Makhtesh

From Wikipedia, the free encyclopedia

Jump to: navigation, search
Image:Makhtesh Ramon.jpg
Makhtesh Ramon
© DigitalGlobe
Image:Makhtesh Sinai.jpg
One of the two makhteshim in Sinai
© DigitalGlobe

A makhtesh (Hebrew: מכתש‎, plural: מכתשים - "makhteshim") is a geological phenomenon in which a hard outer layer of rock covers softer rocks. The erosion process destroys the soft minerals relatively fast, and they are washed away from under the harder ones. The harder rocks eventually collapse under their own weight — the result is a crater-like valley structure.

This phenomenon is often said to be unique to the Negev desert (Israel) and the Sinai Peninsula (Egypt). However, similar features exist also in Turkmenistan (Yor-oilan-duz depression in Badkhyz Highlands) and Iran.

Although the Hebrew term "makhtesh" is usually translated as "crater", there is a difference between the two: Makhteshim are formed by water erosion whereas craters are formed by the impact of a meteor or volcanic eruption. A more accurate translation is "erosion cirque." [1]

In the Negev, there are 5 makhteshim: Makhtesh Ramon, Makhtesh Gadol ("Large Makhtesh"), Makhtesh Qatan ("Small Makhtesh"), and two tiny makhteshim on Mount Arif.

In the cases in the Negev and Sinai, the hard rocks are limestone and dolomites, while the inner softer rocks are chalk or sandstone. [2]

Though in most cases a makhtesh has only one drainage system, Makhtesh Ramon has three.

The two makhteshim in Sinai have no names for the basin, but the their walls have several names - like Jabal al-Manzur or Gebel Maghara.

[edit] References

  1. ^ http://64.233.183.104/search?q=cache:Y3J03fnQ2qcJ:www.bgu.ac.il/desert_ecology/ramon/Krasnov/Krasnovetal96JAridEnviron.pdf+erosion+cirques&hl=en&ct=clnk&cd=10
  2. ^ http://www.mfa.gov.il/MFA/Archive/Communiques/1997/ERETZ+HAMAKHTESHIM-+NATURE+CONSERVATION+AND+DESERT.htm?DisplayMode=print]
  • Mazor, Emanuel and Krasnov, Boris, editors "The Makhteshim Country - a Laboratory of Nature". Pensoft Publishers, Sofia, 2001: , ISBN: 954-642-135-9, 411 pages
MakhteshGadolAcacia.jpg

Acacia tree inside Makhtesh Gadol, Israel; June 2007.

MakhteshGadolCenter.jpg

Center of Makhtesh Gadol, Israel; June 2007.

MakhteshGadolMist.jpg

Mist flowing over the northern rim of Makhtesh Gadol, Israel; June 2007.

MakhteshGadolRoad.jpg

Road on northern side of Maktesh Gadol, Israel; originally built by the British during oil exploration; June 2007.

RamonFault.jpg

Ramon Fault on the southern side of Makhtesh Ramon, Israel; June 2007.

RamonFault1.JPG

Ramon Fault on the southern side of Makhtesh Ramon, Israel; June 2003.

Ramon2004b.jpg

Northern rim of Makhtesh Ramon.

Image:Commons-logo.svg
Wikimedia Commons has media related to:
Makhtesh


Image:Oceanic-continental convergence Fig21oceancont.svg This geology article is a stub. You can help Wikipedia and WikiProject Geology by expanding it.
de:Erosionskrater

he:מכתש אירוזי

Retrieved from "http://india.smashits.com/wikipedia/Makhtesh"
Views
Personal tools

Toolbox