Archaeological Discovery, 2015, 3, 26-31
Published Online January 2015 in SciRes. http://www.scirp.org/journal/ad
How to cite this paper: Mörner, N.-A. (2015). The Flooding of Ur in Mesopotamia in New Perspectives. Archaeological Dis-
covery, 3, 26-31. http://dx.doi.org/10.4236/ad.2015.31003
The Flooding of Ur in Mesopotamia in New
Paleogeophysics & Geodynamics, Stockholm, Sweden
Received 25 October 2014; revised 23 November 2014; accepted 25 December 2014
Academic Editor: Hugo G. Nami, National Council of Scientific and Technical Research (CONICET),
Departamento de Ciencias Geológicas, University of Buenos Aires, Argentina
Copyright © 2015 by author and Scientific Research Publishing Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY).
At around 5000 years BP sea level peaked in the Persian Gulf region at a level of +0.3 m as now
determined in Qatar. This coincides with the famous flooding of the ancient city of Ur, originally
interpreted as due to local changes in the fluvial system. We can now propose that, in fact, it was
the sea level rise that triggered the fluvial reorganization and rise in ground water level that ulti-
mately led to “the flooding of Ur”.
Sea Level Changes, Qatar, The Persian Gulf, The Flooding of Ur
When Sir Leonard Woolley in the 1920s started to excavate the ancient city of Ur in the Chaldees and found
evidence of an ancient flooding episode some 5000 years ago (Woolley, 1929), this came as a great surprise at
the same time as it could be taken to confirm the old tale of a flooding in the Mesopotamian region at approxi-
mately 5000 years ago. Woolley was very clear in his interpretation, however; dismissing the concept of a gen-
eral flooding episode in favour of a local event of fluvial reorganization (Woolley, 1929, 1954).
We now know that the postglacial eustatic rise in sea level from a minimum of about –120 m at around
20,000 BP to its present level reached some 5000 - 6000 years ago occurred in a sequence of transgressional
steps (e.g. Fairbridge, 1961; Mörner, 1971). Each of these rising sea level steps had the potential of being ex-
perienced by ancient people as a disastrous “flooding” episode.
Up to now, the flooding of the ancient city of Ur has not been able to be put into the context of sea level
changes, however. Therefore, the old interpretation of a local change in the fluvial system (Woolley, 1929) has
remained the common explanation.
Thanks to the detailed Google images of the coast of Qatar and a short field expedition in April 2006, we be-
lieve that we are now able to shed new light on the old flooding of the ancient city of Ur by a quite exact quanti-
fication of a rise in sea level and its sharp dating by radiocarbon.
2. The Coastal Record in Qatar
The sea level changes within the Persian Gulf are only superficially known. There is no sea level record that can
be used as a regional standard; only scattered data, which often even contradict each other (the sea level recon-
struction by Lambeck, 1996, is a model-based product of limited practical implication). The coast of Qatar is no
exception. The issue of past sea level changes has been addressed by some authors (Vita-Finzi, 1978; Inizan,
1988) but sharp field studies and good dating still remain to be done. This paper present the initial stage of mod-
ern sea level studies in Qatar restricted to the NE-section of the coast.
The detailed Google image of the AlKhor-AlDakhira area (Figure 1) reveals a remarkable coastal record; viz.
1) a present coastal barrier system dominated by coastal stability at a present sea level position; 2) a gap when
the coastal barrier system is absent; 3) a second coastal barrier system dominated by coastal stability at a sea
level more or less the same as today; 4) a gap when the coastal barrier system is absent; and 5) a third
Figure 1. Google image of the Al Dahkira region in Qatar. It documents the occurrence of three stable coastal barrier sys-
tems 1) the present one; 2) an older one at the same sea level elevation; and 3) a fossil shore now on land from a period when
sea level was 0.3 m higher than today. The 3rd level marks the maximum Holocene sea level position and is now dated at
~5000 calyrs BP (red dot marks sample site). The last interglacial high sea level position is seen further inlands. Each of the
three coastal barrier systems represents a period of coastal stability.
coastal barrier system clearly recognizable on the outer edges of the present land area, implying coastal stability
at a sea level somewhat above the present one, and marking the peak level of the Holocene sea level transgres-
In April 2006, we undertook a short exploratory visit to the region. First we investigated a number of sites in
order to determine the maximum Holocene sea level position. A fossil shore could be traced and followed over a
wide area. Sometimes a coastal flat in front of the shore notch was quite wide. Its sandy sediments contained
shells and corals. At all sites investigate, we found that this level surely was somewhat above the present sea
level, but never more than +0.3 m or at the most +0.4 m. This is illustrated in Figure 2.
We then drove out over the coastal lowland to the third barrier system identified in the Google image (Figure
1). The shore character was clear. The barrier material was graded to a level some 30 - 40 cm above the present
sea level. Obviously, this coastal system represents the maximum Holocene sea level. The sediments were full
of marine organisms. A sample of cemented small Turitella-like shells was collected for C14-dating.
This fossil coastal barrier is covered by remains of human habitation (Figure 3); partly a habitation soil and
partly stones from old buildings. Archeologically, this site is considered to belong to the Kassite period datedat
about 4000 - 3500 BP. These remains represent a low sea level phase following the formation of the 3rd coastal
barrier system, formed when sea level peaked in Mid-Holocene time.
Figure 2. The fossil shore at +0.3 m at AlKhor. Left: The difference in elevation between the present washing-limit and the
fossil shore notch (marking the maximum Holocene sea level) is 0.3 m with a clear fossil shore cliff continuing over a wide
area. Right: In front of the fossil cliff, there is a fairly wide coastal plain full of marine shells and even a coral (inserted pic-
Figure 3. The soil (a) and house foundation (b) on top of the 3rd shore barrier system and hence post-dating this sea level
event. The habitation remains and the soil are believed to belong to the Kassite period dated at about 4000 - 3500 BP. Marine
shells from this shore deposits beneath were C14-dated at ~5000 calyrs BP, which gives the age of the +0.3 m high sea level
of the 3rd shore stage in Figure 1.
3. Age of the Maximum Holocene Level
The sample collected was C14-dated at the Uppsala Laboratory by the AMS method (Lab. no. Ua-32599). The
age was 4740 ± 40 C14-years BP. In order to convert this age into calendar years, we need to apply two correc-
tion factors; one for the marine “reservoir effect” (minus) and one for the atmospheric fluctuations in 14C content
The “reservoir effect” for the Persian Gulf is 441 ± 56 years (Southon et al., 2002). This gives an age of
4299 ± 69 BP, which after atmospheric 14C correction gives a calendar age of 3150 - 2600 BC or 5100 -
4550 BP at a 94.4% confidence level (and 3030 - 2870 BC or 4980 - 4820 BP at a 65.6%
This age is exceptionally interesting and opens for wider interpretations, because it fit perfectly well with the
age of the flooding of Ur. Furthermore, it represents the maximum Holocene sea level position in this region of
the world; not only for Qatar but probably for the entire Persian Gulf region (Figure 4).
4. The Flooding of Ur in New Perspectives
The complex sedimentary evolution of the Euphrates-Tigris delta has been assessed by, for example, Lees and
Falcon (1952) and Kennett and Kennett (2006), but without adequate stratigraphic, radiometric and micro-pa-
leontological data to allow for any interpretation of age and origin of “the flooding of Ur”.
Figure 4. The Persian Gulf at ~5000 calendar years BP. 1) The ancient city of Ur was flooded; 2) The delta margin was lo-
cated some 200 km inland; and 3) Sea level peaked at +0.3 m in Qatar, a level which also represents the Holocene sea level
maximum in this region. A peaking sea level rise has wide effects also upstream the fluvial delta system leading to reorgani-
zations of the fluvial streams, erosion, re-deposition, local flooding and groundwater rise (Mörner, 1987).
When sea level rises in a delta region, this rise has drastic direct and indirect effects far up the river system.
This is especially the case in association with the peak level of the Holocene transgression, as further discussed
elsewhere (e.g. Mörner, 1987). If sea level rose to a maximum level at about 5000 calyrs BP, this rise co-in-
sides with the flooding of Ur. Although, Woolley (1929, 1954) may be completely correct in his interpretation
that this flooding was caused by a reorganization of the river systems, the ultimate driving force for this reor-
ganization may now be given as the rise in sea level.
Consequently, a rise in sea level in to order of 0.5 m (>0.3 m) was able to lead to a considerable reorganiza-
tion of the river systems far inland. The age can now be set at about 5000 calyrs BP, an age which agrees very
well with the preliminary age of the flooding of Ur given by Woolley (1929, 1954) as well as subsequent dating
of the Royal tombs above the flooding deposits (Sumeria, 2007).
The situation is illustrated in Figure 4. At around 5000 calendar years BP, the delta margin was located some
200 km further inlands and the ancient city of Ur, then in coastal position, was flooded and covered by a 3.7 m
layer of clay. At precisely the same time, sea level peaked in Qatar. Therefore, we now argue that it was the sea
level rise that initiated the flooding of Ur.
By the field studies in Qatar, we have now fixed the regional maximum Holocene sea level in elevation (+0.3 m)
and age (~5000 BP), and found that this event is likely to have driven the classical flooding of the ancient city of
The coastal stability of the present barrier system may be of special interest with respect to present discus-
sions of an alarming on-going rise in sea level; pro (e.g. IPPC, 2007) and con (e.g. Mörner, 2004, 2013).
I thank Her Highness Sheikha Mozah Bint Nasser Al-Missned and the Qatar Foundation for inviting me to the
Doha conference in April 2006 during which period I had the opportunity to undertake this short field investiga-
tion. Prof. Fekri Hassan, University Collage of London, and Mr. Mohamed El Obeidilee, Department of Antiq-
uity in Doha, took part in the expedition. Prof. Göran Possnert, Uppsala University, made the C14-dating. To those
persons I express my sincere thanks.
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