Alteration of glassy volcanic rocks to Naand Ca-smectites in the Neogene basin of Manisa, western Anatolia, Turkey

Abstract

Alkali- and Ca-rich smectites occur in association with Neogene lacustrine sedimentary rocks and high-K calc-alkaline volcanic rocks with compositions ranging from andesite to rhyolite in western Anatolia (Turkey). Major clay occurrences are associated predominantly with the Foça and Akçaköy ignimbrites and with the ignimbrites within the Rahmanlar pyroclastics. Experimental studies indicate that the main clay minerals present are Na- and Ca-smectite and subordinate illite, associated with silica polymorphs, trace clinoptilolite and chlorite. The authigenic minerals formed by weathering and metasomatic reactions between hot volcanic material and lake water. Smectite was produced as a result of argillic alteration of the volcanic glass and feldspars of the ignimbrites, Rahmanlar pyroclastics and reworked volcaniclastic sediments through chemical weathering and dissolution-precipitation processes and formed as authigenic phases both in terrestrial and nearby shallow lacustrine environments under prevalent humid or semi-humid climate during the Neogene.

Geology, mineralogy, and geochemistry of the Zarloukh Bentonite −Tuff deposit, Hemrin South Mountain, northern Iraq: implications for genesis and geotectonics

“…It has strong colloidal properties, and its volume increases several times when encountering water, creating a gelatinous and viscous substance. Bentonite deposits worldwide mostly originate from the hydrothermal or diagenetic alteration of pyroclastic rocks of intermediate to acidic compositions (e.g., Yalçin and Gümüşer, 2000;Abdioğlu and Arslan, 2005;Christidis and Huff, 2009;Arslan et al, 2010;Çiflikli et al, 2013;Modabberi et al, 2019;Kadir et al, 2021). Bentonite deposits occur in many countries including USA, Germany, Greece, Spain, Italy, Algeria, Argentina, Australia, Italy, Japan, Hungary, Turkey, and Iran (Modabberi et al, 2019).…”

Determination of uranium and thorium isotopes in kaolinitic samples by ICP-MS/MS

“…The relative proportions between kaolinite and smectites can be used as indicators of the role of chemical weathering: for smectites, there are already described relationships between chemical composition and environmental conditions (ÇIflikli et al, 2013;Dill, 2017). However, the major chemical composition of kaolin minerals is independent of their origin.…”

Mineralogy, geochemistry and physical properties of bentonites from the Western Thrace Region and the islands of Samos and Chios, East Aegean, Greece

“…the Island of Milos, Greece (Christidis et al, 1995;Christidis & Scott, 1996) and minor sites of operation in Kimolos, Greece (Christidis, 1998(Christidis, , 2001, western Anatolia (Abdioglu & Arslan, 2005;Yildiz & Kusçu, 2007;Arslan et al, 2010;Çiflikli et al, 2013;Ekinci Sans et al, 2015), Cyprus (Christidis, 2001(Christidis, , 2006 and Egypt (Agha et al, 2013). All these deposits have been formed at the expense of volcanic and volcaniclastic rocks of rhyolitic to andesitic-basaltic composition mainly via low-temperature hydrothermal alteration or weathering, although diagenesis might also have played some role in the formation of the bentonites (Christidis et al, 1999;Agha et al, 2013;Ekinci Sans et al, 2015).…”