Clay mineralogy, chemistry, and diagenesis of late devonian K-bentonite occurrences in northwestern Turkey

Thin beds of tephra (K-bentonites) formed by the diagenesis of volcanic ash are exposed within the limestone-dolomitic limestone successions of the Yilanli formation at Zonguldak and Bartin in northwestern Turkey. They were deposited on the Middle Devonian-Lower Carboniferous shallow carbonate platform of the Zonguldak terrane. In this study, K-bentonite samples collected from Gavurpinari and Yilanli Burnu limestone quarries are investigated in order to reveal their mineralogical and geochemical characteristics and diagenetic evolution. Illite is the major clay mineral in the studied K-bentonites. Additionally, kaolinite and mixed-layer illite-smectite are identified in some samples. The nonclay minerals calcite, dolomite, quartz, gypsum, feldspar, pyrite, and zircon are also found. Crystal-chemical characteristics (Kiibler index, d060 values, and polytypes of illites) from two different sampling locations do not show significant variations. Kiibler index values for the Yilanli Burnu and Gavurpinari sampling locations, 0.47-0.93 (average: 0.71 A°29) and 0.69-0.77 (average: 0.72 A°29), respectively, indicate that illites were affected by high-grade diagenetic conditions. The swelling (or smectite) component (~5%), crystallite size (N = 10-20 nm), and polytype (2M1 > 1Md) data of illites support the same conditions. Illite d060 values of 1.491-1.503 A correspond to a range of octahedral Mg+Fe values of 0.27-0.51 atoms per formula, indicating a composition between end-member muscovite and phengite unit. Trace and rare earth element-based chemical classification of the K-bentonite samples revealed that composition of original volcanic ash is basaltic. Illitization took place by fixation of K from volcanic minerals and ash, and diffusion of elements (Mg+Fe) into and out of the beds during diagenesis. Mineralogical-chemical data point out that these K-bentonites evolved in high-grade diagenetic conditions (approximately 100-150 °C) from the products of volcanic eruptions of disputed sources and distances during the Late Devonian time. © 2015 TÜBİTAK

Refinements in biostratigraphy of the foraminiferal zone MFZ11 (late early Viséan, Mississippian) in the Cebeciköy Limestone (Ýstanbul Terrane, NW Turkey) and palaeogeographic implications

The Cebecikoy Limestone from the Variscan flysch of the Istanbul Terrane is assigned to the foraminiferal MFZ11 zone (late early Visean, formerly V2a). This zone is essentially the range zone of Uralodiscus rotundus. Additional bioevents are proposed for characterizing the upper part of this biozone (MFZ11B subzone): the LAD of Eoendothyranopsis and the FAD of Pararchaediscus and Conilidiscus. The majority of foraminifers and algae, belonging locally to MFZ11 are well-known, except for the following taxa: Issinella luteotubulifomis sp. nov., I. enormis sp. nov., Vicinesphaera parasqualida sp. nov., Planogloboendothyra modesta sp. nov. and Endothyra irinaeformis sp. nov. The Istanbul Terrane is connected with the southern branch of the Palaeotethys, whereas the Zonguldak Terrane is connected with the northern branch of this one

Autochthonous Upper Permian (Midian) carbonates in the western Sakarya composite terrane, Geyve area, Turkey: Preliminary data

Permian limestones occur widely within the clastic units of the "Karakaya Complex" and are interpreted as allochthonous bodies or olistoliths. In the Kadirler area to the south of Geyve, however, Upper Permian (Midian) quartz sandstones and carbonates with a rich foraminifer fauna disconformably overlie a crystalline basement complex. This basement complex comprises metaclastic rocks, recrystallised limestones, metacherts, and metadiabases, and is intruded by granodiorites. The overlying basal conglomerates and quartzitic sandstones are dominated by pebbles from the basement complex and are followed upward by medium- to thick-bedded dolomites, dolomitic limestones and limestones

The effects of lactic acid bacterial inoculants on the fermentation and aerobic stability of sunflower silages

This study was carried out to determine the effects of homofermentative and/or heterofermentative lactic acid bacteria inoculants on the fermentation, aerobic stability and in vitro organic matter digestibility characteristics of sunflower silages. Sunflower was harvested at the milk stage of maturity. Inoculant 1188 (Pioneer®, USA) was used as homofermentative lactic acid bacteria whereas inoculant 11A44 (Pioneer®, USA) was used as heterofermentative lactic acid bacteria inoculant. Inoculants were applied to the silages at 6.00 log10 cfu/g levels. After treatment, the chopped whole crop sunflower was ensiled in 1.0-litre special anaerobic jars, equipped with a lid enabling gas release only. The jars were stored at 25±2°C under the laboratory conditions. Three jars from each group were sampled for chemical and microbiological analyses 2, 4, 8 and 60 days after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 5 days. In addition, in vitro organic matter digestibility of those silages were determined. The results revealed that homofermentative lactic acid bacteria inoculants increased the characteristics of fermentation but impaired the aerobic stability of the sunflower silages (P0.05). © 2017 Namik Kemal University - Agricultural Faculty. All Rights Reserved

Discovery of an earliest Triassic, post-extinction foraminiferal assemblage above the Permian-Triassic boundary, Strandzha nappes, north-west Turkey

A new foraminiferal fauna from Early Triassic (Induan) strata of the Çaglayik section on the “Strandzha Massif”, north-west Turkey, comprises five species precisely determined and five species in open nomenclature belonging to ten genera. They belong to the post-extinction foraminiferal assemblage of the Permian-Triassic crisis, characterized by the presence of both disaster taxa (Earlandia and Postcladella kalhori) and Lazarus taxa (Diplosphaerina inaequalis, Rectostipulina quadrata, Arenovidalina sp. and Glomospira sp.). The present study at Tütünlüktepe Formation identified for the first time the Permian foraminifers on the Strandzha Massif as relict members of a post-extinction foraminiferal assemblage

Development and directed energy deposition of high strength Hf5Mo15Nb35Ta25Ti20 refractory high entropy alloys

In this study, a novel HfMoNbTaTi refractory high entropy alloy was designed by empirical calculations and CALculation of PHAse Diagram (CALPHAD) method by using ThermoCalc software. Directed energy deposition (DED) based additive manufacturing process was used to produce the alloy. After the process parameter determination studies using single-track productions, cuboids were produced. The microstructural investigations showed that while the central region of cuboids has large grains, the outer region has a dendritic structure with some unmolten Mo powders. Although columnar grain formation, which is the general characteristic of directional solidification, was observed at some points, irregularly shaped grains were dominant in the structure. Moreover, there were micron to nano-sized Hf-Ti-O particles inside the grains and especially around the grain boundaries. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses confirmed the formation of disordered body-centered cubic (BCC) Hf5Mo15Nb35Ta25Ti20 alloy with ∼6 vol% of Hf-Ti-O particles. Electron backscatter diffraction (EBSD) analyses indicated that there is a slight texture in the building direction along 〈111〉. In order to determine the stability of these alloys, ex-situ heat treatments coupled with XRD studies were conducted. As opposed to CALPHAD calculations it was not observed any HCP phase formation. Compression test results showed that Hf5Mo15Nb35Ta25Ti20 alloys have high strength (σy = ∼1300 MPa) and high compressive ductility with good strain-hardening ability. Theoretical calculations revealed that the strength of the alloy mainly originated from solid solution strengthening

occurrences in northwestern Turkey

Thin beds of tephra (K-bentonites) formed by the diagenesis of volcanic ash are exposed within the limestone-dolomitic limestone successions of the Yilanli formation at Zonguldak and Bartin in northwestern Turkey. They were deposited on the Middle Devonian-Lower Carboniferous shallow carbonate platform of the Zonguldak terrane. In this study, K-bentonite samples collected from Gavurpinari and Yilanli Burnu limestone quarries are investigated in order to reveal their mineralogical and geochemical characteristics and diagenetic evolution. Illite is the major clay mineral in the studied K-bentonites. Additionally, kaolinite and mixed-layer illite-smectite are identified in some samples. The nonclay minerals calcite, dolomite, quartz, gypsum, feldspar, pyrite, and zircon are also found. Crystal-chemical characteristics (Kubler index, d(060) values, and polytypes of illites) from two different sampling locations do not show significant variations. Kubler index values for the Yilanli Burnu and Gavurpinari sampling locations, 0.47-0.93 (average: 0.71 Delta degrees 2 theta) and 0.69-0.77 (average: 0.72 Delta degrees 2 theta), respectively, indicate that illites were affected by high-grade diagenetic conditions. The swelling (or smectite) component (similar to 5%), crystallite size (N = 10-20 nm), and polytype (2M(1) > 1M(d)) data of illites support the same conditions. Illite d(060) values of 1.491-1.503 angstrom correspond to a range of octahedral Mg+Fe values of 0.27-0.51 atoms per formula, indicating a composition between end-member muscovite and phengite unit. Trace and rare earth element-based chemical classification of the K-bentonite samples revealed that composition of original volcanic ash is basaltic. Illitization took place by fixation of K from volcanic minerals and ash, and diffusion of elements (Mg+Fe) into and out of the beds during diagenesis. Mineralogical-chemical data point out that these K-bentonites evolved in high-grade diagenetic conditions (approximately 100-150 degrees C) from the products of volcanic eruptions of disputed sources and distances during the Late Devonian time

Geological features and geochemical characteristics of Late Devonian-Early Carboniferous K-bentonites from northwestern Turkey

Newly discovered K-bentonite beds, interstratified with limestones/dolomitic limestones of the Upper Devonian-Lower Carboniferous Yllanll Formation, are exposed in the northwestern Black Sea region of Turkey, around Zonguldak and Bartln. K-bentonite samples collected from four different locations: the Gavurplnarl and Yllanll Burnu quarries from the Bartln area, the Çimşir Çukurlarl quarry from the Şapça area, and the Güdüllü and Gökgöl highway tunnel section near Zonguldak city were investigated using optical microscopy,X-ray diffraction and inductively coupled plasma mass spectrometry in order to reveal their mineralogical and geochemical characteristics and understand their origin and evolution. The K-bentonites occur at different levels in the Yllanll Formation as 2-40 cm-thick, greenish to yellowish beds cropping out several hundred metres along strike. Preliminary biostratigraphic data suggest that the protoliths of the Bartln (Gavurplnarl and Yllanll Burnu) and Güdüllü K-bentonites were deposited at around the boundary between the Frasnian and Famennian, whereas those in the Şapça and Gökgöl sections are slightly younger (Devonian-Carboniferous boundary interval). The lithofacies types of the host carbonate rocks suggest an 'epeiric' shallow carbonate platform environment. Illite and mixed-layer illite-smectite were the major clay minerals in the K-bentonites. The K-bentonites from the Bartln area display a high degree of illitization and consist mainly of illite indicating high-grade diagenesis, whereas illite-smectite-rich samples from the Şapca and Gökgöl tunnel locations reflect relatively lower diagenetic conditions. According to their geochemical compositions, two groups of K-bentonites were distinguished, one with alkali basalt (Bartln area and Güdüllü locations) and one with trachyte affinities (Gökgöl tunnel and Şapça locations). Geochemical fingerprinting of K-bentonites by trace and rare earth element (REE) data suggest that tephras with alkali basalt composition have been derived by a source formed in a 'continental back-arc' setting, whereas the source of K-bentonites with trachytic precursors is related to 'continental within-plate rifting'. An evaluation of the global Late Devonian and Devonian-Carboniferous volcanism suggests that the bentonite precursors may be related to late-Variscan magmatism in Laurussia. © 2016 by Walter de Gruyter Berlin/Boston

A combination of methylprednisolone and quercetin is effective for the treatment of cardiac contusion following blunt chest trauma in rats

Cardiac contusion is a potentially fatal complication of blunt chest trauma. The effects of a combination of quercetin and methylprednisolone against trauma-induced cardiac contusion were studied. Thirty-five female Sprague-Dawley rats were divided into five groups (n=7) as follows: sham, cardiac contusion with no therapy, treated with methylprednisolone (30 mg/kg on the first day, and 3 mg/kg on the following days), treated with quercetin (50 mg·kg−1·day−1), and treated with a combination of methylprednisolone and quercetin. Serum troponin I (Tn-I) and tumor necrosis factor-alpha (TNF-α) levels and cardiac histopathological findings were evaluated. Tn-I and TNF-α levels were elevated after contusion (P=0.001 and P=0.001). Seven days later, Tn-I and TNF-α levels decreased in the rats treated with methylprednisolone, quercetin, and the combination of methylprednisolone and quercetin compared to the rats without therapy, but a statistical significance was found only with the combination therapy (P=0.001 and P=0.011, respectively). Histopathological degeneration and necrosis scores were statistically lower in the methylprednisolone and quercetin combination group compared to the group treated only with methylprednisolone (P=0.017 and P=0.007, respectively). However, only degeneration scores were lower in the combination therapy group compared to the group treated only with quercetin (P=0.017). Inducible nitric oxide synthase positivity scores were decreased in all treatment groups compared to the untreated groups (P=0.097, P=0.026, and P=0.004, respectively). We conclude that a combination of quercetin and methylprednisolone can be used for the specific treatment of cardiac contusion