AN IMPORTANT CHABASITE OCCURRENCE IN CENTRAL ANATOLIA AND ITS MINERALOGICAL FEATURES

Abstract

The Lower - Middle Miocene Aktepe Formation cropping out to the south of Ankara (Central Anatolia) is comprised of volcano - sedimentary lacustrine deposits. In the formation mainly three zeolitic tuffaceous layers including dominant chabasite were determined. Based on the data obtained from XRD and SEM investigations, it was determined that the authigenic zeolite minerals are chabasite, erionite and clinoptilolite, and minor smectite in some samples. Where the clinoptilolite is dominant, at a location, it has been observed that Kfeldspar enters into the mineralogical composition. The main mineral assemblages in zeolitic tuffs are determined as "chabasite + erionite + clinoptilolite" and "chabasite + erionite + clinoptilolite + K-feldspar".The first data obtained points out that the Aktepe Formation has deposited in a saline - alkaline lacustrine environment. It can be said that, the zeolitic tuff occurrences in which chabasite is abundantly present, has economical potential.