Mineralogy, Geochemistry, and Genesis of Mudstones in the Upper Miocene Mustafapaşa Member of the Ürgüp Formation in the Cappadocia Region, Central Anatolia, Turkey

Abstract

The Upper Miocene Mustafapas-a member of the Ürgüp Formation in the Cappadocia region consists predominantly of mudstones, sandstone, and conglomerate lenses with ignimbrite and basalt intercalations. The mudstones are an important source of raw materials for the ceramics industry in Turkey. A detailed mineralogical, geochemical, and genesis study of these materials has not been performed previously and the present study aims to fill that gap. The characteristics of mudstones of the Mustafapas-a member were examined using X-ray diffraction, scanning and transmission electron microscopy, energy dispersive spectroscopy, and chemical analyses. Weathering products of ophiolitic and pyroclastic rocks were transported into the tectonically subsided zone where they accumulated as fluvial and lacustrine deposits.Weathering in the mudstones is evidenced by smectite flakes associated with relict pyroxene, rod-like amphibole, feldspar, and volcanic glass. The chemical composition of mudstones and their distribution suggest that the depositional basin was supplied with ophiolitic material in the south and ignimbrite material in the north. This interpretation is based on an increase in the quantity of feldspar and opal-A and a decrease in the Fe2O3+MgO/Al2O3+SiO2 ratio from south to north in the study area. The northward increases in Light Rare Earth Elements/Heavy Rare Earth Elements, La/Yb, Zr/Ni and Zr/Co ratios and Nb, Ba, Rb, Sr, and Eu in the mudstones of the Mustafapas-a member with positive Eu anomalies suggest that the Fe, Mg, Al, and Si required to form smectite were supplied mainly through the decomposition of amphiboles, pyroxenes, feldspars, and volcanic glass during weathering processes. After the deposition of mudstones, relative increases in evaporation-controlled Ca, K, and Al in pore water favored the partial dissolution of Ca-bearing minerals and smectite flakes and in situ precipitation of calcite and traces of illite fibers under alkaline micro-environmental conditions during early diagenesis.

Preparation and structure’s analyses of lanthanide (Ln) -exchanged bentonites

“…A source of lanthanide cations is the relatively abundant lanthanide ores in a concentration between about 150 to 220 ppm [10] in the Earth's crust [11,12,13,14,15].…”

Mineralogy and genesis of the Ni–Co lateritic regolith deposit of the Çaldağ area (Manisa, western Anatolia), Turkey

“…Smectite formation requires mild leaching conditions. Oxide zones overly a saprolite zone in all pits (Külah et al 2014;Kadir et al 2015;Ekinci Şans et al 2015). The positive correlations between Ni+Co and Mn and Cr 2 O 3 , and relative increases in their abundances with increasing proportion of Fe oxide, Fe-rich smectite and Mn oxide phases in the samples reveal that both Ni and Co are bound within the structures of these minerals (Bocquer et al 2006;Dublet et al 2015).…”

“…Eliopoulos et al (2012) reported that the wide range of arsenic values (0.004-1.07 wt%) in Gördes lateritic regolith and enhance in ferruginous saprolite may suggest enrichment of arsenic after transportation and redeposition. Latest Early Pliocene-Quaternary: extensional basin formation and Çaldağ horst was uplifted during this stage and Plio-Quaternary alluvial fans formed around the Çaldağ horst due to erosion of the rising blocks) (Fig.11e;Şengör and Yılmaz 1981; Yılmaz et al 2000; Ersoy et al 2014;Külah et al 2014).…”

Characterization and distribution of fibrous tremolite and chrysotile minerals in the Eskişehir region of western Turkey

“…In addition, the projection of a few samples close to the supergene/hypogene line may be due to weathering (Faure, 1986). The absence of the Palaeocene and Oligocene sedimentary units in the Mihalıççık region may also suggest that the region was subjected to uplift and chemical weathering (Yılmaz et al, 2000;Ersoy et al, 2014;Külah et al, 2014;Kadir et al, 2015).…”