Tamer Koralay

Gold nanoparticle included graphene oxide modified electrode: Picomole detection of metal ions in seawater by stripping voltammetry

We obtained a gold nanomaterial/graphene oxide-modified glassy carbon electrode and characterized it using transmission electron microscope, scanning electron microscope, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy techniques. A response of the electrode using square wave anodic stripping voltammetry for Pb2+, Cu2+, and Hg2+ was found linear in the range from 1 × 10–7 to 1 × 10–11 M. The detection limits of Pb2+, Cu2+ and Hg2+ were 0.14, 0.5 and 1.2 pM, respectively. The method was applied to the simultaneous determination of Pb2+, Cu2+ and Hg2+ in seawater samples from a coastal region of Anatolia, and the results corresponded well with the values obtained by inductively coupled plasma-optical emission spectroscopy.

Determination of Tourmaline Composition in Pegmatite From Buldan, Denizli (Western Anatolia, Turkey) Using XRD, XRF, and Confocal Raman Spectroscopy

ABSTRACT Tourmaline minerals observed in different geologic environments show significant variations in terms of chemical compositions. Determination of tourmaline species gives useful petrogenetic information about both igneous and metamorphic environments. Microscopic, XRD, XRF, and confocal Raman spectroscopic features of tourmaline segregations that are 2–4 cm thick, dark-blue to black in color, and mostly fractured occurring in the Buldan pegmatite are reported. Under the microscope, tourmaline samples show indigo blue, light blue, and olive-brown pleochroism with a thin long columnar, bladed shape. They exhibit distinctive enrichments in Fe2O3 (7.83–10.16 wt%), V (245.0–591.0 ppm), Sn (70.1–147.3 ppm), W (1076.0–1887.0 ppm), U (1.2–18.2 ppm), and Th (9.6–28.0 ppm). In terms of geochemistry, the tourmaline samples are schorl with Fe/(Fe + Mg) ratios of 0.65–0.74 and Na/(Na + Ca) ratios of 0.88–0.93. Five characteristic bands of tourmaline samples are observed at 1050, 710, 370, 220–245, and 185 cm−1. Tourmaline segregations in the Buldan pegmatite are schorl in composition and are probably generated from Li-poor granitoids and their associated pegmatites.

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.

Multi-Isotope Investigations for Scientific Characterisation and Provenance Implication of Banded Travertines from Tripolis Antique City (Denizli–Turkey)

ABSTRACT The coloured stones used in buildings and monuments were an indicator of power and wealth during the ancient times. In this study, Tripolis city samples have been compared with Tripolis quarry samples in order to recognise the provenance of the banded travertine blocks in the ancient city. The banded travertine samples have similar mineral compositions and mainly consist of calcite with minor amounts of dolomite, aragonite, clay and iron oxide minerals. These results are also supported by CRS studies. Calcite is in the form of needle-shaped crystals ranging between 0.163–1.418 mm (in city) and 0.303–1.270 mm (in quarry). Tripolis banded travertine samples show the similar compositional spread in terms of major oxide, trace elements. δ13CV-PDB values of banded travertines range from 1.93 to 5.25‰ (in city) and 2.99 to 3.99‰ (in quarry), δ18OV-PDB values change between (−16.93)–(−10.08) ‰ and (−15.93)–(−13.01)‰, respectively. The U–Th radiometric ages are determined between ∼267 and 9 ka in Tripolis city samples and ∼350 and 2 ka in Tripolis quarry samples. The minero-petrographic, geochemical, C–O and U–Th isotope results fairly matched with each other. It seems highly probable that the banded travertines in Tripolis city were extracted from the Tripolis quarry, which is located at the northeast of the antique city with a distance of 3 km.

Minero-petrographic and isotopic characterization of two antique marble quarries in the Deni̇zli̇ region (western Anatolia, Turkey)

Abstract 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 white, gray veined and 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 Hiearapolis marble quarry, the δ13C and δ18O values change between 0.63 - 3.52 ‰ and (-9.55) - (-1.21) ‰, in turn. The δ13C and δ18O values of Domuzderesi marble quarry range from (-1.44) ‰ and 3.41 ‰, -13.26 ‰ and (-5.3) ‰, respectively. Minero-petrographic, geochemical and C-O stable isotope results reveal that Hierapolis and Domuzderesi ancient quarries have similar characteristics which have orginated from a same protolith.