scholarly journals Hydroclimatic variability of opposing Late Pleistocene climates in the Levant revealed by deep Dead Sea sediments

2021 ◽  
Vol 17 (6) ◽  
pp. 2653-2677
Author(s):  
Yoav Ben Dor ◽  
Francesco Marra ◽  
Moshe Armon ◽  
Yehouda Enzel ◽  
Achim Brauer ◽  
...  
Keyword(s):  
Lake Level ◽  
Eastern Mediterranean ◽  
Dead Sea ◽  
Flood Frequency ◽  
Multiple Time ◽  
Combined Application ◽  
Pleistocene Climate ◽  
Decadal Scale ◽  
Hydroclimatic Variability

Abstract. Annual and decadal-scale hydroclimatic variability describes key characteristics that are embedded into climate in situ and is of prime importance in subtropical regions. The study of hydroclimatic variability is therefore crucial to understand its manifestation and implications for climate derivatives such as hydrological phenomena and water availability. However, the study of this variability from modern records is limited due to their relatively short span, whereas model simulations relying on modern dynamics could misrepresent some of its aspects. Here we study annual to decadal hydroclimatic variability in the Levant using two sedimentary sections covering ∼ 700 years each, from the depocenter of the Dead Sea, which has been continuously recording environmental conditions since the Pleistocene. We focus on two series of annually deposited laminated intervals (i.e., varves) that represent two episodes of opposing mean climates, deposited during MIS2 lake-level rise and fall at ∼ 27 and 18 ka, respectively. These two series comprise alternations of authigenic aragonite that precipitated during summer and flood-borne detrital laminae deposited by winter floods. Within this record, aragonite laminae form a proxy of annual inflow and the extent of epilimnion dilution, whereas detrital laminae are comprised of sub-laminae deposited by individual flooding events. The two series depict distinct characteristics with increased mean and variance of annual inflow and flood frequency during “wetter”, with respect to the relatively “dryer”, conditions, reflected by opposite lake-level changes. In addition, decades of intense flood frequency (clusters) are identified, reflecting the in situ impact of shifting centennial-scale climate regimes, which are particularly pronounced during wetter conditions. The combined application of multiple time series analyses suggests that the studied episodes are characterized by weak and non-significant cyclical components of sub-decadal frequencies. The interpretation of these observations using modern synoptic-scale hydroclimatology suggests that Pleistocene climate changes resulted in shifts in the dominance of the key synoptic systems that govern rainfall, annual inflow and flood frequency in the eastern Mediterranean Sea over centennial timescales.

scholarly journals Hydroclimatic variability of opposing late Pleistocene climates in the Levant revealed by deep Dead Sea sediments

2021 ◽  
Author(s):  
Yoav Ben Dor ◽  
Francesco Marra ◽  
Moshe Armon ◽  
Yehouda Enzel ◽  
Efrat Morin
Keyword(s):  
Late Pleistocene ◽  
Lake Level ◽  
Eastern Mediterranean ◽  
Dead Sea ◽  
Flood Frequency ◽  
Multiple Time ◽  
Combined Application ◽  
Decadal Scale ◽  
Hydroclimatic Variability ◽  
Periodic Components

Abstract. Annual and decadal-scale hydroclimatic variability is a key characteristic embedded into climate insitu. It is therefore crucial to study hydroclimatic variability in order to understand its effects on climate derivatives such as hydrological processes and water availability. However, the study of this variability from modern records is limited due to their relatively short span, whereas model simulations relaying on modern dynamics could miss some of its aspects. Here we study annual to decadal hydroclimatic variability in the Levant using two sedimentary sections covering ~ 700 years deposited at ~ 18 and ~ 27 Ka retrieved from the depocenter of the Dead Sea, which has been continuously recording environmental conditions throughout the late Pleistocene. We focus on two ~ 700 years long series of annually-deposited laminated intervals (i.e., varves) representing two episodes of opposing mean climates, deposited during lake level rise and fall at 27 and 18 Ka, respectively. These two series comprise alternations of authigenic aragonite precipitated during summer and flood-derived detrital laminae deposited during winter. Within this record, aragonite laminae serve as a proxy of annual inflow and epilimnion dilution, whereas detrital laminae comprise sub-laminae that record individual floods. The two series depict distinct characteristics with increased mean and variance of annual inflow and flood frequency during "wetter", with respect to the "dryer", conditions. In addition, decades of intense flood frequency are identified (e.g., clusters), suggesting shifts between centennial-scale climatic regimes, which are particularly pronounced during wetter, lake-rising conditions. The combined application of multiple time series analyses indicates that episodes of falling lake levels are characterized by multiple pronounced quasi-periodic components with periodicities of 2–4, 6–8 and ~ 12 years, whereas the rising lake level episode presents weaker, less-persistent periodical components with similar periodicities. Combining these observations with the modern synoptic-scale hydroclimatology indicates shifts in the dominance of key synoptic systems governing rainfall, annual inflow and flood frequency in the eastern Mediterranean over centennial time-scale.

scholarly journals Near East Desertification: impact of Dead Sea drying on convective rainfall

2019 ◽  
Author(s):  
Samiro Khodayar ◽  
Johannes Hoerner
Keyword(s):  
Lake Level ◽  
Weather Prediction ◽  
Regional Climate ◽  
Atmospheric Stability ◽  
Lower Boundary ◽  
Heavy Precipitation ◽  
Dead Sea ◽  
Decadal Scale ◽  
The Dead ◽  
The Impact

Abstract. The Dead Sea desertification-threatened region is affected by continual lake level decline and occasional, but life-endangering flash-floods. Climate change has aggravated such issues in the past decades. In this study, the impact of the Dead Sea drying on the severe convection generating heavy precipitation in the region is investigated. Perturbation simulations with the high-resolution convection-permitting regional climate model COSMO-CLM and several numerical weather prediction (NWP) runs on an event time scale are performed over the Dead Sea area. A reference simulation covering the 2003 to 2013 period and a twin sensitivity experiment, in which the Dead Sea is dried out and set to bare soil, are compared. NWP simulations focus on heavy precipitation events exhibiting relevant differences between the reference and the sensitivity decadal realization to assess the impact on the underlying convection-related processes. On a decadal scale, the difference between the simulations points out that in future regional climate, under ongoing lake level decline, a decrease in evaporation, higher air temperatures and less precipitation is to expect. Particularly, an increase in the number of dry days and in the intensity of heavy precipitation is foreseen. The drying of the Dead Sea is seen to affect the atmospheric conditions leading to convection in two ways: (a) the local decrease in evaporation reduces moisture availability in the lower boundary layer locally and in the neighbouring, directly affecting atmospheric stability. Weaker updrafts characterize the drier and more stable atmosphere of the simulations where the Dead Sea has been dried out. (b) Thermally driven wind system circulations and resulting divergence/convergence fields are altered preventing in many occasions convection initiation because of the omission of convergence lines.

Changes in hydroclimate during last deglaciation lake-level fall in the Dead Sea sediment record

2020 ◽  
Author(s):  
Markus J. Schwab ◽  
Daniela Müller ◽  
Ina Neugebauer ◽  
Rik Tjallingii ◽  
Yoav Ben Dor ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Lake Level ◽  
Drainage Basin ◽  
Eastern Mediterranean ◽  
Dead Sea ◽  
Laminated Sediments ◽  
Last Deglaciation ◽  
Sediment Record ◽  
Deep Lake ◽  
The Dead

<p>The drainage basin of the Dead Sea is the largest hydrological system in the Levant and spans across the boundary between the sub-humid to semi-arid Mediterranean and the arid to hyper-arid Saharo-Arabian climate zones. As a terminal lake, precipitation changes due to climatic variations result in extensive fluctuations of lake level and sediment deposition.</p><p>A unique sediment record from the deepest part of the Dead Sea Basin was obtained as part of the ICDP Dead Sea Deep Drilling Project. Here we analyze the partially annually laminated sediments of Core 5017-1-A between 88.5-99.2 m core depth, which comprise the period between ~16.5 and ~11 ka and document a lake level drop of ca 160 m. In the sediments of Core 5017-1-A, this marks the transition from MIS2 aad (alternating aragonite and detritus) sediments to MIS1 halite deposits and ld (laminated detrital marl) sediments, coinciding with increased drying in the Dead Sea watershed.</p><p>Microfacies analyses show the occurrence of several lithological facies that accumulated during MIS2: aad, gd (massive gypsum deposit within marl), native sulfur concretions (associated with greenish colored aad), mtd (mass-transport deposits, typically graded) and homogenites consisting of clay and silt. Further, flood layers have been identified, potentially indicating rainstorms associated with specific eastern Mediterranean synoptic systems. To complement the microfacies analyses, XRF scanning provides continuous Ti/Ca and S/Ca records to reconstruct relative detrital input and gypsum occurrence, respectively. Additionally, to study potential early signs of hydroclimatic change, the deep lake sediments are correlated to the Lisan Formation of the marginal Masada outcrop using distinct gypsum marker layers, indicative of pronounced lake level drops. However, due to a significant lake level decline, the Masada outcrop sediments terminate at around 14.5 ka and the subsequent lake level lowering is solely recorded in the deep lake sediments.</p><p>This study was funded by the German Science Foundation (DFG Grant BR 2208/13-1/-2). Further, it is a contribution to the Helmholtz Association (HFG) climate initiative REKLIM Topic 8 “Abrupt climate change derived from proxy data”.</p>

scholarly journals Hydroclimatic variability in the Levant during the early last glacial (∼  117–75 ka) derived from micro-facies analyses of deep Dead Sea sediments

2016 ◽  
Vol 12 (1) ◽  
pp. 75-90 ◽  
Author(s):  
I. Neugebauer ◽  
M. J. Schwab ◽  
N. D. Waldmann ◽  
R. Tjallingii ◽  
U. Frank ◽  
...  
Keyword(s):  
Lake Level ◽  
Dead Sea ◽  
Lake Levels ◽  
Last Interglacial ◽  
Central Mediterranean ◽  
Close Link ◽  
Last Glacial ◽  
Gravel Layer ◽  
Lower Amplitude ◽  
Hydroclimatic Variability

Abstract. The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present high-resolution sediment facies analysis and elemental composition by micro-X-ray fluorescence (µXRF) scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca. 117 to 75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several metres thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at  ∼  110–108 ± 5 and  ∼  93–87 ± 7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during Marine Isotope Stage (MIS) 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in situ beach deposit. Two intervals of higher lake stands at  ∼  108–93 ± 6 and  ∼  87–75 ± 7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and Greenland interstadials (GI) 24+23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period.

Fluctuations of Lake Lisan (the Dead Sea) during the last glacial: Implications for paleoclimatic changes of the Levant.

2020 ◽  
Author(s):  
Shahrazad Abu Ghazleh ◽  
Stephan Kempe
Keyword(s):  
Fresh Water ◽  
Lake Water ◽  
Lake Level ◽  
Eastern Mediterranean ◽  
Xrd Analysis ◽  
Dead Sea ◽  
Climatic Conditions ◽  
Lake Basin ◽  
Fresh Water Input ◽  
The Dead

<p> </p><p>Calcareous stromatolite crusts overgrowing beach gravels and stabilising piles of rocks were observed on shoreline terraces of Lake Lisan along the eastern coast of the Dead Sea. The stromatolite crusts are thick, massive and hard, with a dark-grey or white-grey finely-laminated structure, indicating that they are mostly calcareous organic build-up of cyanobacterial origin. Samples from these stromatolites have been analyzed using Stable Isotopes (δ13C & δ18O), AAS and XRD analysis. The samples range in altitude between -350 m and -19 m, representing the time interval of Lake Lisan (~ 80-19 ka BP) according to our U/Th dating. Since stromatolites grow in shallow water, they are very sensitive to minor shifts in rainfall and evaporation and therefore an excellent tool to track small changes in hydrology, in climate and in paleoenvironmental conditions of the lake basin.</p><p> </p><p>Oxygen and carbon isotopic compositions of these stromatolites show a linear covariant trend with a strong positive correlation (r = 0.8) and large ranges of 7.85 and 6.78‰, respectively. This trend is most typical of primary carbonates formed in closed lakes. Isotopes analyses show low negative values of stromatolites from the lake highest stands at -76 m to -19 m, reflecting fresh water conditions of the lake basin at the last interglacial-glacial boundary (80-76 ka BP). The lowest values were derived from stromatolites at -103 to -119 m associated with the transgression of the lake to these high stands between 55 and 33 ka BP. The heaviest values were derived from stromatolites at -137 to -160 m indicating a change to dry climatic conditions in the Eastern Mediterranean that caused a subsequent drop of the lake level during MIS 2 (31-19 ka BP).</p><p> </p><p>The Mg/Ca ratio and the XRD analysis of the stromatolites correlate also with transgression-regression phases of the lake. Dominance of calcite in stromatolites at -76 to 0 m and inferred low Mg/Ca ratios of the lake water (i.e. ~2) imply a high fresh water input of the lake during the   highest stands period. A high Mg/Ca ratio of the lake water of >7 inferred from low-level stromatolite at -350 m and the existence of aragonite as the sole mineral reflect low fresh water input and high evaporation rates that caused a lake level regression during H6, ~ 60 ka BP.</p><p> </p><p>Inferred low Mg/Ca ratios of stromatolites at -247 to -101 m and the existence of calcite as a main mineral phase indicate wet climatic conditions of the eastern Mediterranean and lake level transgression to higher than -137 during MIS 3. The appearance of more aragonite in stromatolites at -137 to -154 m and the inferred high Mg/Ca ratio of the lake water points to a return to dry climatic conditions that caused a regression of Lake Lisan between 32 to 22 ka BP (MIS 2). However, the change in the mineral composition to pure calcite at -160 m in addition to the inferred low Mg/Ca ratio correlates well with the transgression of the lake to this level by the end of the LGM.</p><p> </p><p> </p>

scholarly journals Relationships between lake-level changes and water and salt budgets in the Dead Sea during extreme aridities in the Eastern Mediterranean

2017 ◽  
Vol 464 ◽  
pp. 211-226 ◽  
Author(s):  
Yael Kiro ◽  
Steven L. Goldstein ◽  
Javier Garcia-Veigas ◽  
Elan Levy ◽  
Yochanan Kushnir ◽  
...  
Keyword(s):  
Lake Level ◽  
Eastern Mediterranean ◽  
Dead Sea ◽  
Lake Level Changes ◽  
The Dead

scholarly journals Hydroclimatic variability in the Levant during the early last glacial (∼ 117–75 ka) derived from micro-facies analyses of deep Dead Sea sediments

2015 ◽  
Vol 11 (4) ◽  
pp. 3625-3663 ◽  
Author(s):  
I. Neugebauer ◽  
M. J. Schwab ◽  
N. D. Waldmann ◽  
R. Tjallingii ◽  
U. Frank ◽  
...  
Keyword(s):  
Lake Level ◽  
Dead Sea ◽  
Lake Levels ◽  
Last Interglacial ◽  
Central Mediterranean ◽  
Close Link ◽  
Last Glacial ◽  
Gravel Layer ◽  
Lower Amplitude ◽  
Hydroclimatic Variability

Abstract. The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present high-resolution sediment facies analysis and elemental composition by μXRF scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca 117–75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several meters thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at ∼110–108 ± 5 and ∼93–87 ± 7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during MIS 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in-situ beach deposit. Two intervals of higher lake stands at ∼108–93 ± 6 and ∼87–75 ± 7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and GI 24 + 23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period.

scholarly journals Sharp changes in lake-levels preconditioning seismogenic mass failures in the Dead Sea

2020 ◽  
Author(s):  
Yin Lu ◽  
Amotz Agnon ◽  
Shmuel Marco ◽  
Revital Bookman ◽  
Nicolas Waldmann ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Level ◽  
High Amplitude ◽  
Dead Sea ◽  
Age Dating ◽  
Lake Level Changes ◽  
Mass Failure ◽  
The Dead ◽  
The Relationship

<p>Subaqueous mass failures that comprise slides, slumps and debris flows are a major process that transport sediments from the continental shelf and upper slope to the deep basins (both oceans and lacustrine settings). They are often viewed together with other natural hazards such as earthquakes, and can have serious socioeconomic consequences. It is increasingly important to understand the relationship between mass failures and climate-driven factors such as changes in water-level. Despite extensive marine investigations on this topic world-wide, the relationship between changes in water-level and mass failures is still highly disputed. This is due largely to the significant uncertainties in age dating and different potential triggers and preconditioning factors of mass failure events from different geological settings. Here, we present a 70 kyr-long record of mass failure from the Dead Sea Basin center (ICDP Core 5017-1). This sedimentary sequence has been dated in high accuracy (±0.6 kyr) and has similar responses to climate forcing. Moreover, the mass failure record is interpreted to be controlled by a single trigger mechanism (i.e. seismicity).<br>Based on the recent detailed study on the sedimentological signature of seismic shaking in the Dead Sea center, these seismogenic mass failures (seismites) account only for a part of the whole seismites catalog, suggesting that mass failure follows only part of seismic shaking irrespective of intensities of the shaking. This is evidenced by the common absence of mass failures following the in situ developed and preserved seismites (e.g., the in situ folded layer and intraclast breccias layer) which represent different intensities of seismic shaking. This feature implies that some non-seismic factor(s) must have preconditioned for the seismogenic mass failures in the Dead Sea center.<br>Our observations reveal decoupling between change in sedimentation rates and occurrence probability of these seismogenic mass failures, thus suggesting that a change in sedimentation rate is not the preconditioning factor for the failure events. While 79% of seismogenic mass failure events occurred during lake-level rise/drop in contrast to 21% events occurred in the quiescent intervals between. Our dataset implies that seismogenic mass failures can occur at any lake-level state, but are more likely to occur during lake-level rise/drop due to the instability of the basin margins. In addition, the seismogenic mass failures occurred more frequently during glacials (characterized by highstand and high-amplitude lake-level changes) than during interglacials, as a result of the morphologic characteristics of the lake margin slopes and different lithologies (e.g. halite) influences which are both connected to the glacial-interglacial lake-level changes.</p>

Late Holocene climates of the Near East deduced from Dead Sea level variations and modern regional winter rainfall

2003 ◽  
Vol 60 (3) ◽  
pp. 263-273 ◽  
Author(s):  
Yehouda Enzel ◽  
Revital Bookman (Ken Tor) ◽  
David Sharon ◽  
Haim Gvirtzman ◽  
Uri Dayan ◽  
...  
Keyword(s):  
Sea Level ◽  
Lake Level ◽  
Eastern Mediterranean ◽  
Close Association ◽  
Principal Component ◽  
Temporal Variations ◽  
Dead Sea ◽  
Rain Gauge ◽  
The Dead ◽  
Wet Spells

AbstractThe Dead Sea is a terminal lake of one of the largest hydrological systems in the Levant and may thus be viewed as a large rain gauge for the region. Variations of its level are indicative of the climate variations in the region. Here, we present the decadal- to centennial-resolution Holocene lake-level curve of the Dead Sea. Then we determine the regional hydroclimatology that affected level variations. To achieve this goal we compare modern natural lake-level variations and instrumental rainfall records and quantify the hydrology relative to lake-level rise, fall, or stability. To quantify that relationship under natural conditions, rainfall data pre-dating the artificial Dead Sea level drop since the 1960s are used. In this respect, Jerusalem station offers the longest uninterrupted pre-1960s rainfall record and Jerusalem rains serve as an adequate proxy for the Dead Sea headwaters rainfall. Principal component analysis indicates that temporal variations of annual precipitation in all stations in Israel north of the current 200 mm yr−1 average isohyet during 1940–1990 are largely synchronous and in phase (∼70% of the total variance explained by PC1). This station also represents well northern Jordan and the area all the way to Beirut, Lebanon, especially during extreme drought and wet spells. We (a) determine the modern, and propose the past regional hydrology and Eastern Mediterranean (EM) climatology that affected the severity and length of droughts/wet spells associated with multiyear episodes of Dead Sea level falls/rises and (b) determine that EM cyclone tracks were different in average number and latitude in wet and dry years in Jerusalem. The mean composite sea level pressure and 500-mb height anomalies indicate that the potential causes for wet and dry episodes span the entire EM and are rooted in the larger-scale northern hemisphere atmospheric circulation. We also identified remarkably close association (within radiocarbon resolution) between climatic changes in the Levant, reflected by level changes, and culture shifts in this region.

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