Aptian planktonic foraminiferal biostratigraphy and microfacies analyses of Mudurnu – Nallihan sequence (Ankara, Turkey)

Kayhan, Deniz Yağmur
The Mudurnu – Nallıhan Sequence that comprises the Upper Jurassic – Lower Cretaceous carbonate succession was cut by diabase dykes and intercalated with volcano-sedimentary rocks in the Nallıhan region, Ankara, Turkey. The sequence consists of the Yosunlukbayırı Formation and the Soğukçam Limestone. This study focuses on the high-resolution biostratigraphy and microfacies analyses of the Soğukçam Limestone widely exposed in the north of the Nallıhan town. For this purpose, the stratigraphic section was measured (94.73 m thick) and a total of 44 samples were collected from limestone, shale and diabase dyke. By using planktonic foraminiferal bioevents, the following biozones were established in ascending order: Globigerinelloides blowi Zone (Early Aptian), Leupoldina cabri Zone (Early Late Aptian) and Globigerinelloides ferreolensis Zone (Late Aptian). Eight species of Hedbergella, three species of Globigerinelloides, and Leupoldina cabri were identified in the study. Only the presence of these r-mode opportunistic planktonic foraminifera, Hedbergella and Globigerinelloides, in the studied samples indicates that eutrophic environmental conditions prevailed in the Aptian time in the studied region. The elongated chamber forms, such as Hedbergella roblesae and Leupoldina cabri, low-oxygen planktonic foraminifers suggests that the Oceanic Anoxic Event 1a (the Selli Event) has possibly been recorded in the Leupoldina cabri Zone of the studied sequence. In addition, small benthic foraminifera, radiolaria and Cadosina sp. were recorded through the measured section. Based on both lithofacies analysis (determination of the depositional texture), and biofacies analysis (fossil assemblages), microfacies types were defined as MF-1: Radiolarian mudstone / wackestone, MF-2: Planktonic foraminiferal and radiolarian wackestone / packestone and MF-3: Planktonic foraminiferal mudstone / wackestone. In the light of the microfacies analyses, the depositional environments of the Aptian part of the Soğukçam Limestone were determined as toe of slope to deep water basin.


Bengül, Nilya; Altıner, Sevinç; Department of Geological Engineering (2022-8-31)
The Haymana Basin in central Anatolia (Turkey) formed during the closure of the Neo-Tethys in the Late Cretaceous to Middle Eocene as a forearc accretionary wedge. Middle Eocene aged units in this basin are exposed near Çayraz Village, Haymana. The Çayraz Formation is represented by the package of nummulitic banks and intercalation of calcareous mudstones. The aim of this study to investigate the sedimentary cyclicity and depositional sequences in the Eocene successions of the Haymana Basin. To be able to a...
Stratigraphical, sedimentological, geochemical and cyclostratigraphical analyses of upper cretaceous (upper santonian- campanian) pelagic successions of Haymana and Mudurnu-Göynük basins of the Sakarya continent, Turkey
Afridi, Bakht Zamir; Yılmaz, İsmail Ömer; Department of Geological Engineering (2014)
The Upper Cretaceous (Upper Santonian-Campanian) successions were measured from two different basins of Turkey, Haymana basin and Mudurnu-Göynük basin. The measured Alagöz and Göynük sections are dominantly composed of red marly beds and fine grained siliciclastic green-gray beds with occasional interruption of fine grained turbiditic bedding. A variety of lithofacies are identified in the studied sections, including radiolarian packstone, silty marls, marls, mudstone, claystone, siltstone and fine grained ...
Tectono-metamorphic evolution of the northern Menderes Massif : Evidence from the horst between Gördes and Demirci Basins (west Anatolia, Turkey)
Buğdaycıoğlu, Çağrı; Bozkurt, Erdin; Department of Geological Engineering (2004)
The Menderes Massif forms a large metamorphic culmination in western Turkey ا an extensional province where continental lithosphere has been stretching following Palaeogene crustal thickening. Northern sector of the Massif on the horst between Gördes and Demirci Basins was chosen for structural analysis aimed to study the tectono-metamorphic evolution of the northern Menderes Massif. Within the study area, four groups of rocks are recognized: (1) the metamorphic rocks ا orthogneisses and metasediments; (2) ...
Sedimentary cyclicity in the upper cretaceous successions of the Haymana Basin (Turkey): depositional sequences as response to relative sea level changes
Huseynov, Afgan; Altıner, Demir; Department of Geological Engineering (2007)
The Haymana basin in Central Anatolia (Turkey) formed on a Late Cretaceous to Middle Eocene fore arc accretionary wedge. The aim of this study is to investigate the sedimentary cyclicity and depositional sequences in the Upper Cretaceous clastic successions of the Haymana basin. To be able to achieve this objective, a 250 m stratigraphic section, which is mainly composed of siliciclastics has been measured in the Haymana Basin. In this study, detailed lithofacies analyses were performed and five different ...
Responses of the planktonic foraminifera to environmental conditions across the cretaceous/paleogene boundary in the Göynük basin, Northwest Anatolia, Turkey
Özder, Rengin; Özkan Altıner, Sevinç.; Department of Geological Engineering (2019)
The aim of this study is to reveal the evolutionary response of the planktonic foraminifera after the Cretaceous/Paleogene (K/Pg) boundary interval in the Göynük Basin, Northwest Anatolia, Turkey. To achieve this purpose, a multidisciplinary study including biostratigraphy and mineralogy was carried out. In the Göynük area, an 8.55 m-thick section was measured, and a total of 47 samples were collected from the Seben Formation and the Hisarözü member of this formation composed of marls and clayey limestones....
Citation Formats
D. Y. Kayhan, “Aptian planktonic foraminiferal biostratigraphy and microfacies analyses of Mudurnu – Nallihan sequence (Ankara, Turkey),” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Geological Engineering., Middle East Technical University, 2019.