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Mica and Heavy Minerals as Markers to Map Nile Delta Coastline Displacementsduring the HoloceneAuthor(s): Jean-Daniel Stanley and Pablo L. ClementeSource: Journal of Coastal Research, 30(5):904-921. 2014.Published By: Coastal Education and Research FoundationDOI: http://dx.doi.org/10.2112/JCOASTRES-D-14A-00003.1URL: http://www.bioone.org/doi/full/10.2112/JCOASTRES-D-14A-00003.1
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Mica and Heavy Minerals as Markers to Map Nile DeltaCoastline Displacements during the Holocene
Jean-Daniel Stanley* and Pablo L. Clemente
Cities under the Sea Program (CUSP)Department of PaleobiologyNational Museum of Natural HistorySmithsonian InstitutionWashington, DC 20013, U.S.A.
ABSTRACT
Stanley, J.-D. and Clemente, P.L., 2014. Mica and heavy minerals as markers to map Nile Delta coastline displacementsduring the Holocene. Journal of Coastal Research, 30(5), 904–921. Coconut Creek (Florida), ISSN 0749-0208.
Mica and heavy minerals in sediments of Egypt’s Nile Delta are examined to test if measured proportions of these twomineral groups and their distributions can be used to define former coastline positions and their shifts in time and spaceduring the Holocene. The premise of the study is based on the sufficiently different attributes of these two components,especially their shape, density, and size, which could induce their segregation and dissimilar dispersal patterns duringsediment transport. To test this hypothesis, mineralogical data from more than 1400 samples from 87 sediment coresrecovered across the northern third of the delta margin were analyzed. The marked contrast in both temporal and spatialdistributions of high proportions of mica and of heavy minerals indicates distinct separation occurred primarily north ofthe central delta, in an area from ~45 km south of the present shoreline to ~10–15 km offshore during the time spanconsidered. Additionally, detailed examination of core sediment types demonstrates a relationship between theproportions of these two mineral groups and proportions of clay, silt, and sand fractions in which they occur near thepresent coast. Mica is preferentially deposited with silt and clay landward of the modern shore, while heavy mineralconcentrations are generally associated with coarser silt and sand near and seaward of the shoreline. Shifts of the NileDelta margin have been triggered by natural processes leading to insufficient sediment replenishment: relative sea-levelrise involving delta plain subsidence and shoreline erosion, and intensified human activity, especially during the pasttwo centuries, such as construction of dams, barrages, and entrapment by the delta’s expanded canal system. Theapproach used here helps define two of the three major earlier Holocene coastal shifts, and it could be used to measureongoing and future landward shoreline advances onto the delta plain.
ADDITIONAL INDEX WORDS: Climate change, coastal processes, grain density, grain shape, human interference, Nilebranches, northern delta, provenance, relative sea level, relict distributaries, salinization, shoreline shifts, sedimentreplenishment, subsidence.
INTRODUCTIONThis investigation examines two major coastal margin
migrations of the northern Nile Delta during the Holocene,
an earlier one advancing to the north, and a second reverting to
the south. To date, most studies of this delta’s shoreline shifts
along the Mediterranean have focused on factors recently
affecting the coast and its contiguous submerged areas
offshore. There have been far fewer investigations of the Nile’s
coastal migrations based on observations made in the delta’s
northern plain landward of the present shoreline. Our
evaluation of temporal and spatial shoreline shifts in this
region is based on analysis of a newly examined mineralogical
database acquired from sediment cores. This data set is
complemented by information on the Nile’s hydrographical
parameters and coastal processes collected by others at the
shoreline and along nearshore sectors of the Nile shelf.
As has been shown in studies of many of the world’s other
large fluvio-deltaic depocenters, major natural factors that
have controlled the Nile Delta margin’s position and configu-
ration in Holocene time include: climate change and rising sea
level; erosional cutback of low-lying unconsolidated terrains by
active coastal processes; and subsidence of delta plain surfaces
(cf. Broussard, 1975; Coleman, 1982; Coleman et al., 1981;
Wright and Coleman, 1973). In addition to these parameters,
human activity and interference of Nile flow have increasingly
affected this delta’s margin in more recent time, causing
marked decrease of sediment replenishment at and near the
coast. Egypt’s population has grown rapidly, reaching nearly
85 million, with the majority (~60%) highly concentrated in the
Nile Delta between Cairo and the coast (Figure 1A), and the
remaining mostly along the Nile Valley in Middle and Upper
Egypt. It is generally recognized by Egyptians living in the
delta, many experiencing economic hardship, that each new
pressure, whether the result of altered natural processes,
increased human activity, or both, tends to increase threats to
themselves and endanger their country’s most vital breadbas-
ket positioned in this low-lying coastal terrain. This has led to
Egypt’s increased concern with regards to changes that are now
modifying the delta’s coastal margin. Some of these changes
will likely have direct, rapid, and quite probably serious
ramifications in the near future if sea level continues to rise
and encroach farther inland onto the delta plain (Bohannon,
2010; Sestini, 1992; UNDP, 2009).
D O I : 1 0 . 2 1 1 2 / J C O A S T R E S - D - 1 4 A - 0 0 0 0 3 . 1 r e c e i v e d18 February 2014; accepted in revision 21 February 2014; correctedproofs received 9 April 2014; published pre-print online 29 May 2014.*Corresponding author: [email protected]� Coastal Education & Research Foundation 2014
Coconut Creek, Florida September 2014Journal of Coastal Research 30 5 904–921
Figure 1. (A) Google Earth image (2013) showing the Nile Delta bounded to the north by the Mediterranean and to the west and east by desert. Numerous small
towns and cities in the delta appear as light-colored, irregular spots. Numbers on image refer to the following: (1) calcareous ridges, (2) Mariut lagoon, (3)
Alexandria, (4) Abu Qir headland, (5) Abu Qir Bay, (6) truncated Rosetta promontory, (7) Burullus lagoon, (8) Burullus inlet, (9) Burullus headland, (10) Baltim
outlet, (11) high migrating dune fields, (12) Gamasa, (13) Ras El-Barr, (14) truncated Damietta promontory, (15) Damietta promontory spits, (16) Manzala lagoon,
(17) Port Said–Suez Canal entry, (18) salt flats east of canal, (19) Suez Canal. (B) Cores recovered at sites S1 to S87 serve as a database for the present study
(Stanley, McRea, and Waldron, 1996). A¼Alexandria; B¼Burullus headland; Bu¼Burullus lagoon; DP¼Damietta promontory; I¼ Idku lagoon; KZ¼Kafr el-
Zaiyat; Man¼Manzala lagoon; Mar¼Mariut lagoon; PS¼Port Said; T¼Tanta.
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 905
The main focus here is on petrologic information derived
from .1400 sediment samples obtained from numerous
continuous radiocarbon-dated core sections of Holocene age
recovered across the northern delta plain (Figure 1B). Special
attention is paid to the proportions of mica and heavy minerals
in the sand-size fraction of Holocene sections. Selection of these
two mineral groups is based primarily on their significantly
different responses to dynamic transport processes by fluvial,
marine, and eolian agents that have prevailed in the past and
continue to modify this depocenter. Theoretical, laboratory,
and field studies by geologists working in the modern sediment
record and in diverse geological formations have indicated that
some sand-size minerals, such as mica, can be more readily
displaced by currents for greater distances than some other
mineral types. It is also of note that mica has received much
less attention in Nile Delta studies than heavy minerals. With
its characteristic flake shape, mica, once in suspension, would
be carried farther in a flowing or agitated body of water, settle
less rapidly, and be displaced further along a dispersal path
than more spherical grains. These rounder grains are usually
dominated by quartz and feldspar, as well as some associated
denser minerals (especially heavy minerals) that tend to be of
equivalent or smaller size than the mica (Pettijohn, Potter, and
Siever, 1973).
During transport, mica would thus tend to be segregated
from denser heavy minerals of sand size and selectively
transported for greater distances away from sediment entry
points along the Nile in the lower delta and Nile distributary
mouths along the coast. The ability of mica to remain in
agitated or flowing water over longer distances relative to other
grains of the same size helps to explain the generally low
concentrations of mica of Nile River origin presently in the
delta’s coastal sediments. It also illustrates why greater
amounts of mica are deposited in finer-grained sediment of
Nile origin in deeper waters on the Israeli margin hundreds of
kilometers away from Nile Delta sources (Pomerancblum,
1966). In contrast, heavy mineral suites tend to form
concentrated lag deposits in coastal margin settings near the
Nile’s distributary mouths. Such concentrates of greater
densities prevail in seafloor areas reworked by strong bottom
currents and powerful episodic storm wave surges in the high-
energy settings between the inner shelf and the beach (Frihy
and Komar, 1993; Frihy, Lotfy and Komar, 1995).
We propose that mapping and comparing distributions of
these two distinct mineral groups in the subsurface sections of
the delta proper could provide some new information on earlier
positions of Holocene coastlines. Distinguishing their past
distributions in radiocarbon-dated core sections of the northern
delta plain may also offer some additional insight on the
present and future evolution of this now densely populated and
vulnerable low-lying region of significance to Egypt.
SETTING, COASTAL PROCESSES, ANDPROVENANCE
The following section aims to provide a broad framework for
interpreting the mineralogical data presented in this study in a
more comprehensive manner. The topics reviewed include the
basic stratigraphic evolution of the Holocene delta, coastal
processes that have modified its margin, and the provenance of
the delta’s components, including mica and heavy minerals and
major size fractions of the sediments with which these two
mineral groups were deposited.
Figure 2. Schematic of the northern delta and its contiguous coastline and inner shelf. The distribution of sediment types offshore is from Summerhayes et al.
(1978). Theþ1 m contour above msl (dotted line) is from Sestini (1989). Coastal sands on land at present are derived from a 2013 Google Earth image. Black
dashed line indicates the landward limit of the early Holocene coast as determined from core logs in Stanley, McRea, and Waldron (1996). Arrows indicate three
Holocene coastal shifts associated with three phases of the delta’s evolution: (I) landward retreat across the Nile shelf area in the late Pleistocene to early
Holocene; (II) seaward advance during the early Holocene, and through the mid-Holocene to early part of the late Holocene; and, (IIIa) return landward of the
coastline during the late Holocene from the present inner shelf, now submerged. Details reviewed in text.
Journal of Coastal Research, Vol. 30, No. 5, 2014
906 Stanley and Clemente
Three Phases of Delta Coast DevelopmentThe geologic evolution of the Nile Delta’s shoreline during
the Holocene, and that of its adjacent sectors on land and its
contiguous submerged inner shelf, has likely involved three
major phases as schematically depicted by deltaic stratigraphic
models (cf. Curray, 1960; El Askary and Frihy, 1986; Scruton,
1960). These schemes have served to conceptualize the
development of some of the world’s large fluvio-marine deltas
and emphasize the interactive roles of increased sediment
discharge at the coast that can result in their seaward-directed
progradational build-out or their erosion and retrogradational
landward advance. The models identify a sequence of lateral
coastal displacements that essentially result from opposing
forces: a fluvio-delta’s accretion and extension into the marine
environment, and coastal processes that counter such deposi-
tional build-out and can lead to landward retreat of a delta’s
margin. As an example of the latter, it is likely that decreased
fluvial sediment input to the coast coupled with increased
eustatic or relative sea-level rise in conjunction with powerful
coastal marine erosional processes acting along shoreline
sectors would cause a delta-margin cutback. Such phases
involving alternations of seaward delta build-out and of delta
plain removal by erosion of sediment transported via river to
the shoreline are responsible for the multiple shifts of a deltaic
coast that commonly occur through time. Three of these
migrations are indicated by arrows in Figure 2.
During the Nile Delta’s first phase (I), extensive coastline
retreat southward occurred during the late Pleistocene to the
early Holocene, a period when sea level rose rapidly (rates to~1
cm/y) and advanced southward across the shelf platform. A
broad but irregular cover of coarse to fine sand, silt, and clay,
deposited across what was then a subaerial plain, subsequently
became the presently submerged Nile shelf surface positioned
north of the terrestrial depocenter (Stanley and Warne, 1998).
The delta front and shoreline formed in this micro–tidal sea
retreated to a position south of the present subaerial delta coast
(Figure 2, early Holocene, shown as black dashed line), as
recorded in cores by a basal unit largely composed of sand and
silt that dates from about 9000 YBP to 7000 YBP (Figure 2,
arrows depicting phase I). This basal unit in early Holocene
core sections is of modest but uneven thickness, sometimes
formed of reworked and mixed late Pleistocene and early
Holocene sandy deposits, and locally discontinuous due to its
partial erosion by coastal and bottom-current processes in this
actively displaced nearshore setting.
This major landward coastline retreat was followed by a
second phase (II) during which the delta experienced its major
sediment buildup (accretion, locally to nearly 50 m in
thickness) and seaward progradation with a re-advance of
the coast to north of the Nile’s modern subaerial depocenter
(Figure 2, arrows depicting phase II). A study of cores recovered
in the northern third of the present subaerial delta (Figure 1B;
Stanley and Warne, 1998) and those at sea (Summerhayes et
al., 1978) shows that the seaward build-out phase lasted~5000
years, extending from the early (~7500–6500 YBP) and mid-
Holocene to the early part of the late Holocene (~2000 YBP).
Deposition of thick delta-front and prodeltaic facies consists in
large part of fine-to-medium sand, with high proportions of silt
and muddy silt (Stanley and Warne, 1993, 1998; Summerhayes
et al., 1978; UNDP/UNESCO, 1976). One reason for this delta’s
fairly symmetrical arcuate build-out was the delta’s greater
volume of flow seaward during that period via numerous
distributary channels that were responsible for sediment
transported onto what is now the inner shelf. Relict branches
of the Nile that flowed to the coast during phase II may have
numbered as many as ten (Figure 3), but not all were active
simultaneously or of equal importance (Said, 1981; Toussoun,
1922). According to Herodotus’ The History (484–425 BC, 2.17;
translation by Grene, 1987), the branches that were still active
in Greek time as late as about the mid–fifth century BC were
the Canopic, Bolbitinic, Saitic, Bucolic, Mendesian, and
Pelusiac (Figure 3). He also calls special attention to the
importance of the Sebennitic branch, which flowed almost
directly northward to and beyond what is presently the
Burullus headland (Figure 1A, sites 8–9), and he suggests that
its channel was a major source of water flow to the coast,
dividing the delta into two halves. This major delta buildup and
seaward progradational phase included sediment deposited
during pre-Dynastic time (before ~5050 YBP) and lasted
through Egypt’s Dynastic and Ptolemaic periods to the first
century BC (Baines and Malek, 1985; Butzer, 1976).
The third, most recent phase (III) of delta development
(~2000 YBP to present, comprising what here is termed the
late Holocene) is characterized by changes of two natural
factors that, in earlier time, had largely controlled the Nile
Delta’s morphological and stratigraphic evolution. By the late
Holocene, (1) the rate of sea-level rise was substantially lower,
to between 1.7 mm/y and 3.0 mm/y (Lambeck and Purcell, 2005;
Sivan et al., 2001; Woppelman and Marcos, 2012), and (2) the
natural annual volume of Nile River flow and its sediment load
periodically decreased, largely as a response to regional climate
change in the Nile Basin, including cycles of marked aridifica-
tion (Bernhardt, Horton, and Stanley, 2012; Kropelin et al.,
2008; Marriner et al., 2012; Muhs et al., 2013; Said, 1993;
Zviely, Kit, and Klein, 2007). During this same period, the role
of a third controlling factor, (3) subsidence of the delta plain
surface, became increasingly apparent as a major parameter
affecting the delta’s coastline position (Becker and Sultan,
Figure 3. Nile distributaries, including traces of eight relict branches
(dashed lines) and two partially active ones (Bolbitinic/Rosetta and Bucolic/
Damietta). Some, such as the Sebennitic (5), formerly extended seaward of
the present coast. Map is adapted from Wright and Coleman (1973) and Ross
et al. (1978).
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 907
2009; El-Sayed, 1996; Stanley and Clemente, 2014; Stanley and
Corwin, 2013; Stanley and Toscano, 2009; Warne and Stanley,
1993a). Measured land-lowering rates in the northern delta
during the late Holocene (ranging from 3.7 mm/y to 8.4 mm/y;
Stanley and Corwin, 2013) locally began to exceed rates of
eustatic sea-level rise, as determined separately by geophysical
analyses in this general Mediterranean region (Lambeck and
Purcell, 2005). In parallel with significant rates of subsidence
and a relative sea-level rise of ~1 cm/y along the delta’s
northern margin in Greco-Roman (332 BC–AD 395) and
subsequent time, the shoreline retreated landward to its
present position (Figure 2, phase IIIa arrows).
Increased Effects of Human Activity and CoastalProcesses
Population in the delta is estimated to have increased from
about 80,000 at~6000 YBP, to~1.2 million at~3250 YBP, and
then to ~2.16 million at ~2150 YBP in Greek time (Butzer,
1976, his Table 4). From the latter part of phase II and during
the past two millennia (phase IIIa), Egypt’s population has
Figure 4. (A, B) Data on wave directions, wave heights, and wave refraction patterns along the Nile Delta margin. (C) Extent of erosion and accretion,
predominant coastal current directions, and definition of littoral subcells (I to V) in this area. Modified after Frihy and Dewidar (2003).
Journal of Coastal Research, Vol. 30, No. 5, 2014
908 Stanley and Clemente
grown to about 85 million inhabitants at present, with most in
the delta and along the Nile (CIESIN, 2009; UNDP, 2009).
About 18 million are now concentrated in the Cairo region at
the delta’s southern apex, and population densities locally
exceed 1000/km2 in parts of the delta, including some coastal
sectors such as at Alexandria (5.5 million inhabitants) and Port
Said (.0.6 million inhabitants). The much-increased human
activity during phase IIIa along the lower Nile and in the delta
proper now constitutes a major controlling factor of Nile flow.
The resulting effect of anthropogenic influences is the almost
complete cutoff of sediments now carried to the coast by the
only two remaining and altered Nile branches, the Rosetta and
Damietta (Stanley and Wingerath, 1996). These two distribu-
taries, formerly the Bolbitinic and Bucolic, respectively, were
not natural but dug channels according to Herodotus’ The
History. Major changes to the delta’s margin have resulted
directly from emplacement of barrages across the Nile in Upper
and Middle Egypt, construction of the Low Dam at Aswan early
in the twentieth century, closure of the High Dam at Aswan in
1964–65, and near cutoff of freshwater flow into the Mediter-
ranean by closure of two dams ~30 km landward of the two
mouths of the Nile’s Rosetta and Damietta branches (Water-
bury, 1979). It is recalled that, before closure of the High Dam,
Nile sediments transported through the Rosetta and Damietta
branches varied from year to year in the range of 60–100
million tons. At present, only ~10% of the Nile’s flow actually
reaches to and seaward of the delta’s coast (Stanley and
Wingerath, 1996). This reduction has also resulted from almost
complete diversion of Nile flow north of Cairo and its
entrapment across the delta by thousands of kilometers of
canals and drains, and discharge into the partially closed
coastal lagoons (Bohannon, 2010). Such a marked depletion of
the Nile’s natural fluvial sediment supply to the northern delta
and the coast is now only partially offset by the volume of relict
Nile sand and silt displaced southward from offshore onto land
by coastal currents (Frihy, Debes, and El Sayed, 2003; Frihy
and Dewidar, 2003; Frihy and Lotfy, 1997) and by dust and fine
sediment from adjacent desert terrains and more distal regions
released over the delta by seasonal winds (Guerzoni and
Chester, 1996; Khatita, 2011).
In summary, the most recent phase (IIIa) of the Nile Delta’s
coastline change is a consequence of the interaction of the five
previously cited controlling factors: climate change and sea-
level rise, much reduced Nile sediment discharge to the coast,
subsidence of the delta plain, coastal processes, and increased
human activity. Coastal retreat has thus prevailed along many
sectors between the Alexandria region to the west and the
northeastern margin east of Port Said and the Suez Canal
south of the Gulf of Tineh (Figure 1). Of particular note are
combined effects of much decreased volumes of Nile sediment
reaching the coast (Said, 1993) combined with ongoing
nearshore to coastal marine erosive processes at present
(Figure 2, phase IIIa arrows). Many published studies
concerned with this subject have focused primarily on the
post–High Dam effects and related coastal margin evolution,
which have led to recent emplacement of coastal protective
structures to help reduce erosion rates. Much applicable
research has resulted from programs sponsored by UNDP/
UNESCO (1976, 1977, 1978), those of the Egyptian govern-
ment’s Coastal Research Institute at Alexandria, different
science departments at the University of Alexandria, and other
governmental and academic organizations. That work, detail-
ing physical oceanographic parameters and coastal dynamics,
has found that ongoing landward retreat of fluvio-marine delta-
front and prodelta depositional sectors results from a series of
interactive factors that prevail in the southeastern Mediterra-
nean. For example, dominant NW winds drive waves and
produce strong coastal currents toward the east (Figure 4C),
which can reach velocities as high as 100 cm s�1 to 150 cm s�1
(Abo Zed, 2007; El Din, 1974). Additionally, wave heights
reaching 2 m to 5 m can result from storms, especially in
winter, which can produce powerful land-directed surges
(Inman and Jenkins, 1984; UNDP/UNESCO, 1978; Figure
4A). Somewhat deeper bottom and geostrophic currents play a
role in reworking older (relict) Nile sediment on the shelf (El
Din, 1974, 1977; Frihy, 1992a).
In the early twentieth century, very rapid delta coastal
erosion resulted in remarkable shoreline retreat rates mea-
sured at~50–100 m/y along the Rosetta promontory, 10 m/y at
the Damietta promontory, and 5–10 m/y at the central
Burullus headland (Frihy, 1992a,b; Frihy and Deabes, 2011;
Frihy, Debes, and El Sayed, 2003; Frihy et al., 1994).
Substantial rates of sediment accretion were measured locally,
such as in Abu Qir Bay, as a result of significant erosion in
adjacent headland regions (Figure 4C). By ~20 years ago, it
was reported that an approximate average cutback of extensive
shoreline sectors accounted for 54% of the delta coastline, while
accretion occurred along much of the remaining 46% of the
coast (Frihy and Komar, 1993; Figure 4C). In recent years,
erosion rates have been significantly reduced at the more
vulnerable delta headlands following emplacement of coastal
protection structures (Frihy and Dewidar, 2003): at the Rosetta
promontory, �20 cm/y to �50 cm/y, and at the Burullus
headland and Damietta promontory, both at 0 cm/y to �20
cm/y. Accretion of sediment, some of it temporarily stored along
the coast, occurs at more modest rates, ranging from 0 cm/y to
40 cm/y between zones of erosion, such as the eastern Rosetta
margin, Gamasa embayment, and western margin of the Suez
Canal entrance at Port Said and south of the Gulf of Tineh
(Frihy and Dewidar, 2003; Figure 4C).
Heavy mineral concentrations, such as the so-called ‘‘black
sands’’ of economic value, comprise to as high as 70% to 90% of
the sand fraction and occur near the mouths of present as well
as former Nile distributaries subject to erosion (El Fattah and
Frihy, 1988; El-Hinnawi, Niazi, and Samy, 1989; Naim, El
Miligy, and El Azab, 1994). Heavy minerals and textural
attributes of sediment, such as size, have helped define five
sediment transport zones (I–V), termed subcells, along the
present delta’s coastal/nearshore zone, from Abu Qir in the
west to beyond Port Said in the east (Frihy and Dewidar, 2003;
Frihy and Komar, 1993; Frihy, Lotfy, and Komar, 1995; Figure
4C).
Provenance of Coastal Margin SedimentsThe texture and composition of sediments that prevail in the
northern delta study area and offshore, at least to as far as the
middle shelf, record a dominant Nile River origin, with
provenance from both White Nile sources in central Africa
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 909
and Blue Nile–Atbara headlands in the Ethiopian Plateau (El-
Hinnawi, Niazi, and Samy, 1989; Foucault and Stanley, 1989;
Hassan, 1976; Shukri, 1950, 1951; Shukri and Azer, 1952). The
similarity of heavy mineral suites in different late Pleistocene
to modern sand layers along the Nile, in the delta, and in the
inner to midshelf is primarily a function of mineralogical
homogenization during sediment transport. White Nile sedi-
ments are generally masked by dominant Blue Nile and Atbara
components, recycled together north of Khartoum in the Main
Nile, and by subsequent reworking of sediments between
different fluvio-marine environments in the northern delta
(Stanley, Sheng, and Pan, 1988).
The dynamics of multiple processes along the delta’s coastal
margin have further modified the original sediment attributes
both along the shore and shelf, including their original grain-
size distribution and mineralogical content (El-Fishawi and
Molnar, 1985; Frihy and Lotfy, 1994; Frihy, Lotfy, and Komar,
1995; Stanley, 1989). Studies conducted offshore have identi-
fied altered sediment texture and composition as related to the
Nile Delta’s coastal and offshore currents and seafloor
morphology (Coleman et al., 1981; Gheith et al., 1994; Sestini,
1989; Summerhayes et al., 1978) and also to the former coastal
discharge positions of now-relict Nile distributary branches
(Arbouille and Stanley, 1991; Coutellier and Stanley, 1987;
Frihy and Lotfy, 1994; Gheith et al., 1994).
Some offshore sediments examined on the broad expanse of
both inner and middle shelf are identified as older relict Nile
deposits released by the river’s flow on the subaerially exposed
shelf prior to ~9000–8000 YBP; these earlier deposits have
been covered locally by Nile deposits more recently released on
the Nile shelf (Stanley and Warne, 1998). These two sets of
sediment have been reworked, forming a palimpsest deposit
offshore during the Holocene as the delta’s coastline and inner-
shelf environments advanced seaward and then retreated
landward (Sestini, 1992).
Mineral counts of mica, comprising primarily biotite (densi-
ty, g/cm3: 2.8–3.2), have been recorded along the different Nile
sectors between central Africa source areas and the Sudan
northward to the delta coast and offshore, with average relative
percentages ranging from absent and trace amounts to 4% of
the sand fraction (El-Fishawi and Molnar, 1985; Frihy and
Gamai, 1991; Garzanti et al., 2006; Shukri and Azer, 1952).
Mica contents in Middle Egypt sediment (Bustamante-Santa
Cruz, 1995) and those in central Nile Delta deposits examined
in cores S86 and S87 (Figure 1B; this study) range from trace to
,2%. Mica contents along carbonate-enriched beaches west of
Alexandria comprise ,2% (Hassouba, 1995; Philip, 1976;
Shukri and Philip, 1956), and those in delta coastal sands east
of Alexandria generally range from trace amounts to ~3% (El-
Fishawi and Molnar, 1985; Gheith et al., 1994).
Heavy minerals in Nile deposits in the lower Nile basin north
of the African source areas (El-Hinnawi, Niazi, and Samy,
1989) comprise variable amounts (from few grains to .10%) of
the sand fraction. These are composed primarily of opaque iron
minerals, amphiboles, clinopyroxenes, and epidotes (Hassan,
1976; Shukri, 1951; Shukri and Azer, 1952), and they are
included in comprehensive listings that identify as many as 45
mineral species from source areas. The densities of these
mineral types are much higher, ranging from ~3.5 to .5.2
(such as hematite), than the dominant proportions of light
mineral fractions of lower densities with which they are
associated, primarily quartz (2.65) and feldspars (2.57–2.76).
The flake shape of mica and considerably higher densities of
more spherical heavy minerals contribute to segregation of the
two mineral types during transport in aqueous media, first by
the Nile River and then by marine currents along the coast and
inner shelf. Moreover, such displacements of considerable
volumes of sand- and silt-size sediment of Nile derivation and
their differentiated mica and heavy mineral contents have
reached eastward to as far as Israel, as recorded by mineral-
ogical analyses (Inman and Jenkins, 1984; Pomerancblum,
1966; Stanley, 1988; Zviely, Kit, and Klein, 2007).
METHODSThe present investigation takes into consideration the
information summarized in the previous section to help better
interpret the differences in separately mapped temporal and
spatial distributions of mica and heavy minerals during two
major depositional phases of the delta. To achieve this, two
major Holocene stratigraphic sequences of the northern Nile
Delta coastal plain margin are evaluated: (1) an older, thicker
underlying section between the base and 2 m from the core top,
termed Early to mid-Holocene (phase II), that ranges in age
from ~7500 YBP to ~2000 YBP; and (2) a younger overlying
late Holocene section, termed Upper 2 m (phase IIIa), dating
from early Roman time (~2000 YBP) to present. In this
manner, it should be possible to determine whether any notable
differences in the distribution patterns of mica and heavy
minerals of sand size can be identified in the two stratigraphic
sequences in the northern delta and coastline area.
The data utilized herein are derived from laboratory analyses
of numerous (1410) sediment samples taken from 85 drill cores
collected in the northern delta study area and also those from 2
cores recovered in the central delta (Figure 1B). The core sites
and boring numbers are officially recorded as S1 to S87, where
the letter S denotes recovery by the National Museum of
Natural History (NMNH), Smithsonian Institution, Washing-
ton, D.C. The continuous core sections were collected using
Acker II trailer-mounted rigs during five field seasons from
1985 to 1990 with detailed stratigraphic, sedimentological,
textural, and mineralogical data recorded and interpreted
across the northern delta, from east to west (Coutellier and
Stanley, 1987; Stanley et al., 1992; Arbouille and Stanley, 1991;
Chen, Warne, and Stanley, 1992; Warne and Stanley, 1993b).
The total depth of sediment borings ranges from ~20 m to ~60
m, and these include continuous and dated late Quaternary
chronostratigraphic sections that, in most cases, extend from
the late Pleistocene at their base to the late Holocene and
recent time at their top.
Attention in the present study is paid to the Holocene
sections, which range from~2 m to~49 m in length and extend
in age from approximately 8500 YBP to the present. Basal
Holocene sections that reach to the underlying Pleistocene
sequences range from ~8500 YBP to ~6500 YBP, but in most
cases ~7500–7000 YBP. These basal sections are generally
positioned unconformably upon older (usually 12,000 YBP or
greater) underlying late Pleistocene sandy deposits. To
examine representative deposits at each core site, the samples
Journal of Coastal Research, Vol. 30, No. 5, 2014
910 Stanley and Clemente
were selected down-boring at each change of lithology, or at
about 50 cm intervals in the case of long homogeneous sections.
Microscopic analyses of the sand-size components (63 lm to
1000 lm fraction selected for this study) were performed on the
1410 Holocene samples, and based on mineral counts of 300 or
more grains identified in each sample. Detailed lithologic logs
of the 87 cores, radiocarbon dates, and textural and mineral-
ogical numerical data gathered for each sample are recorded in
a monograph published by the Smithsonian Institution
(Stanley, McRea, and Waldron, 1996).
Figure 5. (A) Percentages of the clay-size fraction in sediments that formed the northern Nile Delta region mostly during the early through mid-Holocene
(modified after Stanley and Clemente, 2014). Average rates of sediment compaction (ARC) for this period are from Stanley and Corwin (2013). (B) Averaged
percentages of mica in the sand-size fraction in the four sectors (I–IV) of the study area. (C) Averaged percentages of heavy minerals in the sand-size fraction in
this area. WMND¼western margin of northern delta; EMND¼ eastern margin of northern delta. Details discussed in text.
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 911
Among the mineralogical components identified are light
minerals (primarily quartz and lesser amounts of feldspars),
heavy minerals (both opaque and transparent), micas (primar-
ily biotite, with traces of chlorite and muscovite), glauconite,
pyrite, evaporites, lithologic fragments, aggregates, and nu-
merous components of whole and fragmented fauna and plant
material. In addition to the percentages of mica, heavy
minerals, and other mineral components, the proportions of
clay (,2 lm), silt (2 lm to 63 lm), and sand (63 lm to 2000 lm)
fractions were determined for each sample. Percentages of all
Figure 6. (A) Percentages of the clay-size fraction in sediments that formed the northern Nile Delta region during the late Holocene; nearshore coast-parallel belt
is largely sand (after Stanley and Clemente, 2014). (B) Averaged percentages of mica in the sand-size fraction in this area. (C) Averaged percentages of heavy
minerals in the sand-size fraction in the four sectors (I–IV) of the study area. WMND¼western margin of northern delta; EMND¼ eastern margin of northern
delta. Details discussed in text.
Journal of Coastal Research, Vol. 30, No. 5, 2014
912 Stanley and Clemente
these components are listed by Stanley, McRea, and Waldron
(1996, their pp. 205–424). The primary database used in the
present investigation includes the total relative percentages of
mica and of heavy minerals, which, together, in more than half
of the samples examined, account for only a relatively small
proportion (generally ,10%) of the overall sand-size fraction.
Average values were calculated separately for the total heavy
minerals as one group and total micas as a second group.
Averaged data for each of the two stratigraphic sections in all
cores are available from the second author.
Four different values for each core site include separate
average percentages for mica and heavy minerals in both the
lower and upper stratigraphic sections of each core (data
plotted in Figures 5B, 5C, 6B, and 6C). The number of samples
examined to calculate mica and heavy mineral percentages in
the Early to mid-Holocene average of core sections totals 1197
(samples examined in this stratigraphic section of each core
range from 1 to 48). The number of samples in the Upper 2 m
average of Holocene core sections totals 213 samples (samples
examined in this stratigraphic section of each core range from 1
to 8). Values of both mica (Figures 5B and 6B) and heavy
minerals (Figures 5C and 6C) are shown separately on four
maps by means of contour lines plotted at 3% intervals, from
,3% to .12%.
Each of the four mineral contour maps subdivides core sites
in the study area south of the shoreline into four areal sectors,
denoted I to IV from west to east. In sector I, mineralogical data
are averaged from five cores (S80, S82 to S85) along the
western margin of the northern delta (WMND). Sector II
includes data from 21 cores (S60 to S79, S81) from the western
delta sector to the western bank of the Nile’s Rosetta branch.
Sector III comprises data from 34 cores (S1, S2, S4, S28, S29,
S31 to S59) recovered in the delta from the eastern bank of the
Rosetta branch to the western bank of the Nile’s Damietta
branch. Sector IV includes data from 25 cores (S3, S5 to S27,
S30) east of the Damietta branch to the eastern margin of the
northern delta that extends to the NW Sinai (EMND). The four
sector boundaries were selected on the basis of major
geographic and geologic features such as the eastern limit of
carbonate-rich terrains immediately to the west of the delta
(sector I), the two modern Nile branches (Rosetta and
Damietta) in the north-central delta (sectors II and III) proper,
and the Sinai Desert, which serves as the northeastern delta’s
eastern boundary (sector IV). For comparison purposes, data
are also plotted in similar fashion for samples in the two
different Holocene sections of cores S86 and S87 recovered in
the central Nile Delta, south of the northern delta study area
near Kafr el-Zaiyat and Tanta (Figure 1B).
MICA AND HEAVY MINERALS IN TIME AND SPACEThe major observation of note in this study is the relative
reversal, over time, of areas in the northern delta along the
present coastline that have the highest mica content (mostly
biotite, with only traces of muscovite and chlorite grains) and
those with the highest heavy mineral concentrations (mineral
types listed in Frihy and Dewidar, 2003; Frihy and Komar,
1993; Frihy, Lotfy, and Komar, 1995; Naim, El Miligy, and El
Azab, 1994). The measured overall proportions of the two
mineral groups of sand size in the Early to mid-Holocene
sections (older than ~2000 YBP) averaged for 1197 samples
from the 85 core sites in the study area are as follows (Figures
5B, C): mica, 5.9% and heavy minerals, 2.7%. In contrast,
proportions of those two fractions that make up the bulk of
samples in the younger Upper 2 m averaged for 213 samples
from late Holocene sections in the 85 cores across the northern
delta differ considerably (Figures 6B, C): mica, 2.7% and heavy
minerals, 5.2%. Thus, overall, relative percentages of mica
recorded in the northern delta were reduced by more than half
from the early- and mid-Holocene to the early part of the late
Holocene, while percentages of heavy minerals in that same
period increased almost twofold.
To more specifically identify these changes in the major
mineralogical distributions in the study area, average relative
percentage data were compiled separately for the overall
Holocene and late Holocene core sequences in each of the four
regional sectors (I, II, III, IV) of the northern delta. The
following summarizes major differences in both time-related
and geographic distributions of the two mineral groups as
shown in Figures 5B, 5C, 6B, and 6C:
(1) Mica: Proportions in the Early to mid-Holocene sections
are highest in sector III (7.3%), decrease in sector II
(6.1%), and are lower still in sector IV (4.7%). Percent-
ages are considerably lower in the Upper 2 m sections
than those in the Early to mid-Holocene and decrease
from west to east, from sector II (3.8%) to sector IV
(2.1%).
(2) Heavy minerals: Proportions in Early to mid-Holocene
sections decrease from west to east, between sectors II
(4.4%) and IV (1.5%), a diminution of 2.9%. Percentages
of this component are much higher in the Upper 2 m of
core sections than those of the Early to mid-Holocene, yet
they also follow a similar eastward-decreasing trend from
sector II (7.4%) to sector IV (3.3%), a reduction of 4.1%.
Additional observations are made pertaining to the specific
distribution patterns of mica and heavy minerals relative to
specific geographic sectors (I–IV) and changes with time in the
study area:
(1) Mica in older core sections: This lower stratigraphic unit
is characterized by relatively high proportions of mica in
the Early to mid-Holocene sections that are widely
distributed in cores of sectors II to IV (Figure 5B).
Percentages of mica range from .3% to .12% from Abu
Qir Bay west of the Rosetta promontory to east of the
Suez Canal. A long (~225 km), broad arcuate belt
comprising .3% mica extends across most of sector II,
all of sector III, and most of IV; several small, linear
patches rich in mica (.12%) are recorded within this area
and oriented N-S to E-W. The area with average mica
content of .3% extends to and parallels the coast and has
a broad width that ranges from ~10 km south of the Abu
Qir Bay coast in the west, to ~25 km south of the north-
central Burullus lagoon area, and to .40 km in the
northeastern area of the Damietta promontory and
Manzala lagoon.
(2) Mica in younger core sections: Samples in the Upper 2 m
section record a much different distribution pattern, with
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 913
.3% mica distributed in two smaller areas, and with a
more modest content (Figure 6B) than in the underlying
older core sections (Figure 5B). Areas comprising moder-
ate to high values of mica (.6%) prevail along the
northern segment of the Rosetta branch south of Abu Qir
Bay, and also, to the east, but in a more localized zone
positioned 10 km or more south of Gamasa and the
Damietta promontory. The two E-W–oriented zones with
mica content .3% are well defined: A somewhat longer
western area ~110 km long and to ~25 km in width
comprises values to .12% south of the Rosetta promon-
tory, and an E-W–oriented area ~70 km in length and
~20 km in width is positioned 5–25 km south of Gamasa
and the Damietta promontory. However, most samples
examined in the younger Upper 2 m sections contain only
low percentages (,3%) of mica along the coast east of the
Rosetta promontory and south of the Burullus embay-
ment and headland; this zone of low mica percentages
extends eastward to the Damietta promontory and south
of the coast in the Gulf of Tineh.
(3) Heavy minerals in older core sections: The distribution
pattern of heavy minerals averaged for the Early to mid-
Holocene time span shows a long and very broad expanse
comprising ,3% of these minerals that extends across
most of sectors III and IV (Figure 5C). The largest area
with heavy mineral proportions ranging from 3% to .6%
is long (~140 km) and narrow (~5–15 km), positioned in
the northwestern coastal region, in sector II and western
half of sector III. This enriched zone is aligned parallel to
the coast between the west of Abu Qir headland and the
coastal sandbar that forms the northern boundary of
Burullus lagoon. Heavy mineral concentrations are
highest (.9%) in a small, localized area near what is
now the northern Rosetta branch.
(4) Heavy minerals in younger core sections: In the Upper 2
m section, the average percentage of heavy minerals has
increased to .3% in a long (.250 km), arcuate, coast-
parallel belt that extends continuously from the Abu Qir
headland in sector II eastward along the delta margin all
the way to the Gulf of Tineh in sector IV (Figure 6C).
Figure 7. Four LANSAT-5 Thematic Mapper images showing relatively recent landward incursion of sand-size fraction from the coast onto the Nile Delta.
These, collected in 1986 and 1988, are reduced in size from their original 1:100,000 scale. (A) Abu Qir Bay (AQB) and sand-covered coast between Abu Qir
headland (AQH) and eroded Rosetta promontory (RP) of the Rosetta branch (RB); IL¼Idku lagoon (East Alexandria image). (B) Linear coastal sandbar east of RP
separating Burullus lagoon (BL) from the Mediterranean; Burullus headland (BH) to upper right (Damanhur image). (C) Large sand dune fields between BH and
Gamasa (G) (Mansura image). (D) Incursion of coastal sand between G and the Damietta branch (DB) and its promontory (DP). Note series of E-directed sand-
spits along this eroded E-W promontory coast and older eroded spits and linear islands preserved in Manzala lagoon (ML) (Damietta image).
Journal of Coastal Research, Vol. 30, No. 5, 2014
914 Stanley and Clemente
Within this belt of variable width (5–25 km), values
increase northward from .3% toward the coast proper to
.9% to .12% between Abu Qir Bay and the Burullus
headland, and also in the Damietta promontory and NW
Manzala lagoon. A value of .30% heavy minerals was
measured in one core (core S17, Figure 1B) in this latter
sector.
(5) Areas of lowest mica and heavy mineral proportions: In
westernmost sector I, samples in the two Holocene
sections show only traces to minor amounts of heavy
minerals (averages of 0.7% to 1.9%), and only traces of
mica (averages of 0.1% to 0.6%). Moreover, samples
collected at core sites S86 and S87 in the central delta
have trace to minimal amounts of mica (,3.0%) and
,6.0% of heavy minerals in both Early to mid-Holocene
and Upper 2 m sections.
DISCUSSIONThe temporal and spatial variations of mica and heavy
minerals described in the previous section are not random but
are consequences of the major natural and human-influenced
factors that have controlled the nature and distributions of the
size fractions of sediment in which the two mineral groups were
deposited in the northern delta during the Holocene. These
factors have contributed to time-regional differences in the
proportions of sand, silt, and clay that constitute most sediment
fractions deposited by the Nile in different sectors of the delta
(Stanley and Clemente, 2014). Other variable factors, but not
random during the time span considered here, are the
following: thickness of sedimentary sections; rates of sediment
compaction and subsidence (Stanley and Corwin, 2013);
decreased sediment volume and fluvial discharge toward the
coast resulting from the increased role of artificial barriers; and
diminished replenishment of sediment in northern delta areas.
All have influenced, at least to some extent, the distribution of
the two mineral groups. When considered in this larger
context, especially the size fractions of sediment with which
they are associated, it is not surprising that the distribution
patterns of mica and heavy minerals recorded in Figures 5 and
6 have varied considerably during the Holocene.
Throughout most of the Holocene period encompassing the
two stratigraphic sections focused on herein, the average
percentages of clay-size (Figure 5A) and silt-size fractions in
most of the study area where the cores were recovered range
from .20% to .60%. Although proportions remained generally
similar in much of the northern delta during the late Holocene,
average percentages of these two fractions diminished consid-
erably (with ,20% combined silt and clay) near the coast. In
contrast, the nearshore zone during this time is characterized
by a well-defined coast-parallel belt with .20% to .80% sand
formed along and just south of the shoreline (Stanley and
Clemente, 2014, their Figures 4B, C). This recently formed
sand-rich zone borders the entire coast, extending from the
Alexandria region in the west to the northeastern corner of the
delta south of the Gulf of Tineh (El-Fishawi, 1985; El-Fishawi
et al., 1976). Its width ranges from 10 km in sectors I to III to
.15 km in the Gamasa region of eastern sector III and the
Damietta promontory in the western part of sector IV (Stanley
and Clemente, 2014, their Figure 4A). The coastal strip is
readily visible on satellite images, where the most extensive
stretch includes the broad belt of sand dunes west of the
Gamasa outlet (Figure 1A, sites 10–12). Other important sand-
rich areas include coastal sectors west and east of the Rosetta
mouth (site 6), the long sandbar that separates Burullus lagoon
from the sea (between sites 6 and 9), areas west and east of the
Damietta promontory (sites 13–15), and also Port Said and
adjacent northern Suez Canal (sites 17 and 18). The arcuate
belt of sand-rich and clay- and silt-poor coast-parallel terres-
trial areas is shown in greater detail in Figure 7.
The long and broad distribution of high mica proportions (to
.12%) in the northern delta’s Early to mid-Holocene sections
correlates well with mapped high percentages of clay (.60%)
that formed deposits south of the present coast (Figures 5A, B).
This pattern of mica, prevalent in these older mud-rich core
sections, is also similar to that of the narrower coast-parallel
belt rich in heavy minerals (.12%) mapped in the Upper 2 m
late Holocene core sections (Figure 6C). It is of note that this
latter enriched heavy mineral zone closely resembles the coast-
parallel distribution pattern recorded by the much higher
percentages of sand (to .80%) and low proportions of silt and
clay (both ,40%; Figures 6A, C) mapped by Stanley and
Clemente (2014, their Figure 4A). Thus, on land near the
present coast, high mica content in fine-grained sediments
prevails in the Early to mid-Holocene section, while high heavy
mineral content is more prevalent in the sand-rich Upper 2 m
late Holocene deposits.
During the two periods considered, these reversed distribu-
tion patterns are interpreted as the result of mechanical
separation of mica from heavy mineral grains by transport
processes. The two mineral groups became partially segregated
from each other and, to some extent, from the quartz and
feldspar that constitute most coarse silt- and sand-sized grains
in the northern delta. This segregation phenomenon occurred
in part due to the Nile’s altered seaward flow as the river
subdivided north of the delta apex and its water was diverted
into separate distributary channels extending to the coast
(Figure 3). The different petrological attributes of these
minerals, including size, density, and shape, contributed to
their mechanical separation as the Nile flowed northward to
the coast, and by the effects of marine processes that prevailed
at distributary Nile branch mouths and beyond in nearshore
sectors (El-Fishawi, 1985; El-Fishawi and Molnar, 1985; Frihy
and Komar, 1993; Frihy, Lotfy, and Komar, 1995; Gheith et al.,
1994).
The shoreline during the Early to mid-Holocene shifted north
of the present coast as shown in Figure 2 (phase II arrows).
Proportions of mica well to the south of the then-positioned
sandy shoreline were much higher (to .12%) at that time than
in the same area during the late Holocene (Figure 5B). The
much lower proportions of mica (,3%) in the younger Upper 2
m section along the north delta margin inland from the present
coast, from east of the Bolbitinic-Rosetta promontory to south
of the Gulf of Tineh (Figure 6B), indicate that the sediment
transport regime and depositional conditions in this area of the
delta plain changed markedly during the past ~2000 years. To
interpret these findings, it is recognized that, during much of
the Holocene to present, proportions of clay released in the
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 915
northern delta were considerably higher (to .60%) than those
of clay measured along the present Nile River in Middle and
Upper Egypt (9%), and in the central Nile Delta (11% clay,
according to Morsy, 1981; and ,20% in cores S86 and S87 as
calculated in this study; Figure 6A). The increased proportions
of mica (to .12%; Figure 6C) associated with high percentages
of clay (20% to .40%; Figure 6A) suggest a response to reduced
fluvial flow intensity and transport capacity in sectors north of
the central delta. The delta’s seaward-directed slope diminish-
es substantially from Cairo at its southern apex (elevation to
about 22 m above mean sea level [msl]) to Tanta (elevation of 8
m above msl at ~80 km north of Cairo). The slope continues to
decrease northward, especially where it merges with the near-
horizontal surface of the northern delta plain, which lies at
about 1 m elevation above msl. This latter flat region is~30 km
to ~45 km wide landward of the coast. Before emplacement of
the Aswan High Dam, Nile waters flooded annually in late
summer–early fall and spread across this broad, flat plain’s
surface by channel overbank flow. This led to enhanced
discharge of sediment in that sector with notably higher
proportions of both clay and mica.
Additional information on the causes of distribution differ-
ences of mica in time and space in the study area is provided by
examination of the separately mapped patterns of heavy
minerals. In contrast with mica, these denser minerals (to
3%–6%), especially iron-rich ones, were more prominently
released in the Early to mid-Holocene section and concentrated
primarily in a narrow coastal zone between Alexandria and the
northern Burullus headland (Figure 5C). Higher concentra-
tions (.6%–.12%) at that time are mapped only in two areas of
the Abu Qir Bay region, landward of the former mouths of the
Nile’s Canopic (El Bouseily and Frihy, 1984) and Bolbitinic
branches (Figure 3). It is of note, however, that until the late
Holocene, low proportions (,3%) of heavy minerals occur in
sectors III and IV in most of the northern region, from the
Burullus headland to the delta’s eastern margin (Figure 5C).
During this seaward progradation (phase II) period, the
muddy sand and sandy mud sediment landward of the present
coast was characterized by overall similar average size
fractions of sand (29%), silt (35%), and clay (36%) in the core
recovery area (Stanley and Clemente, 2014, their Figure 3).
This fairly even distribution of the three sediment fractions in
older Holocene sections, however, differs from those forming
the Upper 2 m core sections. In these more recent sediment
units, proportions of sand became coast-parallel, with percent-
ages increasing distinctly northward from ,20% to .80%
towards the present coast (Stanley and Clemente, 2014, their
Figure 4A). Heavy minerals (to .12%) in the coastal zone, and
especially the suite of dominant mineral species that form the
black sand deposits distributed along beaches (El-Hinnawi,
Niazi, and Samy, 1989; Frihy, Lotfy, and Komar, 1995), tend to
be of finer-grained sand size than the bulk of light mineral
grains, such as quartz and feldspar, with which they are
associated. It has been shown that fine-grained beach sands
that consist of large proportions of total heavy minerals tend to
prevail where the coastline sector is subject to greater erosional
intensity and sediment reworking (Frihy and Dewidar, 2003).
While effects of such size sorting are recorded by deposits
displaced by marine processes along the delta coast (Frihy and
Komar, 1993; Frihy and Lotfy, 1994), these phenomena, also
probable along the Nile’s fluvial transport paths between
African source areas and northern delta environments, have
yet to be clearly defined.
High proportions of mica in fine-grained deposits of older core
sections near the coast (Figure 5B) and those of heavy minerals
in sand-rich units in the younger sections near the coast
(Figure 6C) record the close relation among the delta’s
shoreline position, dominant sediment-size fraction released,
and distribution of the two mineral groups. High percentages of
mica in Early to mid-Holocene sections parallel to the present
coast indicate that they were deposited primarily with fine-
grained sediment fractions during phase II and were preserved
in a zone of minimal winnowing well to the south of the former
coastline position at that time (Figure 2). By the end of phase II
and beginning of the late Holocene, much of the delta’s
coastline appears to have been positioned approximately 10
km to 15 km and perhaps locally farther north of the present
shore. This distance estimate is based on two independent sets
of observation: (1) the minimal northern position of sand-rich
deposits on the adjacent inner shelf as mapped by Coleman et
al. (1981, their Figure 4), El-Fishawi et al. (1976, their Figure
4), and Summerhayes et al. (1978, their Figure 6); and (2)
calculation of relative sea-level rise that takes into account
rates of both eustatic rise and lowering of the delta plain
surface. The first item (1) indicates a northern average seaward
position off the Nile shelf delineated by the present approxi-
mate seafloor depth of about 20 m (Figure 2, phase II arrows).
The second item (2) is based on the calculation involving a
modest rate of world sea-level rise (~1.0–1.5 mm/y) during
much of the past~2000 years (Lambeck and Purcell, 2005) plus
the rate of land subsidence in the northern core recovery area of
the delta plain near the coast. The rates of land lowering range
from 3.7 mm/y west of the Rosetta branch, to 7.7 mm/y between
the Rosetta and Damietta branches, and to 8.4 mm/y east of the
Damietta branch (Stanley and Corwin, 2013; ARC in Figure
5A). An average relative sea-level rise rate to 1 cm/y would
have accounted for as much as 20 m of delta plain surface
lowering beneath sea level during the past 2000 years to
present.
A relative sea-level rise of~1 cm/y, and position of the former
shoreline, now subsided to~20 m at a distance of about 10 to 15
km north of the modern coast, would have resulted in average
horizontal rates of landward retreat of the coastline ranging
from approximately 5 m/y to 7.5 m/y from ~2000 YBP at the
end of phase II to the present time (Figure 2, phase IIIa
arrows). Shoreline retreat rates on the order of 2 m/y to 3 m/y
have been estimated in Abu Qir Bay between the offshore
position of now-submerged Greek and Roman centers (Her-
acleion and East Canopus) and the present coast to the south
(Goddio, 2007; Stanley, 2007). These landward incursion rates
approximate those of measured shoreline erosion recorded
along some coastal sectors as recently as the early to mid–
twentieth century, such as at the Burullus headland (cutback
rates of ~5 m/y) prior to recent emplacement of protection
structures at that location (Frihy and Deabes, 2011). It is also
possible for landward retreat to have exceeded these rates at
times when periodic deep-seated readjustments of strata
additionally lowered the delta surface, as was likely in the
Journal of Coastal Research, Vol. 30, No. 5, 2014
916 Stanley and Clemente
sector underlying the Manzala lagoon area in the northeastern
delta (Stanley, 1988, 1990).
CONCLUSIONS AND RAMIFICATIONSThe relationship among mica, heavy minerals, and the
dominant grain-size fractions (sand, silt, or clay) that form
the Holocene deposits in which they occur at and landward of
the coast shows that recorded distributions of the two mineral
groups are able to help identify the Nile Delta’s former coastal
positions. We propose that such mineral/sediment grain-size
associations could potentially also serve as useful indicators to
measure ongoing shoreline changes and perhaps help predict
future displacements.
Of interest in this respect is an examination of sand-rich
nearshore and onshore deposits that have low amounts of mica
(,3%) and a significant heavy mineral content (.3%) that have
shifted landward to south of the delta’s coast during the past
few centuries (Figures 6B, C). Satellite images, such as those of
LANSAT-5 Thematic Mapper (bands 7, 4, 3, 5) acquired in
1985–88 (IWACO-RIGW, 1990, scale 1:100,000), show in detail
the important surficial sand deposits that presently form broad
beaches, lagoon bar barriers, and dunes that have advanced
considerable distances onto the delta plain (Figure 7). Of note
are the present major incursions of sand onto the delta surface.
These have formed the following: broad beaches and dunes
along the eastern third of Abu Qir Bay, reaching inland to
nearly 10 km (Figure 7A); low straight sandbar separating
northern Burullus lagoon from the Mediterranean shoreline (to
5.5 km wide; Figure 7B); high and particularly wide broad sand
dune fields southeast of the Burullus headland and the town of
Gamasa (to 11 km inland; Figure 7C); wide beaches and dune
fields between the Gamasa coast and Damietta promontory (to
5 km wide; Figure 7D); and sand-rich area along the northern
Suez Canal between the Port Said coast and ~10 km to the
south (Figure 1A). Once on land, there are few morphological
relief barriers to retard the sediment’s advance across the low-
lying northern third of the delta plain, which ranges to little
more than 1 m above msl over much of its surface.
Applying the earlier cited averaged coastline retreat rates of
~5 m/y to 7.5 m/y from about 2000 years ago to the present
(phase IIIa) would have produced sand incursion of only 1 km
to 1.5 km over the northern delta, and not the observed 5 km to
11 km cited earlier. Until about an estimated 200 years ago,
displacement of sediment from the foreshore onto back-beach
settings was largely due to wave-current transport and
powerful periodic wave surges. Once ashore, the sand-rich
deposits were displaced further inland by wind onto low-lying
agricultural fields and wetlands (Figure 7). By the early to mid-
1800s, under the rule of Muhammad Ali, Egypt began a
program to emplace large-scale artificial structures such as
barrages capable of altering the Nile’s flow. In the two centuries
following these early modifications, the Nile’s flow pattern has
been substantially altered, resulting in more rapid rates of
landward advance by the sea. For example, a 5 km incursion
landward during the past 200 years would indicate a
southward migration of ~25 m/y. Such an increased landward
advance for extensive distances would likely have involved the
role of several processes in addition to natural coastal erosion
by wave currents and storm surges.
Additional significant factors that have fostered accelerated
entry by the sea onto the coastal margin likely include the
following:
(1) the marked decrease in sediment replenishment in
coastal settings, especially since the closure of the Aswan
High Dam in 1964–65 to establish a constant year-long
flow of the Nile;
(2) emplacement of barrages in the northern delta, which
now severely diminish water and sediment discharge to
the sea via the Rosetta and Damietta branches;
Figure 8. Schematic depicting potential landward shoreline migration southward across the delta plain surface to 1 m elevation above mean sea level (msl) from
present time over the next 100 to 130 years (phase IIIb, shown by arrows), which could result from continued relative sea-level rise. Also shown is the past
landward saline water incursion from the coastal margin inland, with a trend from salt-rich to brackish to freshwater inland (modified after Kashef, 1983).
Salinity in groundwater has continued to increase southward during the past three decades and is now affecting ever-enlarged agricultural and aquacultural
areas of the delta’s northern to central sectors.
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 917
(3) the ever-increasing density of delta canal systems that
trap Nile water and sediment displaced north of Cairo
and allow only a much-reduced discharge to reach near-
coastal environments; and
(4) the artificial removal of sand caused by ongoing extensive
quarrying of this sediment from some coastal areas that,
in effect, removes natural high-relief features (some to
~10 m) such as dunes (migrating barchans and other
types), which would otherwise serve as temporary
barriers to retard further inland marine advance (El-
Banna, 2004; Fazaa and Al-Youm Al-Sabi, 2012).
The recent marked reduction of sediment provided to the
coastal-nearshore system can no longer offset the effects of
delta plain subsidence (to 8 mm/y) and of sea-level rise of ~2
mm/y or more, which continue to produce a rate of relative sea-
level rise of ~1 cm/y. These activities, in conjunction with the
other earlier-cited processes that affect the delta’s margin, will
alter and displace the shoreline position further inland on a
near-continuous basis. Effects of erosional cutback, in conjunc-
tion with relative sea-level rise, will become even more
problematic should a eustatic rise in sea level increase from
20 cm to possibly as high as 100 cm by the end of this century,
as has been projected by some climate change experts and
panels. It is not surprising that the Intergovernmental Panel
on Climate Change (IPCC, 2008) has cited the Nile Delta as one
of the world’s most vulnerable coastal sectors.
Based on observations of the two mineral groups presented in
this study, it is expected that percentages of mica will decrease
in younger sediment core sections, while those of heavy
minerals in these same sections are expected to increase south
of the shore as the delta’s coastline retreats landward.
Associated with this evolution is continued, if not increased,
seawater flooding onto the low-lying plain and wetlands, with
saline groundwater migration extending farther south of the
coast as the delta surface subsides relative to sea level. This
increased groundwater salinization will reduce agricultural
productivity and further decrease arable areas of the delta,
which accounts for ~63% of Egypt’s total cultivated land
(Mabrouk et al., 2013). The persisting problems of saltwater
intrusion (Figure 8) coupled with already considerably de-
creased availability of freshwater from the Nile, rainfall, and
groundwater are inevitably affecting the already densely
populated delta towns and countryside (Dawoud, 2004; El-
Asmar, Hereher, and El-Kafrawy, 2012; Kashef, 1983; Mab-
rouk et al., 2013; Sestini, 1992).
In effect, the modern Nile Delta is no longer evolving as a
natural physical, chemical, and biological fluvio-marine system
but, rather, is now viewed as a relict organic-rich depocenter
that is now in its destruction phase, lacking in freshwater,
increasingly polluted, and decreasing area due to a landward-
retreating shoreline (Stanley and Warne, 1998). Without large-
scale, well-planned protection measures, among them emplace-
ment of a series of protective megastructures along much of the
coast, continued relative sea-level rise could submerge the
surface by about 1 m of seawater within the next 100 to 185
years (Stanley and Corwin, 2013; Figure 8). The coastline’s
form during such a landward retreat would likely become less
arcuate than at present. This progressively straighter elongate
shore cut back by marine erosional processes would also
preserve fewer promontories and headlands. Moreover, if
flooded by the sea, only the upper parts of terrains with
present elevations of 1 m above msl will remain visible as small
islands resembling the present ones in Burullus and Manzala
lagoons (Figures 7B, D). Time is of the essence if the most
vulnerable zone comprising the northern third of the delta’s
22,000 km2 area is to be effectively protected.
In summary, we suggest that the distribution patterns of
mica and heavy minerals recovered in surficial sediments and
short core sections can now be mapped on the northern delta
plain to better define altered positions of the coastline and to
measure its potential landward advance during this critical
stage of the depocenter’s evolution (phase IIIb, Figure 8).
Measurements of the two mineral groups could be made
periodically along a series of transects oriented normal to the
shore, and these compilations can then be compared with
records of coastline positions and elevations of the northern
delta’s surface recorded by remote sensing and geographic
information system (GIS) techniques (Becker and Sultan, 2009;
El Nahry, Ibraheim, and El Baroudy, 2008; White and El
Asmar, 1999). Such coordinated multidisciplinary surveys of
the Nile Delta, made in a systematic and regularly scheduled
manner, would serve to accurately measure rates of coastal
subsidence as well as of landward incursions by the sea at
present and in the years ahead.
ACKNOWLEDGMENTSWe thank the National Museum of Natural History,
Smithsonian Institution, for support during preparation of
this study. We also express appreciation to Drs. C. Grifa and
M.R. Senatore and Ms. K.A. Corwin for their thoughtful
reviews of an earlier draft of this article.
LITERATURE CITEDAbo Zed, A.I., 2007. Effects of waves and currents on the siltation
problem of Damietta harbor, Nile Delta coast, Egypt. Mediterra-nean Marine Science, 8(2), 33–47.
Arbouille, D. and Stanley, J.-D., 1991. Late Quaternary evolution ofthe Burullus lagoon region, north-central Nile Delta, Egypt.Marine Geology, 99(1–2), 45–66.
Baines, J. and Malek, J. 1985. Atlas of Ancient Egypt. New York:Facts on File Publications, 240p.
Becker, R.H. and Sultan, M., 2009. Land subsidence in the Nile Delta:Inferences from radar interferometry. The Holocene, 19(6), 949–954.
Bernhardt, C.E.; Horton, B.P., and Stanley, J.-D., 2012. Nile Deltavegetation response to Holocene climate variability. Geology, 40(7),615–618.
Bohannon, J., 2010. The Nile Delta’s sinking future: Climate changeand damming the Nile threaten Egypt’s agricultural oasis. Science,327(5972), 1444–1447.
Broussard, N.L. (ed.), 1975. Deltas, Models for Exploration. Houston,Texas: Houston Geological Society, 555p.
Bustamante-Santa Cruz, L., 1995. Contribution to the petrographicalcharacterization of Quaternary Nile alluvia at the Egyptian Qenaarea (preliminary notice). Neues Jahrbuch fur Mineralogie, 11,508–512.
Butzer, K.W., 1976. Early Hydraulic Civilization in Egypt: A Study inCultural Ecology. Chicago, Illinois: The University of ChicagoPress, 134p.
Chen, Z.; Warne, A.G., and Stanley, J.-D., 1992. Late Quaternaryevolution of the northwestern Nile Delta between the Rosetta
Journal of Coastal Research, Vol. 30, No. 5, 2014
918 Stanley and Clemente
promontory and Alexandria, Egypt. Journal of Coastal Research,8(3), 527–561.
CIESIN (Center for International Earth Science Information Net-work), 2009. Egypt Population Density and Low Elevation CoastalZones. New York: Columbia University. http://sedac.ciesin.columbia.edu/gpw/maps/lecz/Egypt_Alexandria_population_densi-ty_and_lecz.jpg.
Coleman, J.M., 1982. Deltas: Processes of Deposition & Models forExploration. Boston: International Human Resources DevelopmentCorporation, 124p.
Coleman, J.M.; Roberts, H.H.; Murray, S.P., and Salama, M., 1981.Morphology and dynamic sedimentology of the eastern Nile Deltashelf. Marine Geology, 42(1–4), 301–326.
Coutellier, V. and Stanley, J.-D., 1987. Late Quaternary stratigraphyand paleogeography of the eastern Nile delta, Egypt. MarineGeology, 77(3–4), 257–275.
Curray, J.R., 1960. Sediments and history of Holocene transgression,continental shelf, northwest Gulf of Mexico. In: Shepard, F.P.;Phleger, F.B., and Van Andel, T.H. (eds.), Recent Sediments,Northwest Gulf of Mexico. Tulsa, Oklahoma: American Associationof Petroleum Geologists, pp. 221–266.
Dawoud, A.M., 2004. Design of national groundwater qualitymonitoring network in Egypt. Journal of Environmental Monitor-ing and Assessment, 96(1–3), 99–118.
El Askary, M.A. and Frihy, O.E., 1986. Depositional phases of Rosettaand Damietta promontories on the Nile Delta coast. Journal ofAfrican Earth Sciences, 5(6), 627–633.
El-Asmar, H.M.; Hereher, M.E., and El-Kafrawy, S.B., 2012. Threatsfacing lagoons along the north coast of the Nile Delta, Egypt.International Journal of Remote Sensing Applications, 2(2), 24–29.
El-Banna, N.N., 2004. Nature and human impact on Nile Deltacoastal sand dunes, Egypt. Environmental Geology, 45(5), 690–695.
El Bouseily, A.M. and Frihy, O.E., 1984. Textural and mineralogicalevidence denoting the position of the mouth of the old Canopic Nilebranch on the Mediterranean coast, Egypt. Journal of AfricanEarth Sciences, 2(2), 103–107.
El Din, S.H.S., 1974. Longshore sand transport in the surf zone alongthe Mediterranean Egyptian coast. Limnology and Oceanography,19(2), 182–189.
El Din, S.H.S., 1977. Effect of the Aswan High Dam on the Nile floodand on the estuarine and coastal circulation pattern along theMediterranean Egyptian coast. Limnology and Oceanography,22(2), 194–207.
El Fattah, T.A. and Frihy, O.E., 1988. Magnetic indications of theposition of the mouth of the old Canopic branch on thenorthwestern Nile Delta of Egypt. Journal of Coastal Research,4(3), 483–488.
El-Fishawi, N.M., 1985. Textural characteristics of the Nile Deltacoastal sands: An application in reconstructing the depositionalenvironments. Acta Mineralogica-Petrographica, Szeged, 27, 71–88.
El-Fishawi, N.M. and Molnar, B., 1985. Mineralogical relationshipsbetween the Nile Delta coastal sands. Acta Mineralogica-Petrog-raphica, Szeged, 27, 89–100.
El-Fishawi, N.M.; Fahmy, M.; Sestini, G., and Shawki, A., 1976.Grain size of the Nile Delta beach sands. In: Anwar, Y. (ed.),Proceedings of the Seminar on Nile Delta Sedimentology. Alexan-dria, Egypt: UNDP/UNESCO, pp. 79–94.
El-Hinnawi, E.; Niazi, E., and Samy, Y., 1989. Characteristics of someheavy minerals from Egyptian black sands. Journal of IslamicAcademy of Sciences, 2(2), 147–152.
El Nahry, A.H.; Ibraheim, M.M., and El Baroudy, A.A., 2008.Assessment of soil degradation in the northern part of Nile Delta,Egypt, using remote sensing and GIS techniques. EgyptianJournal of Remote Sensing & Space Sciences, 11, 139–154.
El-Sayed, M.K., 1996. Rising sea-level and subsidence of the northernNile Delta: A case study. In: Milliman, J.D. and Haq, B.U. (eds.),Sea-Level Rise and Coastal Subsidence. Dordrecht, The Nether-lands: Kluwer Academic Publishers, pp. 215–233.
Fazaa, R. and Al-Youm Al-Sabi, 2012. Black Sand Smuggling in theNile Delta. Arab Reporters for Investigative Journalism (ARIJ).http://arij.net/en/black-sand-smuggling-nile-delta.
Foucault, A. and Stanley, J.-D., 1989. Late Quaternary palaeoclimaticoscillations in East Africa recorded by heavy minerals in the Niledelta. Nature, 339(6219), 44–46.
Frihy, O.E., 1992a. Holocene sea level changes at the Nile Deltacoastal zone of Egypt. GeoJournal, 26(3), 389–394.
Frihy, O.E., 1992b. Sea-level rise and shoreline retreat of the NileDelta promontories, Egypt. Natural Hazards, 5(1), 65–81.
Frihy, O.E. and Deabes, E.A., 2011. Beach and nearshore morphody-namics of the central-bulge of the Nile Delta coast, Egypt.International Journal of Environmental Protection, 1(2), 33–46.
Frihy, O.E.; Debes, E.A., and El Sayed, W.R., 2003. Processesreshaping the Nile Delta promontories of Egypt: Pre- and post-protection. Geomorphology, 53(3/4), 263–279.
Frihy, O.E. and Dewidar, K.M., 2003. Patterns of erosion/sedimenta-tion, heavy mineral concentration and grain size to interpretboundaries of littoral sub-cells of the Nile Delta, Egypt. MarineGeology, 199(1), 27–43.
Frihy, O.E. and Gamai, I.H., 1991. Facies analysis of Nile Deltacontinental shelf sediments off Egypt. Netherlands Journal of SeaResearch, 27(2), 165–171.
Frihy, O.E. and Komar, P.D., 1993. Long-term shoreline changes andthe concentration of heavy minerals in beach sands of the NileDelta, Egypt. Marine Geology, 115(3–4), 253–261.
Frihy, O.E. and Lotfy, M.F., 1994. Mineralogic evidence for theremnant Sebennitic promontory on the continental shelf off thecentral Nile Delta. Marine Geology, 117(1–4), 187–194.
Frihy, O.E. and Lotfy, M.F., 1997. Shoreline changes and beach-sandsorting along the northern Sinai coast of Egypt. Geo-MarineLetters, 17(2), 140–146.
Frihy, O.E.; Lotfy, M.F., and Komar, P.D., 1995. Spatial variations inheavy minerals and patterns of sediment sorting along the NileDelta, Egypt. Sedimentary Geology, 97(1–2), 33–41.
Frihy, O.E.; Nasr, S.M.; El Hattab, M.M., and El Raey, M., 1994.Remote sensing of beach erosion along the Rosetta promontory,northwestern Nile delta, Egypt. International Journal of RemoteSensing, 15(8), 1649–1660.
Garzanti, E.; Ando, S.; Vezzoli, G.; Megid, A.A.A.M., and El Kammar,A., 2006. Petrology of Nile River sands (Ethiopia and Sudan):Sediment budgets and erosion patterns. Earth and PlanetaryScience Letters, 252(3–4), 327–341.
Gheith, M.A.; Abd-Alla, M.A.; El-Fayoumy, I.F., and Toubar, N., 1994.Mineralogy as an indicator of various coastal environments alongBurullus area, north Nile Delta, Egypt. Journal of the KingAbdulaziz University: Marine Sciences, 5(1), 73–88.
Goddio, F., 2007. The Topography and Excavation of Heracleion–Thonis and East Canopus (1996–2006). Oxford: Oxford Centre forMaritime Archaeology, Monograph 1, Institute of Archaeology,136p.
Google Earth, 2013. Google Earth image. http://www.google.com/earth/.
Guerzoni, S. and Chester, R., eds., 1996. The Impact of Desert Dustacross the Mediterranean. Dordrecht, Netherlands: Kluwer Aca-demic Publishers, 389p.
Hassan, F.A., 1976. Heavy minerals and the evolution of the modernNile. Quaternary Research, 6(3), 425–444.
Hassouba, A.M.B.H., 1995. Quaternary sediments from the coastalplain of northwestern Egypt (from Alexandria to El Omayid).Carbonates and Evaporites, 10(1), 8–44.
Herodotus, ca. 484–425 BC. The History (Translation by D. Grene,1987). Chicago and London: The University of Chicago Press, 699p.
Inman, D.L. and Jenkins, S.A., 1984. The Nile littoral cell and man’simpact on the coastal littoral zone in the SE Mediterranean.Proceedings, of the 17th International Coastal Engineering Con-ference (Sydney: ASCE), pp. 1600–1617.
IPCC (Intergovernmental Panel on Climate Change), 2008. In: Bates,B.C.; Kundzewicz, Z.W.; Wu, S., and Palutifkof, J.P. (eds.), ClimateChange and Water Technical Paper VI. Geneva: IPCC Secretariat,210p.
IWACO-RIGW (Dutch Consultants for Water and Environment-Egyptian Research Institute for Groundwater), 1990. LANSATThematic Mapper for Hydrological Mapping in Egypt. Delft,
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 919
Netherlands: Netherlands Remote Sensing Board, Survey Depart-ment. (Numerous individual images, scale 1:100,000).
Kashef, A.I., 1983. Salt water intrusion in the Nile Delta. Ground-water, 21(2), 160–167.
Khatita, A.M.A., 2011. Assessment of Soil and Sediment Contamina-tion in the Middle Nile Delta Area (Egypt)—Geo-EnvironmentalStudy Using Combined Sedimentological, Geophysical and Geo-chemical Methods. Erlangen-Nurnberg, Germany: Friedrich-Alex-ander University, Doctoral thesis, 214p.
Kropelin, S.; Verschuren, D.; Lezine, A.-M.; Eggermont, H.; Cocquyt,C.; Francus, P.; Cazet, J.-P.; Fagot, M.; Rumes, B.; Russell, J.M.;Darius, F.; Conley, D.J.; Schuster, M.; von Suchodoletz, H., andEngstrom, D.R., 2008. Climate-driven ecosystem succession in theSahara: The past 6000 years. Science, 320(5877), 765–768.
Lambeck, K. and A. Purcell, 2005. Sea-level change in the Mediter-ranean Sea since the LGM: Model predictions for tectonically-stable areas. Quaternary Science Reviews, 24(18–19), 1969–1988.
Mabrouk, M.B.; Jonoski, A.; Solomatine, D., and Uhlenbrook, S.,2013. A review of seawater intrusion in the Nile Delta groundwatersystem—The basis for assessing impacts due to climate changesand water resources development. Hydrology and Earth SystemSciences, 10, 10873–10911.
Marriner, N.; Flaux, C.; Kaniewski, D.; Morhange, C.; Leduc, G.;Moron, V.; Chen, Z.; Gasse, F.; Empereur, J.-Y., and Stanley, J.-D.,2012. ITCZ and ENSO-like pacing of Nile Delta hydro-geomor-phology during the Holocene. Quaternary Science Reviews, 45(8),73–84.
Morsy, A.M., 1981. Grain size analysis and clay minerals of the Nilebottom sediments, Egypt. Mineralogia Polonica, 12(1), 15–24.
Muhs, D.R.; Roskin, J.; Tsoar, H.; Skipp, G.; Budahn, J.R.; Sneh, A.;Porat, N.; Stanley, J.-D.; Katra, I., and Blumberg, D.G., 2013.Origin of the Sinai-Negev erg, Egypt and Israel: Mineralogical andgeochemical evidence for the importance of the Nile and sea levelhistory. Quaternary Science Reviews, 69(June), 28–48.
Naim, G.M.; El Miligy, A.E.M.T., and El Azab, A.A., 1994. Black SandAssessment. Cairo, Egypt: The Egyptian Geological Survey andMining Authority, Paper No. 67, 48p.
Pettijohn, F.J.; Potter, P.E., and Siever, R., 1973. Sand andSandstone. New York: Springer-Verlag, 618p.
Philip, G., 1976. Morphology of the Mediterranean coastal areabetween Rosetta and Sallum, Egypt. In: Anwar, Y. (ed.), UNDP/UNESCO Proceedings of the Seminar of Nile Delta Sedimentology,Alexandria. Cairo, Egypt: Academy of Scientific Research andTechnology, pp. 25–32.
Pomerancblum, M., 1966. The distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israel. Journal of Sedimentary Petrology, 36(1),162–174.
Ross, D.A.; Uchupi, E.; Summerhayes, C.P.; Koelsch, D.E., and ElShazly, E.M., 1978. Sedimentation and structure of the Nile coneand Levant platform area. In: Stanley, J.-D. and Kelling, G. (eds.),Sedimentation in Submarine Canyons, Fans, and Trenches.Stroudsburg, Pennsylvania: Dowden, Hutchinson and Ross, Inc.,pp. 261–275.
Said, R., 1981. The Geological Evolution of the River Nile. New York:Springer-Verlag, 151p.
Said, R., 1993. The River Nile: Geology, Hydrology, and Utilization.Tarrytown, New York: Pergamon Press, 320p.
Scruton, P.C., 1960. Delta building and the deltaic sequence. In:Shepard, F.P.; Phleger, F.B., and Van Andel, T.H. (eds.), RecentSediments, Northwest Gulf of Mexico. Tulsa, Oklahoma: AmericanAssociation of Petroleum Geologists, pp. 82–102.
Sestini, G., 1989. Nile Delta depositional environments and geologicalhistory. In: Whateley, K.G. and Pikering, K.T. (eds.), Deltas. Sitesand Traps for Fossil Fuels. London, UK: Geological Society, SpecialPublication 41, pp. 99–127.
Sestini, G., 1992. Implications of climatic changes for the Nile Delta.In: Jeftic, L.; Milliman, J.D., and Sestini, G. (eds.), ClimaticChange and the Mediterranean: Environmental and SocietalImpacts of Climatic Change and Sea-level Rise in the Mediterra-nean Region. London, UK: Edward Arnold, pp. 535–601.
Shukri, N.M., 1950. The mineralogy of some Nile sediments.Quarterly Journal of the Geological Society, 105(4), 511–534.
Shukri, N.M., 1951. Mineral analysis tables of some Nile sediments.Bulletin de l’Institut Fouad I du Desert, I(2), 39–67.
Shukri, N.M. and Azer, N., 1952. The mineralogy of Pliocene andmore recent sediments in the Faiyum. Bulletin de l’Institut Fouad IDu Desert, II(1), 11–39.
Shukri, N.M. and Philip, G., 1956. The geology of the Mediterraneancoast between Rosetta and Bardia: Part III: Pleistocene sediments:Mineral analysis. Bulletin de l’Institut d’Egypte, 37(2), 445–463.
Sivan, D.; Wdowinski, S.; Lambeck, K.; Galili, E., and Raban, A.,2001. Holocene sea-level changes along the Mediterranean coast ofIsrael, based on archaeological observations and numerical model.Palaeogeography, Palaeoclimatology, Palaeoecology, 167(1–2), 101–117.
Stanley, J.-D., 1988. Subsidence in the northeastern Nile Delta: Rapidrates, possible causes and consequences. Science, 240(4851), 497–500.
Stanley, J.-D., 1989. Sediment transport on the coast and shelfbetween the Nile Delta and Israeli margin as determined by heavyminerals. Journal of Coastal Research, 5(4), 813–828.
Stanley, J.-D., 1990. Recent subsidence and northeast tilting of theNile Delta, Egypt. Marine Geology, 94(1–2), 147–154.
Stanley, J.-D. (ed.), 2007. Underwater Archaeology in the CanopicRegion in Egypt. Geoarchaeology. Oxford, UK: Oxford Centre forMaritime Archaeology, Institute of Archaeology, Monograph 2,128p.
Stanley, J.-D. and Clemente, P.L., 2014. Clay distributions, grainsizes, sediment thicknesses, and compaction rates to interpretsubsidence in Egypt’s northern Nile Delta. Journal of CoastalResearch, 30(1), 88–101.
Stanley, J.-D. and Corwin, K.A., 2013. Measuring strata thicknessesin cores to assess recent sediment compaction and subsidence ofEgypt’s Nile Delta coastal margin. Journal of Coastal Research,29(3), 657–670.
Stanley, J.-D.; McRea, J.E., Jr., and Waldron, J.C., 1996. Nile Deltadrill core and sample database for 1985–1994: MediterraneanBasin (MEDIBA) Program. Washington, D.C.: Smithsonian Insti-tution Press, Smithsonian Contributions to the Marine Sciences 37,428p.
Stanley, J.-D.; Sheng, H., and Pan, Y., 1988. Heavy minerals andprovenance of late Quaternary sands, eastern Nile delta. Journalof African Earth Sciences, 7(4), 735–741.
Stanley, J.-D. and Toscano, M.A., 2009. Ancient archaeological sitesburied and submerged along Egypt’s Nile Delta coast: Gauges ofHolocene delta margin subsidence. Journal of Coastal Research,25(1), 158–170.
Stanley, J.-D. and Warne, A.G., 1993. Nile Delta: Recent geologicalevolution and human impact. Science, 260(5108), 628–634.
Stanley, J.-D. and Warne, A.G., 1998. Nile Delta in its destructionphase. Journal of Coastal Research, 14(3), 794–825.
Stanley, J.-D.; Warne, A.G.; Davis, H.R.; Bernasconi, M.P., and Chen,Z., 1992. Nile Delta: The late Quaternary north-central Nile Deltafrom Manzala to Burullus lagoons, Egypt. National GeographicResearch and Exploration, 8(1), 22–51.
Stanley, J.-D. and Wingerath, J.G., 1996. Clay mineral distributionsto interpret Nile cell provenance and dispersal: I. Lower river Nileto delta sector. Journal of Coastal Research, 12(4), 911–929.
Summerhayes, C.P.; Sestini, G.; Misdorp, R., and Marks, N., 1978.Nile Delta: Nature and evolution of continental shelf sediments.Marine Geology, 27(1–2), 43–65.
Toussoun, O., 1922. Memoire sur les Anciennes Branches du Nil.Cairo, Egypt: Societe Geographique d’Egypte, Memoire 4, 212p.
UNDP (United Nations Development Programme and Government ofEgypt), 2009. Adaptation to Climate Change in the Nile Deltathrough Integrated Coastal Zone Management. New York: UnitedNations Development Programme, Project Document 3748, 124p.
UNDP/UNESCO (United Nations Development Programme andGovernment of Egypt/United Nations Educational, Scientific, andCultural Organization), 1976. Proceedings of the Seminar of NileDelta Sedimentology, Alexandria. Cairo, Egypt: Academy ofScientific Research and Technology, 257p.
Journal of Coastal Research, Vol. 30, No. 5, 2014
920 Stanley and Clemente
UNDP/UNESCO, 1977. Proceedings of the Seminar on Nile Delta
Coastal Processes with Special Emphasis on Hydrodynamical
Aspects. Alexandria, Egypt: Egyptian Academy of Scientific
Research and Technology, 624p.
UNDP/UNESCO, 1978. Arab Republic of Egypt: Coastal Protection
Studies, Project Findings and Recommendations. Paris, France:
UNDP/UNESCO, UNDP/EGY/73/063 Final Report. FNR/SC/OSP/
78/230, 483p.
Warne, A.G. and Stanley, J.-D., 1993a. Archaeology to refine
Holocene subsidence rates along the Nile Delta margin, Egypt.
Geology, 21(8), 715–718.
Warne, A.G. and Stanley, J.-D., 1993b. Late Quaternary evolution of
the northwest Nile Delta and adjacent coast in the Alexandria
region, Egypt. Journal of Coastal Research, 9(1), 26–64.
Waterbury, J., 1979. Hydropolitics of the Nile Valley. Syracuse, NewYork: Syracuse University Press, 301p.
White, K. and El Asmar, H.M., 1999. Monitoring changing position ofcoastlines using Thematic Mapper imagery, an example from theNile Delta. Geomorphology, 29(1–2), 93–105.
Woppelman, G. and Marcos, M., 2012. Coastal sea level rise insouthern Europe and the nonclimate contribution of vertical landmotion. Journal of Geophysical Research, 117(C1), 1–14.
Wright, L.D. and Coleman, J.M., 1973. Variations in morphology ofmajor river deltas as functions of ocean wave and river dischargeregimes. Bulletin of the American Association of PetroleumGeologists, 57(2), 370–398.
Zviely, D.; Kit, E., and Klein, M., 2007. Longshore sand transportestimates along the Mediterranean coast of Israel in the Holocene.Marine Geology, 238(1–4), 61–73.
Journal of Coastal Research, Vol. 30, No. 5, 2014
Using Mica and Heavy Minerals to Map Nile Delta Coastline 921