism(s) (such

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Fig. 2. Stratigraphic columnar section of the study area. (Modified from Aksoy (1988), Acarlar et al. (1991), and Şenel (2001).)

as rapid sediment deposition, overloading, storm effect, or seismic waves) of the deformation structures according to the properties of their facies. Three sedimentary sequences containing SSDS were measured. The ages of the layers containing SSDS were determined through optically stimulated luminescence (OSL) dating. Luminescence analyses were conducted at the Luminescence Research and Archaeometry Laboratory of Işık University, Turkey.

Results Description of field sections Three sequences (Çatakdibi, Yumrutepe, and Yukarıışıklı) containing SSDS were measured in detail around the Lake Van Basin. Seven sedimentary facies were described from these three sequences, which are; fine-bedded clay-silt-sand alternation (F-1), wave-rippled fine-sand (F2), massive- to parallel-stratified fine-sand (F-3), cross-stratified coarse-sand (F-4), wave-rippled cross-stratified coarse-sand (F-5), large-scale cross-stratified gravel (F-6), and parallel-stratified gravel (F-7) (Table 1). The Çatakdibi sequence is dominated by an alternation of sand beds alternating with silt and clay laminae (Fig. 3). This section is almost horizontal with a thickness ranging from 1 to 60 cm, and indicates a shallow- to deep lacustrine environment. Thicker sandy beds are rare in lacustrine deposits. The ages of the lacustrine deposits in the Çatakdibi sequence were dated to approximately 29.9–28.0 ka, determined through OSL dating.

Coarse-grained sediments are common in the Yumrutepe sequence (Fig. 3). Foreset deposits composed of well-rounded, pebble-, and cobble-sized gravels indicate the presence of fan delta foresets, while the horizontal to sub-horizontal parallel beds, characterized by moderate- to well-sorted, clast-supported, and sub-rounded gravels, indicate wave-modified delta-plain or shore deposits. The Yumrutepe deltaic sediments were dated to 15.1 ka for the lower part and 12.0 ka for the upper part through OSL-dating in a previous study (Görür et al., 2015). The Yukarıışıklı sequence is dominated by alternating of silt and clay laminae with rare sand beds (Fig. 3). These, 20 to 40 cm-thick, waverippled, and horizontal sand beds indicate a shallow lacustrine environment, while the finer-grained laminas represent a deep lacustrine environment. However, no age data could be obtained from the Yukarıışıklı sequence. Soft sediment deformation structures Detailed investigation of the lacustrine deposits of Lake Van revealed remarkable examples of SSDS with dimensions ranging from a few centimeters up to meters at three sites in the shallow-lacustrine and shore facies (Fig. 3). Three types of SSDS are distinguished by their morphological features: (1) load, (2) flame, and (3) slump structures. Load structure Load structure is observed in the medium-bedded sandy and silty lacustrine deposits (F-3) of the Yukarıışıklı sequence. The fine- to

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Table 1 Summary of the descriptions of the clastic facies and environmental interpretation of the lacustrine and deltaic deposits. Facies

Descriptions

Interpretation

F-1: Fine-bedded clay-silt-sand alternation

This lithofacies is composed of beige-to grey-colored fine sand, silt, and clay-sized sediments, and consists of alternating massive-to parallel-laminates or bedded layers. Laterally extensive (40–50 m) thinly interbedded (1 to 10 cm) silts and clays have sharp, flat tops and bases. Grey- to beige-colored facies composed of fine sands with rare gravel-sized sediments. Thin- to moderate-bedded (5–25 cm) facies that are well sorted. Symmetrical wave ripples are common (15 and 3 cm in length and height respectively) in sand beds. This lithofacies is characterized by fine-to coarse-grained gravelly sand and silts. It consists alternation of massive-to parallel-laminated silts and sandy beds. Thin-to thick-bedded (5–60 cm), well-defined sands have sharp and flat bases and tops. The facies contains ripples and bivalve fragments. The facies is composed of well-sorted coarse sands and gravel lens. There are laterally extensive beds with a thickness of 10 to 70 cm. Tabular cross-stratification, wave-ripples, and shell fragments are common in sand beds. Well-rounded, disk-shaped gravels exhibit imbrication in the lens. This facies is represented by grey- to beige-colored, massive coarse sand and granule-sized sediments. The thickness of this facies ranges from 20 to 60 cm. Typical wave-ripple cross-stratification sets are 5–20 cm in thickness and 15–35 cm in width. Facies starts with an erosional surface. This facies is composed of pebble/cobble-sized gravels. The 20–80 cm thick, large-scaled cross-stratified beds have a fine to coarse-grained sandy matrix. Texturally polymodal, moderate- to well-sorted, sub- to well–rounded clasts show a parallel orientation to the bedding plane with imbrications. This facies is characterized by pebble and cobble-sized gravelly beds with sharp and flat bases and tops. Laterally continuous, horizontal to sub-horizontal parallel beds have a thickness of 10 to 40 cm. The facies is characterized by moderate- to well-sorted, clast-supported, sub-rounded gravels.

The occurrence of alternating laminated fine-sand, silt, and clay indicate deposition with suspension fall-out and/or low-density currents in relatively deep water conditions (Colella, 1988).

F-2: Wave-rippled fine-sand

F-3: Massive-to parallel-stratified fine-sand

F-4: Cross-stratified coarse-sand

F-5: Wave-ripple cross-stratified coarse-sand

F-6: Large-scale cross-stratified gravel

F-7: Parallel- stratified gravel

medium-grained, sandy load structure has a width of 50 cm, and exhibits a concave (bowl-like) morphology. The sandy central part of the structure sunk downwards into the silty deposits, and the edges were slightly bent upwards. The load structure exhibits cross-laminated internal fillings in the horizontal beds (Fig. 4a).

Flame structures The flame structures ranged in size from 3 to 50 cm, and occurred in both the sandy and silty sediments of Lake Van, most commonly at the boundary between the silty and sandy layers. The flames have a wide basal area and a relatively narrow tail-like appearance on the upper side. The structures may occur alone or as an array within the layer. Flame structures are observed in the foreset deposits (inclination range of 10–15°) of the Yumrutepe Delta and lacustrine deposits of the Çatakdibi sequences. The Yumrutepe group (height of 13 cm, base width of 2–3 cm) is observed in sandy and silty levels (F-1) of the delta sequence, and is located in the lower levels of the coarse-grained deltaic deposits (Fig. 5a). The silty parts of the structures constitute the flames, which forced the coarse-grained sand to rearrange parallel to the injection. Flames are separated by load-casts of various sizes, and all structures are bounded by undeformed layers at the bottom and top. The flame structures observed at Çatakdibi exhibit different stratigraphic positions to those observed at other locations. The structures are situated at the top of alternating sand-silt, deforming the uppermost level of the horizontally lacustrine deposits. A more coarse-grained sliding body with an inclination of 50° covers the flame structures (Fig. 5b).

Wave-rippled sands indicate the sedimentation under shallow water conditions in wave base (Reineck and Singh, 1973; Dabrio, 1990). The massive coarse-sand beds containing ripples and shell-fragments indicate the occurrence of deposition under high-density currents and/or high wave energy conditions (Mouth, 1984; Postma, 1990). The association of disk-shaped gravels, imbrication, wave-ripples, and broken shell fragments indicate the occurrence of sedimentation under high energy conditions in a coastal area (Massari and Parea, 1988). The wave-rippled cross-stratification and erosional surface can be considered as characteristics of storm-dominated shallow-marine/lake environments (Allen, 1982; Harms et al., 1982). The large-scaled cross-stratified beds and imbrications are interpreted as unidirectional subaqueous flows in fan delta/Gilbert-type delta foresets (Postma, 1990).

Clast- supported, well-sorted, and rounded gravels indicate wave reworking deposition in a wave modified fan-delta front (Orton, 1988; Postma, 1990).

Slump structures Two slump structures were identified in the silty and clayey deposits of the Yumrutepe Fan Delta (F-1). The general trends of the slump structures detected from the folding regions are compatible with the progradation directions of the delta. The slumped sediments rest unconformably between undeformed layers (Fig. 6). Laterally, these folded layers pass undeformed beds, and deposits underlying this level exhibit a gentle (˂10°) inclination towards the basin. The maximum thickness of these structures is 35 cm (Fig. 6).

Discussion Numerous SSDS with different types, sizes, and features were observed in the lacustrine deposits of the Lake Van Basin. Previous studies identified, dated, and associated earthquake-induced SSDS with active faults (Üner et al., 2010; Üner, 2014). However, non-seismically triggered SSDS are rarely observed in these deposits.

Triggering mechanisms The formation of SSDS depends on both the triggering mechanism and sediment properties such as grain size, sorting, and permeability (Lowe, 1975). Several non-seismic triggering mechanisms for the formation of SSDS are considered, including cyclic oscillations (tides), storm waves, and overloading (rapid sediment accumulation or slides). In this study, overloading and the effect of storm waves are mainly considered as there were no data regarding tides.

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Fig. 3. Stratigraphy, lithology, and sedimentary facies of the lacustrine and deltaic deposits observed in the Yukarıışıklı, Çatakdibi, and Yumrutepe sequences. The positions and types of SSDS are also shown. For grain size, st: silt, sd: sand, gr: gravel.

Overloading Although non-seismic triggering mechanisms are often ineffective in lacustrine environments (Ricci Lucchi, 1995; Hibsch et al., 1997), storminduced and overloading-related SSDS have been observed in previous studies (Molina et al., 1998; Jones and Omoto, 2000; Neuwerth et al.,

2006; Li et al., 2007; Moretti and Sabato, 2007; Chakraborty, 2011; Liu et al., 2012; Van Loon et al., 2016). Flame structures, which were identified in the Yumrutepe Fan Delta sediments, were deposited when the lake's water level was 70 m higher than it currently is. These structures, which are observed as silt injections into the sand layers, were settled at the low-inclination delta-

Fig. 4. Images showing (a) the load structure from the Yukarıışıklı sequence, and (b) a close-up of the wave-rippled cross-laminates in the storm deposits.

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and sedimentary facies properties of the block indicate that it is not in its original position. Field observations demonstrate that this block was formerly deposited horizontally or gently inclined at the marginal area of the lake (Fig. 7a), and later slid into the deeper section owing to underwater mass movements (Fig. 7b, c). This movement would have generated a single large impact that caused liquefaction on the watersaturated and unconsolidated underlying sediments resulting in a flame-like deformation (Owen, 1987). Storm waves

Fig. 5. Images showing the flame structures observed in the (a) Yumrutepe and (b) Çatakdibi sequences.

front/prodelta (Fig. 5a). These asymmetrical deformation structures, located below the large-scale cross-stratified and coarse-grained deposits (F-6), may have formed through liquefaction, driven by the tangential shear forces of sediment loading acting upon the layer interface (Dzulynski et al., 1972). The sediment load increases the pore-water pressure and forms load-induced deformation structures (Martinsen, 1989; Chiarella et al., 2016). Çatakdibi flame structures are observed at the top of the horizontally-bedded lacustrine deposits composed of alternating finesand and silt (F-1) (Fig. 5b). A block inclined at 50° with alternating coarse-sand and fine-pebbles stands over this structure. The inclination

Fig. 6. Images showing the slump structures observed in the (a) sandy and silty delta front and (b) silty and clayey prodelta deposits of the Yumrutepe sequence.

Storm waves are one of the mechanisms triggering the generation of SSDS by liquefaction and/or fluidization, with three main processes that include: (1) the rapid deposition of sediment on the sea/lake floor during a storm (Owen, 1987); (2) the direct impact of breaking storm waves on unconsolidated sediments (Dalrymple, 1979; Massari and Parea, 1988); and (3) the cyclic stresses of successive storm waves (Allen, 1982; Owen, 1987; Molina et al., 1998). Load structures in fine-grained sands (F-3) are stratigraphically located just below the wave-rippled cross-stratified coarse sands (F-5) in the Yukarıışıklı section, which are separated by an erosional surface (Fig. 4a). The coexistence of wave-rippled cross-bedded layers (Fig. 4b), which exhibit multidirectional underflow and intense oscillation of gravitational waves on the surface and erosional surfaces scoured by strong flows, demonstrated the occurrence of storm wave-induced deformation. Additionally, some areas of the load structures that are filled with waverippled cross-beds provide other evidence for the coeval occurrence of storm activity and deformation. This composition is the clearest indicator of the storm wave effect (Allen, 1982; Alfaro et al., 2002; Morton et al., 2007; Morsilli and Pomar, 2012; Phantuwongraj et al., 2013; Li et al., 2014). The formation of load structures under these environmental conditions can be explained by the cyclic stresses caused by storm-induced waves and related liquefaction (Owen, 1987). Responsible conditions Environmental conditions affect regional sedimentation processes through either erosion or deposition. In particular, the rapid melting following the glaciation periods and subsequent erosion with fast and abundant sediment accumulation can influence the regional depositional dynamics. Such accumulation and associated overloading may cause liquefaction in soft sediments (Moretti et al., 2001). The flame structures observed in the sandy deposits of The Yumrutepe Fan Delta are located below the coarse-grained deposits. These structures may have formed under the effect of overloading. The depositional period of the Yumrutepe Delta (15.1–12.0 ka) (Görür et al., 2015) coincides with Turkey's regional Late Glacial Maximum (14 ka) (Sarıkaya and Çiner, 2015) and the following period. The rapid accumulation process mentioned above, and associated overburden is the most rational mechanism triggering the formation of flame structures. Storm-induced sedimentary structures and deposits are another indicator of sedimentation. Although Lake Van is a closed basin surrounded by mountains (Nemrut, Süphan, Erek, Artos, and İhtiyar Şahap Mountains), storm effects and related sedimentation records are observed in ancient lacustrine deposits (Üner, 2018). Waverippled cross-beds and the erosional surface just above the load structures at the Yukarıışıklı section clearly indicate the effect of storms on sedimentation and deformation. Underwater mass movements are another phenomenon that should be considered for the formation of SSDS, and can be related to inclination, sediment load, and triggers (such as seismicity or volcanic shakes) alone or in combination. The triggering mechanism that causes the block located on the horizontal lacustrine deposits in the Çatakdibi section to slide could not be determined through field studies. However, the age of the flame structure (29.9 ± 2.7 ka) is well-correlated with the regional geodynamics and the timing of the caldera collapse of the

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Fig. 7. Conceptual model explaining the position and movement of the sliding block (a–b). Photograph showing the sliding block and the location of the flame structure observed in the Çatakdibi sequence.

Nemrut Volcano (30.0 ka) (Çubukçu et al., 2012; Schmincke et al., 2012; Ulusoy et al., 2012). The collapse of the caldera and related shakes are the most likely mechanism triggering the sliding of the block that caused the formation of flame structure in the Çatakdibi section. It was most difficult to determine the triggering mechanism of the slumps of the studied structures. These structures are observed in two levels of the Yumrutepe Fan Delta sediments. Although the Lake Van Basin is an active region in terms of its seismicity, the inclined morphology and coarse-sediment content of the deltaic body indicate the nonseismic formation of the slump structures. Conclusions In this study, SSDS in the lacustrine deposits of Lake Van Basin are examined. The following conclusions can be drawn: (1) Numerous SSDS of various types were observed in the ancient lacustrine deposits of Lake Van. The triggering mechanisms of these SSDS were determined, and they were separated based on their seismic or non-seismic origin. (2) The non-seismic SSDS detected at three locations (Çatakdibi, Yumrutepe, and Yukarıışıklı) are identified as load, flame, and slump structures. (3) Field observations and the facies characteristics of sedimentary deposits containing SSDS indicate overloading and storm waves as mechanisms triggering the deformation of lacustrine deposits. The gravitational density gradient was determined as the driving force for the structures formed by liquefaction. Only the asymmetric flame structures observed in the Yumrutepe Fan Delta occurred under tangential shear stresses. (4) Environmental conditions are directly and/or indirectly responsible for the storm-induced SSDS detected in Yukarıışıklı and the overload-induced SSDS in deltaic deposits of the Yumrutepe

region. The slump structures in the Yumrutepe deposits may have formed by the sediment load. (5) The overloading-induced SSDS observed in lacustrine deposits of the Çatakdibi region was formed by the overburden of sliding block that was likely moved by volcanic shake(s).

Acknowledgment This study was supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK) Scientific Research Project (114Y216). The authors are grateful to Merve Gizem Alırız and Mustafa Karabıyıkoğlu for their help and suggestions. The authors are also grateful to Massimo Moretti and other anonymous reviewers for their constructive comments on the manuscript. Language editing support was provided by Editage. References Acarlar, M., Bilgin, A.Z., Elibol, E., Erkan, T., Gedik, İ., Güner, E., Hakyemez, Y., Şen, A.M., Uğuz, M.F., Umut, M., 1991. Van Gölü doğusu ve kuzeyinin jeolojisi [Geology of the eastern and northern part of Lake Van]. Miner. Res. Explor. Inst. Turkey (MTA) Technical Report Nr. 9469. Aksoy, E., 1988. Stratigraphy and Tectonic of the Eastern-Northeastern Part of Van City. Ph.D. thesis, Fırat University, Elazığ, Turkey. Alfaro, P., Delgado, J., Estevez, A., Molina, J.M., Moretti, M., Soria, J.M., 2002. Liquefaction and fluidization structures in Messinian storm deposits (Bajo Segura Basin, Betic Cordillera, southern Spain). Int. J. Earth Sci. 91, 505–513. Allen, J.R.L., 1982. Sedimentary structures: their character and physical basis. Dev. Sedimentol. 30. Elsevier, Amsterdam. Chakraborty, P.P., 2011. Slides, soft-sediment deformations, and mass flows from Proterozoic Lakheri Limestone Formation, Vindhyan Supergroup, central India, and their implications towards basin tectonics. Facies 57, 331–349. Chiarella, D., Moretti, M., Longhitano, S.G., Muto, F., 2016. Deformed cross-stratified deposits in the Early Pleistocene tidally-dominated Catanzaro strait-fill succession, Calabrian Arc (Southern Italy): triggering mechanisms and environmental significance. Sediment. Geol. 344, 277–289.

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