SEDIMENTOLOGY OF BEYKOYU FORMATION (MIOCENE) AROUND BEYKOYU – KUSKUNCUK – GOKCEYAZI (EREGLI – KONYA - TURKEY)

8th International Scientific Conference - SGEM2008, www.sgem.org, SGEM2008 Conference Proceedings/ ISBN: 954-918181-2, June 16-20, 2008, Vol. 1, 193-200 pp

ABSTRACT

The basement of the investigated area consists of Upper Permian – Upper cretaceous
aged the Bolkardagi Group and several formations situated in the Bolkardagi Unit,
tectonostratigraphic units of the Taurus, viz., Paleocene – Lower Eocene aged the
Güneydağı formation, and Upper Paleocene – Eocene aged the Halkapınar formation.
The limestone of the Guneydagı formation is observed as a basement rock in the area,
and is overlied with angular unconformity by Miocene aged the Beykoyu formation,
which is made up of members of the Kabaktepe gypsum and the Kayalidagtepe
stromatolitic limestone. The Beykoyu formation is overlied with an angular
unconformity by Upper Pliocene – Holocene aged the Kuskuncuk formation, which
consists of alternation of conglomerate, sandstone and mudstone including caliche
bands in some levels. While the Beyköyü formation was formed in lacustrine
environment, the Kuskuncuk formation was developed in environments of alluvial fan
and braided stream.

The Kabaktepe gypsum member, basement of the Beykoyu formation, is white – gray in
colour and is usually massive, rondomly medium to thick strata and have a laminae. The
gypsum of the Kabaktepe gypsum member is usually white in colour and cyrstalized
texture, at some levels they are prismatic and transparent, and folded in places. At some
places, at the bottom of the gypsum, alternating of conglomerate - sandstone and
mudstone can be observed. Through the upper part, the alternating of greenish – gray,
brown sandstones and green – red coloured mudstones are present. In the upper levels
they are in the form of gypsum with muddy stone interlayer. Over the gypsum,
stromatolitic limestones belonging to the Kayalidagtepe member are found. The
stromatolites are beige, brown in colour, medium to thick layered, and these are in the
types of lateral linked hemispheroidal (LLH type), stacked hemispheroidal (SH type)
and onkoides (SS type). The stromatolitic limestones have interlayering gray mudstones,
red conglomerate, sandstones and mudstones. In some levels the stromatolites can be
seen as sandy – gravel limestones which have ostrocode and gastropoda fossiliferous
limestones alternating with marls. The formation of stromatolitic limestones belonging
to the Kayalıdağtepe member is strictly depending on the blue – green algae of
Shizothrix sp., Phormidium sp. and Scytonema sp.

Keywords: Beykoyu, gypsum, stromatolite, lacustrine.