Very few studies have investigated the occurrence and genesis of fibrous clay minerals in soils and associated Tertiary sediments in Iran. This investigation aimed: (1) to identify the distribution and genesis of palygorskite and sepiolite in soils and their associated Tertiary parent sediments in central Iran and Zagros regions, and (2) to identify the changes in physicochemical and mineralogical compositions of the dust particles deposited along an elevational transect ranging from central Iran to the Zagros Mountains. Thirty four Tertiary sediments from both central Iran and Zagros regions and a total number of 24 soil profiles developed on these sediments were sampled and analyzed for their physicochemical and mineralogical characteristics. Dust samples from 12 locations along a transect from central Iran to Zagros Mountains were also sampled and analyzed. Results showed that all soils, sediments of Neogene ages and dust samples from central Iran are highly palygorskitic. However, no trace of palygorskite was found in soils and studied Tertiary sediments of Zagros region. Both pedogenic and inheritance origin have been involved in the distribution of palygorskite in soils of central Iran. The properties of dust samples along the studied transect highly depend on the elevation and climate. However, the properties can be influenced by the dust storms probably originating from sources outside the country.
