Abstract: Aluminum sulfate minerals, kaolin and bentonitic clay deposits and zeolites occur within upper Miocene-Pliocene high-Kandesitic-dacitic volcanic rocks and lacustrine sediments in the west southwest of Konya, Turkey. In the area, post-volcanic phenomena, such as solfatara activity, has already been continued.The samples taken from the study area were mineralogically and chemically examined using XRD, SEM-EDS, XRF,AAS, DTA-TG and microprobe instruments. As a result of this investigation, it has been determined that alteration mineralsformed by early-and/or post volcanic acid solutions reacted with the solutions were highly acidic in character, alunite and natroalunite were produced by the alteration of mainly dacitic volcanic rocks, while minamiite was formed by the alteration ofandesitic volcanic rocks. However, acidic or weakly acidic solutions yielded kaolinite and/or halloysite and illite.Alunite group minerals are K, Na and Ca sulfate with formula (Ca, Na, K) A13(SO4) 2 (OH) 6 and mainly form as hydrothermal minerals in the study area. Nearly pure minamiite and alunite have been found in a few samples. They are commonly associated with silica polymorphs, kaolinite and halloysite in various parts of the study area.Stability relations of minerals in the advanced argillic alteration zone indicate alteration took place under acidic conditionsin the near-surface environment. Mineralogical and textural evidence also suggests alteration occurred in steam-heated environment, rather in a supergene or magmatic hydrothermal origin.