Origin and palaeodepositional environment of evaporites in the Bala sub-basin, Central Anatolia, Turkiye


Demir E., Varol E.

INTERNATIONAL GEOLOGY REVIEW, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1080/00206814.2022.2114021
  • Journal Name: INTERNATIONAL GEOLOGY REVIEW
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC, Pollution Abstracts
  • Keywords: Bala sub-basin, Central Anatolia, evaporite, shallow marine, sabkha, salt diapir, tectonic, SIVAS BASIN, STRUCTURAL EVOLUTION, ISOTOPIC COMPOSITION, TRIASSIC EVAPORITES, TECTONIC EVOLUTION, SEAWATER SULFATE, TUZ GOLU, GYPSUM, SULFUR, STRONTIUM
  • Hacettepe University Affiliated: Yes

Abstract

Bala is located in Central Anatolia and is a sub-basin of the Tuzgolu basin, which consists of many basins formed in response to the closure of the Neotethys ocean. The evaporites in Bala sub-basin formed under the influence of regional uplifting during the Middle Eocene period with gradual shallowing in response to the structural compressional regime. The Bala sub-basin comprises four units from bottom to top: the Lower Unit (BU1) consisting of mudstone, claystone with limestone layers; the Evaporites (BU2) containing dominant gypsum with anhydrite; mixed siliciclastic-carbonate-evaporitic deposits (BU3); and the Upper Unit (BU4) containing conglomerate-sandstone-claystone and siltstones. The evaporitic unit, which are the main subject of study consists of primary selenitic gypsum, anhydrite, locally celestite crystals and secondary gypsum formed due to the anhydritization of primary gypsum and then hydration of these anhydrites. The results obtained from mineralogical-petrographic, geochemical and isotopic (delta O-18 and delta S-34) investigations indicate that these evaporites were deposited in shallow marine to sabkha environments dominated by arid conditions. The presence of primary selenite crystals, the anhydrite with nodular, chicken-wire, and mosaic structures support precipitation occurred in a partially saline shallow water. The excessive thickness of the evaporitic accumulation, chaotic masses including gypsum breccia, salt diapirs and dome structures are attributed to tectonic processes acting during the formation of the Central Anatolian basins.