Stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils and sediments in Loot Desert, central Iran

Soil–geomorphology relationships in Sirjan playa, south central Iran

“…On the other hand, developed gypsic horizons in rock and mantled pediments of the Rafsajan, Isfahan, Kerman, and Jiroft areas in central Iran with aridic moisture regime have been reported by Farpoor et al (2003), Khademi and Mermut (2003), Moazallahi and Farpoor (2009) and Sanjari et al (2011), respectively. Two probable reasons for lack of formation of gypsic horizons in pediment soils in this study could be 1) leaching of calcium sulfate due to more available moisture in a xeric regime in this geomorphic position, and 2) high elevation of pediment position causing this landform not to be affected by closed water bodies of Miocene as the source of gypsum in central Iran (Khademi and Mermut, 1998;Farpoor et al, 2004;Farpoor and Krouse, 2008). Since no increase in gypsum content was observed with depth in these pedons, the above-mentioned reason seems to be more probable.…”

Wind Erosion in Drylands

“…The lowest elevation in Iran, and the most arid region of the central plateau, is the Lut Desert (Farpoor and Krouse, 2008), an area of about 80 000 km 2 , which is home to yardangs, sand dunes, regs and playas. The Lut Desert is extremely dry, with an average annual rainfall of less than 10 mm, and many years may pass without precipitation.…”

“…The yardangs are orientated at 330 • (northwest to southeast), parallel to the prevailing winds, which reach their greatest intensity in April, with an average speed of 9.35 m/s (Ehsani and Quiel, 2008). The yardangs are formed from Pleistocene lake deposits (Bobek, 1969), formed from easily erodible clays, which include illite, kaolinite, montmorillonite and chlorite (Farpoor and Krouse, 2008). The presence of palygorskite in different layers in the yardangs suggests an evaporite origin for the materials forming the huge yardangs (Farpoor and Krouse, 2008).…”

“…The yardangs are formed from Pleistocene lake deposits (Bobek, 1969), formed from easily erodible clays, which include illite, kaolinite, montmorillonite and chlorite (Farpoor and Krouse, 2008). The presence of palygorskite in different layers in the yardangs suggests an evaporite origin for the materials forming the huge yardangs (Farpoor and Krouse, 2008). In addition to wind erosion, cracking, piping, rilling, slumping and salt weathering modify the surface, suggesting that even in this very arid environment both wind and water are essential to the overall development of yardangs.…”

“…The presence of salts in deserts, particularly in association with lacustrine sediments, means that salt solution processes and salt weathering play an important role in yardang formation and modification. The Lut Formation of the Lut Desert, for example, consists of horizontally bedded lacustrine sediments, 135-200 m in thickness (Krinsley, 1970), that include gypsum and other more soluble sulfate salts (Farpoor and Krouse, 2008). Elongate depressions, commonly filled with salt, are orientated at 333 • , parallel to the prevailing wind and yardang axes (Krinsley, 1970).…”