A makhtesh ( (), Hebrew plural: ( – ''Makhteshim'') is a geological landform found in the

Negev The Negev ( ; ) or Naqab (), is a desert and semidesert region of southern Israel. The region's largest city and administrative capital is Beersheba (pop. ), in the north. At its southern end is the Gulf of Aqaba and the resort town, resort city ...

desert of Israel and the

Sinai Peninsula The Sinai Peninsula, or simply Sinai ( ; ; ; ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is a land bridge between Asia and Afri ...

of Egypt. A makhtesh has steep walls of resistant rock surrounding a deep closed valley, which is usually drained by a single

wadi Wadi ( ; ) is a river valley or a wet (ephemerality, ephemeral) Stream bed, riverbed that contains water only when heavy rain occurs. Wadis are located on gently sloping, nearly flat parts of deserts; commonly they begin on the distal portion ...

. The valleys have limited vegetation and soil, containing a variety of different colored rocks and diverse fauna and flora. The best known and largest makhtesh is

Makhtesh Ramon Makhtesh Ramon (; ''lit.'' Ramon Crater/ Makhtesh; ; ''lit.'' The Ruman Wadi) is a geological feature of Israel's Negev desert. Located some 85 km south of Beersheba, the landform is the world's largest "erosion cirque" (steephead valley ...

Etymology

Although commonly referred to as " craters", these formations are "erosion cirques" (

steephead valley A steephead valley, steephead or blind valley is a deep, narrow, flat bottomed valley with an abrupt ending. Such closed valleys may arise in limestone or karst landscapes, where a layer of permeable rock lies above an impermeable substrate such ...

s or box canyons). Craters are formed by the impact of a meteor or

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

eruption, whereas makhteshim are created by

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

. The word makhtesh is the Hebrew word for a mortar grinder (). The geological landform was given this name because of its similarity to a grinding bowl.

Geology

Where a hard outer layer of rock covers softer rocks, erosion removes the softer minerals relatively quickly, 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 makhteshes, the hard rocks are

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

and dolomites, while the inner softer rocks are

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

. The center of the Negev is dominated by northeast-southwest anticlinal ridges. The crests of four ridges host five deep valleys surrounded by steep walls. The upper half consists of hard limestone and dolomite, and the bottom is friable sandstone. Each valley, known as a makhtesh, is drained by a narrow river bed.''Makhteshim Country''
at UNESCO World Heritage Convention. Submitted by Israel, 30/9/2001. Re-accessed 12/3/2023.

Negev

The Negev has five makhteshes: Makhtesh Ramon, Makhtesh Gadol, Makhtesh Katan, and two small makhteshes on Mount Arif, south of Makhtesh Ramon. *

is exceptional as it is drained by two rivers (Nahal Ramon and Nahal Ardon). It is the largest makhtesh at over 40 km long, 2–10 km wide and over 500 m deep. The rocks in this makhtesh contain thousands of

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

fossils, as well as volcanic and

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

rocks. *

Makhtesh Gadol HaMakhtesh HaGadol (, ''lit.'' The Big Crater) or simply Makhtesh HaGadol or Makhtesh Gadol, is a makhtesh, a geology, geological erosional landform of Israel, Israel's Negev desert. It measures 5 x 10 km. A makhtesh has steep walls of resi ...

(''Large Makhtesh''). At the time of naming, Makhtesh Ramon was uncharted, and so this was thought to be the largest makhtesh, at 10 km by 5 km. *

Makhtesh Katan HaMakhtesh HaKatan (, ''lit.'' The Small Crater) or simply Makhtesh HaKatan or Makhtesh Katan, is a makhtesh, a geological erosional landform, situated in Israel's Negev desert. At 5 km by 7 km, it is the third largest of the five makh ...

(''Small Makhtesh'') is the smallest major makhtesh at 7 km by 5 km and was charted in 1942 by Jewish explorers.

Sinai

The two makhteshes in Sinai, Egypt, have no names for the basin, but their walls have several names including ''Jabal al-Manzur'' or ''Gebel Maghara''.

Jordan

Several similar geological formations are also found in Wadi Rum in southern Jordan.

Gallery

File:SmallCrater01 ST 08.JPG, The walls of Makhtesh Katan (the Small Makhtesh) File:SmallCrater05 ST 08.JPG, Colorful sandstone in Makhtesh Katan Image:SmallCrater03 ST 08.JPG, Makhtesh Katan Image:SmallCrater06 ST 08.JPG, Colorful sandstone in the Small Makhtesh Image:MakhteshGadolAcacia.jpg, Acacia tree inside Makhtesh Gadol Image:MakhteshGadolMist.jpg, Mist flowing over the northern rim of Makhtesh Gadol Image:RamonFault.jpg, Ramon Monocline on the southern side of Makhtesh Ramon Image:RamonFault1.JPG, Ramon Fault on the southern side of Makhtesh Ramon