Umm al Binni lake

Umm al Binni lake is a mostly dry lake in Maysan Governorate in southern Iraq within the Central Marshes. The 3.4 km wide lake is approximately 45 km northwest of the Tigris–Euphrates confluence. Because of its shape and location, it has been suggested to represent an impact crater.

The name means "Mother of Mesopotamic barbels", after the binni (Mesopotamic Barbel, Mesopotamichthys sharpeyi), a fish species formerly common in the lake and traditionally harvested by the spear-and-poison fishermen of the Marsh Arabs. Even though the lake has fallen dry in modern times, its name attests to the former abundance of M. sharpeyi, of which it may have been a spawning ground.

Evidence as an impact crater

Using satellite imagery, Master (2001, 2002) suggests the 3.4 km diameter dry lake may be an impact crater based on its nearly circular, slightly polygonal shape, rim shape, and contrasting shape to other lakes in the region. As to its origin, Master rules out Karst solution, salt doming, tectonic deformation, and igneous intrusion as well as possible bombing or man-made origins of the structure.

Master (2001, 2002) estimates the age of the crater to be less than 5,000 years, due to the deposition of sediments of the Tigris-Euphrates plain as a result of the 130–150 km seaward progradation of the Persian Gulf during that time period (Larsen & Evans 1978). A lack of writings describing this event by contemporary authors, such as Herodotus (484–425 BC) and Nearchus (360–300 BC) or later historians, suggests the impact may have taken place between 3000 and 5000 years BP (Master 2002). During this time period, the Al Amarah region was under the Persian Gulf at a depth of approximately 10 m (Larsen & Evans 1978: 237). Impact-induced tsunamis would have devastated coastal Sumerian cities. This may provide an alternate origin of the 2.6 m sediment layer discovered during an excavation of the Sumerian city of Ur by Leonard Woolley in 1922-1934. Descriptive passages in The Epic of Gilgamesh (circa 1600–1800 BCE) may describe such an impact and tsunami, suggesting a link to the Sumerian Deluge (Matthews 2001; Britt 2001):

...and the seven judges of Hell, the Annunaki, raised their torches, lighting the land with their livid flame. A stupor of despair went up to heaven when the god of the storm turned daylight into darkness, when he smashed the land like a cup. One whole day the tempest raged, gathering fury as it went, it poured over the people like tides of battle; a man could not see his brother nor the people be seen from heaven. Even the gods were terrified at the flood, they fled to the highest heaven, the firmament of Anu; they crouched against the walls, cowering like curs. (Sanders 1960).

Climate change and impact effects

It has been suggested that sudden climate changes and catastrophic events around 2200 BCE (including the collapse of the Sumerian civilisation) could be linked to a comet or asteroid impact (Courty 1997, 1998; Peiser 1997; Napier 1997; Bjorkman 1973, Weiss et al. 1993, Master 2001, 2002). It has been suggested by Master (2001, 2002), Master & Woldai (2004, 2006) that the alleged Umm al Binni impact could be responsible for this catastrophe, producing the energy equivalent to thousands of Hiroshima-sized bombs.

Using equations describing impact effects based on work from Collins et al. (2004), Shoemaker (1983), Glasstone & Dolan (1977) and others, Hamacher (2005) determined that an impacting bolide would have produced energy in the range of 190 to 750 megatons of TNT (for an asteroid and comet impact, respectively). This result is dependent on the impactor's density, size, and impact velocity. In order to produce an impact crater with the dimensions of Umm al Binni lake, a comet (density = 500 kg/m^3, v = 25 km/s) would have been between 200 and 300 m in diameter while a Ni-Fe asteroid (density = 7860 kg/m^3, v = 15 km/s) would have been between 90 and 110 m in diameter. The resulting impact effects would have caused massive devastation to an area thousands of square kilometres in size, but would not have been sufficient on its own to have caused the wide-scale damage seen at distances exceeding ~100 kilometers from the impact and thus could not be responsible for many of the more distant devastating effects on its own.

Although a large mount of circumstantial evidence has been published in the literature suggesting Umm al Binni is an impact crater, no on-site analysis has been done, primarily due to the current volatile and dangerous situation in Iraq. Therefore, Umm al Binni lake remains a possible, albeit unconfirmed, impact structure.

References

• Bjorkman, J.K., (1973) Meteors and Meteorites in the Ancient Near East, Meteoritics 8(2): 91
• Britt, R.R. (2001) Comets, meteors and myth: New evidence for toppled civilisations and Biblical tales, Posted 13 November 2001
• Collins, G. S.; Melosh, H. J.; Marcus, R. A. (2005) Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth, Meteoritics & Planetary Science 40: 817
• Courty, M.A., (1997) Causes And Effects of the 2350 BC Middle East Anomaly Evidenced By Micro-debris Fallout, Surface Combustion and Soil Explosion, Society for Interdisciplinary Studies Conference: Natural Catastrophes during Bronze Age Civilizations, July 11–13, 1997 Cambridge, UK.
• Glasstone, S. and Dolan, P. J., (1977) Effects of Nuclear Weapons 3rd Edition, Washington D.C.: United States, Department of Defense and Department of Energy
• Hamacher, D.W. (2005), The Umm Al Binni Structure and Bronze Age Catastrophes, The Artifact: Publications of the El Paso Archaeological Society, vol 43, pp 115–138
• Larsen, C.E. and Evans, G. (Brice W.C. Ed.), (1978) The Holocene Geological History of the Tigris-Euphrates-Karun Delta in The Environmental History of the Near and Middle East Since the Last Ice Age. Academic Press, London. pp. 227–244
• Master, S. (2001) A Possible Holocene Impact Structure in the Al Amarah Marshes, Near the Tigris-Euphrates Confluence, Southern Iraq, Meteoritics & Planetary Science 36: A124
• Master, S. (2002) Umm al Binni lake, a possible Holocene impact structure in the marshes of southern Iraq: Geological evidence for its age, and implications for Bronze-age Mesopotamia. In: Leroy, S. and Stewart, I.S. (Eds.), Environmental Catastrophes and Recovery in the Holocene, Abstracts Volume, Department of Geography, Brunel University, Uxbridge, West London, UK, 29 August - 2 September 2002, pp. 56–57
• Master, S. and Woldai, T., (2004) The Umm al Binni structure in the Mesopotamian marshlands of southern Iraq, as a postulated late Holocene meteorite impact crater: geological setting and new Landsat ETM and Aster satellite imagery. Economic Geology Research Institute Information Circular, October 2004, University of Witwatersrand - Johannesburg, South Africa

     http://www.itc.nl/library/Papers_2004/tech_rep/woldai_umm.pdf (1.56 MB)

• Master, S. and Woldai, T., (2006 - in press) Umm al Binni structure, southern, as a postulated late Holocene meteorite impact crater: new satellite imagery, and proposals for future research. In: Bobrowsky, P. and Rickmann, H. (Eds.), Comet/Asteroid Impacts and Human Society, Springer-Verlag, Heidelberg
• Matthews, R. (2001) Meteor clue to end of Middle-East civilisations, Telegraph Online Magazine.
• Napier, W., (1997) Cometary Catastrophes, Cosmic Dust and Ecological Disasters in Historical Times: The Astronomical Framework, Society for Interdisciplinary Studies Conference: Natural Catastrophes during Bronze Age Civilizations, July 11–13, 1997 in Cambridge, UK.
• Peiser, B. (1997) Comets and Disaster in the Bronze Age, British Archaeology 30: 6-7
• Sanders, N.K. (1960) The Epic of Gilgamesh, Penguin Books, London
• Shoemaker, E.M. (1983) Asteroid and comet bombardment of the Earth, Annual Reviews of Earth and Planetary Science 1(1): 461-494
• Weiss, H., Courty, M.-A., Wetterstrom, W., Guichard, F., Senior, L., Meadow, R. and Curnow, A. (1993) The genesis and collapse of Third Millennium North Mesopotamian civilization, Science 261, pp. 995–1004