Türkiye Jeoloji Bülteni

Geology, Mineralogy and Economic Potantial of Sultançayır (Susurluk- Balıkesir) Boratiferous Gypsum Basin

Abstract: Metamorphic basement complex are unconformably overlain by the Triassic Dışkaya (Karakaya) formation which is intruded by the Paleocene Çataldağ granidiorite unit. Lower Miocene andesite-aglomera and tuff unitrest top of all these older unit with unconformity, Midle-Upper Miocene sediments overly all the older units, and contents in ascending order, basement conglomarate, lower limestone, sandy claystone and upper limestone units. According to the petrographic studies, metamorphic basement complex are composed of amphibolite and quartz -muscovite schist, whereas Dışkaya formation are composed of neomorphic limestone blocks, shale and lithareniüc sandstones, Sandstones taken from basement conglomerate unit show feldspatic litharenite composition.Boratiferous gypsum beds varying 10 to 15 metre in thichnesses, occur within the sandy claystone unit. Nodularpandermite and howlite minerals are present within these gypsum horizons. Chemical analysis shows that pandermiteand howlite minerals have 46.49% and 40.69% B2O3 mean values respectively, It is estimated that the reserve of theSultançayır borate deposit is approximately 1 million metric tons. Howewer, a great amount of this reserve was minedout by the French and English companies during the period between the years of 1865 and 1955. In addition, probabledistribution of gypsum beds are determined and 300 million ton geologic reserv arc calculated. These gypsum beds have34% SO3 mean value and the properties of gypsum beds are suitable for the cement industry.