Geochemistry and mineralogy of zeolitic tuffs from the Alaçatı (Çeşme) area, Turkey

Abstract

Silicic vitric tuffs of the Alaçatı (Çeşme) area, west of Izmir (Turkey), are partly altered to authigenic zeolites and clay minerals. Mordenite and clinoptilolite-heulandite accompanied by smectite are the main alteration products of the tuffs. Scanning electron microscope examination indicates that mordenite forms mainly from a gel-like precursor and to a lesser degree from volcanic glass. Mordenite and clinoptilolite-heulandite have formed by the hydrolysis and dissolution of silicic vitric tuffs by thermal waters which circulated through the fracture zone into porous vitric tuffs. These thermal waters, which resulted from mixing of thermal (Na-Cl type) and groundwaters, provided the extra Na and Ca that are necessary for the formation of mordenite. Various percentages of calcite are present in the altered tuffs. The enrichment of calcite in the altered tuffs indicates that thermal waters supply Ca, sourced from dissolution of Triassic carbonate rocks.The alteration minerals in the Alaçatı (Çeşme) area do not seem to be laterally zoned. The occurrence of the zeolites seems to be related to inferred fracture zones trending NE—SW. These fracture zones are important because they provide porosity and permeability in the tuffs for zeolite formation. The large glass content and permeability of tuffs accompanied by the favorable hydrochemical condition resulted in zeolitization of the Alaçatı (Çeşme) area.

Mineralogical and physico-chemical properties of Heu-type zeolitic rocks SE of Ankara, central Turkey

“…Well known zeolite deposits, especially of Cpt, are located in western and NW Turkey (Esenli & Özpeker, 1993;Helvacı et al, 1993;Gündogdu et al, 1996;Temel & Gündogdu, 1996;Esenli & Kumbasar, 1998;Kaçmaz & Köktürk, 2004;Kılıç & Kılıç, 2006;Snellings et al, 2008). The present study area is located SE of Ankara in the lacustrine Tuzgölü basin of Tertiary age which contains widespread volcanic and zeolite-bearing volcanoclastic rocks (Fig.…”

ÇEŞME YARIMADASI’NIN NEOJEN STRATİGRAFİSİ ve BÖLGESEL KORELASYONU, BATI ANADOLU

“…The main geological surveys starting with Kalafatçıoğlu (1961) in the Karaburun Peninsula are mainly related to pre-Neogene rock units (Çakmakoğlu and Bilgin, 2006). Few studies on Neogene carried out in the Çeşme Peninsula include magmatism (Innocenti and Mazzuoli, 1972;Borsi et al, 1972;Türkecan et al, 1998;Kaçmaz and Köktürk, 2004;Helvacı et al, 2009), hydrogeology-geothermal energy (Koçak, 1974;Yılmazer and Yakabağı, 1995;Gemici and Filiz, 2001) and Neogene geology (Besenecker, 1973;Göktaş, 2010Göktaş, , 2016b. Innocenti and Mazzuoli (1972) put forward that the "Alaçatı massif" (Armağandağı volcanics in this study) is represented by the calcalkaline character of latite-andesitic volcanics in their pioneering studies in which they examined petrochemical properties of the Neogene volcanics in the Karaburun Peninsula.…”

“…Besenecker (1973) showed that there were correlating equivalents of Neogene deposits of Chios Island in the Çeşme Peninsula by means of lithostratigraphic correlations and large mammal fossils. Kaçmaz and Köktürk (2004) examined the geochemical and mineralogical properties of "silicic vitric tuffs" (Alaçatı pyroclastics) near Alaçatı and stated that authigenic zeolitizations (mordenite, clinoptilotite-heulandite) developed in the parts subjected to partial alteration. The stratigraphies proposed for Neogene rock units in the Karaburun Peninsula by Türkecan et al (1998) and Helvacı et al (2009) were constructed based on the radiometric ages and it was accepted that the Neogene sedimentation and volcanism had developed in a laterally relationship from bottom to top.…”

Mineralogical and petrographic study of zeolitic tuffs from Yenice-Saraycık (Demirci, Manisa), Turkey

“…The Neogene volcano-sedimentary units containing zeolites are widely located in Western Turkey. The presence of zeolites within these units is mostly associated with altered tuffs [2][3][4].…”