A prelimennary study: Celestite-bearing gypsum in the Tertiary Sivas basin, central-eastern Turkey

Abstract

Celestite-bearing evaporite mineralization is common in the Tertiary evaporitic units of Ulas-Sivas basin, East-Central Turkey.The firstoccurrenceof gypsum which is "laminated in character" (Balatinogypsum)took place in the shallow inner-lagoonor depressions duringregressioninthe upperEocene. Thickgypsumandoverlyingbedscomposedof the bedded,nodulargypsumand sandstonealternations were formed in a coastal sabkha and abandonedchannels within the meanderedrivers through the Oligocene time. The last occurrenceof evaporiticunits, representedby massive and bedded gypsum alternatingwith sandstonesand fossiliferous limestones resultedfrom limited marine transgressionin the early Miocene along the southern margin of the Sivas Tertiary basin.The celestitemineralizationpreferentiallytookplace withinthe Mioceneevaporitesand subordinateamountin the shallowmarinelimestones and terrestrial siliciclasticsranging from late Eocene to Oligocene in age. Celestite shows different depositional characters such as stratabound,massive,fractureand cave filling. Accordingto microscopicstudies,threepetrographictypes have been determinedin these different beds of celestite. They are prismatic and bar-like; sub-idiotopicand tabular; fibrous-radial.The sourceof the celestitein the Sivas Tertiarybasin has been debated.Thereis little evidencefor suggestingsedimentary-syngenetic origin. Many geologistsbelieve that it formed during late diagenesisor epigeneticstages,but this interpretation reflects a lack of a comprehensive study and only depends on field observations. This paper includes both field and laboratory studies (light, ore and electron microscopes, microprobe,87186Sr isotopes)and obtainedinitial results which have inclinedto the diagenetic-epigenetic origin.

Cretaceous-Tertiary (K-T) boundary evaporites in the Malatya Basin, eastern Turkey

“…This feature confirms that celestite replaced the host rock lithologies (limestone, gypsum), and it was followed by massive celestite precipitation. The host rock dissolution could be realized during atmospheric condition driven by uplifting of the carbonate platform in the late diagenesis and/or deep brines entered into underlying sediments, and they leached considerable amounts of strontium from host sediments Once these Sr-enriched fluids discharged backup into overlying beds containing gypsum and carbonate material (Tekin et al 2001;Ehya et al 2013), and formed both replacive and cementing celestite in the host rock (Fig. 9).…”

“…Messinian evaporates are restricted to the southern part of Turkey and are exposed in the İskenderun-Hatay and Adana basins (Tekin et al 2010;Ilgar et al 2013). Terrestrial evaporates accumulated in the Ç ankırı-Ç orum, Sivas and Tuz Gölü basins during the Tertiary following deposition of marine evaporates (Varol et al 2002;Tekin et al 2001;Gundogan et al 2005;Ayyıldız et al 2009). In contrast, certain central and western Anatolian Miocene basins, such as the Beypazarı, Emet, Bigadiç and Sultançayır basins, are characterized by trona (older) and borate deposited in hydrothermal-induced lake environments (e.g., Ortí et al 1998;Helvacı and Orti 1998;Gündogan and Helvacı 2001;García-Veigas et al 2010;García-Veigas and Helvaci 2013).…”

Stratigraphy, mineralogy and depositional environment of the evaporite unit in the Aşkale (Erzurum) sub-basin, Eastern Anatolia (Turkey)

“…These Srrich fluids circulated within the evaporitic units and either making compounds with SO 4 2À replaced to anhydrite or precipitated in cavities in carbonate rocks resulted from partial dissolution of carbonates during circulation of fluids. These processes also help the hydration of the last stage anhydrite occurrences (Ceyhan, 1996;Tekin et al, 2001Tekin et al, , 2002. Calcite and aragonite is syn-sedimentary mineral formed during early diagenesis (e.g., € Onalgil et al, 2015) and later transformed to dolomite by circulation of Mg-rich fluids (Fig.…”

“…These deposits consist of mainly gypsum, anhydrite, halite, thenardite, and glauberite (e.g., G€ okçe and Ceyhan, 1988;Çubuk, 1994;Ya gmurlu and Helvacı, 1994;Ceyhan, 1996;Gündo gan and Helvacı, 2001;Tekin et al, 2001;Çiner et al, 2002;Orti et al, 2002;Türkmen, 2004;Palmer et al, 2004;Gündo gan et al, 2005;Zeybek, 2007;Kırtıl, 2008;Yeş ilova and Helvacı, 2013). The Neogene basins and sub-basins in the Eastern Anatolia of Turkey between the _ IzmirEeAnkaraeErzincan and the AssyrianeZagros suture zones (Fig.…”

Gypsiferous carbonates at Honaz Dağı (Denizli): First documentation of Triassic gypsum in western Turkey and its tectonic significance

“…Tertiary evaporites were extensively deposited in various sedimentary basins (Ergü n, 1977;Helvacı, 1978;Gö kçen and Kelling, 1985;Gö kçe and Ceyhan, 1988;Gü ndogan and Helvacı, 1993;Yagmurlu and Helvacı, 1994;Helvacı, 1995;Helvacı and Yagmurlu, 1995;Helvacı, 1998;Helvacı and Orti, 1998;Orti et al, 1998;Gü ndogan, 2000;Helvacı and Alonso, 2000;Gü ndogan and Helvacı, 2001;Tekin et al, 2001;Orti et al, 2002;Palmer et al, 2004;Gündogan et al, 2005) but there is no record of Triassic evaporites in Turkey. New evidence is presented here that the gypsum-bearing sequence exposed between Mentes ße and Aydınlar villages is Triassic in age, based on first-hand geological mapping, several measured sections, and new isotopic data.…”