Browsing by Author "Yesilova, Pelin Gungor"

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Genesis of Sulfate Lithofacies Between Erzincan-Divriği Basin With Sedimentologic and Geochemical Evidences: an Example From the Paleogene Basins of Eastern Turkey
(Springer, 2024) Yesilova, Pelin Gungor
This study provided insight into the origin, age, and formation conditions of the Late Oligocene sulfate lithofacies that were deposited in the SW Erzincan Basin throughout a broad region. Primary, secondary gypsum, and anhydrite make up the majority of sulfates, which are interbedded with clastic, volcanic, volcaniclastic and carbonated rocks. During the early-late diagenetic processes, primary gypsum changes into secondary gypsum along with primary anhydrite that is growing within the host-sediment. In the lithofacies, sedimentary structures created by tectonism and diagenesis are commonly found. The distribution of element concentrations shows that continental detrital input has a significant impact. Fe- and Mg-rich clays imply alkaline and hot-humid environmental conditions in the basin. The negative trend relationship of CaO with MgO refers to carbonation in the environment, while Sr, Ba, U, Mo, Ni, Cu and Zn values and Co, Ni/Co (0.98), Co/Zn (11.3), Cu/Zn (1.39) ratios and the high positive correlation of Cu with Al2O3 (r = +0.72) indicate the dominance of biologic factor, high salinity and reducing conditions in sulfates. The presence and values of Fe-Mn-rich alteration zones detected by field, mineralogical and geochemical studies within the gypsum revealed the hydrothermal solution activity in the region. 87Sr/86Sr, 18O/16O, 34S/32S and delta 13C isotope data are consistent with Late Oligocene marine sulfates and suggest occasional mixing of freshwater. In addition, the origin and age data revealed by this study; It contributed to the paleogeographic evolution of the northern branch of Neotethys (Inner Tauride Ocean), which extends along the Central and northern-central Anatolia and Eastern Anatolia basins line, which includes Paleogene evaporitic deposits in Turkey, where the study area is located. Accordingly, it is obvious that the Neotethys, which extends along the basins from west to east, is quite shallow (lagoonal and coastal sabkha, etc.) and started to close further east during the Middle-Late Miocene (Erzurum-Pasinler- Horasan, Erzurum-H & imath;n & imath;s-Tekman, I & gbreve;d & imath;r-Tuzluca lacustrine basins, etc.).
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.
Gypsum in Diatomaceous Strata of the Trans-Urals Region: Morphology, Lithogeochemistry, and Genetic Link To Global Warming at the Paleocene-Eocene Boundary
(Elsevier, 2022) Smirnov, Pavel; Yesilova, Pelin Gungor; Trubin, Yaroslav; Deryagina, Oksana; Novoselov, Andrey; Batalin, Georgii; Minnebayev, Kamil
This paper reports the geochemical, structural, and textural properties of evaporite minerals (gypsum) interbed-ded with from the Early Paleogene diatomite and clastics exposed in the diatomite quarry in the Kamyshlov town quarry, Trans-Urals region (Sverdlovsk Oblast, Russia). This article is the first to reveal the occurrence of these atypical minerals in local sediments for the Trans-Urals region, dating from the Paleocene to the Early Eocene. The investigated aggregates included gypsum, anhydrite, and diatomite. Gypsum crystallization occurred rapidly in the low-density non-lithified stratum of the seafloor sediment under warm conditions. Gypsum elemental composition reflects its genesis in a low bio-productivity environment strongly influenced by the influx of highly mineralized groundwater. Terrigenous influx (coarse-grained quartz and fine clay fractions) is high. As a result, radial-fibrous stellate gypsum crystals formed in the fissures that penetrated the diatomite stratum. Geochemical indicators, such as Sr/Ba ratios, show that the salinity of the watershed was variable at the onset of evaporitic con-ditions. Chronologically, gypsum formation is dated to the beginning of the transgressive cycle (early Eocene, the end of the Paleocene-Eocene Thermal Maximum (PETM)) or to the end of post-PETM sedimentation. (c) 2022 Elsevier B.V. All rights reserved.
Origin and Paleoenvironmental Conditions of the Kopruagzi Evaporites (Eastern Anatolia, Turkey): Sedimentological, Mineralogical and Geochemical Constraints
(Mdpi, 2023) Yesilova, Pelin Gungor; Baran, Ozan
Kopruagzi evaporites mainly consist of primary (selenite and gypsarenite) and secondary (massive, laminated and satin-spar) gypsum lithofacies, as well as minor anhydrite, and are interbedded with clastic and carbonate units. Sedimentological-mineralogical and geochemical findings reveal that the depositional basin extends from a lagoon to the hinterland. These data confirm that too much detrital input was transported into the basin with multiple salinity and pH value fluctuations, organic matter activity and reducing conditions. Geochemical data point out the shallow environment and the mixing of hydrothermal fluids and fresh waters. The investigated evaporites were exposed to diagenesis and alteration under the influence of a hot-dry and minor humid climate, tectonism and pressure. The Sr-87/Sr-86, delta S-34 and delta O-18 isotope values of Kopruagzi evaporites reveal that they are of Miocene marine sulfate origin.
The Paleodepositional Environment, Diagenetic and Depositional Conditions of the Middle-Late Miocene Koluz Gypsum Member (Ne Van, Eastern Turkey)
(Springer, 2020) Yesilova, Pelin Gungor; Gokmen, Deniz
This study investigates the depositional setting and diagenetic processes of gypsiferous sediments known as the Koluz gypsum member located in the northeast of Van (Eastern Anatolia-Turkey). The commencement of still-active contractional regime due to the collision of Eurasian and Arabian plates gave way to uplift events on the active Eurasian margin. This uplift initially resulted in termination of marine sedimentation and commencement of continental deposition in the region. The Middle-Late Miocene Kurtdeligi formation is one of the oldest products of the continental setting in the Eastern Anatolia. Sedimentologic and petrographic analyses conducted on the Koluz gypsum member of the formation, the main concern of this study, indicate that the member is represented by secondary gypsum (massive, laminated, nodular, satin spar) and primary gypsum lithofacies (selenite, gypsum arenite, discoidal and radial). The secondary gypsum facies are formed after hydration of anhydrite and anhydritizated primary gypsums. Additionally, mineralogical and geochemical studies suggest that carbonate (dolomite and calcite) and detrital materials found within the member formed during the deposition or late diagenetic processes. The high major and trace element values determined by XRF analyses also indicate intense detrital influx and accordingly terrestrial origin for the basin. Sedimentary textures and lithofacies of the member show a typical ephemeral playa complex, which was likely fed by both evaporation and groundwater discharge. Tectonism, climate, salinity variation, biologic activity and diagenetic and hydrothermal fluids play major roles in the formation and transformation of these sediments to each other.
Petrographic Study and Geochemical Investigation of the Evaporites Associated With the Germik Formation (Siirt Basin, Turkey)
(Springer, 2017) Yesilova, Pelin Gungor; Helvaci, Cahit
Evaporites of the Oligocene Germik Formation are represented by massive, laminated, laminated-banded, banded, nodular and/or brecciated nodular and nodular-banded lithofacies in the Siirt-Kurtalan area. Observations of massive and laminated-banded gypsums with undulated-shaped stromatolitic algal mats, corrugated folded structures and clay-carbonate and interlayered marl in laminated gypsum levels are very important in terms of their mechanisms of occurrences. Petrographic and mineralogic examinations of secondary gypsums in the Germik Formation generally display alabastrine and porphyroblastic textures with corroded anhydrite. Structures as satin-spar, chickenwire, enterolithic and minerals as dolomite, calcite and celestite are also observed. Geochemical evaluations of gypsum and anhydrite samples belong to the lithofacies have provided an approach of their original formation and understandings the environmental impacts (such as pH, paleotemperature, paleosalinity, surface-groundwater activity and bacterial activity). Therefore, a number of analyses were conducted on the different samples for major and trace elements and the gypsum-anhydrite samples were analyzed for isotope compositions. Trace elements of these evaporites were found to be in the range of the geochemical values of the depositional environment of shallow marine evaporites. These values show also occasional influx of terrestrial waters to the environment. Moreover, the differences in the isotopic values of the lithofacies identified by the stable isotopic studies indicate the effects of temperature, salinity, biogenic activity and diagenetic processes for the formation of evaporites, under the influence of climate. Geochemical evolution of gypsum and anhydrite lithofacies of the Germik Formation leads up to muddy evaporites indicating that they were deposited in the coastal sabkha or shallow marine environments within effectively developed paleoclimatic conditions, tectonic activities, diagenetic processes and depositional system.
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.