Browsing by Author "Yesilova, Cetin"

Now showing 1 - 7 of 7

Evaporitic Sedimentation in the Southeastern Anatolian Foreland Basin: New Insights on the Neotethys Closure
(Elsevier, 2018) Yesilova, Cetin; Helvaci, Cahit; Carrillo, Emilio
We integrate stratigraphic, petrographic and geochemical analysis of subsurface data (wells) together with field surveys to study the sedimentation of a marginal Miocene sub-basin of the Southeastern Anatolian Foreland Basin (SEAFB; SE Turkey). This sub-basin, located in the Batman-Siirt region, is characterized by the existence of evaporites (carbonates, sulphates and chlorides) and alluvial detritus which were divided in the following five lithostratigraphic members, from older to younger: Lower and Upper Yaprlar; and Lower, Middle and Upper Sulha. These members deposited in an epicontinental mudflat during the Early Miocene. Both the bromine content and the sulphur and oxygen isotope composition (delta S-34(v-CDT) and delta O-18(v-SMOW)) of halite and sulphates samples, respectively, also suggest a marine origin of the precipitation brines. However, influence of geothermal fluids and dissolution-and-re-precipitation of evaporites from uplifted areas in these brines, such as the Early Miocene members and/or Triassic units, is interpreted. Comparing and integrating our results with data documented in previous works, it is here recognized that the depositional model of the studied sub-basin differs from that which explain the coeval sedimentation of units situated in the western part of the SEAFB. Moreover, our model shows some depositional and paleoenvironmental similarities with Miocene evaporites located in the Mesopotamian Foreland Basin. This work provides valuable insights on the Middle Miocene Salinity Crisis which is related to the evolution of the Neotethys closure. (C) 2018 Elsevier B.V. All rights reserved.
Geochemical Characteristics of Gypsum Lithofacies in Northeastern of Mus (Eastern Anatolia-Turkey): an Indication of the Neotethys Closure
(Springer, 2020) Yesilova, Pelin Gungor; Yesilova, Cetin; Aclan, Mustafa; Gundogan, Ibrahim
The study investigates the origin, age, paleo-depositional environment and formation conditions of gypsum lithofacies deposited in northeastern Mus in Eastern Anatolia using element analysis and sulfur, oxygen and strontium isotope combinations. The correlation diagrams of major ions and trace elements plots in the gypsum lithofacies indicate that carbonates and clastics carried by terrestrial waters (streams, rivers, etc.) significantly contributed to the evaporitic phases. Furthermore, the effects of hydrothermal solutions, increased salinity of the basin and presence of biological activity were associated with high values for major ions and trace elements. While the delta O-18 and delta S-34 isotope contents of some gypsum lithofacies samples show that they are of terrestrial or marine origin, others do not indicate either origin because they are affected by other factors such as water salinity variations, bacterial sulfate reduction, new terrestrial water and detrital inputs carried into the basin. However,Sr-87/Sr-86 isotope concentrations analyzed in gypsum lithofacies in the study area indicate Rupelian (Lower Oligocene) time, which is compatible with the Cenozoic age curve. Based on all these data, gypsum lithofacies in this basin were deposited in a transition zone (shallow sea-lagoon-inland sabkha-mudflats) under the influence of both marine and terrestrial conditions. Therefore, we claim that this basin formed during the Rupelian (Early Oligocene), at a time when the sea connection between the Indian Ocean and the eastern Mediterranean was restricted; that is, the southern branch of the Neotethys was extremely shallow during this period and almost terminated in the study area.
Geologic and Geochemical Properties of the Mafic-Clastic Type Sariseki Volcanogenic Massive Sulfide Deposit, Central Pontides, Turkey
(E Schweizerbartsche verlagsbuchhandlung, 2021) Baran, Cuneyt; Yesilova, Cetin; Gunay, Kurtulus
The Sariseki mineralization has 4.3 million tonnes of 0.47wt% Cu and is one of the newly-discovered massive sulfide formations in the Central Pontides. Mineralization occurred within deep marine sediments interlayered with mafic sills and/or lavas of the cangaldag Metamorphic Complex. The lithologic units in the area of mineralization are metamorphosed under lower-greenschist facics conditions. The metamorphism transformed deep marine sediments into phyllites, whilst mafic sills and/or lava were transformed into chlorite-actinolite schist, chlorite schist and chlorite-epidote schist. The mineral paragenesis of the mineralization is represented by the following minerals in decreasing order of abundance; pyrite, chalcopyrite, sphalerite, and magnetite. Mineralization at different levels has three different textures; banded-disseminated, semi-massive and massive. The Sariseki mineralization has maximum Cu and Zn contents of 3.4 % Cu and 0.24 % Zn, in the Cu-dominant massive sulfide formations. Within the ore, silicified relict sections of wall rock lithology and grading in the mineralized sections indicates that mineralization might have developed by sub-seafloor replacement processes. Mineralization is dominantly formed within wall rock and metamorphic rocks with elastic origin, with no feeder zones in the lower sections of massive sulfide masses, irregular lenses in mineralization and a strata-bound structure. The mafic-clastic formation of Sariseki mineralization has similar features to Besshi-type Volcanogenic Massive Sulfide (VMS), an observation that is also supported by the results of ore and wall rock geochemistry.
Giant Tufas of Lake Van Record Lake-Level Fluctuations and Climatic Changes in Eastern Anatolia,turkey
(Elsevier, 2019) Yesilova, Cetin; Gulyuz, Erhan; Huang, Ci-Rong; Shen, Chuan-Chou
Lake Van, the largest soda lake in the world, is a key area where climatic changes are recorded by well-preserved sedimentary successions. In spite of the existence of such sequences, the ancient lake levels are still under debate. Here, we present U/Th ages of tufa layers exposed along the northern margin of the lake near the town of Adilcevaz. Tufa are interpreted to form during humid and temperate climate conditions in the contact zone between the highly alkaline lake water - rich in bicarbonate and carbonate ions - and calcium-rich groundwater. These contact zones most likely appear near shore. Thus, U/Th ages and altitude of the tufa present minimum ancient lakestands. The tufas obtained in our study are dated between 112.7 and 19.3 ka. They are interpreted to record two transgressional intervals, the first starting at 1701 meters above sea level (masl) altitude at 112.7 ka reaching 1706 masl at 72.5 ka (based on three U/Th ages). The second transgression starts at the present Lake Van level of 1646 masl at 30.1 ka, reaching 1725 masl at 19.3 ka (based on 15 U/Th ages). Comparison with climate proxies reveals that the first transgression was caused by intensified precipitation accompanied by warming, while the second transgression was triggered mainly by warming that initiated melting of glaciers. The lake-level fluctuations described here are almost in line with the ones gathered from dated lake terraces but contradict lake-level reconstruction based on pore water salinity.
Microfacies Properties of Adilcevaz Limestone (North of Lake Van)
(Tmmob Jeoloji Muhendisleri Odasi, 2007) Yesilova, Cetin; Yakupoglu, Turker
in this study, the sedimentological characteristics of lower Miocene (Burdigalian) aged Adilcevaz limestone that outcrops north of lake Van were determined by means offacies analysis. Using these data, an approach to establish the Lower Miocenepaleogeography of the study area was made. After field studies, laboratory studies were undertaken and the limestone was separated into 6 micro facieses. These are 1. Wackestone-packstonefacies with redalgae and coarse bentonicforaminifera 2. Boundstonefacies with red algae and Bryozoa 3. Boundstonefacies with red algae and coral 4. Calciruditefacies with redalgae and coarse bentonicforaminifera 5. Wackestone-packstonefacies with Globigerinoidae 6. JVackestonefacies with red algae and Lepidocyclina sp. These facieses were used in an approach to the paleogeographical evolution of Adilcevaz limestone. Observations infieldstudies and findings infacies analysis indicate that the Adilcevaz limestone was deposited in a carbonate shelf which bears abundant red algae.
The Traces of Earthquake (Seismites): Examples From Lake Van Deposits (Turkey)
(intech Europe, 2012) Uner, Serkan; Yesilova, Cetin; Yakupoglu, Turker
U-Th Ages and Facies Properties of Edremit Travertines and Tufas, Van, Eastern Anatolia: Implications for the Neotectonics of the Region
(Polish Geological inst, 2021) Yesilova, Cetin; Yesilova, Pelin Gungor; Aclan, Mustafa; Yu, Tsai-Luen; Shen, Chuan-Chou
Travertine formation is one of the most important archives of active tectonics in a region and provides information about climate, water temperature and quantity, and biological activity. The Edremit travertines and tufas extend over nearly160 km(2) within the boundaries of the Edremit area to the east of Lake Van (eastern Turkey), and yield important evidence towards understanding the neotectonics of the region. The Edremit travertines and tufas were studied throughout their full stratigraphic extent, the factors controlling the formation of these deposits were examined, and the succession was sampled for U/Th analysis. Travertine formation was found to occur from 542-29.7 ka, with two different tufa formation periods: from 29.7-5.8 ka and 5.8-2.08 ka. Pauses in travertine formation (palaeosols) were identified from 510-470 ka, 289-269 ka and 91-34 ka. Our study showed that climate parameters affected the formation of tufa, while the Edremit travertines developed under the control of tectonism. The Van Fault is directly associated with travertine development and its age was identified as 542 ka or older. Since the Gurpinar Fault, one of the most important faults in the region, is effective in shaping the southern slope of the travertines and limiting the movement of the Van Fault, its age should be younger than 542.4 ka. The Elmalik Fault played an active role in the formation of the Edremit tufas and is proposed to be 29.7 ka in age, from stratigraphic relationships in the region.