Fluvial incision and coarse gravel redistribution across the modern Dead Sea shelf as a result of base‐level fall

Simulation scenarios of sediment flux variation and topographic changes due to dam removal have been investigated in a reservoir catchment of the axial zone of southern Italy through the application of a landscape evolution model (i.e.,: the Caesar–Lisflood landscape evolution models, LEM). LEM simulation highlights that the abrupt change in base level due to dam removal induces a significant increase in erosion ability of main channels and a strong incision of the reservoir infill. Analysis of the sediment dynamics resulting from the dam removal highlights a significant increase of the total eroded volumes in the post dam scenario of a factor higher than 4. Model results also predict a strong modification of the longitudinal profile of main channels, which promoted fluvial incision upstream and downstream of the former reservoir area. Such a geomorphic response is in agreement with previous analysis of the fluvial system short-term response induced by base-level lowering, thus demonstrating the reliability of LEM-based analysis for solving open problems in applied geomorphology such as perturbations and short-term landscape modification natural processes or human impact.

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Dynamics of hydrological and geomorphological processes in evaporite karst at the eastern Dead Sea – a multidisciplinary study

Hydrology and Earth System Sciences ◽

10.5194/hess-25-3351-2021 ◽

2021 ◽

Vol 25 (6) ◽

pp. 3351-3395

Author(s):

Djamil Al-Halbouni ◽

Robert A. Watson ◽

Eoghan P. Holohan ◽

Rena Meyer ◽

Ulrich Polom ◽

...

Keyword(s):

Remote Sensing ◽

Groundwater Flow ◽

Shear Wave ◽

Water Flow ◽

Dead Sea ◽

Stream Channels ◽

Evaporite Karst ◽

Base Level ◽

Geomorphological Processes ◽

The Dead

Abstract. Karst groundwater systems are characterized by the presence of multiple porosity types. Of these, subsurface conduits that facilitate concentrated, heterogeneous flow are challenging to resolve geologically and geophysically. This is especially the case in evaporite karst systems, such as those present on the shores of the Dead Sea, where rapid geomorphological changes are linked to a fall in base level by over 35 m since 1967. Here we combine field observations, remote-sensing analysis, and multiple geophysical surveying methods (shear wave reflection seismics, electrical resistivity tomography, ERT, self-potential, SP, and ground-penetrating radar, GPR) to investigate the nature of subsurface groundwater flow and its interaction with hypersaline Dead Sea water on the rapidly retreating eastern shoreline, near Ghor Al-Haditha in Jordan. Remote-sensing data highlight links between the evolution of surface stream channels fed by groundwater springs and the development of surface subsidence patterns over a 25-year period. ERT and SP data from the head of one groundwater-fed channel adjacent to the former lakeshore show anomalies that point to concentrated, multidirectional water flow in conduits located in the shallow subsurface (< 25 m depth). ERT surveys further inland show anomalies that are coincident with the axis of a major depression and that we interpret as representing subsurface water flow. Low-frequency GPR surveys reveal the limit between unsaturated and saturated zones (< 30 m depth) surrounding the main depression area. Shear wave seismic reflection data nearly 1 km further inland reveal buried paleochannels within alluvial fan deposits, which we interpret as pathways for groundwater flow from the main wadi in the area towards the springs feeding the surface streams. Finally, simulations of density-driven flow of hypersaline and undersaturated groundwaters in response to base-level fall perform realistically if they include the generation of karst conduits near the shoreline. The combined approaches lead to a refined conceptual model of the hydrological and geomorphological processes developed at this part of the Dead Sea, whereby matrix flow through the superficial aquifer inland transitions to conduit flow nearer the shore where evaporite deposits are encountered. These conduits play a key role in the development of springs, stream channels and subsidence across the study area.

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GEOMORPHIC RESPONSE OF A LONG LOW-GRADIENT CHANNEL TO MODERN, DECADES-LONG AND CONTINUOUS BASE-LEVEL LOWERING: NAHAL HAARAVA, THE DEAD SEA

10.1130/abs/2017am-297297 ◽

2017 ◽

Author(s):

Yehouda Enzel ◽

◽

Elad Dente ◽

Nadav G. Lensky‬‏ ◽

Efrat Morin ◽

...

Keyword(s):

Dead Sea ◽

Base Level ◽

Geomorphic Response ◽

Gradient Channel ◽

The Dead ◽

Level Lowering

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The declining but non-rejuvenating base level—The Lisan lake, the Dead Sea area, Israel

Earth Surface Processes and Landforms ◽

10.1002/esp.3290130305 ◽

1988 ◽

Vol 13 (3) ◽

pp. 239-249 ◽

Cited By ~ 21

Author(s):

D. Bowman

Keyword(s):

Dead Sea ◽

Base Level ◽

The Dead ◽

Sea Area

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Differentiating Pleistocene tectonically driven and climate-related fluvial incision: the Sanggan River, Datong Basin, North China

Geological Magazine ◽

10.1017/s0016756806001956 ◽

2006 ◽

Vol 143 (3) ◽

pp. 393-410 ◽

Cited By ~ 5

Author(s):

CHENG SHAO-PING ◽

LI CHUAN-YOU ◽

YANG GUI-ZHI ◽

ZHOU SHI-WEI

Keyword(s):

North China ◽

Profile Analysis ◽

High Water ◽

Water Levels ◽

Humid Climate ◽

Datong Basin ◽

Base Level ◽

Fluvial Incision ◽

Equilibrium Profile ◽

Basaltic Flow

The Sanggan River is an alluvial river flowing through a graben basin system of the northern Shanxi Rift Zone, North China. During Pleistocene times, the river reach in the Datong Basin was affected successively by various external variables, such as invasion by basaltic flow, along-valley faulting and climatic change. Therefore, it provides excellent constraints for differentiating tectonically driven and climate-related fluvial incision in the context of tectonic subsidence. Based on equilibrium profile analysis, K–Ar dating of basalts (0.74–0.41 Ma), studies of the river terrace and of stream action history, we present a conceptual model for differentiating fault-driven and climate-related fluvial incision by the river. The results show that fluvial incision induced by tectonic lowering of the base-level due to along-valley movement on the Sanggan River fault is equal to fault displacement. The amount of post-basalt fluvial incision of the reach upstream from the lava dam is 23 to 25 m, of which the fault-driven and climate-related incisions are 15 m and 8 to 10 m, respectively, the former predominating over the latter. The total amount of incision in the lava dam reach is 40 to 47 m, of which the fault-driven and climate-related incisions are 10 m and 30–37 m, respectively; here the latter is predominant over the former. Since 0.41 ± 0.10 Ma, the rate of fluvial incision of the lava dam reach of the river has reached 98–115 m/Ma, which is 1.5–2 times as great as those of the reaches upstream and downstream from the lava dam. The higher rate of fluvial incision can be attributed to high water levels supplied by the onset and maintenance of backwater conditions in the reach upstream from the lava dam, due to the long period of warm and humid climate in this region. Plucking, abrasion and knickpoint migration appear to be the primary erosional processes in the lava dam reach.

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O CAMINHO DAS PEDRAS

Revista Geonomos ◽

10.18285/geonomos.v4i1.196 ◽

1996 ◽

Author(s):

Pedro Angelo Almeida Abreu

Keyword(s):

Primary Source ◽

Explosive Volcanism ◽

Individual Characteristics ◽

Source Rocks ◽

Normal Faults ◽

Alluvial Fans ◽

Base Level ◽

Fluvial Incision ◽

The Individual ◽

Relationship Of

Application of modern geological concepts lead to the identification of different processes involvedin the geodynamic evolution of the southern Serra do Espinhaço, Minas Gerais, Brazil with special referenceto its depositional systems (Tab. 1 and 2), paleoclimatology and synsedimentary crustal extension history.Within this context a detailed analysis of the Espinhaço Rift, especially of the area Sopa - Guinda nearDiamantina (Fig. 1) lead to the identification of the precise magnitude of the source areas of the diamondscontained in the Sopa-Brumadinho Formation and consequently to the location of the primary sourcerocks of the diamonds.The primary source rocks of the diamonds (kimberlites or lamproites ?) are deeply altered either bycontemporaneous Proterozoic weathering or to less extent by recent weathering. The emplacement ofthose rocks along normal faults which controlled the local base level establishes a clear relation of causeand effect (consequence). The intrusions are coeval with the fault movements which defined adjacenttectonic cells where coarse clastics are deposited by the relief as well as the erosion products of the hostrocks ejected by the explosive volcanism (Fig. 4).The granulometric constancy of the conglomerates in the different alluvial fans, the uniform grade ofdiamond within these fans, and the absence of significant fluvial incision demonstrate that the system ofsynsedimentary normal faults was rift prograding, i.e. in the same direction as the sedimentary flow (Fig.4).On the other hand, the quartzitic breccia of the Campo Sampaio Member represents a vent brecciawhich accumulated in maar type craters, sometimes with local sedimentary reworking (Fig. 5).The individual characteristics of the diamonds of each of the diamond-bearing province within thesouthern Serra do Espinhaço (Fig. 1) suggest an intrinsic relationship of origin and space of the depository.Surface peculiarities of the diamonds are contrasting. Stones from the present three hydrographicbasins of the region show remarkable traces (unhas, jaças, many chips) of sedimentary reworking whereaslots of diamonds from conglomerates are found virtually intact, indicating negligible transport from theprimary source rock to the site of deposition within the Proterozoic coarse clastics.

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Sinkholes and uvalas in evaporite karst: spatio-temporal development with links to base-level fall on the eastern shore of the Dead Sea

Solid Earth ◽

10.5194/se-10-1451-2019 ◽

2019 ◽

Vol 10 (4) ◽

pp. 1451-1468 ◽

Cited By ~ 1

Author(s):

Robert A. Watson ◽

Eoghan P. Holohan ◽

Djamil Al-Halbouni ◽

Leila Saberi ◽

Ali Sawarieh ◽

...

Keyword(s):

Sea Water ◽

Dead Sea ◽

Eastern Coast ◽

Temporal Development ◽

Evaporite Karst ◽

Base Level ◽

Theoretical Predictions ◽

The Dead ◽

Spatio Temporal ◽

Karst Landscapes

Abstract. Enclosed topographic depressions are characteristic of karst landscapes on Earth. The developmental relationship between depression types, such as sinkholes (dolines) and uvalas, has been the subject of debate, mainly because the long developmental timescales in classical limestone karst settings impede direct observation. Here we characterize the morphometric properties and spatio-temporal development of ∼1150 sinkholes and five uvalas formed from ∼1980 to 2017 in an evaporite karst setting along the eastern coast of the hypersaline Dead Sea (at Ghor Al-Haditha, Jordan). The development of sinkhole populations and individual uvalas is intertwined in terms of onset, evolution and cessation. The sinkholes commonly develop in clusters, within which they may coalesce to form compound or nested sinkholes. In general, however, the uvalas are not defined by coalescence of sinkholes. Although each uvala usually encloses several clusters of sinkholes, it develops as a larger-scale, gentler and structurally distinct depression. The location of new sinkholes and uvalas shows a marked shoreline-parallel migration with time, followed by a marked shoreline-perpendicular (i.e. seaward) growth with time. These observations are consistent with theoretical predictions of karstification controlled by a laterally migrating interface between saturated and undersaturated groundwater, as induced by the 35 m fall in the Dead Sea water level since 1967. More generally, our observations indicate that uvalas and the sinkhole populations within them, although morphometrically distinct, can develop near-synchronously by subsidence in response to subsurface erosion.

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