Makhtesh
Encyclopedia
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
landform considered unique to the Negev
Negev
The Negev is a desert and semidesert region of southern Israel. The Arabs, including the native Bedouin population of the region, refer to the desert as al-Naqab. The origin of the word Neghebh is from the Hebrew root denoting 'dry'...
desert of Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
and the Sinai Peninsula
Sinai Peninsula
The Sinai Peninsula or Sinai is a triangular peninsula in Egypt about in area. It is situated between the Mediterranean Sea to the north, and the Red Sea to the south, and is the only part of Egyptian territory located in Asia as opposed to Africa, effectively serving as a land bridge between two...
. Although commonly known as "craters" (a literal reading of the Hebrew, and due to the visual similarity), these formations are more accurately described as erosion cirques (steephead valley
Steephead valley
A steephead valley, steephead or blind valley is a deep, narrow, flat bottomed valley with an abrupt ending. Such valleys arise in limestone or karst landscapes, where a layer of permeable rock lies above an impermeable substrate such as marl...
s or box canyon
Box canyon
Box Canyon is a Box canyon in Ouray County, Colorado, United States. It was originally founded as a mining camp and helped the city of Ouray establish itself as a permanent community. Box Canyon is home to Box Canyon Falls, a 285-foot waterfall, with quartzite walls that extend almost one hundred...
s). A makhtesh has steep walls of resistant rock surrounding a deep closed valley which is usually drained by a single wadi
Wadi
Wadi is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry riverbed that contains water only during times of heavy rain or simply an intermittent stream.-Variant names:...
. The valleys have limited vegetation and soil, containing a variety of different colored rocks and a diverse fauna and flora which has been protected and preserved over millions of years. The best known (and largest) makhtesh is Makhtesh Ramon
Makhtesh Ramon
Makhtesh Ramon is a geological feature of Israel's Negev desert. Located at the peak of Mount Negev, some 85 km south of the city of Beersheba, the landform is not actually an impact crater from a meteor, but rather is the world's largest makhtesh. The crater is 40 km long, 2-10 km wide and 500...
of Israel's Negev desert.
Formation
A hard outer layer of rock covered softer rocks. ErosionErosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
relatively quickly removes the softer minerals, and they are washed away from under the harder rock. The harder rocks eventually collapse under their own weight and a crater-like valley structure is formed. In Negev and Sinai makhteshim, the hard rocks are limestone and dolomites, while the inner softer rocks are chalk or sandstone. In most cases, makhteshim only have one drainage system, although the Makhtesh Ramon has three.
The Hebrew term makhtesh ordinarily means "crater", and was used to describe these features before the geological formation processes were understood. In fact, proper craters are formed by the impact
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...
of a meteor or volcanic
Volcanic crater
A volcanic crater is a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent from which magma erupts as gases, lava, and ejecta. A crater can be of large dimensions, and sometimes of great depth...
eruption. Adopting the Hebrew words allows English speakers to distinguish the two kinds of features; an alternative English term for makhtesh can be "erosion cirque."
Makhteshim
The presence of Makteshim is said to be unique to the NegevNegev
The Negev is a desert and semidesert region of southern Israel. The Arabs, including the native Bedouin population of the region, refer to the desert as al-Naqab. The origin of the word Neghebh is from the Hebrew root denoting 'dry'...
desert of Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
and the Sinai Peninsula
Sinai Peninsula
The Sinai Peninsula or Sinai is a triangular peninsula in Egypt about in area. It is situated between the Mediterranean Sea to the north, and the Red Sea to the south, and is the only part of Egyptian territory located in Asia as opposed to Africa, effectively serving as a land bridge between two...
of Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
although similar features do exist in Turkmenistan
Turkmenistan
Turkmenistan , formerly also known as Turkmenia is one of the Turkic states in Central Asia. Until 1991, it was a constituent republic of the Soviet Union, the Turkmen Soviet Socialist Republic . Turkmenistan is one of the six independent Turkic states...
(Yor-oilan-duz depression in Badkhyz Highlands) and Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
.
Negev
The Negev desert of Southern Israel is home to five Makhteshim; Makhtesh Ramon, Makhtesh Gadol, Makhtesh Katan, and two further tiny makhteshim on Mount Arif, to the south of Makhtesh Ramon.- Makhtesh RamonMakhtesh RamonMakhtesh Ramon is a geological feature of Israel's Negev desert. Located at the peak of Mount Negev, some 85 km south of the city of Beersheba, the landform is not actually an impact crater from a meteor, but rather is the world's largest makhtesh. The crater is 40 km long, 2-10 km wide and 500...
is exceptional as it is drained by two rivers (Nahal Ramon and Nahal Ardon). It is the largest Makhtesh at over 40km long, 2-10km wide and over 500m deep. The rocks in this makhtesh contain thousands of ammoniteAmmoniteAmmonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...
fossils, as well as volcanic and metamorphic rocks. - Makhtesh GadolMakhtesh GadolHaMakhtesh HaGadol is a makhtesh, a geological erosional landform of Israel's Negev desert.A makhtesh has steep walls of resistant rock surrounding a deep closed valley. One of five makhteshim in Israel and seven in the world, HaMakhtesh HaGadol is the second largest, being exceptional in that it...
(The Large Makhtesh) At the time of naming, Makhtesh Ramon was uncharted and so this was thought to be the largest Makhtesh. - Makhtesh KatanMakhtesh KatanHaMakhtesh HaKatan is a makhtesh, a geological erosional landform of Israel's Negev desert. One of five makhteshim in Israel, and seven in the world, it is the third largest in Israel at 5 km by 7 km. It was charted in 1942 by Jewish explorers....
(The Small Makhtesh) is the smallest major makhtesh at 5km by 7km and was charted in 1942 by Jewish explorers.
