The Upper cretaceous calciclastic submarine fan deposits in the Eastern Pontides, NE Turkey: facies architecture and controlling factors

The Tonya Formation, which represents the uppermost part of the Mesozoic sequence in the Eastern Pontides, consists of calciturbidites in Trabzon and its surrounding region. Two stratigraphic sections of the unit were measured in the Hacımehmet and Gürbulak areas to decipher the distribution of rock types, facies architecture, sediment textures and depositional environment. The grain size, channels, suprafan lobes and slump structures of the sediments suggest that calciclastic sequences were deposited in a submarine fan system. Calcarenites/calcirudites and hemipelagic rocks, comprising an alternation of marls and mudstones, are the two dominant lithologies described in the studied calciclastic submarine fan system. Calciclastic facies, which are identified as middle fan deposits, indicate high-concentration turbidity currents in the sequences. The hemipelagic rocks, which are delineated as outer fan deposits, suggest low-energy, deep-marine conditions. The microfacies description and fauna determinations propose the gravity origin for these calciclastic submarine fan deposits. Rudstones, grainstones and packstones are the dominant carbonate textures in the calcarenites. Pelagic marls and mudstones are characterised by a planktonic, foraminifera-bearing, wackestone-mudstone texture. Biogene parts of the calciclastics are fragments of benthonic foraminifers, algae, rudists, echinoids, bryozoa, inoceramids and neritic and pelagic carbonate lithoclasts, which suggest a close contemporaneous shallow marine carbonate depositional environment as their source during their deposition. Palaeocurrent directions, measured from the base of the calciturbidites, show that the components of the calciturbidites were transported from a shallow marine environment lying to the E or SE. The lateral and vertical facies organisation of these calciturbidites favours a deposition of the calciclastic submarine fan model. These deposits were fed by material derived from a shallower water carbonate depositional environment in the Eastern Pontides during the Late Campanian. All the sedimentological properties, combined with the regional data, suggest that the Late Campanian sedimentation in the Eastern Pontides formed in a backarc environment

Determining Secondary School Students’ Knowledge and Awareness about Antarctica

Antarctica has been an object of interest for a long. It is considered important to increase individuals awareness and knowledge about Antarctica. The accuracy of individuals’ scientific knowledge plays an important role in creating the awareness. In this study, the 349 secondary school students’ knowledge and awareness about Antarctica was determined quantitatively with a questionnaire. Nineteen questions, including current topics were prepared. that addressed from biological geographic and climatic perspectives. According to the findings, 40% of the students thought Antarctica is in the North Pole, 42.6% thought polar bears and penguins live together; 46.6% thought Antarctica is best visited during summer months, 70.5% thought most glaciers are located in the northern hemisphere. Based on these findings, it can be said that students have inadequate and alternative conceptions about Antarctica. Studies can be conducted to determine how best to increase students’ awareness

Age constraints on intra-formational unconformities in Upper Jurassic-Lower Cretaceous carbonates in northeast Turkey; geodynamic and hydrocarbon implications

Upper Jurassic-lowermost Cretaceous carbonate build-ups are imaged on seismic data in the Black Sea. They form important, untested, hydrocarbon reservoirs that are the focus of active exploration. Outcrop analogues to these build-ups around the Black Sea contain a series of subaerial exposure surfaces. The hiatuses associated with a number of these subaerial exposure surfaces have been dated in a well exposed Callovian or Upper Oxfordian to Barremian shallow-water inner platform carbonate succession (the Berdiga Formation) in the Eastern Pontides using strontium isotope stratigraphy and foraminiferal biostratigraphy. They span the latest Kimmeridgian to Tithonian or Berriasian, and the Hauterivian to Barremian. Less well constrained, but broadly contemporaneous stratigraphic gaps in multiple successions around the Black Sea provide additional insights and point to a regional driving mechanism. The timing of hiatus formation does not correspond to periods of eustatic lowstand. It does coincide, however, with Late Tithonian to Berriasian and Hauterivian to Early Aptian episodes of rifting in the Greater Caucasus Basin, located farther to the north. Thus, it is possible that subaerial exposure was caused by rift flank uplift during periods of regional extension. Uplift due to slab break off is discounted as a control because it post-dates (rather than pre-dates) locally developed Kimmeridgian magmatism. Rift-flank uplift is likely to have also affected carbonate build-ups on the intervening rift shoulders of the eastern Black Sea, the Shatskiy Ridge and the Mid Black Sea High. At outcrop, subaerial exposure is often associated with karstification and secondary porosity development. Similar processes may have occurred in the offshore helping to enhance the reservoir quality of these exploration targets

The multidisciplinary approaches on facies developments and depositional systems of the Bahcecik travertines, Gumushane, NE-Turkey

The Bahcecik travertines, located in Gumushane (NE-Turkey) have been investigated for the first time using a multidisciplinary approach, which included sedimentological (lithofacies, depositional system), petrographic, radiometric Th-230 dating, geochemical analysis (stable isotopes), palynomorphs and geophysics (GPR). A carbonate build-up, 12 m thick, was formed with some interruptions, through the middle Pleistocene period. For this study, two travertine sections (F and D) were extensively used to figure out palaeoenvironmental and palaeoclimatic proxies. The main precipitation cycles, separated by palaeosol levels, have been described and interpreted from a sedimentological perspective. The carbonate deposits consist of shrubs, crystalline crust, reed, laminated (micritic), pisoids, oncoids, calcite thin rafts and coated gas bubbles, lithoclasts, and palaeosol levels. The sedimentological fieldwork and petrographic analysis show that the Bahcecik travertines formed in depression depositional and slope depositional systems. Moreover, the first Th-230 ages, stable isotopic results and palynofloral data in this study, prove that the Bahcecik travertines might have been affected by climatic and tectonic interruptions. According to dating results, the travertine occurrences began to precipitate during the 353 ka and continued into the 263 ka. Based on the palynological data, an abundance of herbaceous plants species was recorded in the warming period of climate. The thickness ranges from 2 to 12 m of the Bahcecik travertines. This precise thickness and also the presence of two different travertine formations, separated by a palaeosol erosional surface, were recorded by the ground penetrating radar (GPR) geophysical method.Science Vanguard Research Program of the Ministry of Science and Technology (MOST), Taiwan, ROC 109-2123-M-002-001Higher Education Sprout Project of the Ministry of Education, Taiwan, ROC 109L901001National Taiwan University 110L890

Relative contributions of crust and mantle to generation of Campanian high-K calc-alkaline I-type granitoids in a subduction setting, with special reference to the Harsit Pluton, Eastern Turkey

We present elemental and Sr-Nd-Pb isotopic data for the magmatic suite (similar to 79 Ma) of the Harsit pluton, from the Eastern Pontides (NE Turkey), with the aim of determining its magma source and geodynamic evolution. The pluton comprises granite, granodiorite, tonalite and minor diorite (SiO(2) = 59.43-76.95 wt%), with only minor gabbroic diorite mafic microgranular enclaves in composition (SiO(2) = 54.95-56.32 wt%), and exhibits low Mg# (<46). All samples show a high-K calc-alkaline differentiation trend and I-type features. The chondrite-normalized REE patterns are fractionated [(La/Yb)(n) = 2.40-12.44] and display weak Eu anomalies (Eu/Eu* = 0.30-0.76). The rocks are characterized by enrichment of LILE and depletion of HFSE. The Harsit host rocks have weak concave-upward REE patterns, suggesting that amphibole and garnet played a significant role in their generation during magma segregation. The host rocks and their enclaves are isotopically indistinguishable. Sr-Nd isotopic data for all of the samples display I(Sr) = 0.70676-0.70708, epsilon(Nd)(79 Ma) = -4.4 to -3.3, with T(DM) = 1.09-1.36 Ga. The lead isotopic ratios are ((206)Pb/(204)pb) = 18.79-18.87, ((207)Pb/(204)Pb) = 15.59-15.61 and ((208)Pb/(204)Pb) = 38.71-38.83. These geochemical data rule out pure crustal-derived magma genesis in a post-collision extensional stage and suggest mixed-origin magma generation in a subduction setting. The melting that generated these high-K granitoidic rocks may have resulted from the upper Cretaceous subduction of the Izmir-Ankara-Erzincan oceanic slab beneath the Eurasian block in the region. The back-arc extensional events would have caused melting of the enriched subcontinental lithospheric mantle and formed mafic magma. The underplating of the lower crust by mafic magmas would have played a significant role in the generation of high-K magma. Thus, a thermal anomaly induced by underplated basic magma into a hot crust would have caused partial melting in the lower part of the crust. In this scenario, the lithospheric mantle-derived basaltic melt first mixed with granitic magma of crustal origin at depth. Then, the melts, which subsequently underwent a fractional crystallization and crustal assimilation processes, could ascend to shallower crustal levels to generate a variety of rock types ranging from diorite to granite. Sr-Nd isotope modeling shows that the generation of these magmas involved similar to 65-75% of the lower crustal-derived melt and similar to 25-35% of subcontinental lithospheric mantle. Further, geochemical data and the Ar-Ar plateau age on hornblende, combined with regional studies, imply that the Harsit pluton formed in a subduction setting and that the back-arc extensional period started by least similar to 79 Ma in the Eastern Pontides.Geochemistry & GeophysicsMineralogySCI(E)33ARTICLE4467-48716

The bio-lithoclastic carbonate facies analysis: Sahinkaya Member Maastrichtian (Late Cretaceous) skeletal carbonate deposit, Sakarya Zone, NE Turkey

Koroglu, Fatih/0000-0002-2430-1161; KANDEMIR, RAIF/0000-0002-0344-9159WOS: 000496621400036The eastern Sakarya Zone is consensually known as a back-arc setting during the Late Cretaceous period. the region has records, which are in accordance with the environments unstable and carbonate sedimentation formed into different stages of subduction-related conditions. the Tonya Formation that outcropped in the area represents the uppermost part of the Mesozoic sequence in the eastern Sakarya Zone. the Tonya Formation is mainly composed of calciclastic turbidites, including thin grey-red pelagic limestone. the Tonya Formation was subdivided into the Sahinkaya Member basing on its sedimentological properties and fauna contents. the Sahinkaya Member is interpreted as a thick carbonate succession of the Maastrichtian in the study area. To decipher the facies and depositional environment of the Sahinkaya Member, two measured sections were studied in the Cayrba-Calkoy area in terms of microfacies analyses. Here, six microfacies types were distinguished based on their depositional texture, petrographic characteristics, and fauna content. Bio-lithoclastic rudstones, grainstones, and packstones are common texture in the carbonates. For the first time, the conglomerate levels have been defined within the member and correspond to an unconformity surface or hiatus together with angular differences in the layers, which have developed due to regional tectonic events such as erosion/uplift and magmatic intrusions. the facies characteristics of the carbonates and the fossil fauna findings included in the Sahinkaya Member of the Tonya Formation point to the development of a slope/toe of slope environment. All the sedimentological properties, combined with the regional data, suggest that the member was deposited at the shore of the back-arc Black Sea basin during the northward subduction of Neotethyan Oceanic Lithosphere and affected by the outcrop of the subduction-related magmatic products

Vulnerable Geosites of cayirbagi-calkoy (Duzkoy-Trabzon) in the Eastern Black Sea Region of NE Turkey and Their Geotourism Potential

Koroglu, Fatih/0000-0002-2430-1161; KANDEMIR, RAIF/0000-0002-0344-9159WOS: 000481874400029Geotourism is a relatively new branch of tourism dealing with geosites, which are special places that exhibit aspects that characterize the complex history of the Earth. This contribution aims to report an inventory of features of geological interest occurring in the cayirbagi-calkoy area in the Eastern Black Sea Region in Turkey. Among these is cal Cave, a site that attracts local and foreign visitors and can potentially contribute to the development of tourism in the study region. Further, there is a well-developed karstic system in the area. A number of caves and dolines in cal-Camili Natural Park are a part of this system. There are also volcanic and volcano-sedimentary rocks outcrops in the region. Numerous forms such as dikes, pillow lava, and exfoliation structures show the formation dynamics of rocks and characterize the region. the Sahinkaya Member is among the unique places in the Eastern Pontides region, where the K-Pg boundary can be observed. Along with "pure" geological features, the region also offers visitors many other historical, cultural, and natural resources. cal-Camili Natural Park was raised to the status of natural park for its biological (plant and wildlife) diversity and the integrity of its landscape. Rising from green forests, the white rocky structure of the Sahinkaya Member stands out against the surrounding dark landscape. the combination of valuable elements of different natures (i.e. geologic, naturalistic, historical) could allow sustainable local development

Sedimentological and geochemical characteristics of Lower Jurassic Sandstones from Gumushane, NE Turkey: implications for source to sink processes, paleoenvironmental conditions, provenance and tectonic settings

The eastern Sakarya Zone (SZ), one of the Alpine Himalayan Belt's main components, has complex Mesozoic-Cenozoic geodynamic evolution, which remains controversial. Early-Middle Jurassic volcano-sedimentary successions (Senkoy Formation) extensively outcrops in Gumushane region, NE Turkey. It is regarded as a critical unit to understand the Mesozoic tectonic evolution of the eastern Sakarya Zone. One of the Senkoy Formation's predominant units is sandstone succession, preserving implications for paleoenvironmental conditions and tectono-sedimentary development of Neotethys Ocean. Thus, a combined analysis of comprehensive petrography, whole-rock major, trace and rare earth element data is carried out on the sandstones, which are well constrained as late Sinemurian- Pliensbachian. The sandstones are mainly arkosic to lithic arenites in lithology showing poor textural maturities. They are mostly represented by relatively high ICV, low CIA, high K2O/Al2O3, Fe2O3+ MgO, TiO2, Th/U, pronounced negative Eu anomaly, enriched LREEs, elevated Gd-N/Yb-N, low Ce/Ce*, Ni/Co, La/V and Zr/Ti. The petrographic and geochemical characteristics imply that the sediments may have experienced relatively low chemical weathering processes and slight reworking and recycling processes with a short transport distance before deposition in the basin. Early Jurassic sandstone successions were interpreted as a transgressive series, showing a predominantly open sea environment with oxidizing paleoenvironmental conditions. The sandstone samples' paleoenvironment is likely to be located along the southern margin of the arc and the Neotethyan basin to the south. The extensional and trans-extensional tectonic regime might have played an essential role in controlling the basin's isolated-half graben and/or asymmetric geometry, leading to changes in the provenance of studied sandstone samples. Thus, the geochemical signature differences are probably associated with basement-related proximal origins and minor effects of the multi-phases petrogenesis that experienced different source to sink processes. Early Jurassic sandstones were probably derived from multi-genetic source rocks, including (i) granite and (ii) metamorphic rocks. Our new data has also indicated that other source rocks can include mafic to felsic volcanic succession. The possible provenance for granitic pluton and metamorphic rocks can be provided by the Hercynian heterogenetic crystalline basement widespread throughout the SZ. However, mafic to felsic volcanic rock source is likely to be associated with the pre-Early Jurassic nearby volcanic-arc, which is rarely recorded in the eastern SZ. The source rock signatures may imply a close genetic link with ancient magmatic-arc generation due to the southward subduction of Palaeotethys

Subduction-related late carboniferous to early permian magmatism in the eastern pontides, the Camlik and Casurluk plutons: insights from geochemistry, whole-rock Sr-Nd and in situ zircon Lu-Hf isotopes, and U-Pb geochronology

KANDEMIR, RAIF/0000-0002-0344-9159WOS: 000390724200007Late Carboniferous to early Permian granitoid rocks represent a volumetrically minor component of the Eastern Pontide lithosphere, but they preserve useful information about the region's tectonomagmatic history. the Casurluk and Camlik plutons primarily consist of gabbro, gabbroic diorite, diorite, monzogabbro, monzodiorite and monzonite, which intrude early to middle Carboniferous granitic basement rocks in the region. in this study, we use in situ zircon U-Pb ages and Lu-Hf isotopic values, whole-rock Sr-Nd isotopic values, and mineral chemistry and geochemistry of these plutons to determine petrogenesis and crustal evolution; we also discuss geodynamic implications. LA-ICP-MS zircon U-Pb dating of magmatic zircons from the rocks suggests that the plutons were emplaced during the late Carboniferous to early Permian (302 Ma). the metaluminous and I-type intrusive rocks belong to the high-K calc-alkaline series. in addition, they are relatively enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs); they are depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs), such as Nb and Ti. All of the samples have homogeneous initial I-Sr values (0.70675 to 0.70792) and low epsilon(Nd) (t) values (-5.1 to -3.3). Zircons from the rocks of both plutons have uniform negative to slightly positive epsilon(Hf) (t) values (-3.5 to 1.4) and old Hf two-stage model ages (1323 to 1548 Ma), implying that they have the same source, as well as suggesting the involvement of old enriched litho spheric mantle materials during their magma genesis. These results, combined with the epsilon(Hf) (t) values and two stage model ages, demonstrate that the primary magmas were derived from partial melting of old lithospheric mantle material metasomatized by subduction-related fluids. Considering other regional geological data from the Sakarya Zone where these plutons formed, we conclude that late Carboniferous to early Permian magmatism in the area involved the partial melting of a phlogopite- and spinel-bearing lherzolite under an extensional regime in a subduction-related setting. Such an extension event would have caused hot asthenospheric upwelling and was likely triggered by back-arc rifting during subduction of the Paleo-Tethyan oceanic slab. Thus, the magmas are likely subduction-related products, implying that southward subduction of Paleo-Tethys oceanic lithosphere in the region began during the late Carboniferous to early Permian. (C) 2016 Elsevier B.V. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112Y103]We thank to Faruk Aydin, Ibrahim Uysal and Yilmaz Demir for their assistances in field and lab works. This study was financially supported by a grant # 112Y103 from the Scientific and Technological Research Council of Turkey (TUBITAK). Special thanks go to E. Yalcin Ersoy for the geochemical modeling. We are very grateful to Jacqueline O'Neill Ozcelik for her English editing of the manuscript

Zircon Lu-Hf isotope systematics and U-Pb geochronology, whole-rock Sr-Nd isotopes and geochemistry of the early Jurassic Gokcedere pluton, Sakarya Zone-NE Turkey: a magmatic response to roll-back of the Paleo-Tethyan oceanic lithosphere

KANDEMIR, RAIF/0000-0002-0344-9159WOS: 000403544100007The early Mesozoic was a critical era for the geodynamic evolution of the Sakarya Zone as transition from accretion to collision events in the region. However, its complex evolutionary history is still debated. To address this issue, we present new in situ zircon U-Pb ages and Lu-Hf isotope data, whole-rock Sr-Nd isotopes, and mineral chemistry and geochemistry data of plutonic rocks to better understand the magmatic processes. the Gokcedere pluton is mainly composed of gabbro and gabbroic diorite. LA-ICP-MS zircon U-Pb dating reveals that the pluton was emplaced in the early Jurassic (177 Ma). These gabbros and gabbroic diorites are characterized by relatively low SiO2 content of 47.09 to 57.15 wt% and high Mg# values varying from 46 to 75. the samples belong to the calc-alkaline series and exhibit a metaluminous I-type character. Moreover, they are slightly enriched in large ion lithophile elements (Rb, Ba, Th and K) and light rare earth elements and depleted in high field strength elements (Nb and Ti). Gabbroic rocks of the pluton have a depleted Sr-Nd isotopic composition, including low initial Sr-87/Sr-86 ranging from 0.705124 to 0.705599, relatively high epsilon(Nd) (t) values varying from 0.1 to 3.5 and single-stage Nd model ages (T-DM1 = 0.65-0.95 Ga). in situ zircon analyses show that the rocks have variable and positive epsilon(Hf) (t) values (4.6 to 13.5) and single-stage Hf model ages (T-DM1 = 0.30 to 0.65 Ga). Both the geochemical signature and Sr-Nd-Hf isotopic composition of the gabbroic rocks reveal that the magma of the studied rocks was formed by the partial melting of a depleted mantle wedge metasomatized by slab-derived fluids. the influence of slab fluids is mirrored by their trace-element characteristics. Trace-element modeling suggests that the primary magma was generated by a low and variable degree of partial melting (similar to 5-15%) of a depleted and young lithospheric mantle wedge consisting of phlogopite-and spinel-bearing lherzolite. Heat to melt the mantle material was supplied by the ascendance of a hot asthenosphere triggered by the roll-back of the Paleo-Tethyan oceanic lithosphere. the rising melts were accompanied by fractional crystallization and encountered no or minor crustal contamination en route to the surface. Taking into account these geochemical data and integrating them with regional geological evidence, we propose a slab roll-back model; this model suggests that the Gokcedere gabbroic pluton originated in a back-arc extensional environment associated with the southward subduction of the Paleo-Tethyan oceanic lithosphere during the early Jurassic period. Such an extensional event led to the opening of the northern branch of the Neotethys as a back-arc basin. Consequently, we conclude that the gabbroic pluton was related to intensive extensional tectonic events, which peaked during the early Jurassic in response to the roll-back of Paleo-Tethyan oceanic slab in the final stage of oceanic closure.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112Y103]This research was financially supported by Grant # 112Y103 from the Scientific and Technological Research Council of Turkey (TUBITAK). Faruk Aydin, Ibrahim Uysal, Yilmaz Demir and Mehdi Ilhan are thanked for their assistance in field and lab works. We would like to thank to E. Yalcin Ersoy for the geo-chemical modeling of the trace-element data. We gratefully acknowledge on English editing efforts of the manuscript by Jacqueline O'Neill Ozcelik. Special thanks to three anonymous reviewers whose comments improved this paper significantly. Further thanks are owed to Gordon Moore for his editorial effort and constructive comments