ABSTRACT: Triassic-Cretaceous aged Akdağ limestones and Burdigalian aged flysch unit occur at the basement,, Gölcük- Isparta around. In the vicinity of Gölcük, Pliocene, volcanism has an, .andezitic .and trachiandezitic character. Its products are lava, dyke and. pyrociastics. The volcanism. erupted several times,,, in the area. Pyroclaslic units in connection with the Gölcük volcanism are divided into volcanic brechia and. aglomerates, over volcano- sedimentary unit, pumice levels and. upper volcano-sedimentary unit. In. this pyroclastic unit, the pumice deposits present mainly in. two different horizons; block-bearing pumice and economic pumice, Pümice deposits formed depending on explosive trachi-andesitic volcanism. Gölcük-Isparta pumice deposits can supply for the light building materials needs of the central Mediterranean and Lakes districts, not only by their quality but also their reserves.