Geomorphic Evolution of The Kurkur-Dungul area in...

International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 15 No: 01 1

157801-6565-IJECS-IJENS © February 2015 IJENS

I J E N S

Geomorphic Evolution of The Kurkur-Dungul area in

Response to Tectonic Uplifting and Climatic

Changes, South Western Desert, Egypt

Kamal Abou Elmagd1*

, Mohamed W. Ali-Bik2, Ashraf Emam

1

1 Geology Department, Faculty of Science, Aswan University, Egypt

2 Geological Sciences Department, National Research Centre, Dokki, Cairo, Egypt

*Corresponding author: [email protected]

Abstract-- The Kurkur-Dungul area at South Western Desert

of Egypt is an unique hyper-arid region, in which one of the

oldest civilizations appeared. The sedimentary record of the

area is represented by Cretaceous Nubia Sandstone, Paleocene,

Eocene and Quaternary deposits. The sedimentary sequences of

the area are the end products of characteristic geomorphic

processes developed in response to equilibrated constructive

and destructive mechanisms. The area encompasses an

outstanding variety of landforms of third order extent including

River Nile, Nubian Plain, oases, playas, isolated crystalline hills

and Sinn El-Kaddab limestone plateau. Beside these

geomorphic features, there is also a number of small-scale

characteristic landforms including terraces, terrestrial carbonates

including travertine, conglomerate and scattered sheets of gravel,

flint and sand as well as, deep-seated, strike-slip faults and

accompanied folds. All of these landforms were developed mainly

in response to tectono-magmatic and seismic activities, sea level

fluctuation and climatic changes. The main natural agents of

changes include the interaction of Tethys Sea, rain falls,

tectonics, weathering, erosion and wind action. Damming of the

Nile and the subsequent accelerated seismic effects as well as

sand dune encroachment turned the area to be one of the

most dynamic regions in the Arabian-Nubian Shield. Its

landforms are susceptible to substantial changes in very short

periods of time. In conjunction with the field observations,

remote sensing and GIS techniques were applied using digital

elevation model (DEM) and multispectral data to produce a

digitized visual form of geomorphologic f eatures of the area

including drainage network, basins, slope configuration and

structures.

Index Term-- climatic changes - drainage network –

escarpment – landforms - remote sensing. I. INTRODUCTION

The hyper-arid, Kurkur-Dungul area at South Western

Desert of Egypt (Fig. 1) is a famous historic region, at which one

of the oldest, unrivaled civilizations appeared. From a

geomorphologic point of view, the area is dominated by bimodal

gentle and steep slope distribution [1]. It encompasses an unique

variety of landforms of third order extent including River Nile,

Nubian Plain, oases, playas, isolated crystalline hills, and Sinn

El-Kaddab limestone plateau (Fig. 2). Beside these geomorphic

features, there is also a number of small-scale characteristic

landforms including terraces, terrestrial carbonates including

travertine, conglomerate and scattered sheets of gravel, flint

and sand as well as, deep-seated, strike-slip faults and

accompanied folds.

All of these landforms had been formed mainly in

response to tectono-magmatic and seismic activities, sea

level fluctuation and climatic changes. The main natural

agents of modifications include the mutual interactions of

the Tethys Sea, River Nile, rain falls, hydrothermal

springs, weathering, erosion and wind actions as well as

tectonic and seismic disturbances.

Tectonically, the study area is located within the

relatively unstable (?) Nubian Swell zone [2], which had

suffered tectonic uplift during Cenozoic (Fig. 2); the

process which is still episodically active. Damming of the

River Nile at Aswan in the sixties of last century and the

formation of the great Lake Nasser in the front of the

Aswan High Dam accelerated and enhanced the agents of

landform changes in the study area. The great artificial

Lake Nasser which covers an area of about 6000 km2

is

greatly impacted the geomorphology of the area in

terms of filling the surrounding Khors (embayments) and

the nearby depressions and hence, rejuvenating the major

strike-slip faults of the area such as Kalabsha fault. Here

we recall the famous 14 November 1981earthquake with

5.6 M magnitude which struck the area [3] and its still

ongoing aftershocks.

In such dynamic and complex geomorphic areas,

analysis of landforms and the surface geologic processes as

well as evaluation of the natural raw materials are essential in

land management perspectives. In this context, the thematic

maps are widely used in representation, analysis and

visualization of geological processes. Among the large

variety of thematic maps, geomorphologic maps play an

essential role in understanding earth surface processes,

natural hazards and landscape evolution [4], [5]. Recent

advances in remote sensing, GIS and geospatial technologies

and numerical modeling of surface processes, have

revolutionized the field of geomorphology [5], [6].

mailto:[email protected]



I J E N S

Fig. 1. Lithologic map of Kurkur-Dungul area, South Western Desert of Egypt.

Fig. 2. 3D model of the digital elevation relief data covering Kurkur-Dungul area.

GIS technology integrates common database operations

such as query and statistical analysis with the unique

visualization and geographic analysis benefits offered by

maps [7]. Advances in GIS technology and increasing

availability of remote sensing data (particularly Digital

Elevation Models, DEMs) have led to a growing application

of GIS tools in many areas of geomorphology. These GIS

tools enable the representation and characterization of earth

surfaces, landform structure and other geomorphologic

phenomena. Such information has traditionally been

documented in geomorphologic maps at various scales to

show land units based on their shape, material, processes

and genesis [8], [9], [10]. It is now possible to quantify



I J E N S

morphology [11], [12], assess surface biophysical conditions

[13], [14], [15], [16], and link process with patterns [17].

Scope and limitations: The present study aims at

using the remote sensing data and GIS tools in

conjunction with the field observations to identify

landforms, geomorphic units and then, area mapping of

Sinn El-Kaddab plateau and environs in southern Egypt.

Reclamation and cultivation of the uninhabited deserts (up

to about 93% of the total area of Egypt) is the main

challenge of the Egyptian government to increase the

national income and to redistribute the current crowded

population masses over the whole Egyptian territory. In this

context, the land use planning is an important process in

sustainable development of such remote area in southern

Egypt. This is realized to be developed in an integrated and

comprehensive manner based on tectono-geomorphologic

investigation of the target area.

II. MATERIALS AND METHODOLOGY

The most significant contribution of remote sensing to

geomorphology is the use of passive and active sensors to

generate surface elevation data commonly referred to as a

digital elevation model (DEM). To achieve the main

objectives of the present study, geomorphologic mapping has

been carried out using DEM data with 30 m resolution,

obtained through Advanced Spaceborne Thermal Emission

and Reflection Radiometer (ASTER).

Automation of drainage networks extraction from

DEM in general has received considerable attention and has

been the main objective for many natural resource

management issues [18], [19], [20], [21], [22]. The drainage

network of the study area was automatically extracted from

ASTER DEM by using the hydrology toolset in ArcGIS

software, version 10.2. This automated method for

delineating streams followed a series of steps including

sink filling, identification of flow direction, calculation of

flow accumulation and stream ordering. Also, the

morphometric measurements such as slope, aspect, relative

relief, drainage density and drainage frequency, basins

delineation were deduced and various thematic maps

pertaining to all these aspects were generated.

III. RESULTS

Geology and geomorphology of the study area

The geological record of the area reveals episodes of

late Neoproterozoic plutonic magma activity, followed by

uplift, erosion and subaerial volcanism. This was followed

in Phanerozoic by clastic and carbonate sedimentations,

which are distinguishable in the field into: Cretaceous Nubia

Sandstone, Paleocene, Eocene and Quaternary deposits

(Fig.1). The youngest deposits and landforms include

terrestrial carbonates (lacustrine limestone, hydrothermal

groundwater travertine deposits and calcite), terraces,

conglomerate, playas and sand sheets [23].

The outcropping sedimentary sequences of the area

are the end products of characteristic geomorphic processes

developed in response to equilibrated constructive

(magmatic and sedimentation input) and destructive

(weathering and erosion output) mechanisms. The main

landforms of the Kurkur-Dungul area are best distinguished

genetically and chronologically into: 1) Intrusive

Precambrian crystalline basement outcrops and the extrusive

Phanerozoic subaerial volcanics, 2) Aqueous systems, 3)

Tectonic landforms, and 4) Aeolian landforms:

1. Intrusive Precambrian crystalline rocks and

Phanerozoic subaerial volcanic extrusives: The intrusive late Neoproterozoic basement rock

units (Fig. 1) of the area could collectively be distinguished

into gneisses, amphibolites and granitoids. The contact

between the gneisses and granitoids is of intrusive nature

without any zones of transition. In the study area and its

westward extension, towards Egyptian frontiers, the

Precambrian crystalline basement rocks were suffered

intensive ancient erosion. In the present time, the basement

igneous and metamorphic rocks are feebly dipping to the

north east and sink to the north under a thick Nubia

Sandstone succession [24].

In the study area, the basement rocks are exposed

along the crest of t he exposed Aswan Hills as well as small

inlier and islands in the Nubian Plain and Lake Nasser,

respectively (Fig. 1). Of the granitoids, Aswan pink granite

is peculiar as it exhibits fine to course grained texture and

abundant orthoclase and microcline porphyroblasts.

Genetically, the granitoids could be broadly classified into: a)

subduction-related tonalite, granodiorite and granites, and b)

within-plate granites and syenite. Reference[23] distinguished

the granitoids of the study area into: 1) biotite hornblende

tonalite, granodiorite and quartz diorite in addition to granites

and monzogranites, 2) aegrine syenite (El-Hamra oval-

shaped mass of ~ 0.8x0.3 km size), and 3) fine-grained

granophyre and coarse-grained syenite and diorite (El- Soda

mass of about 3.75x0.7 km size). The Precambrian basement

rocks were subsequently extruded by Phanerozoic dike

swarms of different compositions including diabase dikes,

sheets and volcanic breccias.

2. Aqueous-related landforms:

2.1. Tethys landforms (inverted basins):

Sinn El-Kaddab plateau

This is the most peculiar landscape in the study area,

whereas its relief varies from 220 to 550 m above sea level (Figs.

1&2). It bounds from the west the Nubian Plain and the Lake

Nasser, forming an irregular escarpment pattern and demarcating

the traces of the old fault systems of the area [23]. The

architecture of the plateau over the Nubian Plain is built up of

alternative shale and limestone beds, forming altogether two

successive escarpments, each of them forms a characteristic

ledge (Fig. 2). The lower scarp face of the plateau over the



I J E N S

Nubian plain (lower ledge) is composed –from bottom to top- of

Dakhla Shale, Kurkur Formation and Garra Formation (Fig. 1).

The main geomorphic landforms of the lower scarp (lower

ledge) are Kurkur oasis, Wadi Kurkur, playa, mesas and cuestas

and wind deflated surface. Wadi Kurkur is drained to Lake

Nasser and pertains to the River Nile geomorphic system. The

upper escarpment is built up of Dungul Formation, being

composed of two members [25]: the lower shale unit (Abu

Ghurra Member) and the upper limestone one (Naqb Dungul

Member).

The Dakhla Formation (Dakhla basin) in the study area

has a maximum thickness of 250 m, being composed mainly of

grey, grayish-black and greenish shales. It overlies the

variegated, marine shale unit which accumulated in the Dakhla

basin [26]. This is followed upward in the study area by Kurkur

Formation (see Fig. 1) which is composed of two siliceous

limestone beds, intercalated by clastics with or without

phosphatic components. The color of the formation is typically

brown, and locally contains abundant marine invertebrate

fossils. Sediments of the formation were deposited during the

early Paleocene in shallow marine environments.

The Garra Formation (Garra basin) is composed of

thick limestone beds with chalk, marl, and shale intercalations

and unconformably overlies the Kurkur Formation (Fig. 1).

The age of the unit is late Paleocene to early Eocene. The

sediments were deposited in shallow, protected, marine

shelf through deep marine environments. The Garra formation

is exposed at Kurkur oasis near the wadi level and then it

outcrops along the face of Sinn El-Kaddab escarpment, where

it makes some prominent ridges to the west of Gebel

Kalabsha, passing by Dungul oasis and further westwards.

On the other hand, the Dungul Formation (Fig. 1)

consists of bentonitic shale beds at the base and a limestone

ledge at the top. Flint concretions and chert bands are common

features at the base of the limestone bed, which has a grey,

faint green to faint yellow and white colored appearance. The

Dungul Formation forms the topmost surface of the plateau,

west of Kurkur oasis and stretches further to the extreme

northwestern part of the area under investigation.

2.2. Nubian Plain

The Nubian Plain represents the eastern part of the

Sandstone Pediplain [27], which extends from Gilf Kebir in the

west to the boarder of the Lake Nasser in the east (Figs. 1 & 2).

The Nubian Plain is composed chiefly from Nubia Sandstone

with a wind-deflated surface [28], [29]. Its thickness varies from

place to another (100-200m above sea level), probably

reflecting the paleo-relief variation of the basement crystalline

rock units. Based on the nature of the cement materials [30] the

sandstone beds were classified into two varieties: a) sandstone

cemented by silica, and b) sandstone cemented by calcite,

dolomite and detritus clayey-size materials. The Nubia

Sandstone –in general- exhibits varied depositional

environments, ranging from shallow marine platform to

continental and Aeolian and probably fluviatile environments

[23]. Reference [30] gave a detailed lithofacies description of a

complete section of the Nubia Formation at Aswan, where they

discriminated five depositional facies of regression and

transgression nature. Accordingly, the older facies 1 points to

regressive fluvial deposits, while facies 2 and 3 document a

southward transgression of the Tethys accompanied by waning

detrital input. Facies 4 and 5 reflect the interaction between a

southward transgression of the Tethys in late Cretaceous and

accompanied northward progradation of feldspathic sand

derived from the south.

2.3. Watersheds and underground water systems

2.3.1. Drainage network

2.3.1.1. Automated extraction of drainage network

A major problem with drainage network delineation

using DEM is the presence of sinks or depressions [31], [32],

[33]. In this process, sinks are defined as cells which have

no neighbors at a lower elevation and consequently, have no

downslope flow path to a neighboring cell [32]. According to

[34] the main problem is the positioning of the ends of

drainage networks and the assignment of flow directions to

individual cells, particularly in flat areas and depressions.

Therefore, the sinks are commonly removed prior to DEM

processing for drainage identification [35],[36] by increasing

their cell values to lowest overflow points out of the sinks.

After the sink filling, the second step was the

identification and calculations of flow directions from each cell

in the raster data of DEM, using the procedures based on [36]

algorithm. The flow direction is determined by finding the

direction of the steepest descent from each cell taking into

account its eight neighboring cells.

The flow direction raster is then used to compute the

flow accumulation of each cell, where the value stored in the

cell represents the accumulated number of cells flowing into it.

A threshold value must be applied for its final delineation,

whereas only the cells with a flow accumulation value above

the proposed threshold will belong to the drainage network.

The resulting grid outlining the drainage network of the

Kurkur-Dungul area is given in Figure 3A, where the overall

drainage picture reflects an early stage of dendritic pattern

with visible traces of parallel dendritic and trellis patterns

in between.

The streams of drainage network in the study area

were ordered using the method given by [37] and transformed

to vector layer for further analysis. During the stream ordering,

the channel segments were ordered numerically, where the

tributaries at the stream's headwaters being assigned as 1st

order. The stream segments that resulted from the joining of 1st

order segments were assigned as the 2nd

order. Joining of 2nd

order segments form the 3rd

order streams and so on. The

obtained stream ordering map (Fig. 3B) shows five orders of

streams.

2.3.1.2. Drainage network analysis

Drainage network of Kurkur-Dungul area has been divided into

four main drainage basins namely, Dungul, Kalabsha, Kurkur

and Abu Domi (Fig. 4A). Important morphometric parameters

such as area, perimeter, drainage density, bifurcation ratio,

elongation ratio and circulatory ratio have been computed in

GIS environment (Table1). Dungul drainage basin is the



I J E N S

largest, having an area of 6581.6 Km2, perimeter of 506.7 Km

and basin length of 116.65 Km. A total of 207 stream segments

in Dungul drainage basin were ordered numerically and five

stream orders were resulted (Fig. 3B). The number and total

length of stream segments under each stream order were

computed (Table 1). Kalabsha and Kurkur drainage basins

have areas of 4261.5 and 3353.2 Km2, respectively. Kalabsha

basin has 70.38 Km length and 124 stream segments, which

were clustered into four stream orders (Fig. 3B). On the other

hand, Kurkur drainage basin has 87.98 Km length and 148

stream segments (Fig. 4A). Abu Domi drainage basin is the

smallest, having an area of 850.8 Km2, perimeter of 169.2 Km

and basin length of 32.16 Km.

Fig. 3. (A) Drainage network of Kurkur-Dungul area. (B) Stream orders of drainage network of Kurkur-Dungul area.

Drainage density is the sum of the length of the

streams divided by the area of the basin i.e. the total length of

the stream channel per unit area [38]. The values of drainage

density for Dungul, Kalabsha, Kurkur and Abu Domi basins

are 0.16, 0.17, 0.14 and 0.25 respectively. Meanwhile, the

stream frequency is the number of streams per unit area

and is obtained by dividing total number of streams by total

drainage area [37]. The values of stream frequency for

Dungul, Kalabsha, Kurkur and Abu Domi basins are 0.03,

0.03, 0.04 and 0.06 respectively. According to [39], the

elongation ratio is defined as the ratio of diameter of a circle of

the same area as the basin to the maximum basin length. The

varying slopes of watershed can be classified with the help of

the index of elongation ratio, i.e. circular (0.9-1.0), oval (0.8-

0.9), less elongated (0.7-0.8), elongated (0.5-0.7), and more

elongated (less than 0.5). Further values near to 1.0 are

typical of regions of very low relief, whereas values in the

range of 0.6 to 0.8 are associated with strong relief and steep

ground slope. The values of elongation ratio obtained for

Dungul, Kalabsha, Kurkur and Abu Domi basins are 0.785,

1.05, 0.743 and 1.02 respectively. The mean Stream length is

a dimensional property revealing the characteristic size of

components of a drainage network and its contributing

watershed surfaces [37]. It is obtained by dividing the total



I J E N S

length of stream of an order by total number of segments in

the order. The mean stream length values obtained for the

investigated drainage basins are illustrated in (Table 1).

Moreover, the bifurcation ratio is the ratio of the number of

streams of any order to the number of streams in the next

higher order [39]. The computed values of bifurcation ratio are

shown in (Table 1). The values of bifurcation ratio are either

lower or higher than the range (3-5) indicating structural

control over them.

2.3.2. Playas and oases:

In the study area and its environs there are remnants of

three ancient and world-renowned playa-flats that embraced

one of the oldest human civilizations. These are Kurkur (Fig.

4B), Dungul (Fig. 5A) and Nabta (to the south west of the

study area). Reference [28] classified the playas of the western

Desert of Egypt on the basis of two main aspects, either to their

source of water or their sediments composition. Generally, the

playas of clastic sediments and fed by surface water are the

most common one. However, in the southern part of the

western Desert of Egypt, the participation of underground

water in addition to surface water in the formation of the

playas are also common and attributed to the local tectonics

[28].

Fig. 4. (A) Watersheds and drainage basins of Kurkur-Dungul area. (B) Google Earth satellite image of Kurkur Oasis and Kurkur playa.



I J E N S

Table I

Characteristics and morphometric parameters of drainage network in Kurkur-Dungul area.

Parameters Drainage basins

Dungul Kurkur Kalabsha Abu Domi

Area 6581.6 3353.2 4261.5 850.8

Perimeter 506.7 457.6 429.7 169.2

Basin length 116.65 87.98 70.38 32.16

Total No. of segments 207 148 124 48

Total stream length 1040.68 473.14 718.33 214.95

Drainage density 0.16 0.14 0.17 0.25

Stream frequency 0.03 0.04 0.03 0.06

Drainage texture 0.41 0.32 0.29 0.28

Circularity ratio 0.32 0.20 0.29 0.37

elongation ratio 0.785 0.743 1.05 1.02

Length of overland flow 3.16 3.54 2.97 1.98

Dungul basin

Stream order 1st order 2

nd order 3

rd order 4

th order 5

th order

No. of segments 107 48 33 6 13

Stream length 510.79 258.73 209.22 36.97 24.97

Mean stream length 4.77 5.39 6.34 6.16 1.92

Stream length ratio - 0.51 0.81 0.18 0.68

Bifurcation ratio 2.23 1.45 5.50 0.46 -

Kurkur basin


nd order 3

rd order 4

th order -

No. of segments 65 24 12 47 -

Stream length 252.78 129.73 53.03 37.6 -

Mean stream length 3.89 5.41 4.42 0.80 -

Stream length ratio - 0.51 0.41 0.71 -

Bifurcation ratio 2.71 2.00 0.26 - -

Kalabsha basin


nd order 3

rd order 4

th order -

No. of segments 63 38 20 3 -

Stream length 400.36 162.14 131.6 24.23 -

Mean stream length 6.35 4.27 6.58 8.08 -

Stream length ratio - 0.40 0.81 0.18 -

Bifurcation ratio 1.66 1.90 6.67 - -

Abu Domi basin


nd order 3

rd order - -

No. of segments 25 21 2 - -

Stream length 110.38 69.92 34.65 - -

Mean stream length 4.42 3.33 17.33 - -

Stream length ratio - 0.63 0.50 - -

Bifurcation ratio 1.19 10.50 - - -



I J E N S

The Kurkur and Dungul playas represent shallow

ancient lakes that drained internally in the low land of the

Nubian plain (internal basins). They are oval in shape,

sometimes with straight edges against the fault planes (Fig.

4B). In general, their soils are composed of finely laminated

lacustrine sediments and characterized by mud cracks (Fig.

5A).

Kurkur (Fig. 5B) and Dungul oases are small

uninhabited oases, but are of great importance in wildlife

conservation for a number of animals such as deer. They

represent ancient transit stations for the passengers and camel

troops through Darb El Arbian desert track between Sudan

and Egypt. They exhibit elongate form associated with E-W

trending faults.

2.3.3. Flash floods and Quaternary ancient

stream sediments

These outcrops are represented in the study area as

natural levee of dry channels (Fig. 5C), conglomerate

accumulations (Figs. 5D) and boulders & gravels sheets

(Fig. 5E). The main conglomerate components (boulders,

gravel and flint) were derived from Dungul Formation at

the top of the Sinn El-Kaddab plateau. The boulders and

gravel particles of the conglomerate sheets are subangular

and cemented by clayey matrix. On the other hand, non-

cohesive free flint gravels spread and cover the low hills

and lands of the study area.

2.3.4. Karst and karstification: The Upper Eocene Naqb Dungul limestone exhibits a

characteristic karst (cavernous) structure (Fig. 5F). It is

highly engraved by voids and caves of varying size and

shapes, implying the former presence of considerable

siliceous components (chert nodules and flint particles).

2.3.5. River Nile and Lake Nasser:

The River Nile in the study area is a part of the so-

called Nubian Nile, which was a narrow stream in the study

area before damming the River in the 1960s. Water is

naturally flow gravitationally northward forming a narrow

valley with steep-sided bed rocks on the banks.

Lake Nasser is one of the largest artificial lakes in the

world with about 6000 km2 size in southern Egypt and

northern Sudan (till the Second Cataract). It had been formed

after the damming the River Nile in 1960s. The covered land

by water is dominated by crystalline basement rocks and

Nubia sandstones. It is governed mainly by low-land

topography and numerous fault planes that prevailed in the

area, giving rise to the formation of the characteristic Khors

(embayments) (Fig. 1) of different lengths and extents,



I J E N S

Fig. 5. Field photographs showing: (A) Sun cracks on playa of Naqb Dungul area. (B) Palm and Hyphaene thebaica trees in Kurkur Oasis. (C) Natural levee

on the bank of dry channel. (D) Conglomerate accumulations. (E) Boulders and gravel sheet. (F) Karstification of limestone beds, dissolved parts leaving

large voids and caves, Dungul Formation.

following the ancient drainage patterns of the area [29].

However, the outlines of the Lake Nasser is still developing

and its geomorphic impacts on the study area is ongoing by

water flow through the cracks and the main fault planes,

leading to the formation of swamps on the low-land areas.

About 3 billion m3 of water is annually lost and evaporated

only through the Khor Kalabsha [40].

2.3.6. Fresh water carbonates

These include terrestrial carbonates which are

represented in the study area by lacustrine limestone, calcite

deposits, travertine and tufa. Reference [23] considered all of

these terrestrial carbonates as Quaternary deposits. Reference

[23] recorded fresh water carbonates in the study area based

on the lack of marine fossils and their intercalation with tufa.

Based on field relations, [41] distinguished different tufa

generations in the study area.

The distribution of the terrestrial carbonates in the

study area seems to be structurally controlled. Ridges of

travertine (Figs. 6A & 6B) as well as calcite deposits are

concentrated along fault planes and seem to be formed by the

circulation of supersaturated calcium bicarbonate-enriched

hydrothermal groundwater through fissures and cracks.

3. TECTONIC LANDFORMS

The structural geomorphic landforms of the Kurkur-

Dungul area are the net resultant of uplifting of the basement

rocks of the area [23] accompanied by extensional fault-

propagation folding [42]. Ductile and brittle deformation

styles are conspicuous in the Kurkur-Dungul area, where the

region is dissected by characteristic deep-seated, E-W and N-S

trending active fault systems (Figs. 6C, 6D, 7, 8A). Defiantly,

the activity of these faults, particularly the E-W trending

Kalabsha fault (Figs. 7 & 8A) is conspicuously enhanced in



I J E N S

the late decades by invasion and percolation of the Lake

Nasser water through cracks and fissures after the construction

of the High Dam and development of the great artificial Lake

Nasser reservoir.

The tectonics and structural elements and patterns of

the Kurkur-Dungul area were investigated in detail by [23],

who subdivided the region structurally into 8 sectors. For each

sector, he plotted the general structural trends on frequency

distribution diagrams, Fig. 6 in [23]. In addition to the main E-

W and N-S trending fault systems, there are also subordinate

NE and NW trending, relatively small faults at the study

area. In general, the E-W trending faults of the area are longer,

compared to the N-S trending fault systems. Beside these

brittle deformation styles, there are also a number of ductile

deformation features in the form of elongate domes and basins

that scattered in different orientations. These deformational

styles (˂250 m to ˃1.5 km length) are conspicuous in satellite

images of the study area and southern parts of the Egyptian

Western Desert as characteristic Desert Eyes [42]. Hence, a

number of characteristic small-scale, open anticlines and

synclines are prominent in the study area and scattered in

different orientations. In general, two main ductile

deformation systems are distinguishable in the area: the first

are concentrated close to the main E-W and N-S trending fault

planes, where their axial traces follow more or less the fault

planes, whereas the second fold system is slightly apart from

the fault planes and their axial traces mainly in NE direction.

Of the crystalline basement rocks and Sinn El-Kaddab

limestone plateau, Jointing is a common feature, where

different jointing trends are recorded [23].

Fig. 6. (A) A low relief travertine ridge. (B) Crystalline spheroidal crusts of travertine.

(C) Desert eyes ductile structure along the E-W trending Seyal fault. (D) A syncline fold on the main Seyal fault plane.

3.1. E-W trending faults

These are represented by a number of mainly E-W

and ENE trending long faults such as Kalabsha (160km),

Seyal (~85km), El Faliq (70km), Aba Silla and Barqat faults

(Fig. 7). The Aba Silla (~ 100 km) and Barqat (~53 km)

dissect in the limestone plateau, while Kalabsha and Seyal

faults cut in the escarpment and Nubian plain and limestone

plateau as well. Reference [3] studied the seismicity and

earthquake hazards at Kalabsha area and distinguished five

seismic zones, from which two zones are related to the E-W

trending fault systems: a) Gebel Marawa active zone (between

15 to 26km depth) around the center of the 14 November

1981main quake on Kalabsha fault, and b) East of Gebel

Marawa zone along the Kalabsha fault, where focal seismicity

depth is relatively shallower (0-10km). In general, the E-W

trending faults of the study area are longer, compared to the

N-S fault systems and exhibit right-slip displacement ~

0.03mm per year [3].



I J E N S

Fig. 7. A structural map of the study area compiled from satellite images and field checking.

3.2. N-S trending faults

These are represented by a number of mainly N-S

trending faults, which cut in the Nubian plain at the eastern part

of the given map (Fig. 7) such as Khor El Ramla (~40km) and

Kurkur (~40km) faults as well as Abu Dirwa (~20km)

and Gazelle (~15km) faults, north and south of the E-W

trending Kalabsha fault, respectively. The Khor el Ramla fault

is seismically an active fault where seismicity is shallower, 0

to10km, [3]. The Kurkur fault is among the active old stream

zone which extends to about 40km from Khor Kalabsha at the

south to Khor Kurkur at the north [3]. The N-S trending Abu

Dirwa fault, south of Kalabsha fault is an active strike slip and

dip slip fault and belongs to the Abu Dirwa seismically active

zone. Abu Dirwa fault zone, which is characterized by strike-

slip and normal faulting with strike 177°N and dip 61° and the

N-S trending fault system, in general exhibits a left-slip

displacement of 0.01-0.02mm per year [3].

3.3. Desert eyes (folds, basins and domes)

According to [23], folds are of secondary importance

in Kurkur-Dungul area, compared to the fault systems. The

latter author distinguished a number of anticlines and synclines

in addition to double plunging fold systems with axes trending

mainly in NE-SW, E-W and N-S directions. Reference [23]

also distinguished a number of closed basins and domes of

different areal extent. Obviously, there is a linear alignment of

these domes and basins [42] and all of these structural

landforms are easily recognizable in Satellite images as desert

eyes (Figs. 6C & 6D).

In general, all of these ductile deformational styles

could be distinguished into two main systems: 1) folded basins

and domes (up to 1.8 km length) that are spatially connected to

the main E-W, N-S and NE trending fault systems (Figs. 6C,

6D, 8B, & 8A). As deduced from these figures, these ductile

deformational features are older than nearby faults and clearly

affected by them. 2) folded basins and domes away from the

main faults (Figs. 8C & 8D) occur in between the major faults

and in comparison with the faulted basins and domes, their

country rocks do not exhibit the characteristic bubble warp

(desert eyes) structures [42].

4. AEOLIAN LANDFORMS

These are the sand accumulations which are scattered

as small sand sheets on the Nubian plain (Fig. 8E). Reference

[44] monitored, on recent satellite images the steady

southeasterly sand movement in the study area and calculated

its creeping speed as 15 m/year. Other sand accumulations are

obvious as hanging dunes southwest of the study area.

Generally speaking, the prevailing winds in Egypt blow from

the NW to the SE most of the time of the year [43]. It seems

that this NW-SE wind direction was almost constant for the

last 40 thousands of years as deduced from the characteristic

NW-SE direction of the mega dune belts of the southern

Western Desert of Egypt [44].



I J E N S

Fig. 8. Folds and desert eye structures. (A) Anticline fold on the main Kalabsha strike slip active fault. (B) A faulted out desert eye. (C) Circular basin

confined two core smaller basins. (D) Non faulted out desert eye. (E) A fine sand sheet.

IV. DISCUSSION AND CONCLUSION

The study area is characterized by moderate to low relief

and its continental crust ranges from ~ 35 to about 40 km thick

[2]. The main stratigraphic column of the area was almost

completed in Eocene with less voluminous Quaternary

input, but sculpturing of the main landforms had been taken

place under semiarid to hyper-arid climatic conditions in

late Tertiary and early Pleistocene [1].

The Kurkur-Dungul area encompasses a number of

unique geomorphic landforms including River Nile and Sinn

El-Kaddab plateau with its two escarpments, each of them

forms a characteristic ledge. The lower ledge over the Nubia

sandstone is composed of shale (Dakhla Formation) and

limestone intercalated with shale beds (Kurkur and Garra

formations). The main geomorphic landforms of the lower scarp

(lower ledge) are Kurkur oasis, Wadi Kurkur, playas, mesas,

cuestas and wind deflated surface. The upper escarp face

(Dungul Formation) is composed of Abu Ghurra shale Member

and Naqb Dungul limestone Member. Mesas, cuestas, playas

as well as the steepness degrees of the plateau escarpments are

the result of a long-term tectonic disturbances as well as the

actions of differential erosion and weathering processes

prevailed in alternative arid and pluvial episodes during

Quaternary [45] and older epochs since the Middle Eocene

[29]. Due to erosional resistance variation of the different

rocks, the weaker rocks (shales) are eroded away, leaving the

more competent rock beds (limestone) at higher topography

than their surroundings. Also, the same process is observed in

the Upper Paleocene Garra Formation, where alternative

limestone and shale beds prevail. The washed away shale

components by the rain fall action leave longitudinal spaces

between the competent limestone beds.



I J E N S

On the other hand, the effect of pluvial periods on the

Lower Eocene Naqb Dungul limestone is different. The Eocene

limestone rocks of Egypt are characteristically siliceous and

contain chert nodules and bands as well as large spherical flint

concretions [46]. By the action of the rains, these insoluble

components detached and separated leaving karst (cavernous)

features (see Fig. 5F). The detached siliceous concretions fall

down either by gravity in situ or transported away by the flash

floods, and hence disintegrated as boulders, gravel and flint

sheets (Fig. 5E). The natural levee (Fig. 5C) and terraces at the

foot of the plateau scarp and the conglomerate accumulations

(Fig. 5D) were deposited during the pluvial periods also

(probably by Quaternary flash floods), whereas their clasts were

derived from the top of the Sinn El-Kaddab plateau. The

subangular nature of their boulders and gravel particles enhances

their nearby sources.

The study area lies geographically in the tropics where

it passes by the Tropic of Cancer. It characterized by arid to

hyper-arid climate and dearth of rainwater. However, during

the Holocene the conditions were not such cruelty, whereas the

area experienced several pluvial periods with about 500 ml/cm

[28]. The main drainage network (watersheds) of the study area

(represented in present by wadies), seems to be constructed

during these pluvial periods.

The present River Nile represents the fourth stage

of the Neonile which commenced after the last glaciation

period (13500 and 11500 BP) due to temperature rise on global

scale [28]. According to the later author, the deepening and

widening of the Neonile channel in Nubia and upper Egypt had

been accomplished by the action of torrential flood water that

flowed from the Nile headwaters in Africa (Victoria and Albert

Lakes) across the White Nile during the period 12,500 to 12,000

BP. The contribution of the blue Nile started with the

Holocene, in sync with the pluvial period that prevailed the

southern Egypt and northern Sudan, giving rise to the

formation of the fertile flood plain and Delta [28].

In general, the course, depth and extent of the Nile

River is governed by pre-Nile topography of the area as well as

the nature and type of the sculptured bedrocks [43]. Hence,

where the crystalline basement rocks are dominate the stream is

narrow and deep, while on passing on the Nubian Plain the river

becomes much wider and shallower.

Reference [47] gave the relative radiocarbon ages of

the sediments of both Kurkur and Dungul playas at about 7,900

BP. These playas drained internally and represent

topographically low lands (ancient lakes). The Early Holocene

small lakes (closed basins), were the cradle of the one of the

oldest human civilization in Nabta Playa (south west the

study area), Wadi Kurkur and Dungul area.

Archeological investigations revealed evidence for Pre-

dynastic activity at Kurkur oasis [48]. Oases are located in the

lowest topographic areas of the region which collect the flash

flood water from time to time in addition to the little seasonal

rain water. Generally, the area is dissected by a number of fold

and fault systems and the Kurkur oasis is located along the axis

of a syncline fold or failed rifting zone. At the present, these are

failed oases due to scarcity of groundwater which barely reach

about 60 gallons /day of non-drinkable saline water. The Kurkur

oasis is located on the surface of Garra Fm which encompasses

alternating limestone and shale beds; hence the observed salinity

of the oasis water is expected. On the basis of salinity nature and

scarcity of the groundwater, it is fair to deduce a shallow source

which definitely does not reach the huge Nubia Sandstone

reservoir at relatively large depths. Thus the capillary flow of

few – shallow- groundwater via small cracks and channel ways

ensure the moisture of the oasis and provide a limited growth

environment of some savanna plants as well as palms and

Hyphaene thebaica [49], [50].

The contacts between the different rock units of the

study area are structurally controlled. In general, the area is

dissected by numerous deep-seated strike-slip and dip-slip faults,

mainly in E-W, NNE-SSW and N-S directions (Fig. 7). Along

these faults and in between, a number of small-scale, folded

domes and basins are scattered, forming in many cases the so-

called desert-eyes structure. The aligned fold chains along the

fault planes are faulted out. Such spatial relation indicates

extensional fault propagation folding [42]. The later authors

attributed the small-scale folded domes of the study area to the

rheological variation of the deformed rocks.

The mutual interaction of the Tethys with River Nile,

rain falls, hydrothermal springs, weathering, erosion and wind

actions in conjunction with tectonic and seismic disturbances are

the main agents of landform changes. The study area pertains to

the tectonically-active (?) region known as Nubian Swell [2].

Since the beginning of the Cenozoic the basement complex and

the overlaid Phanerozoic sedimentary successions are suffering

tectonic uplift, and hence were more susceptible to intensive

weathering and sever erosion.

From geomorphologic point of view, the study area

represents one of the most dynamic regions in the Arabian-

Nubian Shield. Its landforms are susceptible to substantial

changes in very short periods of time. Major risks and hazards

that threaten the region and hamper the process of sustainable

development can be summarized in the following notes:

1. Lake Nasser

The man-made Lake Nasser is one of the greatest fresh

water reservoirs on the globe. Annually, it provides Egypt by

more than 55 billion cubic meters of water. There is a gradual

and rapid size extension of the Lake Nasser at expense of the

Nubian Plain, and hence, large amounts of water are annually

lost due to evaporation in this arid region. Waterproofing

heavily into cracks and crevasses scattered around the lake

is another major challenge. Only, via Kalabsha fault more than 3

billion cubic meters are wasted per year [3]. The continues

overload of the lake water and water incursion across the

major faults in this tectonically unstable region represent

additional hazard factors, and hence, accelerate and enhance the

seismicity of the area.



I J E N S

2. Hazards of continuous sand encroachment

In general, wind blow in the southern Western Desert

of Egypt predominantly from NW to the SE throughout the year.

The NW-SE wind had played an important role in shaping the

mega-dune belts in the Western Desert [44]. According to the

latter authors, the NW-SE wind impacted the area for thousands

of years. The mobile dunes and sand covered the ancient

monuments and invaded oases, roads and had left catastrophic

effects on all aspects of urbanization in the Western Desert. In

the study area, the wind transfer huge quantities of sand annually

to the Lake Nasser. It is very important to emphasize the need to

continuous monitoring of the ongoing movement of sand across

the area every three to five years via satellite images [43], [51].

ACKNOWLEDGMENT

This project was supported financially by the Science and

Technology Development Fund (STDF), Egypt, Grant No. 4440.

REFERENCES

[1] K.W. Butzer, (1965) Desert landforms at the Kurkur Oasis. Egypt

Ann Assoc Amer Geographers, 55, 578–591. [2] A.K. Thurmond, R.J. Stern, M.G. Abdelsalam, K.C. Nielsen, M.M.

Abdeen, E. Hinz, (2004). The Nubian swell. J Afr Earth Sci

39:401–407. [3] R.E. Fat-Helbary, A.Tealb, (2002). A study of seismicity and

Earthquake Hazard at the proposed Kalabsha Dam Site, Aswan

Egypt. Natural Hazards 25: 117 - 133. [4] J.S. Blaszczynski, (1997). Landform characterization with

geographic information systems. Photogrammetric Engineering

and Remote Sensing 63 (2), 183–191. [5] M.P. Bishop, Jr. Shroder, JF, Eds., (2004a). Geographic

Information Science and Mountain Geomorphology. Springer-

Praxis, Chichester. 486pp.

[6] Jr. Shroder, JF, M.P. Bishop, (2003). A perspective on computer

modeling and fieldwork. Geomorphology 53, 1–9. [7] P.A. Burrough, (1986). Principles of Geographical Information

System for Land Resources Assessment. Oxford University Press,

193 pp. [8] M. Klimaszewski, (1982). "Detailed geomorphological maps”.

ITC journal 3, 265-271.

[9] D. Barsch, K. Fischer, G. Stäblein, (1987) Geomorphological mapping of high mountain relief, Federal Republic of Germany

(with geomorphology map of Königsee, scale 1:25 000)“.

Mountain Research and Development 7, 4, 361-374. [10] L.W.S. De Graaff, M.G.G. De Jong, J. Rupke, J. Verhofstad,

(1987). A geomorphological mapping system at scale 1 :10,000 for

mountainous areas. Zeitschrift für Geomorphologie N.F. 13, 229–242.

[11] R.J. Pike, (2000). Geomorphometry - diversity in quantitative

surface analysis. Progress in Physical Geography 24 (1), 1–20. [12] T. Hengl, H.I. Reuter, (Eds.), (2009). Geomorphometry: Concepts,

Software, and Applications. Developments in Soil Science,

Elsevier, Amsterdam, 33: 31-63.

[13] I.V. Florinsky, (1998). Combined analysis of digital terrain models

and remotely sensed data in landscape investigations. Progess in

Physical Geography 22 (1), 33-60. [14] S. Liang, (2007). Recent developments in estimating land surface

biophysical variables from optical remote sensing. Progress in

Physical Geography 31 (5), 501-516. [15] M.J. Smith, C.F. Pain, (2009). Applications of remote sensing in

geomorphology. Progress in Physical Geography 33 (4), 568-582.

[16] P. Tarolli, J.R. Arrowsmith, E.R. Vivoni, (2009). Understanding Earth surface processes from remotely sensed digital terrain

models. Geomorphology 113, 1-3.

[17] T.R. Allen, S.J. Walsh, (1993) Characterizing multitemporal alpine

snowmelt patterns for ecological inferences. Photogrammetric Engineering and Remote Sensing 59 (10), 1521-1529.

[18] W.T. Lin, W.C. Chou, C.Y. Lin, P.H. Huang, J.S. Tsai, (2005).

Automated suitable drainage network extraction from digital elevation models in Taiwan’s upstream watersheds. Hydrological

Processes, 20: 289-306.

[19] K. Paik, (2008). Global search algorithm for nondispersive flow path. Journal of Geographical Research, 113: F04001,

doi:10.1029/2007JF000964.

[20] X. Liu, Z. Zhang, (2011). Drainage network extraction using LiDAR-derived DEM in volcanic plains. Area, 43 (1): 42–52.

[21] S.R. Hosseinzadeh, (2011). Drainage Network Analysis, Comparis

of Digital Elevation Model(DEM) from ASTER with High Resolution Satellite Image and Areal Photographs. International

Journal of Environmental Science and Development, Vol. 2, No. 3,

194-198. [22] S. Gayen, G.S. Bhunia, P.K. Shit, (2013) Morphometric analysis

of Kangshabati-Darkeswar Interfluves area in West Bengal, India

using ASTER DEM and GIS techniques. Geol Geosci 2(4):1–10. [23] B. Issawi, (1968). The geology of Kurkur–Dungul area. Geol Surv

Egypt 46:1–102

[24] W.F. Hume, (1934). Geology of Egypt, Vol. II (The fundamental Pre-Cambrian rocks of Egypt and the Sudan; their distribution,

age, and character). 300pp. and 124 pp., index.

[25] Kh. Ouda, & A. Tantawy, ( 1996): Stratigraphy of the Late Cretaceous-Early Tertiary sediments of Sinn El Kaddab-Wadi Abu

Ghurra stretch, southwest of the Nile Valley, Egypt. In: The Cretaceous of Egypt. Geol.Soc. of Egypt. Sp. Publi. No. 2.

[26] R. Said, (1962). The Geology of Egypt. Elsevier, Amsterdam-New

York, 377pp. [27] R. Said, (1975). Some observations on the geomorphological

evolution of the South Western of Egypt and its relation to the

origin of the ground water. Ann Geol Surv Egypt 5:67–70 [28] N.S. Embabi, (2004) The geomorphology of Egypt, landforms and

evolution, Volume I: The Nile Valley and the Western Desert.

Spec. Pub., Egypt. Geograph. Soc., 447 pp [29] K. Abou Elmagd, M.W. Ali-Bik, S.D. Abayazeed, (2014) Geology

and geochemistry of Kurkur bentonites, southern Egypt:

provenance, depositional environment, and compositional

implication of Paleocene–Eocene thermal maximum". Arab J

Geosci., V.7, Issue 3, pp. 899-916.

[30] F.B. Van Houten, D.P. Bhattacharyya, (1979). Late Cretaceous Nubia Formation at Aswan southeastern Desert, Egypt. Annals

Geol Surv. Egypt, IX, 408-431.

[31] J. Chorowicz, C. Ichoku, S. Riazznoff, Y.J. Kim, B. Cervelle, (1992). A combined algorithm for automated drainage network

extraction. Water Resources Research, 28(5):1293-1302.

[32] L.W. Martz, J. Garbrecht, (1992). Numerical definition of drainage network and subcatchment areas from digital

elevation models. Computer and Geosciences, 18(6):747-761.

[33] K.G. Nikolakopoulos, E.K. Karmaratakis, N. Chrysoulakis, (2006). “SRTM vs ASTER Elevation Products. Comparison for

two Regions in Crete Greece,” International Journal of remote

sensing, vol. 27(21), 4819-4838. [34] A. Tribe, (1992). “Automated recognition of valley lines and

drainage networks from grid digital elevation Models: a review

and a new method. ,” Journal of Hydrology, 139, 263-293.

[35] Wu. Simon, Li. Jonathan, G.H. Huang, (2008). “A study on DEM-

derived Primary Topographic Attributes for Hydrologic

Applications: Sensitviy to Elevation Data Resolution”. Applied Geography, 28, 210-223.

[36] S.K. Jenson, J.O. Domingue, (1988). “Extracting Topographic

Structure from Digital Elevation Data for Geographic Information System Analysis,” Photogrametric Engineering and Remote

Sensing, vol. 54, pp. 1593-1600.

[37] A.N. Strahler, (1964), “Quantitative Geomorphology of Drainage Basin and Channel Network”, Handbook of Applied Hydrology

(Ed. Ven Te Chow). McGraw Hill Book Company, New York, pp

39-76.

http://dx.doi.org.dlib.eul.edu.eg/10.1016/j.jafrearsci.2004.07.027



I J E N S

[38] K.J. Gregory, D.E. Walling, (1968). The variation of drainage

density within a catchment, International Association of Scientific Hydrology - Bulletin, 13, 61-68.

[39] S.A. Schumm, (1956). Evolution of drainage systems & slopes in

Badlands at Perth Anboy, New Jersey, Bulletin of the Geological Society of America, 67, 597-646.

[40] E. Elba, D. Farghaly, B. Urban, (2014) Modeling High Aswan

Dam Reservoir Morphology Using Remote Sensing to Reduce Evaporation. International Journal of Geosciences, 5, pp. 156-169.

doi.org/10.4236/ijg.2014.52017

[41] R. Said, B. Issawi, (1964). Preliminary report of a geological expedition to Lower Nubia and to Kurkur and Dungul oases,

Egypt. Museum of New Mexico, Santa Fe. New Mexico, 28pp.

[42] B. Tewksbury, M. Abdelsalam, C. Tewksbury, J. Hogan, T. Jerris, A. Pandey, (2009). Reconnaissance study of domes and basins in

Tertiary sedimentary rocks in the Western Desert of Egypt using

high resolution satellite imagery. Abstract with Programs-Geological Society of America, Vol. 41, no 1, pp

[43] E. Khedr, K. Abou Elmagd, M. Halfawy, (2014). Rate and budget

of blown sand movement along the western bank of lake Nasser, southern Egypt. Arab J Geosci, 7, 3441-3453.

[44] F. Wendorf, R. Schild, (1976) Prehistory of the Nile Valley.

Academic, 627, New York.

[45] R. Said, (1990) Cenozoic. In: Said R (ed) The geology of

Egypt. Balkema, Brookfield, pp 451–486

[46] M. Hermina, E. Klitzesch, and F.K. List (1989) Stratigraphic lexicon and explanatory notes to the geological map of Egypt:

Conoco Coral and Egyptian General Petrol Corporation, (Cairo).

[47] K.M. Banks (1984) Climates, Cultures, and Cattle: The Holocene Archeology of the Eastern Sahara: Southern Methodist University.

Dallas Circular.

[48] Darnell, Darnell (2006). The Archaeology of Kurkur Oasis, Nuq‘ Maneih, and the Sinn el-Kiddab. Copyright 2006 Yale

Egyptological Institute in Egypt.

http://www.yale.edu/egyptology/ae_kurkur.htm

[49] M.G. Sheded, L.M. Hassan, (1998) Vegetation of Kurkur Oasis in

South-Western Egypt..J.Union Arab. Biol.Cairo:6:129-144.

[50] R. Bornkamm, I. Springuel, F. Darius, M.G. Sheded, M. Radi,

(2000) Some observations on the plant communities of Dungul

Oasis (Western Desert,Egypt). Acta Bot. Croat.59: pp. 101-109.

[51] E. Khedr, K. Abou Elmagd, M. Halfawy, (2013). Factor analysis of Meteorological and granulometrical data of Aeolian sands in

arid areas as a geo-environmental clue: a case study from western

bank of lake Nasser, Egypt. International Journal of Civil & Environmental Engineering, 13, 21-37.

http://www.yale.edu/egyptology/ae_kurkur.htm

Geomorphic Evolution of The Kurkur-Dungul area in...

Documents

Transcript of Geomorphic Evolution of The Kurkur-Dungul area in...