Abstract 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.

Abstract Fault-related calcite precipitates taken from different segments along the East Anatolian (SE Turkey) and Dead Sea (Israel) fault zones were investigated structurally, geochemically and geochronologically. The results indicate major differences in the nature of calcite precipitates and temporal relationship to faulting. In the Düziçi Fault, calcite-filled veins and hydraulic fractures precipitated co-seismically during three consecutive faulting events. Calcite precipitated in veins at the Har Zefiyya Fault was controlled by near-surface karst processes. Initial opening of the veins occurred prior to about 500 ka and may represent the onset of an east–west contractional deformation. In the Carmel Fault Zone the calcite coating the fault plane precipitated by karst processes, with no evidence of subsequent deformation. Calcite fault gouge from the same site are a mix of host-rock gouge and newly formed authigenic calcite, and their overall geochemistry suggests pervasive fluid–rock interaction in the fault zone. In the Baraq Fault Zone the precipitation of calcite within syntectonic tension gashes and veins occurred prior to 540 ka by the pervasive infiltration of meteoric water into the fault zone. The results demonstrate that geochemical and structural analyses, combined with U–Th geochronology, can shed light on co-seismic and inter-seismic fault activity, and can potentially provide precise age constraints on the timing of brittle deformation.

Abstract Orientations of folds and small faults were measured in Turonian and Senonian rocks along the western limb of the Ramallah monocline in Israel, one of the structures comprising the Syrian Arc fold belt (SAFB). The minority of the folds, aligned NNE–SSW, are compatible with the WNW–ESE shortening trend of the SAFB, whereas the majority of them, aligned ENE–WSW, are not compatible with this shortening trend. Kinematic analysis of faults’ attitude indicates NNW–SSE shortening and ENE–WSW extension in accordance with the shortening of the majority of folds. Based on the folds trends, scale, and geometry, as well as the associated fault kinematics, we conclude that the folding mechanism is tectonic shortening and not intraformational folding due to landsliding or collapse owing to karst activity as previously postulated. We propose that a minority of the folds, compatible with the major trend of the Ramallah monocline, are parasitic small folds within the SAFB. The majority of the folds, which are not compatible with the SAFB, were formed owing to NNW–SSE shortening that has been associated with Miocene to Recent movement along the Dead Sea Transform.

Mount Sedom is the surface expression of a salt diapir that has emerged since the Pleistocene in the southwestern part of the Dead Sea basin. Milestones in the uplift history of the Sedom salt diapir since its inception were deduced from angular and erosional unconformities, thickness variations, caprock formation, chemistry and isotope composition of lacustrine aragonite, cave morphology, precise leveling, and satellite geodesy. Thickness variations of the overburden observed in transverse seismic lines suggest that significant growth of the Sedom diapir may have initiated only after this thickness exceeded ∼2400 m in the Late Pliocene. The formation of the caprock signifies the arrival of the Sedom diapir from depth to the dissolution level between 300,000–100,000 yr B.P. During this period and later, angular and erosional unconformities in the upper part of the overburden near Mount Sedom are attributed to the piercing diapir. Rapid solution of rock salt from parts of Mount Sedom inundated by Lake Lisan after ca. 40,000 yr B.P. is inferred from Na/Ca ratios in aragonite and their relation to δ 13 C. On the mountain itself, the older parts (70,000–43,000 yr B.P.) of the lacustrine Lisan Formation are missing. The top of the preserved sediments is covered by alluvial sediments that must have been deposited when the elevation of Mount Sedom was not higher than 265 m below sea level (mbsl) at ca. 14,000 yr B.P. The present elevation of these sediments at 190 mbsl indicates an average uplift rate of ∼5 mm/yr over the past 14,000 yr. Similar uplift rates of 6–9 mm/yr are inferred for the Holocene from displacement of the “salt mirror” and hanging passages of caves. The present uplift rate, calculated from precise leveling and interferometric synthetic aperture radar (InSAR), is similar to the average Holocene rate. Based on the gathered data, we reconstruct the topographic rise of Sedom diapir and its relation to lake level variations during the late Pleistocene and Holocene.