A new, detailed lake level curve for Lake Lisan (the Last Glacial Dead Sea) reveals a high frequency of abrupt fluctuations during Marine Isotope Stage 3 (MIS3) compared to the relatively high stand ...characterizing MIS2, and the significantly lower Holocene lake. The lake level fluctuations reflect the hydrological conditions in the large watershed of the lake, which in turn reflects the hydro-climatic conditions in the central Levant region. The new curve shows that the fluctuations coincide on millennial timescales with temperature variations recorded in Greenland. Four patterns of correlation are observed through the last ice age: (1) maximum lake elevations were reached during MIS2, the coldest interval; (2) abrupt lake level drops to the lowest elevations coincided with the occurrence of Heinrich (H) events; (3) the lake returned to higher-stand conditions along with warming in Greenland that followed H-events; (4) significant lake level fluctuations coincided with virtually every Greenland stadial–interstadial cycle.
Over glacial–interglacial time-scales, Northern Hemisphere glacial cooling induces extreme wetness in the Levant, with high lake levels reaching ∼160 m below mean sea level (mbmsl), approximately 240 m above typical Holocene levels of ∼400 mbmsl. These orbital time-scale shifts are driven by expansions of the European ice sheet, which deflect westerly storm tracks southward to the Eastern Mediterranean, resulting in increased sea-air temperature gradients that invoke increased cyclogenesis, and enhanced moisture delivery to the Levant. The millennial-scale lake level drops associated with Greenland stadials are most extreme during Heinrich stadials and reflect abrupt cooling of the Eastern Mediterranean atmosphere and sea-surface, which weaken the cyclogenic rain engine and cause extreme Levant droughts. During the recovery from the effect of Heinrich stadials, the regional climate configuration resumed typical glacial conditions, with enhanced Levant precipitation and a rise in Lake Lisan levels. Similar cyclicity in the transfer of moisture to the Levant affected lake levels during all of the non-Heinrich stadial–interstadial cycles.
The mineralogical, grain size and geochemical properties (e.g., Nd and Sr isotopes, Mg/Al ratios) of fine detritus that accumulated in the Dead Sea during the late Glacial to early Holocene time ...(∼22–7 ka) are used to identify its sources and modes of transport and to reconstruct the hydroclimate conditions in the Dead Sea watershed. Samples were retrieved from the DSDDP -5017-1A core that was drilled in the deep floor of the lake, and from various exposures of surface cover in the lake's watershed. The data show that during most of the late glacial, detrital particles were either directly blown mostly from the north Sahara Desert or were washed from the surface cover (loessial soils) of the north Negev Desert and Judea Desert. This picture changed during the end of the last glacial to the early Holocene (∼14 - 7 ka) when the fine detritus showed evidence for contribution from surface cover that contained basaltic soils. The contribution of basaltic soils to the fine detritus inventory of the Dead Sea and to terraces in the Jordan Valley, indicates a period of intense erosion in the northern highlands of the Dead Sea watershed, at an interval that partly coincides with Sapropel S1. In contrast, during the last interglacial Sapropel S5, fine detritus was mostly mobilized to the lake from southern and eastern region of the watershed. The formation and accumulation of terraces from this basaltic-derived material could be an important factor in the establishment of early agriculture settlements in the Jordan Valley.
•The synoptic conditions prevailing at the Levant during the last glacial interglacial transition are reconstructed.•Since the early Holocene basaltic material introduced to the deep lake of the Dead Sea and the lower Jordan Valley.•Increased erosion at the northern parts of the watershed washed the exposed basaltic soils of the Galilee.
Reconstruction of paleo-synoptic conditions (e.g. past atmospheric circulation) involves tracing the origins and routes of transport of particles comprising eolian archives (i.e., desert dust). ...Lacustrine deposits that accumulated in the Quaternary lakes filling the Dead Sea Basin include remobilized eolian desert dust that was washed to the lakes by floods. Here, we analyze the mineralogical, chemical compositions (e.g. Mg/Al ratios) and 87Sr/86Sr and 143Nd/144Nd (εNd values) isotope ratios of fine siliciclastic particles that form the modern surface cover of the Dead Sea watershed (e.g., loess, mountain soils) and flood particles that are mobilized to the lake during distinct synoptic conditions. The data comprises reference data set that can be used for paleo-synoptic interpretation enhancing our ability to decipher the paleoclimate history during the Quaternary in the Levant. The εNd values and 87Sr/86Sr ratios of the fine detritus lie between −8 and −6 and 0.7035 to 0.7188 reflecting the values of erosional products of granitoids that are exposed in the Sahara and Arabia deserts, and (the unradiogenic Sr) from local soils in the Dead Sea watershed. Particles with low Mg/Al ratios (i.e., 0.17–0.31) are transported by the western winds associated with the Mediterranean cyclones, transporting dust from the Sahara, while particles with high Mg/Al ratios (0.27–0.68) are associated with storms blowing dusts from east to the Dead Sea watershed (Saudi Arabia and Syrian deserts) during Red Sea Trough synoptic conditions. Fine particles blown from the Sahara deserts during winter storms, are rapidly washed to the lake by subsequent floods. Whereas the particles blown during dry storms associated with Red Sea Trough synoptic conditions, accumulate on the surface of the Dead Sea watershed and can be washed later to the lake during extensive rain events.
Archeomagnetic data from the Levant revealed periods within the Holocene with fast and extreme changes in the geomagnetic field. Yet, the availability of the archeomagnetic data is sporadic and the ...correlation with the available sedimentary records from the region is rather poor. To further explore decadal variations in the directions of the field, we investigate three outcrops of the late Holocene Dead Sea that are exposed along the western retreating shores of the modern lake. The sediments were deposited under spatially varying limnological‐environmental conditions, influencing their magnetic properties. The southern section, located near Ein‐Gedi Spa (EG section) is dominated by detrital titanomagnetite whereas the northern sections, Nahal Og (Og section) and Ein‐Feshkha (EF section), are dominated by authigenic greigite. The chronology of the sections was established by radiocarbon dating of short lived organic debris. The magnetic data were obtained in a 2 cm resolution. The EF section, spanning the time interval from ca. 2,500 cal yr BP to ca. 1,000 cal yr BP, is dominated by greigite and thus providing the most robust geomagnetic record with precise paleomagnetic directions. Greigite forms very early in the sediment and the effects of smoothing and the inclination shallowing are negligible. The new data reveal a maximal deviation of 20° from the geocentric axial dipole field between 2,400 to 2,200 cal yr BP accompanied with a fast swing in inclination from 60° to 35° over about a century. This suggests high geomagnetic field activity associated with the Levantine Iron Age geomagnetic anomaly.
Key Points
Rock and paleomagnetic data at decadal resolution from three coeval radiocarbon‐dated late‐Holocene sections of the Dead Sea, Israel
Paleomagnetic data from sediments with high greigite content are compatible with archeomagnetic data
Smoothing and inclination shallowing of the paleomagnetic data carried by greigite are negligible
Chemical compositions of rock varnish from the Negev Desert of Israel and local settled dust were used to constrain the mechanisms of varnish formation and patterns of Mn enrichment and accumulation ...in the varnish. Rock varnish was sampled from coeval, undisturbed prehistoric flint artifacts along a south–north climatic transect (∼30–120mm/yr of rain). Our analyses indicate that Mn, Ba and Pb in the varnish are significantly enriched (∼100×) in respect to the local settling dust and that Mn content systematically fluctuates with depth in the varnish. The varnish and settled dust data combined with basic thermodynamic and kinetic reasoning are used to constrain the following geochemical model of rock varnish formation: dust accumulates in micro-basins on exposed rock surfaces, under pH ∼8 (common Negev value) and during wetting by dew and rain, Mn in the dust is mobilized and leached to a depth of ∼5μm under the varnish surface where Hollandite Mn-oxides precipitate and are adsorbed onto and between the porous clay minerals that comprise most of the varnish. During its mobile phase Mn-oxide is negatively charged and adsorbs rare earth elements. Once the solution dries abrasion removes the upper, weakly cemented dust sediment, which contains mainly Si, Al and Fe (which are not mobile at pH ∼8). Ca is also removed in large quantities. Mn, Ba, Pb and the REE are deposited at a depth and thus, protected from erosion. Reoccurrences of these processes result in a noticeable accumulation of these elements, but not of Si, Al or Fe. The alternating Mn-rich and Mn-poor laminas form as a result of a competition between the leaching rate of Mn and the adhesion rate of the clay minerals. When moisture is high (low), lamina with high (low) Mn/clay mineral ratio forms.
The Dead Sea Deep Drilling Project drilled 456 meters into the deepest floor of the Dead Sea and recovered a record of the past ∼220 kyr of the Levant hydroclimate history, that is, Marine Isotope ...Stages 1–7, including the last three interglacials and the last two glacials. We present an updated chronology of the core from DSDDP Hole 5017-1-A, from the Dead Sea’s deepest basin, that refines our previous chronology (Torfstein et al. 2015) based on new information. The updated chronology uses the following approaches: (1) radiocarbon ages of Kitagawa et al. (2017); (2) correlation of specific layers in the core with U–Th-dated sediments on the Dead Sea margin, particularly during the interval of glacial Lake Lisan (MIS 2,3,4); (3) tuning of the δ18O data of DSDDP core aragonite to the U–Th dated oxygen isotopes of regional cave speleothems; and (4) tuning of the DSDDP aragonite δ18O data to summer insolation curves when the cave δ18O chronology is less clear. The updated chronology reveals a strong relationship between the sedimentary facies comprising the core and Northern Hemisphere summer insolation variations. It shows that sequences of sediments marking drier/wetter/drier climate conditions in the lake’s watershed (e.g., salt/muds/salt, respectively) appear across the flank/peak/flank segments of several summer insolation peaks. In particular, the transition from drier to wetter sedimentary facies during mid-latitude insolation peaks coincides with the intervals of sapropel conditions in the Mediterranean, reflecting enhanced Nile flow due to intense African monsoonal conditions, and marking the impact of the tropical precession cycles on Eastern Mediterranean hydroclimate. This pattern was lost during MIS 2,3,4, when mostly sequences of primary aragonite are punctuated by gypsum precipitation during Heinrich events, marking the strong impact of the North Atlantic on the last glacial Levant hydroclimate.
•Updated chronology of the ICDP Dead Sea drill core DSDDP Hole 5017-1-A.•Strong relationships persist between the core’s sedimentary facies and NH summer insolation.•Interglacial arid conditions occurred during intervals of enhanced changes in insolation.•Interglacial Levant wetter conditions coincide with Mediterranean sapropels and other NH summer insolation peaks.
Sediment cores recovered by the Dead Sea Deep Drilling Project (DSDDP) from the deepest basin of the hypersaline, terminal Dead Sea (lake floor at ∼725 m below mean sea level) reveal the detailed ...climate history of the lake's watershed during the last interglacial period (Marine Isotope Stage 5; MIS5). The results document both a more intense aridity during MIS5 than during the Holocene, and the moderating impacts derived from the intense MIS5e African Monsoon. Early MIS5e (∼133–128 ka) was dominated by hyperarid conditions in the Eastern Mediterranean–Levant, indicated by thick halite deposition triggered by a lake-level drop. Halite deposition was interrupted however, during the MIS5e peak (∼128–122 ka) by sequences of flood deposits, which are coeval with the timing of the intense precession-forced African monsoon that generated Mediterranean sapropel S5. A subsequent weakening of this humidity source triggered extreme aridity in the Dead Sea watershed and resulting in the biggest known lake level drawdown in its history, reflected by the deposition of thick salt layers, and a capping pebble layer corresponding to a hiatus at ∼116–110 ka. The DSDDP core provides the first evidence for a direct association of the African monsoon with mid subtropical latitude climate systems effecting the Dead Sea watershed. Combined with coeval deposition of Arabia and southern Negev speleothems, Arava travertines, and calcification of Red Sea corals, the evidence points to a climatically wet corridor that could have facilitated homo sapiens migration “out of Africa” during the MIS5e peak. The hyperaridity documented during MIS5e may provide an important analogue for future warming of arid regions of the Eastern Mediterranean–Levant.
•High-resolution structure of MIS5e is revealed by deep-drilling in the bottom of the Dead Sea.•Two severe arid spells at the start and end of MIS5e (∼133–128 and 122–116 ka) bracket a relatively wet episode in the Dead Sea at the peak of MIS5e.•The wet interval during MIS5e is coeval with the precession-driven African monsoon that caused the Mediterranean S5 sapropel.•Periods of wetness and extreme aridity are suggested as important controls over hominin dispersal along the rift valley.•The climate dynamics during MIS5e provide an analogue for future climate conditions in the Levant in a warming world.
The Dead Sea, located at the deepest place on continent and between the subtropical Mediterranean zone and the desert, reflects in its water composition and levels, and sedimentary records the ...hydrological conditions in the southern Levant region. Temporal variations in rainfall and temperatures of the Holocene Levant are reconstructed here from pollen data recovered from a sediment core drilled at the Ein Gedi shore, applying a novel biome model based on Bayesian statistics. Our results suggest that the region was arid and warm in the early Holocene period (∼10–6.5 ka cal BP), wetter and colder in the mid Holocene (6.3–3.3 ka cal BP), and drier and warmer in the late Holocene (∼3.2 ka cal BP to present). These periods comprise multi-centennial climate cycles that are characterized by rapid changes in temperature and precipitation reflecting Sea Surface Temperature (SST) and atmospheric conditions over the Atlantic Ocean. The pollen record responds within a short time interval to the climate conditions and marks rapid shifts from Mediterranean to desert environmental conditions and back in the southern Levant region. We also evaluate our results in the light of possible disturbances of the natural vegetation, e.g. the possibility of forest decrease, since the Neolithic.
► We present temporal rainfall and temperature variations in the Levant (Near East) during the last 10,000 years. ► The reconstruction is based on the longest and most continuous pollen record of the Holocene Dead Sea. ► The pollen record marks rapid shifts from Mediterranean to desert conditions and back. ► We apply a novel biome model based on Bayesian statistics to quantify the variability of climate parameters. ► The results compares favorably with reconstructions of the lake levels of the Dead Sea.
This paper examines the hydroclimate history of the Eastern Mediterranean (EM) region during the 10th to 14th centuries C.E., a period known as the Medieval Climate Anomaly (MCA), a time of ...significant historical turmoil and change in the region. The study assembles several regional hydroclimatic archives, primarily the Dead Sea reconstructed lake level curve together with the recently extracted deep-lake sediment record, the Soreq Cave speleothem record and its counterpart, the EM marine sediment record and the Cairo Nilometer record of annual maximum summer flood levels in lower Egypt. The Dead Sea record is a primary indicator of the intensity of the EM cold-season storm activity while the Nilometer reflects the intensity of the late summer monsoon rains over Ethiopia. These two climate systems control the annual rainfall amounts and water availability in the two regional breadbaskets of old, in Mesopotamia and Egypt. The paleoclimate archives portray a variable MCA in both the Levant and the Ethiopian Highlands with an overall dry, early-medieval climate that turned wetter in the 12th century C.E. However, the paleoclimatic records are markedly punctuated by episodes of extreme aridity. In particular, the Dead Sea displays extreme low lake levels and significant salt deposits starting as early as the 9th century C.E. and ending in the late 11th century. The Nile summer flood levels were particularly low during the 10th and 11th centuries, as is also recorded in a large number of historical chronicles that described a large cluster of droughts that led to dire human strife associated with famine, pestilence and conflict. During that time droughts and cold spells also affected the northeastern Middle East, in Persia and Mesopotamia. Seeking an explanation for the pronounced aridity and human consequences across the entire EM, we note that the 10th–11th century events coincide with the medieval Oort Grand Solar Minimum, which came at the height of an interval of relatively high solar irradiance. Bringing together other tropical and Northern Hemisphere paleoclimatic evidence, we argue for the role of long-term variations in solar irradiance in shaping the early MCA in the EM and highlight their relevance to the present and near-term future.
Thick halite intervals recovered by the Dead Sea Deep Drilling Project cores show evidence for severely arid climatic conditions in the eastern Mediterranean during the last three interglacials. In ...particular, the core interval corresponding to the peak of the last interglacial (Marine Isotope Stage 5e or MIS 5e) contains ∼30 m of salt over 85 m of core length, making this the driest known period in that region during the late Quaternary. This study reconstructs Dead Sea lake levels during the salt deposition intervals, based on water and salt budgets derived from the Dead Sea brine composition and the amount of salt in the core. Modern water and salt budgets indicate that halite precipitates only during declining lake levels, while the amount of dissolved Na+ and Cl− accumulates during wetter intervals. Based on the compositions of Dead Sea brines from pore waters and halite fluid inclusions, we estimate that ∼12–16 cm of halite precipitated per meter of lake-level drop. During periods of halite precipitation, the Mg2+ concentration increases and the Na+/Cl− ratio decreases in the lake. Our calculations indicate major lake-level drops of ∼170 m from lake levels of 320 and 310 m below sea level (mbsl) down to lake levels of ∼490 and ∼480 mbsl, during MIS 5e and the Holocene, respectively. These lake levels are much lower than typical interglacial lake levels of around 400 mbsl. These lake-level drops occurred as a result of major decreases in average fresh water runoff, to ∼40% of the modern value (pre-1964, before major fresh water diversions), reflecting severe droughts during which annual precipitation in Jerusalem was lower than 350 mm/y, compared to ∼600 mm/y today. Nevertheless, even during salt intervals, the changes in halite facies and the occurrence of alternating periods of halite and detritus in the Dead Sea core stratigraphy reflect fluctuations between drier and wetter conditions around our estimated average. The halite intervals include periods that are richer and poorer in halite, indicating (based on the sedimentation rate) that severe dry conditions with water availability as low as ∼20% of the present day, continued for periods of decades to centuries, and fluctuated with wetter conditions that spanned centuries to millennia when water availability was ∼50–100% of the present day. These conclusions have potential implications for the coming decades, as climate models predict greater aridity in the region.
•Extreme aridity in the Eastern Mediterranean/Levant during interglacials, lasting over thousands of years.•A quantitative approach is presented to reconstruct Dead Sea lake levels and regional water availability.•The model is based on data and stratigraphy from the ICDP Dead Sea Deep Drilling Project.•Water flow into the Dead Sea decreased by 50–80% during hyper-arid warm intervals.
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