Abstract The late Pleistocene in the Dead Sea Basin is one of the most studied and well-dated under-filled lacustrine deposits in the world and therefore provides a unique opportunity for analyzing individual controlling factors by applying field data into a forward model. The analysis of the depositional history of basins commonly shows a nonunique solution caused by the interdependence of the depositional controlling factors. This can be demonstrated by modeling stratigraphic successions that were constructed using different sedimentary and tectonic values but visually look the same. Here, we used the computer forward simulation SEDPAK to reconstruct the stratigraphic sequences observed in the field using multiple data sets that were established for these deposits. By applying a high-resolution lake level curve, subsidence history, and depositional rates in the offshore sections, we reduced the uncertainties of the model that match outcrop observations. We were then able to test the sensitivity of the simulated cross section to changes in individual parameters and evaluate the contribution of each of them to the result. This allows checking for errors and locations where more data are needed. It also provides insights into the distribution and character of potential hydrocarbon reservoir facies.

Recent studies on the evolution of the Dead Sea basin have shed light on the intricate tectonic regime of the area. Combined with newly available data from Jordan, a new picture of a symmetrical deep basin is emerging. Salt is prevalent over the entire width of the basin in the south. The original thickness of this layer was calculated to be ∼2 km, but at present it does not exceed 900 m. Crustal studies indicate a difference between the southern and northern basins, which are separated by a large, normal fault. Depth to the basement in the northern basin is estimated to be 6–8 km, while that of the southern basin is 12 km. Relocation of deep earthquakes revealed that the majority of well-constrained micro-earthquakes (M L ≤ 3.2) occurred at depths much deeper than previously expected (20–32 km). Seismicity and the low value of regional heat flow suggest that the lower crust might be cool and brittle. A lithospheric strength profile was calculated, indicating a narrow brittle-to-ductile transition at a depth of 31 km. Uplift measurements, submersible studies, and combined geological-geophysical mapping are some of the new techniques applied to the area to solve the complex neotectonic structure. Results indicate that the southern and northern basins are both currently active. In addition to tectonics, activity is also inferred by the presence of salt diapirs, whose uplift or subsidence may be related to current motion along active faults. Discrepancies in earthquake-reoccurrence times may indicate that the main fault in the northern Dead Sea basin, the Jericho fault (also known as the Jordan fault), is segmented, or that earthquakes occur in clusters. One such segment is responsible for the formation of a small subbasin on the northwestern shore of the lake, the Qumran basin, whose complex neotectonic regime includes strike-slip, reverse and normal faulting, folding, right bending splays, and a migrating depocenter. Recent global positioning system measurements provide slip-rates of 2.6–3.8 mm/yr for the current plate motion in this area. An open crack between the seafloor and a sharp bathymetric cliff in the lake provides visual evidence for this motion, while data from shallow seismic surveys present paleoseismic information on this activity.

The Dead Sea Depression is an ∼230-km-long and up to ∼10-km-deep structural-gravitational low along the southern Dead Sea Transform plate boundary between Africa and Arabia. Following an early Miocene–Pliocene deformation phase of localized strike slip faulting and intense fluvial deposition in confined pull-apart basins, delocalization of the Dead Sea Transform and formation of a shear zone over the entire current width of the Dead Sea Depression took place in late Pliocene–early Pleistocene time. Integration of relocated epicenters and focal mechanisms of M L 2.5 earthquakes with a range of structural and geophysical data shows that the late-phase asymmetrical shear zone consists of a distinct sinistral boundary fault in the east and a broad zone of distributed shear to the west. It is characterized by a penetrative, bimodal (NW and NE) structural orientation pattern reflected in earthquake focal mechanisms, segments of the western boundary fault system, fracture sets, geomorphic lineaments, and linear clusters of collapse sinkholes. These phenomena are a manifestation of a long-term persistent deformation field that involves at least the entire upper crust. The shear zone fault structure consists of normal-dextral, NE-oriented faults that extend northeastward from the western boundary fault and intervening NW-trending normal faults. These fault sets produce subsided, fault-bounded depocenters within the Dead Sea basin. The NE-oriented and axially extending blocks are expected to rotate in a clockwise sense with the relative sinistral plate motion, resulting in both normal-dextral and normal-sinistral slip events along the western boundary fault system. Since the Dead Sea Transform plate boundary is non-convergent and probably driven by sinistral basal flow, the Dead Sea Depression shear zone is internally contracting and subsiding. Partition of the relative plate motion between sinistral slip along the eastern boundary fault and distributed shear within the Dead Sea Depression may explain the apparent deficiency in seismic slip along the southern Dead Sea Transform relative to average long-term geological slip.

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.

The Dead Sea, located along the boundary separating semiarid climate from arid climate, is prone to flash flooding caused mainly by severe convection generating heavy precipitation. An overview of the main responsible synoptic systems (tropical and extra-tropical) accounting for most of the major flash floods is presented. The moisture for developing intensive convection over the region can be originated not only from the adjacent Mediterranean Sea but also from distant upwind sources. Under tropical air mass intrusions, convection generated by static instability seems to play a more important role than synoptic-scale vertical motions. The essential subsynoptic scale processes leading to deep convection and the resulting spatio-temporal rainfall characteristics are discussed through examples of selected storms previously analyzed.

The Dead Sea (drainage area of ∼42,200 km 2 ) is a terminal lake fed from the north by the Jordan River. The main water source into the Dead Sea is runoff, and its level is highly sensitive to the annual rainfall in the upper Jordan River drainage basin. Here, we summarize relevant data about present and past surface-water hydrology in the drainage basin and water input into the Dead Sea. The lower Jordan River, with a natural mean annual discharge of ∼1100 10 6 m 3 yr −1 , drains Mediterranean to semiarid areas in northern Israel, Jordan, Syria, and Lebanon. Additional water is contributed from tributaries such as the Zarqa River (64 10 6 m 3 yr −1 ). The diversion of water from these and other sources since the 1960s to an inflow of only ∼210 10 6 m 3 yr −1 caused a 20 m decline of the Dead Sea level. The ephemeral Nahal Arava drains hyperarid areas south of the Dead Sea and contributes small volumes of water (∼5 10 6 m 3 yr −1 ) but experiences occasional large floods (up to 1000 m 3 s −1 ); the smaller, steep ephemeral tributaries west of the Dead Sea produce relatively large floods (up to 775 m 3 s −1 ) due to their wetter headwaters, but their volumes are relatively small (<3 10 6 m 3 ). The annual inflow (∼200 10 6 m 3 yr −1 ) to the Dead Sea from the eastern, semiarid tributaries is divided between base flows (∼65% of annual discharge) and winter floods. In the arid part of the basin, transmission losses and recharge into the shallow alluvial aquifers and probably also to the deeper aquifers during floods are directly related to flow volume. Transmission losses in Nahal Zin decrease with flood magnitude from ∼86% to 100% in small floods of <10 m 3 s −1 to ∼10% for large floods of up to 1500 m 3 s −1 . During the largest floods, the volume of these losses can exceed 4 10 6 m 3 . Rare paleofloods during the past 2000 yr in the Negev were 2–3 times larger than present-day measured floods. The temporal distribution of paleofloods shows that periods with a high frequency of large floods alternate with periods of few large floods. Periods with a high frequency of large floods correlate with high Dead Sea levels, and a low frequency of floods correlates with low lake levels.

The Dead Sea rift valley serves as a deep base level, to which surface waters and groundwaters drain. Two lakes are currently located within the rift: the fresh-water Sea of Galilee (210 m below mean sea level [bmsl]) and the hyper-saline Dead Sea (415 m bmsl). Fresh groundwaters and hot brines flow toward these lakes through carbonate, basaltic, sandstone, and alluvium aquifers. The Dead Sea rift is a unique global site for studying the coupled relationships between basin evolution and groundwater flow. The temporal and spatial distributions of elevations and salinities of groundwaters and lakes are strongly related to past conditions of tectonics, sedimentation, and erosion. Moreover, climate variations have induced changes in the rift's water mass balance, triggering lake level fluctuations and temporal and spatial changes in lake salinity. These effects were analyzed using basin-scale transient hydrogeological numerical models that solve the coupled variable-density groundwater flow and transport of heat and solutes. Furthermore, several ambiguous hydrological phenomena are currently observed at the Dead Sea rift: the existence of fresh and saline springs near each other as well as hot and cold ones; direct and opposite relationships between springs' discharge-salinity-temperature; different geochemical compositions of waters and brines; and complicated spatial distribution of groundwater heads. These phenomena are also explained and analyzed using various hydrogeological numerical models. In addition, quantitative examples of groundwater flow regimes in a few aquifers at the rift vicinity are provided.

The Dead Sea is an extremely dynamic hydrologic system, where the base level is currently declining at a rate of ∼1 m/yr. The groundwater level follows this drop within a relatively short time (a few days in the case of the extensive floods in the winter of 1991–1992). The fresh-saline water interface is very shallow, compared to that of the ocean, due to the large density difference between the fresh and saline water bodies. The interface was found to be steeper near the marginal faults, tracked in a time domain electromagnetic geophysical survey, due to the relatively low horizontal hydraulic conductivity at the fault zone. SUTRA code simulations support this result. Near the shoreline of the Dead Sea, a new coastal area is exposed, whereby the main processes are flushing of most of the section and evaporation and precipitation of salts near the surface. The effect of flushing is seen in several in situ profiles that show much lower concentrations than the original Dead Sea brine, which existed only a few decades ago. Preliminary simulations on a larger scale imply that the Dead Sea water level drop will influence groundwater levels at least several kilometers from the shoreline, increasing the hydraulic gradient and thus also the discharge to the Dead Sea.

The Dead Sea Basin, with its various depositional environments, provides excellent field settings for analyzing sedimentary facies distribution through time and space. This continental rift basin is bounded by steep escarpments, with narrow zones of onshore environments, including fluvial streams, mudflats, and shore and fan-deltas, as well as a variety of offshore environments. Rapid twentieth century lake-level declines and infrequent lake-level rises, involving modern shoreline regressions and telescoping coarse clastic deltas provide a rare opportunity to combine and compare modern to Pleistocene sedimentary sequences in one basin. Here we explore the sedimentary attributes of the various depositional environments along the present Dead Sea Basin. Comparison between observed processes and the older depositional systems provides a means for understanding similar depositional systems here and in other rift basins for purposes of sequence analysis, lakes level reconstruction, and geomorphic response to climate.

Precise and high-resolution chronologies of continental sedimentary records (e.g., lacustrine and cave deposits) are instrumental for establishing Quaternary climatic pattern on the continents and for comparison to marine and ice core records of climate change. Radiocarbon is the major dating method for establishing Holocene and late-glacial chronologies, yet its use often requires determination of the reservoir age, and beyond ca. 24 ka cal. B.P., the calibration curve to calendar years is not well established. Thus, beyond the youngest portion of the last Glacial period, U-Th dating of carbonates becomes the major means in obtaining high-resolution chronologies. However, these age determinations are hampered by contamination of the samples with detrital U and Th and by the presence of aqueous Th. Here we summarize the approaches used to address the problems in U-Th and radiocarbon dating of the late Pleistocene and Holocene sedimentary records of the Dead Sea basin. This mainly includes solutions for the problem of detrital U and Th and aqueous (initial) Th in the Lisan carbonates and the evaluation of “reservoir ages” in the determination of carbonate radiocarbon ages. The calendar U-Th and calibrated radiocarbon ages are used for establishing the environmental (climate and seismological) chronology of the region (e.g., reconstruction of a high-resolution lake level curve and correlation with global climatic records), for paleomagnetic reconstruction (e.g., the documentation of secular variations and geomagnetic excursions such as the Laschamp Event ca. 40 ka cal B.P.), and extending the calibration of the radiocarbon time scale.

We dedicate this manuscript to Dr. Cipora Klein, who studied the historic levels of the Dead Sea . This paper reviews the research and lake level reconstruction of the late Pleistocene and Holocene lakes in the Dead Sea basin. Lake Lisan and the Dead Sea occupied the Dead Sea basin during the past 70 k.y., and responded to and amplified regional climatological variations in the Eastern Mediterranean. Overall, the lake level history is correlative with global climate patterns. The Lake Lisan high levels correspond to the last Glacial period (marine isotope stages 2–4); its dramatic level drop to the transition to the Holocene, and the Dead Sea low stands to the current interglacial period. The Lisan level record also appears to show relationships to millennial events in Greenland ice and deep-sea cores. The paper describes the methodologies applied to identify indicators of lake level elevations and the determination of their ages. It is divided to (1) the early research history (mainly commencing at the nineteenth century) in the Dead Sea basin; (2) the early efforts of lake level curve reconstructions; and (3) the most recent studies that yield well-dated, high resolution lake level chronologies.

We have studied the magnetic properties of wet and dry late Pleistocene Lake Lisan sediments and the Holocene Dead Sea sediments. Our initial prediction was that the properties of both would be quite similar, because they have similar source and lake conditions, unless diagenetic change had occurred. Rock magnetic and paleomagnetic experiments revealed three stages of magnetization acquisition. Our findings suggest two magnetic carriers in the Holocene Dead Sea and wet Lisan sediments: titanomagnetite and greigite. The titanomagnetite grains are detrital and carry a detrital remanent magnetization (DRM), whereas the greigite is diagenetic in origin and carries a chemical remanent magnetization (CRM) that dominates the total natural remanent magnetization (NRM) of Holocene Dead Sea and wet Lisan sediments. The magnetization of dry Lisan sediments is a DRM and resides in multidomain (MD) grains. We propose that magnetic properties of the Lisan Formation and Holocene Dead Sea sediments can be explained by a model that incorporates dissolution, precipitation, and alteration of magnetic carriers. At the time of deposition, titanomagnetite grains of varying size were deposited in Lake Lisan and the Holocene Dead Sea, recording the geomagnetic field via a primary DRM. Sedimentation was followed by partial or complete dissolution of titanomagnetite in anoxic lake bottom conditions. As the kinetics of dissolution depends upon surface area, the single-domain (SD) grains dissolved faster, leaving only the larger pseudo-single domain (PSD) and MD grains. Titanomagnetite dissolution occurred simultaneously with precipitation of greigite in anoxic, sulfate-reducing conditions probably related to bacterial degradation of organic matter. This process added a secondary CRM that overwhelmed the DRM and the primary geomagnetic record. Later, when the level of Lake Lisan dropped, these sediments were exposed to air. At this time, the greigite was oxidized, removing the CRM from the system and leaving only the original detrital PSD and MD titanomagnetite grains as the dominant DRM carriers. Presently, wet Lisan sediments have not been completely altered and therefore contain secondary greigite preserved by the original formation water that carries a secondary CRM. Thus, the magnetization in the Holocene Dead Sea and the wet Lisan magnetic record cannot be considered as an accurate, reliable geomagnetic record, while magnetization of dry Lisan sediments is a primary DRM.

This paper summarizes the research efforts devoted over the years to the understanding of the origin and evolution of brines in the Dead Sea basin. These brines are characterized by a unique Ca-Chloride composition, which evolved from interaction of evaporated seawater filling the late Neogene Sedom lagoon with the Cretaceous carbonate rocks exposed at the basin-bounding escarpments. Following the disconnection of the lagoon from the open sea and the development of inland lakes, the composition of the ancient Sedom brine changed due to precipitation of evaporites and addition of salts from incoming fresh water. Relative to highly evaporated seawater, these processes led to enrichment of the brines in Cl, Br, Mg, Ca, and K and depletion in Na and SO 4 . The modern Dead Sea, representing a recent product of these evolutionary processes, derived its ingredients from residual brines that remained after the desiccation of the late Pleistocene Lake Lisan, from incoming fresh water, and from saline springs that emerge along the western shores of the Dead Sea. Similar sources probably dictated the composition of the Pleistocene lakes (Amora, Lisan), though their relative contribution changed through time, reflecting the control of climate on the hydrological system (e.g., the activity of saline springs).

Observations of intraclast breccia layers in the Dead Sea basin, formerly termed “mixed layers,” provide an exceptionally long and detailed record of past earthquakes and define a frontier of paleoseismic research. Multiple studies of these seismites have advanced our understanding of the earthquake history of the Dead Sea and of the processes that form the intraclast breccias. In this paper, we describe a systematic study of intraclast breccia layers in laminated sequences. The relationship of intraclast breccia layers to intraformational fault scarps has motivated the investigation of these seismites. Geophysical evidence shows that the faults extend into the subsurface, supporting their potential association with strong earthquakes. We define field criteria for the recognition of intraclast breccias, focusing on features diagnostic of a seismic origin. The field criteria stem from our understanding of the mechanisms of breccia formation, which include ground acceleration, shearing, liquefaction, water escape, fluidization, and resuspension of the originally laminated mud. Comparison between a dated record of breccia layer and the record of historical earthquakes provides an independent test for a seismic origin. The historical dating is significantly more precise and accurate than the radiocarbon dating of breccia layers. Yet, assuming that the lamination of the sediments shows an annual cycle, the precision of counting laminae may approach the precision of the historical record. A similar accuracy is then expected for the intervals between earthquakes. We review our work based on counting laminae representing the historical period, mutually corroborating the seismic origin and the annual lamination. The correlation of documented historical earthquakes with individual breccia layers provides quantitative estimates for the threshold of ground motion for breccia formation in terms of earthquake magnitude and epicentral distance. The investigation of breccia layers and the associated historical earthquakes has underscored cases in which a breccia layer represents a pair of earthquakes. We consider the resolution of individual events in records of breccia layers. A thick breccia layer can account for multiple events, biasing the paleoseismic record. The resolution of an interseismic time interval is no better than the ratio between the thickness of a breccia layer and the rate of sedimentation. We use revised age data for the Lisan Formation and reassess temporal clustering of earthquakes during the late Pleistocene. The variation of recurrence interval corroborates significant clustering. During periods of clustered earthquakes, of order of 1000–5000 yr, the interseismic interval becomes short, and the resolution diminishes, so the peak rate of recurrence may be underestimated. Recurrence intervals inferred from the Dead Sea record of Holocene breccia layers do not feature the extreme variation encountered in the late Pleistocene record. Yet the Holocene record shows marked transitions between periods, each with relatively uniform recurrence interval. Two of the transitions are contemporaneous with transitions in the recurrence intervals of the Anatolian faults, implying broad-scale elastic coupling.

This paper describes some new archaeological findings of settlements around the Dead Sea's shores in the Late Hellenistic and Early Roman periods (second century B.C. to first century A.D.). Evidence is presented for the level of the Dead Sea (∼-395 m) in that period. The settlement pattern of the region sheds light on the level of the Dead Sea in various periods and on the intensive use of the land by the occupants of the sea's shoreline in antiquity. Special attention is paid to two anchorages of this period, Rujm el-Bahr at the northern end of the Dead Sea and Khirbet Mazin on the western shore, and to the fortified roadside station of Qasr et-Turabeh on the western shore. These sites provide important evidence of the lake level at the time of their existence.

The invention of the camera in 1839 opened new vistas and opportunities the world over. As to the Near East, this development meant people could now view the lands of the Bible, previously only imagined and documented in other artistic media. The first known photograph of the Dead Sea was taken in 1857, and in the decades that followed, numerous photographers captured this landscape for purposes of science, commerce, and religion. This chapter offers a short review of Dead Sea photography prior to 1900, focusing on images that provide details of interest to the environmental and earth sciences community, and that can be precisely traced and located today. Moreover, it contains a relevant initial database of images and their sources, dates, and bibliographical information, marking the first step in cataloging the photographs of the Dead Sea from the nineteenth century.

Over the past several years, the coastal area around the declining Dead Sea has undergone a catastrophic collapse. One of the major expressions of this process is the sudden appearance of hundreds of collapse sinkholes, causing a severe threat to the future of this region. Here we review results and inferences obtained from a multidisciplinary research conducted since 1999. Observations were obtained by geological mapping, aerial photographs, drilling, groundwater geochemistry, seismic refraction and reflection, and satellite radar interferometry. The suggested model for the formation of the Dead Sea sinkholes is based on the following observations: (1) presence of a thick salt layer (or layers) at depths between 20 and 50 m (depth of layer top), and sandwiched between aquiclude layers of clay and silt; (2) identification of cavities within the salt layer in sinkhole sites; (3) presence of water undersaturated with respect to halite in aquifers confined beneath the salt layer; (4) composition of the groundwater in the salt layer that indicates salt dissolution; (5) association between sinkhole sites and land subsidence; and (6) formation of sinkholes along and above buried faults. These observations combine to suggest that the primary cause of sinkhole formation is dissolution of the salt layer by undersaturated groundwater. The interface between the Dead Sea brine and this groundwater migrated eastward due to the Dead Sea decline. Undersaturated water accessed the salt layer via faults that cut through the soft aquiclude layers. The opening of these conduit-faults is likely due to differential compaction of the aquiclude layers, explaining the correlation between the land subsidence and sinkhole sites. It appears that the decline of the Dead Sea level affects the formation of sinkholes in three ways: (1) opening the way to eastward migration of the fresh-saline water interface and thus to undersaturated groundwater, (2) generating differential compaction of fine-grained sediments, and (3) destabilization of underground cavities, which catalyzes their collapse.