Qanats on the Varamin Plain, Iran

Bibliographic Data

ID8964351
AuthorsPeter Beaumont (corresponding author)
Year1968
Issue45
Pages169-169
Publication date1968-09-01
Peer ReviewedYes
Open AccessNo
TypeARTICLE
VenueTransactions of the Institute of British Geographers (JOURNAL)
Journal identifiersISSN: 0020-2754 • E-ISSN: 1475-5661
PublisherWiley (PUBLISHER • GB)
DOI10.2307/621400
OpenAlexW2326143960
LanguageEN
Citations received10
References cited1

THE VARAMIN PLAIN is situated in northern Iran, 40 km south-east of the capital Tehran, and lies between the barren slopes of the Elburz mountains and the desolate salt waste of the Great Kavir (Fig. i). It covers an area of approximately I300 km2, and owes its origin to alluvial deposition in the form of a large cone, at a point where the Jajerud (River Jaj) leaves the foothill zone. The highest point of the plain reaches II o m at the mouth of theJajerud, and drops to 800 m some 50 km farther south on the edge of the desert. The plain is almost completely flat, and the drainage of theJajerud consists of a maze of braided channels incised i-5 m below the general level of the plain. The climate is of the continental desert type. Rainfall is low and comes mainly in the form of light showers between December and April. Precipitation totals over the plain average about ISo mm, but yearly variations from 54 to 230 mm have been recorded. The winters are cold with a mean January temperature of 3.7°C, and a minimum recorded temperature of - I7°C. Air frosts are common in December and January, but snowfall is rare. In contrast, the summers are extremely hot and dry, with a meanJuly temperature of28.9°C, and maximum recorded temperatures up to 47°C. The prevailing winds in summer are from the south-east, and bring with them large quantities of dust from the edge of the Kavir. Geologically, the plain is a structural basin at the southern margin of the Elburz mountains, formed by the downwarping of Palaeozoic and Mesozoic sediments and Eocene volcanics. In this basin thick Miocene beds were laid down, and more recently thick alluvial deposits from the Jajerud. On the plain itself, all evidence of the older strata is deeply buried beneath recent alluvium, except for a discontinuous line of hills stretching westward from Pishva. In the Pishva ridge, Tertiary or Mesozoic limestone is exposed together with Miocene gravels, while in the extreme western part of the plain, Oligo-Miocene andesitic lavas rise from beneath alluvial deposits to form steep-sided massifs. The recent alluvial gravels, which are in places more than 250 m in thickness, consist mainly of coarse gravels at the apex of the fan, grading to clays and fine-grained loessic material at the desert margin. The soils of the plain are derived from the alluvial deposits of the Jajerud and eolian material from the Kavir. Three main soil associations can be distinguished. Near the mouth of theJajerud, the parent material is coarse gravel, and the soils are thin and lack horizon development. The absence of fme-grained material and organic matter means that these soils have little agricultural value. To the south of the alluvial cone and forming most of the area of plain are deep sandy loam or silty loam soils. These desert to semi-desert soils possess good arable and irrigable qualities, and form the basis of the agricultural productivity of the plain. Calcium carbonate accumulations are common in the profile of these soils and, where there has been no recent irrigation, salt accumulations are sometimes found. Where these soils lack protective vegetation cover they are particularly susceptible to wind erosion. On the extreme southern and western margins of the plain Solonchak soils are found. In this area a high saline

Geography · Ancient Mediterranean Archaeology and History · Environmental Science · Marine and environmental studies · Water management and technologies

Tools

Open DOISci-Hub