Dust Availability in Desert Terrains
Abstract
The study deals with dust in desert terrains-its composition, distribution and the relation to landforms, climate and age. Most of the dust in deserts is derived from soils and surficial deposits. These, in turn, are associated with landforms that are readily identifiable on airphotos (and in many cases-on topographic maps and space imagery). Emphasis is placed on particle size distribution, mineral composition, the composition of salts and the distribution with depth. The interrelations with atmospheric dust in and from deserts are underlined. The largest content of dust is found in loessial soils, Takyr soils ad the thick Reg and Hammada soils. Young gravelly alluvium, dune sand and some playa soils are rather poor in dust content. The thickness of the continuous dust-rich layer is greatest in loessial soils and deposits and Takyr soils. The thinest dust horizons are found in young Reg and Hammada soils. Salts and gypsum are typical constituents in desert soils. Usually there is more gypsum than salts. Both show in the dust and the sand fractions and their content increases with soil depth. The most saline are Solonchak and Reg soils. The least saline are sand dune soils, young gravelly soils and loessial soils in the less arid environments. The composition and distribution of the dust-sized materials are presented in quantitative terms. Ground cover/protection is of several types: desert pavement, loessial crusts, biologic crusts and salt crusts. A procedure for evaluation of dust availability in dessert terrains accompanies this report.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1985
- Accession Number
- ADA166447
Entities
People
- Ran Gerson
- Rivka Amit
- Sari Grossman
Organizations
- Hebrew University of Jerusalem