Umm al Binni lake
Encyclopedia
Umm al Binni lake is a 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
.
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 Wooley in 1954. 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).
ian 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.
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
in Maysan Governorate in southern Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
within the Central Marshes
Central Marshes
The Central or Qurna Marshes were a large complex of wetlands in Iraq that were part of the Tigris-Euphrates river system, along with the Hawizeh and Hammar Marshes...
. The 3.4 km wide lake is approximately 45 km northwest of the Tigris
Tigris
The Tigris River is the eastern member of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of southeastern Turkey through Iraq.-Geography:...
–Euphrates
Euphrates
The Euphrates is the longest and one of the most historically important rivers of Western Asia. Together with the Tigris, it is one of the two defining rivers of Mesopotamia...
confluence. Because of its shape and location, it has been suggested to represent an impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
.
Evidence as an impact crater
Using satellite imagery, Master (2001, 2002) suggests the 3.4 km diameter dry lake may be an impact craterImpact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
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
Progradation
In sedimentary geology and geomorphology, the term progradation refers to the growth of a river delta farther out into the sea over time. This occurs when the mass balance of sediment into the delta is such that the volume of incoming sediment is greater than the volume of the delta that is lost...
of the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
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
Ur
Ur was an important city-state in ancient Sumer located at the site of modern Tell el-Muqayyar in Iraq's Dhi Qar Governorate...
by Leonard Wooley in 1954. Descriptive passages in The Epic of Gilgamesh
Epic of Gilgamesh
Epic of Gilgamesh is an epic poem from Mesopotamia and is among the earliest known works of literature. Scholars believe that it originated as a series of Sumerian legends and poems about the protagonist of the story, Gilgamesh king of Uruk, which were fashioned into a longer Akkadian epic much...
(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 SumerSumer
Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....
ian civilisation) could be linked to a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
or asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
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
Hiroshima
is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshu, the largest island of Japan. It became best known as the first city in history to be destroyed by a nuclear weapon when the United States Army Air Forces dropped an atomic bomb on it at 8:15 A.M...
-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
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
and comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the 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.