Evaluation of Nardin Cave (Bilecik) Deposits in Relation To Paleoenvironmental Conditions

Abstract

The limestone, cropping out in the Western-Central Anatolian Region represents a unique example of dissected and relict karst types. It is important evidence the processes that affected the evoluation of karstic rocks in this region which has distinctive characteristics compared with the other karst regions of Turkey. The Nardin cave deposits were examined in relation to processes which control karstification of the region. In this framework, chemical and physical properties of the deposits in Nardin cave, which formed in Bilecik limestone of Jurassic age, were evaluated in relation to determination of climatic and hydrologic processes of the region. Identifiable columnar sections of cave deposits preserved on the cave walls were drawn. Color, texture, age of the formation and iron contents of the deposits were investigated. According to chemical analyses performed, brown colored deposits have high iron content and yellowish colored deposits have high organic matter content U/Th dating analyses indicate that the cave was completely closed by interior deposits about 150 ky before present. Cave morphology, stratigraphy of the cave interior deposits and chemical analyses suggest that after catastrophic rainy period, two cold climatic spells and one mild climatic spell prevailed successively in the region.