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A hamada ( ar, حمادة, ) is a type of desert landscape consisting of high, largely barren, hard rocky plateaus, where most of the
A hamada ( ar, حمادة, ) is a type of desert landscape consisting of high, largely barren, hard rocky plateaus, where most of the sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...
has been removed by deflation
In economics, deflation is a decrease in the general price level of goods and services. Deflation occurs when the inflation rate falls below 0% (a negative inflation rate). Inflation reduces the value of currency over time, but sudden deflatio ...
. The majority of the Sahara is in fact hamada. Other examples are Negev
The Negev or Negeb (; he, הַנֶּגֶב, hanNegév; ar, ٱلنَّقَب, an-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 sout ...
desert in Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
and the in Algeria.
Formation
Hamadas are produced by the wind removing the fine products of weathering: an aeolian process known as deflation. The finer-grained products are taken away in suspension, while the sand is removed through saltation and surface creep, leaving behind a landscape of gravel, boulders and bare rock.Related landforms
Hamada is related todesert pavement
A desert pavement, also called reg (in the western Sahara), serir (eastern Sahara), gibber (in Australia), or saï (central Asia) is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cob ...
(known variously as reg, serir, gibber or saï), which occurs as stony plains or depressions covered with gravels or boulders, rather than as highland plateaus.
Hamadas exist in contrast to ''ergs
The erg is a unit of energy equal to 10−7joules (100 nJ). It originated in the Centimetre–gram–second system of units (CGS). It has the symbol ''erg''. The erg is not an SI unit. Its name is derived from (), a Greek word meaning 'work' o ...
'', which are large areas of shifting sand dunes.McKnight, Tom L. and Darrel Hess. ''Physical Geography: A Landscape Appreciation'', 8th ed., pp. 495-6. Upper Saddle River, NJ: Pearson Education, Inc. 2005. ()
See also
'' Hammada'', a genus of flowering plants belonging to the familyAmaranthaceae
Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus ''Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it ...
.
References
{{Geology-stub Deserts and xeric shrublands Arabic words and phrases