Fluid Mechanics of the Dead Sea

<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>

The effect of base level changes and geological structures on the location of the groundwater divide, as exhibited in the hydrological system between the Dead Sea and the Mediterranean Sea

Modeling radium distribution in coastal aquifers during sea level changes: The Dead Sea case

Constraints on evaporation and dilution of terminal, hypersaline lakes under negative water balance: The Dead Sea, Israel

Facies patterns and subsidence history of the Jumilla-Cieza region (southeastern Spain)

Volcanism has affected the environment of our planet over a broad range of spatial (local to global) and temporal (<1yr to 100s Myr) scales and will continue to do so. As well as examining the Earth's geological record and using computer modelling to understand these effects, much of our knowledge of these processes comes from studying volcanism on the present-day planet. Understanding the full spectrum of possible routes and mechanisms by which volcanism can affect the environment is key to developing a realistic appreciation of possible past and potential future volcanic impact scenarios. This review paper seeks to give a synoptic overview of these potential mechanisms, focussing on those that we can seek to understand over human timescales by studying current volcanic activity. These effects are wide ranging from well-documented planetary-scale impacts (e.g., cooling by stratospheric aerosol veils) to more subtle or localised processes like ash fertilisation of ocean biota and impacts on cloud properties, atmospheric oxidant levels and terrestrial ecosystems. There is still much to be gained by studying present-day volcanic emissions. This review highlights the need for further work in three example areas. Firstly, to understand regional and arc-scale volcanic emissions, especially cycling of elements through subduction zones, more volatile measurements are needed to contribute to a fundamental and systematic understanding of these processes throughout geological time. Secondly, there is still uncertainty surrounding whether stratospheric ozone depletion following volcanic eruptions results solely from activation of anthropogenic halogen species. We should be poised to study future eruptions into the stratosphere with regard to their impacts and halogen load and work to improve our models and understanding of the relevant underlying processes within the Earth and the atmosphere. Thirdly, we lack a systematic understanding of trace metal volatility from magmas, which is of importance in terms of understanding their geochemical cycling and use as tracers in environmental archives and of igneous processes on Earth and more broadly on silicate planetary bodies. Measurements of volcanic rock suites and metals in volcanic plumes have an important part to play in moving towards this goal.

Coasts are natural dynamic systems that are constantly changing. Several factors, such as sea level change, sediment availability and coastal processes strongly influence the evolution of the coastal landscape. However, the tectonic setting of the coast and the rate of sea level rise can also be important factors to consider. Coastal landforms are a consequence of the simultaneous operation of erosion, transportation and deposition processes and have evolved over a geologically short time, with several of them being almost exclusively the result of the action of ocean waves. The world’s most spectacular and dramatic erosional landforms are due to wave action, whereas the reduction of wave energy created deposition landforms. This paper presents an analysis of the coastal landforms caused by deposition and erosion along the shoreline in the sector between Punta Brava and Punta Betín, Santa Marta region, Colombian Caribbean. On the other hand, it is a contribution to the geological knowledge of the Geotectonic Province of Santa Marta and emerges as an alternative solution to various problems. It also promotes research on this region regarding other factors such as the increasing marine activity, population in coastal areas, development of tourism, as well as a series of geological evolutionary processes that reflect in coastal morphology. Coastal landforms are valuable environmental, aesthetic, and recreational resources that are subject to natural processes as well as to the effects of human activities. The results of this study can provide a sound basis for sustainable planning and management of the territory. © 2016. Acad. Colomb. Cienc. Ex. Fis. Nat. Todos los derechos reservados.

The Dead Sea is a terminal lake with great historical, cultural, and economic significance. The sea sits at the confluence of East and West, on the borders of the Hashemite Kingdom of Jordan, Israel, and the Palestinian National Authority, an area that has transported people, goods, and ideas for generations. For at least the past 150 years, serious proposals have been made to engineer a connection between the Red Sea, the Mediterranean Sea, and the Dead Sea. The political, social, water, and environmental needs of the region have each, over time, contributed to the endurance of this idea; hammers, as they say, tend to manifest a great deal of nails, and humans have an affinity for large, complex hammers. Over time, the proposal has been offered as a means to facilitate transportation, generate electricity, supply freshwater through desalination, and advance broader regional peace and economic development. This Water Brief report summarizes both the history of and recent events in the proposals to build major infrastructure in this region.1

A global sea-level history determined by Vail et al consists of 23 sea-level cycles between the base of the Cenozoic and the Pliocene-Pleistocene boundary (65 to 1.8 Ma). We have examined the relation between this global sea-level history and the New Zealand and Australian continental margin shallow-marine sedimentary record. Sedimentary cycles in the Australian Cenozoic marginal-marine sequences are bounded by unconformities of various durations. The tectonic stability and aridity of the western and southwestern margin of Australia during the Cenozoic produced a sedimentary record dominated by hiatuses. This contrasts with the relatively complete sequences of the tectonically more active southeastern marginal basins. The four major sedimentary cycles in the Australian Cenozoic (Paleocene to early Eocene; middle to late Eocene; latest Oligocene to late middle Miocene; and latest Miocene to Quaternary) correlate with the supercycles Ta, Tb, Tc, Td, and Te of Vail et al. In New Zealand, most of the Cenozoic stages represent classic sedimentary cycles bounded by unconformities or correlative conformities formed as a result of large, rapid eustatic sea-level changes. The marine Tertiary sequence in New Zealand consists of 23 stages. Of the 18 stage boundaries between the end of the Paleocene (53 Ma) and the end of the Miocene (5 Ma), 16 appear to correlate with the boundaries of eustatic sea-level cycles. Eustatic sea-level lowstands are well recorded (as unconformities) in New Zealand as a result of its unique tectonic setting during the Cenozoic. For most of the early Cenozoic until the middle Oligocene (~ 30 Ma) New Zealand was generally subsiding. After the middle Oligocene this region began to be uplifted as the Pacific-Australian plate boundary migrated onto New Zealand, climaxing in the latest Cenozoic (late Pliocene-Quaternary), thus exposing a nearly complete sequence of marine Cenozoic strata well suited for the study of sedimentary cycles. Unconformities, which form as a result of eustatic sea-level changes, represent a very useful correlation tool, especially on continental margins with a sufficiently high terrigenous sediment supply, and can be used to supplement paleontologic correlations. Their ultimate usefulness for correlation depends on the rapidity of the sea-level changes or the speed at which sedimentary facies change in response to sea-level changes. If sea level changes rapidly (10 m/1,000 years), stratigraphic resolution will be high (±105 years) but resolution decreases as the speed of sea-level change decreases. Unconformities may well prove to be a vital tool linking the classic land-based sections around the world with deep-sea sections.

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

The Late Cambrian to middle Devonian stratigraphic and faunal record i the western United States may be divided into at least five first-order or primary depositional cycles delimited by tectonically controlled sea level changes. These tectonically controlled sea level changes essentially are changes in rate of platform subsidence. Rate of platform subsidence is reflected in changes in the succession of depositional environments. Tectonically controlled sea level changes are reflected in the succession of faunas as well as in the depositional environment record. The primary rate of subsidence-related sea level changes took place at the following times: latest Cambrian, latest Ibexian (Early Ordovician), and late Early Devonian. A prominent set of glacio-eustatic sea level changes occurred in the latest Ordovician-earliest Silurian. That glacial interval was one in which significant mass mortalities and subsequent re-radiations took place among marine invertebrates. Although the boundaries of the first-order cycles, both in the stratigraphic depositional cycles appear to be diachronous across the Great Basin, the rock suites comprising the cycles are delimited clearly. Second-order cycles may be recognized within the first-order cycles, both in the stratigraphic and faunal record. The second-order cycles also reflect sea level changes. Major oceanic surface water currents were deflected around more » plate and related platform margins during intervals of regression from the platform, enhancing upwelling along the plate margins during such intervals. « less

Unique gypsum structures: large capes (termed “gypsum deltas”) and small pitted gypsum mounds are exposed along the western shores of the currently retreating Dead Sea, the hypersaline terminal lake in the Dead Sea Basin. The gypsum deltas were formed during time intervals of low lake stands (∼420 ± 10 m below mean sea level), when sulfate‐rich Ca chloride brines discharged from the coastal aquifer via saline springs, mixed with the Dead Sea brine and precipitated the gypsum (outsalting process). The ages of formation of the gypsum structures coincide with times of North Atlantic cooling events and grand solar minima suggesting a direct impact of the latter on the Dead Sea hydrology and high sensitivity of the regional hydrology (controlling lake level) to global solar‐related events. The temporal occurrence and numbers of the gypsum structures appear to follow the Hallstatt Cycle that approaches minima at ∼3,000–2,000 years before present.

Impact of lake water level decline on river evolution in Ebinur Lake Basin (an ungauged terminal lake basin)

Two continuous cores (Unda and Clino) drilled during the initial phase of the Bahamas Drilling Project on top of the western Great Bahama Bank (GBB) penetrated proximal portions of prograding seismic sequences.As such, these cores provide the shallow-water record of sea-level changes and fluid flow of the Bahamas Transect that was completed with the deeper water sites of Ocean Drilling Program (ODP) Leg 166 in the Straits of Florida.The record of several hierarchies of sea-level fluctuations is identified in the lithology and log signature of two core borings (Unda and Clino), and the nature of fluids responsible for diagenetic alteration is interpreted from formation waters and the stable isotope signal of the sediments and rocks.Facies successions document that several hierarchies of changes in relative sea level are responsible for pulses of progradation.These pulses are seen on seismic data as seismic sequences and in the cores as depositional successions.On the platform, the boundaries of the depositional successions are indicated by subaerial exposure, changes in facies, and diagenetic overprint.On the slope, the sequence boundaries are marked by major discontinuity surfaces within the depositional successions consisting mainly of fine-grained skeletal and nonskeletal sediments.These discontinuity surfaces are characterized by hardgrounds that are overlain by 7-and 28-m-thick, coarser grained packages containing sand-sized blackened lithoclasts, planktonic foraminifers and minor amounts of platform-derived grains.The coarser grained intervals are interpreted as deposits during relative sea-level lowstands, while the fine-grained sediments are interpreted as highstand deposits.Higher order sea-level changes are recorded in the rocks and in the geophysical logs.On the platform top, these changes are recorded in shallowing-upward cycles bounded by exposure horizons.On the slopes, higher order sea-level changes are recognized by facies variations, whereby intervals of coarser grained sediments in the periplatform ooze indicate sea-level falls.The change in sedimentation rate and hydrology during these intervals results in the formation of firmgrounds.The intervals are well recognized as sharp peaks on the gamma-ray and velocity logs.The lower permeability on top of these intervals is likely to separate the fluid flow into several levels within each sequence and influence later patterns of diagenesis.The next higher order of cyclicity is represented by alternations (0.3-1 m) of coarser and finer grained beds within the coarse-grained intervals.Because of their relatively thin nature and low contrast in rock properties, these high-frequency cycles are not recorded in the logs.The slope portions of Unda and Clino yield several age diagnostic foraminifers and nannofossil marker species.Although low in abundance, these microfossils are good indicators of depositional age and provide the base for age determination.By combining micropaleontology, strontium-isotope stratigraphy, and magnetostratigraphy, a chronostratigraphy is obtainable in the prograding margin of GBB.The chronostratigraphy helps assess the stratigraphic evolution of the Great Bahama Bank margin, the timing of sea-level changes observed in the sedimentary record, and the synchroneity of the seismic sequence boundaries.The correlation of the rock with the seismic record not only confirms some of the major assumptions of the sequence stratigraphic concept but also showed some of the limitations when using sequence stratigraphy as a dating tool.The assumption that seismic reflections follow depositional surfaces (i.e., time lines) is indicated by two lines of evidence.The combination of changes in composition and diagenesis produces the necessary impedance contrasts for the imaging depositional unit boundaries as seismic reflections.In addition, chronostratigraphic dating shows no crossing of seismic reflections with time lines.The inability to recognize condensed or expanded sections causes problems when dating sequences solely by correlation to the global cycle chart.For example, the condensed interval in the early Pliocene falls below seismic resolution, whereas the thick Quaternary sequences are of different duration than the ones shown on the global chart of Haq et al. (1987).Geochemical data from the rocks and fluid samples taken during the drilling provide abundant evidence of the existence of fluid flow within the margin of Great Bahama Bank.Despite pervasive alteration and marine cementation, pore water analyses in the upper 100 m show an essentially isochemical profile suggesting the active flushing of seawater through this interval.Below 100 m in both cores, there are large increases in the concentration of nonconservative elements such as Sr, indicating dissolution and cementation processes.

Keywords:Geoarchaeology, Palaeoenvironmental, Palaeo-Sediments, Landslide and Tectonic Movments, Roman Anchor, Greek harbour, Holocene Sea level change, Ras Hawala, Ras Alam El-Rum, Palaeo- tsunami, Graias Gony harbour, Egypt. Abstract:Graias Gony is submerged harbour in Ras Alam El-Rom area as a part of the NW coast of Egypt. Some geoarchaeological remains were discovered by Underwater Archaeology 20- 23rd October survey in the eastern side of Ras Alam El-Rum coastline on the NW coast of Egypt, East of Matruh city with extension about 16.9 km, SW Ras Alam El-Rom, in the same location of the above submerged harbours were described by another early writers.The geomorphological characteristics were studied for all locations but the coastline were changed from the Roman period up to recent time by coastal erosion and other geomorphic processes in addition to the Holocene sea level change.It was mentioned by Claude Ptolmee, who named it the Geographer Ptolemios, in his book in the year 150 AD in a list of ports in the Mediterranean Sea (Abd El Maguid. 2001). This port is one of the largest ports located on NW coast of Egypt and was recently named Rumaila harbour in reference to the type of coastal rock deposits spread in it along with The sandy sediments diminished greatly, which prompted the Bedouins to give it this name. The researcher found clear evidence showing sea level changes in this harbour, the most important of which are Notches and submerged platforms. I studied the geomorphological characteristics for their location, noting that coastal erosion, other geomorphic processes, and the Holocene Sea level change have altered the coastline from the Greek and Roman periods to the present. Alternating Quaternary limestone, part of an eroded carbonate coastal ridge, occupies the study area. We observed geomorphic coastal landforms along the shore, such as multi-level marine notches, platforms, and caves. These features were created at the Holocene relative sea level. We also observed solution microlandforms such as holes, channels, pits, and residual pinnacles. Sea water sculpted these features on carbonate rocks.