Pedogenic Indicators of Paleoclilnate in an Arid Region, Central Iran

One of the methods to investigate the climate change and its consequences is the application of models based on past evidences, present information and modern technology. The objective of this study was to use pedogenic indicators for describing paleoclimate in an arid zone of Isfahan. Selected soil profiles were studied and their diagnostic subsurface horizons were described. Soil samples as well as pedogenic carbonate samples were taken from different pedons. The physico-chemical and micro morphological properties of soils were studied. Also, the isotopic composition of soil and parent rock carbonates was determined. Despite the calcareous parent materials, it was concluded that argillic horizons developed in the area under a different climate from that of today. The present mean annual precipitation of lsfahan is about 110 mm and it is not enough for the formation of argillic horizons. Therefore, the existence of argillic horizon in arid area of central Iran indicates a more humid conditions andlor lower temperature during late Quaternary period. Besides, both C and 0 isotopic composition of soil carbonates and C isotopic composition of soil organic carbon and current -egetation also indicate that a different climate prevailed in the area in the past under which the vegetation cover was not similar to that of today.

کلیدواژه ها:

Pedogenic evidence ، Paleoclimate ، Arid zones ، Iran