Micromorphology of takyrs and the desert 'papyrus' of Southwestern Turkmenia.

摘要

The perception of takyrs as clayey mineral soils extremely poor in humus and occurring in deserts was supported by micromorphological studies with the first ones being performed by I.I. Feofarova for the takyrs in Western Turkmenia. However, in the fundamental monograph of 1956, there were abundant data on the contribution of biota (primarily of algae and invertebrates) to the takyr formation. The importance of the biota was emphasized by N.I. Bazilevich, who was an active participant in terrain and analytical investigations of Western Turkmenia takyrs. The micromorphological analysis, along with the studies of the chemical and mineralogical properties of the algal takyr on the Kopet-Dag piedmont plain, made it possible to introduce some corrections to the concepts concerning the mechanisms of takyr development; the contribution of bluegreen algae, microorganisms, and zooplankton was shown to be prominent. The available information on the properties and ecology of blue-green algae enabled the authors to interpret both their own data and the micromorphological descriptions made by I.I. Feofarova in the 1950s. The uppermost subhorizons are proposed to be regarded as the soil miniprofiles, whose properties are strongly affected by the activity of aquatic and terrestrial microorganisms, rather than the sedimentation strata.Digital Object Identifier http://dx.doi.org/10.1134/S1064229310110049