volcanics (Central Anatolia Turkey)

The Tekkedag volcanic complex, which extends as a ridge in the direction of NW-SE, is one of the poorly known volcanic centers and is exposed to the southwest of Kayseri located within the Central Anatolian Volcanic Province (CAVP) of Turkey. The mineralogical composition of Tekkedag volcanics reveals an assemblage of plagioclase (labradorite, bytownite)+pyroxene (augite, diopside and enstatite)+Fe-Ti oxide (magnetite, rutile) +/- olivine (forsterite) mineral composition having hypocrystaline porphryric, hypohyaline porphryric, gleomeroporphryric and senate textures under the microscope. Confocal Raman Spectroscopy (CRS) has been used to define the mineral types. Tekkedag volcanics have medium K(2)O contents and are calc-alkaline in character. Geochemically, Tekkedag volcanics show a narrow range of major element compositions and are classified as augite andesite/basaltic andesite. On the variation diagrams based on MgO versus major and trace elements, they show good positive and negative correlations, indicating fractional crystallization of plagioclase, clinopyroxene and Fe-Ti oxide. Tekkedag volcanics display enrichment in large-ion lithophile elements (LILEs) relative to high field-strength elements (HFSEs) in chondrite, MORB, E-MORB and lower crust normalized multi-element diagrams. In all normalized multi-element diagrams, the trace element patterns of all samples are similar in shape and exhibit depletions in Ba, Nb, P and Ti as characteristics of subduction-related magmas. Rare earth element (REE) patterns for Tekkedag volcanics show REE enrichment with respect to chondrite values. They exhibit marked enrichment in light rare earth elements (LREEs) ((La/Sm)(N)=4.13-4.62) relative to heavy rare earth elements (HREEs) ((Sm/Lu)(N)=1.34-1.92). Furthermore, all samples have negative Eu anomalies ((Eu/Eu*)(N)= 0.77-0.90), indicating the significant role of plagioclase in the fractional crystallization. Elemental ratios such as K/P (15.46-21.69), La/Nb (2.01-4.26), Rb/Nb (8.74-10.59), Ba/Nb (38.54-75.77), Nb/Ta (1.16-2.14), Ce/P (2.13-4.32) and Th/U (1.77-3.97) propose that the magma was subjected to conceivable crustal contamination during the evolution of these Tekkedag volcanics. This statement is supported by the AFC modeling based on the trace elements. As a result, despite the lack of isotopic data, the petrographic and geochemical results suggest a significant role of plagioclase, clinopyroxene and Fe-Ti oxide fractionation during the evolution of the Volcanic Arc Basalts (VAB) nature of the Tekkedag volcanics. Furthermore, these results reveal that the volcanics of Tekkedag were produced from a parental magma derived from an enriched source of mixed subduction and/or crustal products. (C) 2010 Elsevier GmbH. All rights reserved

The origin and determination of silica types in the silica occurrences from Altintaş region (Uşak-Western Anatolia) using multianalytical techniques.

The studied area is located in Western Anatolia and situated on the NE-SW directed Uşak-Güre cross-graben that developed under a crustal extensional regime during the Late Miocene-Pliocene. Silica occurrences have been mostly found as mushroom-shaped big caps. They also show sedimentary structures such as stratification. Silica occurrences are milky white, yellowish white, yellow to chocolate brown and rarely pale blue, bluish gray in color and have no crystal forms in hand specimen. Some of the silica samples show conchoidal fracture. Silica minerals are mostly chalcedony, low-quartz (α-quartz) and sporadically opal-CT in spectras, according to confocal Raman spectrometry. The silica samples have enrichment of Fe (1000-24,600 ppm), Ca (100-10,200 ppm), P (4-3950 ppm) and Mn (8-3020 ppm). Other striking elements in fewer amounts are Ba (0.9-609.6 ppm), Ni (15.7-182.3 ppm) and Co (18.6-343.1 ppm). In chondrite-normalized spider diagram, silica samples display partial enrichment in LIL elements (Rb, Ba, Th). The δ(18)O (‰ V-SMOW) values for silica samples vary from 18.4‰ to 22.8‰ and are similar to low temperature hydrothermal silica. Confocal Raman spectrometry and oxygen isotope indicate that the silica minerals may precipitate from host fluid which is relatively has low temperatures hydrothermal solutions derived from the residual melt of basaltic magma

Reasons of different colors in the ignimbrite lithology: micro-XRF and confocal Raman spectrometry method.

Medium to large volume ignimbrites usually show vertical changes in terms of color, mineral components, texture and geochemistry. Determination of vertical changes in single extensive ignimbrite flow unit is difficult and requires careful studies. Color changes in ignimbrite flow units are very important for earth scientists. This may cause to identify the same ignimbrite series with different definition. Incesu ignimbrite has a wide distribution in the Central Anatolian Volcanic Province (CAVP). It is classified into three levels as lower, middle and upper according to color and welding degree. There is a sharp contact between the lower and middle level. The lower level is dark brown to black in color and the middle level has pinkish red to red color. The present paper focuses on the investigation of color changes between the ignimbrite levels by using micro-XRF and confocal Raman spectrometry. Micro-XRF and Raman spectrometry studies were performed on the polished thin sections of the lower and middle levels with different compositions. These differences were because of the compositional changes of K and slightly Fe elements distribution within the matrix. The dark brown to black color of the lower level was related to the high concentration of the K and Fe relatively to the middle level. Confocal Raman spectrometry investigations exhibited the matrix of the lower level mainly composed of anorthoclase, supporting the results of the micro-XRF

confocal Raman spectrometry method

Medium to large volume ignimbrites usually show vertical changes in terms of color, mineral components, texture and geochemistry. Determination of vertical changes in single extensive ignimbrite flow unit is difficult and requires careful studies. Color changes in ignimbrite flow units are very important for earth scientists. This may cause to identify the same ignimbrite series with different definition. Incesu ignimbrite has a wide distribution in the Central Anatolian Volcanic Province (CAVP). It is classified into three levels as lower, middle and upper according to color and welding degree. There is a sharp contact between the lower and middle level. The lower level is dark brown to black in color and the middle level has pinkish red to red color. The present paper focuses on the investigation of color changes between the ignimbrite levels by using micro-XRF and confocal Raman spectrometry.Micro-XRF and Raman spectrometry studies were performed on the polished thin sections of the lower and, middle levels with different compositions. These differences were because of the compositional changes of K and slightly Fe elements distribution within the matrix. The dark brown to black color of the lower level was related to the high concentration of the K and Fe relatively to the middle level. Confocal Raman spectrometry investigations exhibited the matrix of the lower level mainly composed of anorthoclase, supporting the results of the micro-XRF. (C) 2007 Elsevier B.V. All rights reserved

quarries in the Denizli region (western Anatolia, Turkey)

The marbles are widely used rock types in the structures of today and ancient world. In this study, two ancient marble quarries named as Hierapolis and Domuzderesi in Denizli region, have been examined. The marble samples from these quarries can be grouped into three types, based on color, crystal size, crystal boundaries and foliation status. These groups are identified as i) white, ii) gray veined and iii) gray marbles. In terms of microscopic features, heteroblastic polygonal (white marbles in Hierapolis, gray-veined and gray marbles in Domuzderesi) and homeoblastic polygonal textures (white marbles in Domuzderesi) have been defined. The mineral compositions of all marble groups are quite similar. They are consisting predominantly of carbonate minerals (calcite, dolomite) and, as accessory minerals quartz, muscovite, pyroxene and ferric iron oxides. These results are also supported by the XRD studies. According to the geochemical analyses, protoliths of Hierapolis and Domuzderesi marbles are limestone. In Hierapolis marble quarry, the delta C-13 and delta O-18 values change between 0.63 - 3.52 parts per thousand and (-9.55) - (-1.21) parts per thousand, in turn. The delta C-13 and delta O-18 values of Domuzderesi marble quarry range from (-1.44) parts per thousand and 3.41 parts per thousand, -13.26 parts per thousand and (-5.3) parts per thousand, respectively. Minero-petrographic, geochemical and C-O stable isotope results reveal that Hierapolis and Domuzderesi ancient quarries have similar characteristics which have originated from a same protolith

Minero-petrographical, physical, and mechanical properties of moderately welded ignimbrite as a traditional building stone from Uşak Region (SW Turkey)

Ignimbrites are commonly used building stone since the ancient times because of its lightweight, soft, and insulating properties. However, they are prone to deteriorate due to their weak structure. The moderately welded Uşak ignimbrite has a wide range of exposure in the Uşak region of the inner western part of Anatolia. It is mainly composed of plagioclase (oligoclase, andesine), biotite, Fe-Ti oxides (magnetite, hematite), and low amount of amphibole (brown hornblende), quartz mineral composition having hypocrystalline and eutaxitic texture. Geochemical data reveal that the ignimbrite is characterized by trachyandesite composition, calc-alkaline and peraluminous in character. According to the calculated weathering index values, the ignimbrite shows slight to moderate weathering. Apparent dry and partially saturated unit weights are 10.49 and 13.90 kN/m3, respectively. Open porosity is 35.4%. This high value results in high water absorption capacity and low uniaxial compressive strength. Capillary water absorption capacity was determined as 51.84 g/m2 s0.5; with this value, the ignimbrite is in “high” water absorption rock class. Dry and partially saturated uniaxial compressive strength values were determined as 6.89 MPa and 3.45 MPa respectively. Tested ignimbrite specimens are in “weak rock class” according to UCS values both in dry and partially saturated conditions. Therefore, the stone loses about 50% of its strength in partially saturated condition. Longitudinal and shear wave velocities of the specimens were determined as 2.4 and 1.32 km/s respectively. Based on these values, dynamic shear modulus, Poisson’s ratio, and Young’s modulus were calculated as 1.91 GPa, 0.27 GPa, and 4.87 GPa, respectively. Slake durability tests were carried out on ignimbrite specimens after the second cycle 91.33%; Uşak ignimbrite is characterized by “medium-high” durability. Specimens were exposed to 25 freeze and thaw cycles and the average of the weight lost values were determined as 0.89%. Thermal conductivity properties were investigated by the thermal conductivity coefficient which was ranged between 0.352 and 0.449 W/mK. Minero-petrographic investigations and geochemical and physico-mechanical test results indicate that the structure of Uşak ignimbrite is weak and sensitive to environmental and utilization condition. Therefore, it is necessary to pay attention to this feature in the areas of utilization. © 2019, Saudi Society for Geosciences

Investigation of the usability of leeb hardness criterion in the determination of physicomechanical properties of travertine

Travertine is a natural building stone widely preferred in our country and in many parts of the world. Travertine has a wide range of physical and mechanical properties depending on the depositional conditions. Practical and economical prediction of these properties ranging in such a wide range are preferred by practitioners. Leeb hardness measurement method, which has become widespread in recent years, is used to determine the surface hardness of the materials. In this study, it was aimed to investigate the correlations of physical and mechanical properties of travertine samples obtained from 16 different quarries in Denizli region with Leeb hardness values. For this purpose, dry and saturated density (γk, γd) apparent porosity (nA), water absorption by weight (ws), sonic velocity (Vp), wide wheel abrasion (DA), uniaxial compressive strength (TSD) values of the prepared cube samples were determined and correlated with Leeb hardness values (HL). In addition, the L type Schmidt hammer hardness values (HS) which are widely used in characterization of rock materials were obtained for all samples and compared with HL values. Investigation of the physico-mechanical properties of Denizli travertine with economic and practical Leeb hardness test has been revealed. The proposed correlation equations were obtained in linear forms and presented with their coefficients of correlation and brought into literature. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved

ignimbrite, Central Anatolian Volcanic Province (Kayseri - Turkey)

The Central Anatolian Volcanic Province (CAVP), one of four major volcanic provinces in Turkey, plays a significant role in the interpretation of the tectonic evolution of Central Anatolia. The CAVP developed within a complex collisional system involving the African, Arabian and Eurasian plates during the Miocene. The volcanism exhibits complicated variations in mineralogical, petrological and geochemical compositions resulting from post-collisional lithospheric dynamics. The Incesu ignimbrite has 5-20 m thick and covers an area of similar to 7800 km(2). It is composed of three stratigraphic levels. The lower level (LL) shows blackish brown and glassy welded structure. The middle level (ML) is a well-welded, reddish pink in color and has large amounts of fiamme. The upper level (UL) is grayish pink, weakly welded and has rock fragments of different compositions. The Incesu ignimbrite is composed of plagioclase (oligoclase, andesine) + pyroxene (augite, clinoenstatite) + opaque minerals and low amount of amphibole, biotite and quartz. Eutaxitic texture is dominant in ML and LL samples; these levels are more strongly and contain more flattened pumice fragments and volcanic glass shards than in the UL. A sharp color contrast defines the contact between LL and MLMajor, trace and rare earth element of the Incesu ignimbrite, characterized by their rhyolite, rhyodacite-dacite composition, medium-high K, calcalkaline and peraluminous nature, show fractional crystallization primarily controlled by plagioclase, clinopyroxene, magnetite, ilmenite and titanomagnetite. Sr and Nd isotopic ratios of Incesu ignimbrite display isotopic variations between the ignimbrite levels; they exhibit a limited range in Sr-87/Sr-86 (0.7043-0.7049) and Nd-143/Nd-144 (0.512716-0.512760). The Sr-Nd isotopic ratio of Incesu ignimbrite reveals an age of 3 Ma. The ignimbrite evolved through fractional crystallization and crystal contamination of the parent magma derived from Ocean Island Basalt (OIB) like magma. This suggestion is supported by the AFC modeling based on the trace elements and Sr isotope data.Variation of several major oxide concentrations (Fe2O3, TiO2, CaO and K2O), trace element concetrations (V, Sr, Cs and Rb) and trace element ratios (Ba/Rb, Sr/, K/Sr, K/Nb, Rb/Sr, Rb/Y and Rb/Nb) versus SiO2 concentration show the magma chamber that generated the Incesu ignimbrite was compositionally zoned. All geochemical and Sr-Nd isotpic datas can be interepreted to be the result of a subduction related source. (C) 2010 Elsevier Ltd. All rights reserved

Assessments on minero-petrographics, geochemical and physical-mechanical properties of emirdaǧ (Afyonkarahisar) travertines

In this study, the minero-petrographical, chemical properties as well as basic physical and mechanical properties of the travertine samples, known as Afyon Silver from Emirdaǧ (Afyonkarahisar) region were comprehensively examined. The travertine samples have completely crystalline texture and consist of carbonate minerals (calcite in composition) with ranging from 100-250 μm. XRD and Confocal Raman Spectrometer studies are supported these results. The average CaO content of the travertine samples were 55.75%, MgO content <0.012%, Fe2O3 (as total iron) content 0.020% and MnO content 0.101%. According to the results of the physico-mechanical test, the apparent dry density values were between 2.38 and 2.52 g/cm3 and the saturated density values were between 2.43 and 2.55 g/cm3. Open porosity and water absorption values were determined as 5.24% and 1.21% to 2.19%, respectively. The vertical abrasion values of the travertine samples were between 22.99 and 28.13 mm, and the average value was 25.91 mm. Sonic velocity values were measured between 4.49 and 5.87 km/s. The uniaxial compressive strength was determined between 23.17 and 53.22 MPa. In addition, 3 and 4 point bending strength tests were performed on the plate samples and the mean values were determined as 14.67 and 11.19 MPa, respectively. According to the freeze-thaw test results, the average loss of material by weight was 0.86% and there is a negligible amount of differences in uniaxial compressive strength. As a result of mineralogical, petrographic, chemical and physico-mechanical tests, It is determined that travertine samples have the characteristics that can be used as natural building stones. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved