Micropalentological analysis and sequence stratigraphy through upper tournaisian substage in Aladağ unit (Central Taurides, Turkey)


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Jeoloji Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2009

Öğrenci: AKSEL TUĞBA DİNÇ

Danışman: DEMİR ALTINER

Özet:

The purpose of this study is to investigate the Upper Tournaisian substage within the Carboniferous carbonate deposits of the Aladağ Unit in the Hadim region (Central Taurides) based on foraminiferal diversity and to study the meter scale cyclicity in order to explain the sequence stratigraphic evolution of the carbonate succession. In this study, a 27.01 m thick stratigraphic section consisting of limestones and shales was measured and 89 samples, collected along this section, were analyzed. Micropaleontological analyses are based on benthic foraminifera. According to the benthic foraminiferal assemblages, two biozones were identified as Zone Ut1 and Zone Ut2 within the Upper Tournaisian. Zone Ut1 is characterized by a poor foraminiferal assemblage while the Zone Ut2 consists of a diverse Upper Tournaisian foraminiferal fauna. In order to construct a sequence stratigraphic framework and appreciate depositional environmental changes, microfacies studies were carried out. Seven microfacies types were recognized and depending on the stacking patterns of these microfacies types, two fundamental types of cycles, A and B, were identified. Through the measured section, twenty-five shallowing-upward meter scale cycles and two sequence boundaries were determined. Quantitative analysis of benthic foraminifera was used to demonstrate the biological response to cyclicity. Since foraminifers are very sensitive to sea level changes, the abundance of benthic foraminifera displays a good response to sedimentary cyclicity. In order to apply a worldwide sequence stratigraphic correlation, the sequence boundaries and the meter scale cycles of this study were compared with those described in South China and Western European platform and the Moscow Syneclise. An Early Tournaisian transgression was followed by a major fall in relative sea level during the Late Tournaisian. Two sequence boundaries recognized in the measured section correspond to global sea level falls in the Late Tournaisian.