MINERALOGICAL AND PETROGRAPHIC STUDY OF ZEOLITIC TUFFS FROM YENİCESARAYCIK (DEMİRCİ, MANİSA), TURKEY

Dokuz Eylül Üniversitesi-Mühendislik Fakültesi Fen ve Mühendislik Dergisi Cilt 20, Sayı 59 , Mayıs, 2018 Dokuz Eylul University-Faculty of Engineering Journal of Science and Engineering Volume 20, Issue 59, May, 2018 DOI: 10.21205/deufmd.2018205950 Mineralogical and petrographic study of zeolitic tuffs from YeniceSaraycık (Demirci, Manisa), Turkey Hülya KAÇMAZ Dokuz Eylül Üniversitesi, Mühendislik Fakültesi, Jeoloji Mühendisliği Bölümü, 35370, İzmir (ORCID: 0000-0001-7752-0408) (Alınış / Received: 10.01.2018, Kabul / Accepted: 23.02.2018, Online Yayınlanma / Published Online: 15.05.2018) Keywords Zeolite, tuff, alteration, petrography, mineralogy Abstract: The mineralogical and petrographic properties of the zeolitic tuffs around the Yenice-Saraycık, southwestern of Demirci (Manisa), were studied by using the polarizing microscope and powder X-ray diffraction (PXRD). Microscopic observations revealed that the tuffs are dominated volcanic glass however, contain small amounts of crystal and rock fragments. The crystal fragments consist mainly of quartz, k-feldspar, plagioclase and trace amounts of biotite. The glassy tuffs were altered to zeolites and other minerals. PXRD analysis of the tuff samples supports the microscopic observations. The PXRD results showed that the tuffs are mainly altered to zeolite minerals, clinoptilolite-heulandite. Smectite is the most common clay mineral coexisting with zeolites. However, kaolinite and/or chlorite were detected in some zeolitic tuff examined. Quartz, plagioclase, K-feldspar and mica/illite were determined in the most of samples. Additionally, opal-CT was found together with kaolinite/chlorite in zeolitic tuffs near the Saraycık area. Yenice-Saraycık (Demirci, Manisa) civarındaki zeolitik tüflerinin mineralojik ve petrografik incelenmesi Anahtar Kelimeler Zeolit, tüf, alterasyon, petrografi, mineraloji Özet: Bu çalışmada Demirci’nin (Manisa) güney batısında, Yenice-Saraycık civarındaki zeolitik tüflerin mineralojik ve petrografik özellikleri polarizan mikroskop ve X-ışını difraktometre (XRD) yöntemleri kullanılarak incelenmiştir. Mikroskobik gözlemler tüflerin camsı yapıda olduğunu, bununla birlikte az miktarda kristal ve kaya parçaları içerdiğini göstermektedir. Kristaller kuvars, plajiyoklaz, potasyum feldispat ve az miktarda biyotittir. Camsı özellik gösteren tüfler zeolitlere ve bazı diğer minerallere dönüşmüştür. 647 H.Kacmaz/Mineralogical and Petrographic Study of Zeolitic Tuffs from Yenice-Saraycık (Demirci, Manisa), Turkey Tüf örneklerinde yapılan XRD analizleri mikroskobik çalışmaları destekler niteliktedir. XRD çalışmaları tüflerin yaygın olarak klinoptilolit-höylandit gibi zeolit minerallerine dönüştüğünü göstermektedir. Smektit tüf örneklerinde zeolitlerle birlikte görülen en yaygın kil mineralidir. Bununla birlikte bazı tüf örneklerinin kaolinit ve/veya klorit içerdiği belirlenmiştir. Örneklerin birçoğunda kuvars, potasyum feldispat, plajiyoklaz ve mika/illit saptanmıştır. Saraycık bölgesi civarındaki zeolitik tüflerde kaolinit/klorit ile birlikte Opal-CT mineraline rastlanmıştır. Corresponding author: 1. Introduction Zeolites are microporous, hydrated aluminosilicate minerals. They occur most commonly in volcanoclastic sediments, especially altered vitric tuffs. [1]. 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 [2-4]. overlie the basement metamorphic rocks. These units are overlain unconformably by the Neogene sediments of fluvial, lacustrine mainly consisting of sandstone, conglomerate, siltstone, mudstone alternations and limestone, marl, shale and claystone alternations [6]. The volcano-sedimentary units are commonly exposed in the Demirci (Manisa) area, Western Turkey. Recently, a study on tuffs around southwestern part of the Demirci, Yenice-Saraycık area, was carried out [5] and the geochemical characteristics of the tuffs have been described in detail. The purpose of this study is to define the mineralogical and petrographic features of the zeolitic tuffs around Yenice-Saraycık area. 2. Geologic setting The study area, Yenice-Saraycık, is located in the southwestern part of the Demirci (Manisa) area (Figure 1). The main rocks outcropping in the study area are the Neogene fluvio-lacustrine sediments, Mesozoic carbonate rocks and Metamorphic rocks of the Menderes massif (Figure 2). The Menderes Massif metamorphic rocks form the basement rocks of the studied area. The recrystallized limestones of Mesozoic Figure 1. Location map of the study area. The main rocks outcropping in the study area are the Neogene fluvial and lacustrine sediments. The tuffs studied here are intercalated with the fluviolacustrine sediments of Neogene. They have nearly horizontal layers and are 648 H.Kacmaz/Mineralogical and Petrographic Study of Zeolitic Tuffs from Yenice-Saraycık (Demirci, Manisa), Turkey generally white, yellowish white or cream-colored. The geochemical studies [5] show that the tuffs are peraluminous, calc-alkaline and also rhyolitic and rhyodacitic in composition. 3. Material and Method The tuff samples collected from YeniceSaraycık (Demirci) area were investigated by using polarizing microscope and standard X-ray diffraction (XRD) analyses. Thin sections of tuff samples were prepared at Dokuz Eylul University. The petrographic examination was performed by polarizing microscope on selected thin sections. The mineralogy of the bulk samples was determined by X-ray diffraction (XRD) analysis. For the XRD analysis, pulverized powders were scanned from 4oto 65o 2θ at a speed of 2o/min using CuKα radiation. Figure 2. Simplified geological map of the study area. Modified from [6]. 3. Results and Discussion Tuff is consolidated volcanic ash. They contain mainly glass, crystal and rock fragments. The percentages of these fragments are used in naming the tuffs as vitric, crystal or lithic [7]. Microscopic studies reveal that the studied tuffs are made up of abundant proportions of glassy fragments. However, crystal and rock fragments are generally less than 10 percent of the tuff, so that the tuffs in the study area are classified as ‘vitric tuffs’. The glassy fragments are observed both as pumice fragments and glass shards (Figure 3a and 3b). The glass shards have mostly angular, curved shapes. The shapes of the glass shards are considerably well preserved. The pumice fragments are generally elongate and flattened. They are colorless to lightbrown under plane polarized light and isotropic under cross polarized light. Some pumice fragments have been partly or wholly replaced by calcite (Figure 3c and 3d). The rock fragments observed rarely consist mainly of volcanic and lesser metamorphic rock fragments (Figure 3e and 3f). Various types of pyrogenic crystals are seen in the thin section. These crystals are chiefly alkali feldspar, plagioclase and quartz. The alkali f (...truncated)