History Forum / General / Archaeology / March 2006

<snip>

 Eric:
 Check out this Geotimes article:

http://www.agiweb.org/geotimes/apr05/feature_NileFloods.html

"A team of scientists, led by Jean-Daniel Stanley of the Smithsonian
Institution, has now substantiated this explanation, by analyzing
sediments obtained from drilling the subsurface sediments of the Delta.
The geologists noticed a distinctly thin layer of reddish-brown silt
dating between 2250 to 2050 B.C., coincident with the time of the
collapse of the Old Kingdom. The layer indicated that the delta
floodplain dried up for a long period of time, allowing reddish-brown
iron oxides to accumulate at the surface. The scientists also detected
a significant change in the ratio of strontium isotopes, which they
interpret as evidence for a decline of rainfall in Ethiopia, the main
source of Nile floods."

 The source article:

Stanley, Jean-Daniel; Krom, Michael D; Cliff, Robert A; Woodward, Jamie
C
Short contribution; Nile flow failure at the end of the Old Kingdom,
Egypt; strontium isotopic and petrologic evidence
Geoarchaeology, vol.18, no.3, pp.395-402, Mar 2003

http://www3.interscience.wiley.com/cgi-bin/fulltext/102531618/PDFSTART

Abstract
Strontium isotopic and petrologic information, obtained from sediment
cores collected in the Nile delta of Egypt, indicate that paleoclimatic
and Nile baseflow conditions changed considerably from about 4200 to
4000 cal yr B.P. in the Nile basin. Our study records a higher
proportion of White Nile sediment transported during the annual floods
at ca. 6100 cal yr B.P. than towards 4200 cal yr B.P., at which time
suspended sediment from the Blue Nile formed a significantly larger
fraction of the total load. This resulted from a decrease in vegetative
cover and an increase in erosion rate accompanying the marked decline
in rainfall. These new geoscience data indicate major changes in annual
flooding and baseflow of the river Nile, marked short-term
paleoclimatic-related events that may in part have led to the collapse
of the Old Kingdom. © 2003 Wiley Periodicals, Inc.

"A PALEOCLIMATIC CAUSE FOR THE COLLAPSE OF THE
OLD KINGDOM
Historical records show that the Old Kingdom in Egypt continued
successfully
until 2160 B.C. (4160 cal yr B.P.; Kitchen, 1991) when it quite
suddenly
collapsed into anarchy (Bell, 1971). It has been suggested that this
was due,
in large part, to catastrophic failure of the annual Nile flood for a
period of 30
years. This was apparently followed by a second, shorter 10-year period
of
drought starting in 2020 B.C. (4020 cal yr B.P.). At this time, it was
written in
the inscription of Ankhtifi that:
All of Upper Egypt was dying of hunger, to such a degree that
everyone had come to eating his children. . . .The entire country
had become like a starved (?) grasshopper, with people going to
the north and to the south (in search of grain) . . . ( Bell, 1971, p.
9)
Bell (1971) argues that the use of the Egyptian symbol tzw, in this and
other
texts, represents an image of exposed sandbanks, which, in this
context,
suggests that failed Nile floods caused the severe famine. There is,
for
example, a minimum in the 87Sr/86Sr ratio defined at a depth of 36 m in
our
delta core S-21 record. This minimum occurs at ca. 4600 cal yr B.P. as
determined from the radiocarbon measurements of Stanley and Goodfriend
(1997). However, their calculation assumed that the carbonate age of
the
molluscs used in dating was zero initially. Core S-21 was deposited in
Lake
Manzalla very close to the sea. In an adjacent study, Schilman et al.
(2001)
have used a correction factor of 400 years for the age of planktonic
foraminifera sampled from surface waters of the Levantine basin off the
coast
of Israel. It is, therefore, reasonable to use a similar correction for
the ages of
core S-21 (i.e., 400 years) to produce the age profile given in Figure
1.
After such a correction is made, the age of the minimum in the
87Sr/86Sr
ratio defined at a depth f 36 m becomes ca. 4200 cal yr B.P.
In the prophesy of Neferty, which remembers the short and chaotic
1st Intermediate eriod, it is written that:
"The river of Egypt is empty, men cross over the water on foot"
and that "Birds no longer hatch their eggs in the swamps of the delta
. . . "
( Bell, 1971, p. 17).
At present, the flow of the White Nile is maintained by equatorial
rainfall and
is reasonably constant throughout the year, supplying most of the
baseflow
during nonflood periods (Said, 1993). The above writings imply that the

baseflow component from the White Nile was also exceptionally low
during
this drought period, indicating that this climatic anomaly affected the
entire
catchment.
Direct evidence for such low baseflow at that time is provided by two
cores
collected in the central Nile delta (cores S-86, along the Rosetta
branch,
and S-87, near the town of Tanta), which were recovered within the
freshwater region (Figure 1D).
A distinctive thin (~5 cm), reddish-brown silt layer containing
iron/manganese
hydroxide is present in each core and nowhere else within the two
mid-Holocene
core sections (Stanley et al., 1996). Sediment that has been allowed to
dry out
in air will form iron oxides that are resistant to later chemical
changes, even
once the delta system becomes flooded again. Visually, these layers
resemble
modified paleosol horizons (Figure 3) characteristic of sediment that
has dried
out and been subaerially exposed for a prolonged period. Note that the
ages of
these two horizons are 4250 cal yr B.P. in core S-86 and 4050 cal yr
B.P. in
core S-87, based on interpolated radiocarbon ages from these cores (cf.
Stanley
et al., 1996). It is also useful to recall the similar age, ca. 4200
cal yr B.P., of
the sediment section defined by the minimal isotopic ratio in Nile
delta coastal
core S-21."

Bell, B. (1971).
The Dark Ages in ancient history: The first dark age in Egypt.
American Journal of Archaeology, 75, 1-25.

Kitchen, K.A. (1991).
The chronology of ancient Egypt.
World Archaeology, 23, 201-208.

Owens, R.B., Barthelme, J.W., Renaut, R.W., & Vincens, A. (1982).
Palaeolimnology and archaeology of
Holocene deposits northeast of Lake Turkana, Kenya.
Nature, 298, 523-529.

Pachur, H.J., & Kro¨ pelin, St. (1987).
Wadi Howar: Paleoclimatic evidence from an extinct river system
in the southeastern Sahara.
Science, 237, 298-300.

Said, R. (1993).
The River Nile.
Oxford: Pergamon Press.

Schilman, B., Almogi-Lapin, A., Bar-Matthews, M., Labeyrie, L.,
Paterne, M., & Luz, B. (2001).
Long- and short-term carbon fluctuations in the Eastern Mediterranean
during the late Holocene.
Geology, 29, 1099-1102.

Stanley, D.J., & Goodfriend, G.A. (1997).
Recent subsidence of the northern Suez Canal
Nature, 388, 335-336.

Stanley, D.J., McRae, J.E., Jr., & Waldron, J.C. (1996).
Nile delta drill core and sample database for 1985-1994:
Mediterranean Basin (Mediba) Program,
Smithsonian Contribution to the Marine Sciences.
Washington, DC: Smithsonian Institution.

Talbot, M.R., Williams, M.A.J., & Adamson, D.A. (2000).
Strontium isotope evidence for late Pleistocene
re-establishment of an integrated Nile drainage network.
Geology, 28, 343-346.

'Nuff Said?
Daryl Krupa