Şen, Gül
The studied Triassic-aged successions indicate a large-scale tripartite sequence of depositional environments in the Amasra-Kastamonu region, the NW Anatolia. Sedimentological, petrographic, magnetic susceptibility, elemental geochemistry, cyclostratigraphic, and palynological analyses are carried out in order to determine the types of depositional environment where six stratigraphic sections were measured, to define the cyclic characteristics of the successions, to find out exact age of the Çakrazboz formation and to reveal prevailing paleoclimate conditions in the studied region. Based on the detailed analysis of facies, the depositional environment is characterized by a fluvial, shallow lake and deep lake from east to west. Various lithofacies are identified in the studied sections, including carbonates (limestone, marl, and calcrete) and siliciclastics (conglomerate, sandstone, siltstone, and mudstone). The fluvial environment deposits consist of meandering river sandstones and floodplain mudstones. Palustrine deposits represent the rhythmic alternation of greenish-grey and brownish-grey marlstones related to wetting and drying climate conditions and reddish-brown pedogenic calcretes related to extended pedogenesis. Lacustrine deposits are composed of carbonated mudstones, wackestones, and packstones formed under oxygenated water conditions. Based on detailed facies analysis and field observations, this study suggests that Çakrazboz formation was deposited in a balanced-fill type lake basin within the extensional regime in foreland settings. The magnetic susceptibility analysis was performed on 347 rock samples and 120 thin sections from whole measured stratigraphic sections. The presence of high magnetic susceptibility values (23,25 and 129,39*10-6 SI) in carbonates indicates a detrital entry into the lacustrine environment. Moreover, the presence of high ms values (212,49 and 160,38*10-6 SI) in brecciated limestone facies indicate that the facies exposed due to the decrease in the water level of the lake, and the extended subaerially exposure. As a result, the high magnetic values in lacustrine carbonates are linked to erosion-transportation and pedogenetic processes, and associated with bacterial origin. Elemental geochemistry method was carried out on the 152 samples from the Çakrazboz Formation were analyzed for determining CaCO3, SiO2 and organic matter. Based on elemental geochemical analysis of the Çakrazboz Formation, it is revealed that organic matter content of the mudstones, marlstones and, limestones generally varies between 0% and 3%. Furthermore, the cyclic geochemical condition is documented in successive accumulation of reddish-brown marlstone and desiccated greenish-grey marlstones. These alternations reflect fluctuations of Eh and PH conditions in lacustrine and palustrine settings. Moreover, Milankovitch-like cycles have been identified along the measured stratigraphic sections. Potential Milankovitch-like cycles have been determined along the six measured stratigraphic sections. Based on the facies analysis 3 main cycles and 11 sub-types of cycles are determined in the measured sections. Centimeter to meter-scale cycles, are generally represented by profundal to supratidal facies. A-type main cycles start with the carbonate mudstone at base, and are followed by wackestone and packstone microfacies types. B type main cycles are represented by an alternation of grey laminated mudstone and brown to green marlstone facies in Bozköy and İncigez section, and an alternation of mottled limestone and pedogenic and groundwater calcrete-like facies in Başköy-1 section. C-type main cycles are represented by sandstone and mudstone alternations in the Başköy-2 and Başköy-3 sections. The measured stratigraphic sections are commonly represented by five precession (≃19-21 ka) and one eccentricity (≃100 ka) cycles. Based on data, it is suggested that the cyclicity in these successions has similar characteristics with the cyclicity in Triassic terrestrial succession around the World. Palynological investigation was carried out to determine the age of the Çakrazboz Formation in the Amasra-Kastamonu zone. Palynological analysis was carried out on 13 samples selected from the Çakrazboz, İncigez and Başköy-1 successions. Palynological data were obtained only from samples GBK1-11, 16 and 44 of Başköy-1 succession. The studied assemblage preserves index taxa (e.g., Ovalipollis ovallis, Triradispora, and Enzonalapollenites), suggesting a Late Ladinian to Carnian age. It also indicates relatively dry climatic conditions, possibly interrupted by short periods of humid climatic conditions. As a result, detailed petrography supported sedimentology analysis suggests that Çakrazboz formation was deposited in a balanced-fill type lake basin, magnetic susceptibility analysis indicates that the high magnetic values in lacustrine carbonates are linked to erosion-transportation and pedogenetic processes, and associated with bacterial origin. Elemental geochemical analysis represents fluctuations of Eh and PH condition in lacustrine and palustrine settings. Cyclostratigraphic analysis reveals that the measured stratigraphic sections are commonly represented by precession (≃19-21 ka) and eccentricity (≃100 ka) cycles. Palynological analysis refers Late Ladinian-Carnian age for the Çakrazboz Formation. Data obtained from all analyses indicate relatively dry climatic conditions, possibly interrupted by short periods of humid climatic conditions.


Sedimentology, cyclostratigraphy, sequence stratigraphy and geochemistry of the middle eocene lacustrine-marine oil-shales transition, Mudurnu Göynük basin, NW Anatolia, Turkey
Afridi, Bakht Zamir; Yılmaz, İsmail Ömer; Department of Geological Engineering (2019)
Continuous studied successions of the Middle Eocene, Mudurnu-Göynük basin, in the NW Anatolia indicate a transition from marine-influence lacustrine to marine environment due to the relative rise in sea-level, which was separated by barrier deposits. Different lithofacies are identified in the studied sections, including limestone, marl, oil-shale, calcareous sandstone, conglomeratic and bio-calcirudite. Number of fossil assemblages are recorded including ostracods, charophyte gyrogonites, gastropods, bival...
Palaeoenvironmental and chronological constraints on the Tuglu Formation (Cankiri Basin, Central Anatolia, Turkey)
Mazzini, Ilaria; Hudackova, Natalia; Joniak, Peter; Kovacova, Marianna; Mikes, Tamas; Mulch, Andreas; Rojay, Fuat Bora; Lucifora, Stella; Esu, Daniela; Soulie-Maersche, Ingeborg (2013-01-01)
The Cankiri Basin, located in the northern part of the Central Anatolian Plateau, is a large Tertiary basin where thick Miocene to Quaternary continental sediments overlay the Cretaceous-Tertiary units. This investigation focuses on the Tuglu Formation, an Upper Miocene succession mainly composed of dark grey silty and organic rich clays. The type section of Tuglu has been sampled for an array of multidisciplinary analyses. The palaeontological proxies included ostracod, foraminifer, nannoplankton, pollen, ...
Esmeray-Senlet, Selen; Altıner, Sevinç; Altıner, Demir; Miller, Kenneth G. (2015-05-01)
The Cretaceous-Paleogene (K/Pg) boundary in the Haymana Basin, Central Anatolia, Turkey, was delineated using planktonic foraminiferal biostratigraphy, microfacies analysis, and sequence stratigraphy. An similar to 29 m outcrop consisting of limestone and marl was measured, and four planktonic foraminiferal biozones were identified spanning the boundary. Planktonic foraminiferal extinction across the K/Pg boundary was catastrophic and abrupt. The extinction level is overlain by a unit (Zone P0) showing an i...
Middle-Late Triassic radiolarian cherts from the Arkotdag m lange in northern Turkey: implications for the life span of the northern Neotethyan branch
TEKİN, UĞUR KAĞAN; Göncüoğlu, Mehmet Cemal; Pandolfi, Luca; Marroni, Michele (2012-09-01)
Moderately to well-preserved, relatively diverse Middle and Late Triassic radiolarian assemblages have been obtained from the chert slide-blocks within the Late Cretaceous melange of the IntraPontide Suture Zone at the Pelitoren village to the NE of Kastamonu-Arac in northern Central Anatolia. In this locality, chert slide-blocks are tectonically overlain by metamorphic sole of the serpentinized peridotites belonging to the IntraPontide ophiolites. The oldest radiolarian assemblages, with the middle Late An...
Planktonic foraminiferal biostratigraphy, sequence stratigraphy and foraminiferal response to sedimentary cyclicity in the upper cretaceous-paleocene of the Haymana basin (Central Anatolia, Turkey)
Amirov, Elnur; Altıner, Sevinç; Department of Geological Engineering (2008)
The aim of this study is to establish the planktonic foraminiferal biozonation, to construct the sequence stratigraphical framework and to determine the foraminiferal response to sedimentary cyclicity in the sedimentary sequence spanning Upper Cretaceous-Paleocene in the Haymana basin (Central Anatolia, Turkey). In order to achieve this study, the stratigraphic section was measured from sedimentary sequence of the Haymana, Beyobası and Yeşilyurt formations. The sedimentary sequence is mainly characterized b...
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