Muazzez Çelik Karakaya

CLASTOUR: a computer program for classification of the minerals of the tourmaline group

Tourmaline is the most important borosilicate mineral and a dominant carrier of boron, occurring in different geologic environments. Recently, many investigators have focused on the enhanced understanding of crystal chemistry of this complex mineral group. CLASTOUR is a program package for IBM-compatible personal computers that can be used for classification of the tourmaline group. The program classifies most of the currently valid tourmaline end-members together with other hypothetical end-members. Because it is difficult to establish OH- and O2- contents at the V- and W-sites without carrying out bond valance sum (BVS) calculations, CLASTOUR gives alternative names for some tourmalines including dominant O2- anion at their V- and W-sites. The program is developed to edit, to store and to calculate the tourmaline analyses obtained both from electron-microprobe and wet-chemical studies. It is designed to calculate entered tourmaline analyses into cation and molecular percentages, to share cation site-allocations at the different structural positions and to give mole percent of the end-members of alkali-, calcic-, and X-site vacant-group tourmalines. Thus, CLASTOUR makes it possible to plot various types of binary and ternary diagrams under the Grapher software. This program is a user-friendly software with pull-down menus, base-function keys, help menus, extensive error codes and mouse options. The compiled program together with the test data files and graphic files is approximately 1160 kB.

Trace-element, rare-earth element and boron isotopic compositions of tourmaline from a vein-type Pb–Zn–Cu ± U deposit, NE Turkey

This paper reports trace-element, rare-earth element (REE) and boron isotopic compositions of tourmaline in the Asarcık granitoid and quartz veins at Şebinkarahisar. Abundant tourmaline occurs in the vein-type Pb–Zn–Cu ± U deposit, within the northeastern Pontide Metallogenic Belt, both within the Late Cretaceous Asarcık granitoid and in associated quartz–tourmaline veins. Tourmaline in the granitoid forms as rosettes up to 1.5 cm in diameter, whereas in quartz–tourmaline veins a few centimetres to a few metres wide, it occurs as black needles and masses that cut the pluton. We present a systematic geochemical study of these tourmalines – all of the schorl-dravite series. Tourmalines from the quartz veins contain high concentrations of ore metals such as Ag, Bi and Zn and have higher Sr, Cr and Sn contents than tourmalines in the Asarcık granitoid. Tourmalines from intensively altered parts of the pluton are characterized by higher concentrations of trace elements such as Ba, Rb, V, Sc, Th and Zr compared with occurrences in the quartz veins and in the fresh and less-altered granitoid. Chondrite-normalized patterns of REEs in tourmalines from the Asarcık granitoid are generally similar to those of tourmalines in the quartz veins. All vein tourmalines, however, are characterized by heavy REE enrichments, in sharp contrast to those in the granitoid. Boron isotopic compositions of tourmalines range from − 14.0 to − 2.2‰ and fall within the δ11B range of this mineral in granite-related settings. Tourmaline rosettes from the Asarcık granitoid show relatively lighter δ11B values ( − 14.0 to − 12.2‰) in comparison with those in the quartz veins ( − 10.4 to − 2.2‰).

MINERALOGICAL AND GEOCHEMICAL PROPERTIES OF THE Na- AND Ca-BENTONITES OF ORDU (NE TURKEY)

A number of different types of bentonite deposits formed by hydrothermal alteration and diagenetic processes are to be found in the Ordu area of the Eastern Black Sea region. The Ca- and Na-bentonite deposits are related to Upper Cretaceous tholeitic to calc-alkaline volcanites, predominantly dacite and andesite, and also include rhyodacite with lesser basalt and their pyroclastic equivalents. In the present study, dacite (PR1), perlite (PR2), moderately altered rocks (MPR), and Na- and Ca-bentonites were studied to describe and compare their mineralogical and geochemical properties and their conditions of formation by means of X-ray diffraction, optical microscopy, scanning electron microscopy, and chemical analytical techniques.Ca-bentonites, except for smectite, contain opal-CT, feldspar, biotite, and rarely pyrite, while Na-bentonites contain smectite and less feldspar, opal-CT, kaolinite, and illite.Progressive alteration of the PR2 caused depletion in K2O and Na2O and enrichment in MgO and CaO in all of the Ca-bentonite samples. Na2O was depleted in all of the Na-bentonites and in most of the MPR. The medium and heavy rare earth elements (MREE and HREE) show mass gain or mass loss in the Na-bentonites. The HREE show nearly immobile behavior in the Ca-bentonites. The rare earth elements (REE) and transition elements (TRE) mostly gained mass in the Ca-bentonites in contrast to Na-bentonites. Large-ion lithophile elements (LILE) are strongly depleted in all of the bentonites. The LREE, MREE, and HREE were strongly depleted in most of the MPR samples. TiO2, Lu, Tm, and Tb show immobile behavior in all samples.PR1 exhibits a slightly positive Eu anomaly. Two MPR samples show slightly positive Eu anomalies (1.03, 1.13), and one Na-bentonite sample displays a slightly positive Eu anomaly (1.04). Most of the Nabentonites have weakly negative Eu anomalies, whereas perlite and the Ca-bentonite have a strongly negative Eu anomaly. The PR1, PR2, MPR, and Na-bentonite present a positive Ce anomaly, and the Ca-bentonite shows a moderately negative Ce anomaly. The Ca-montmorillonites are mainly hydrothermal in origin and derived from alteration of volcanoclastic material in situ and/or in the subaerial environment. The Na-montmorillonites formed by alteration and diagenesis of volcanoclastic material in the sedimentary basin.

A Windows program for calculation and classification of tourmaline-supergroup (IMA-2011)

A Microsoft Visual Basic program, WinTcac, has been developed to calculate structural formulae of tourmaline analyses based on the Subcommittee on Tourmaline Nomenclature (STN) of the International Mineralogical Associations Commission on New Minerals, Nomenclature and Classification (IMA-CNMCN) scheme. WinTcac calculates and classifies tourmaline-supergroup minerals based on 31 O atoms for complete tourmaline analyses. For electron-microprobe-derived tourmaline analyses site occupancy can be estimated by using the stoichiometric H2O (wt%) and B2O3 (wt%) contents. This program also allows the user to process tourmaline analyses using 15 cations and 6 silicons normalization schemes. WinTcac provides the user to display tourmaline analyses in a various classification, environmental, substitution, and miscellaneous plots by using the Golden Softwares Grapher program. The program is developed to predict cation site-allocations at the different structural positions, including the T, Z, Y, and X sites, as well as to estimate the OH1-, F1-, Cl1-, and O2- contents. WinTcac provides editing and loading Microsoft Excel files to calculate multiple tourmaline analyses. This software generates and stores all the calculated results in the output of Microsoft Excel file, which can be displayed and processed by any other software for verification, general data manipulation, and graphing purposes. The compiled program code is distributed as a self-extracting setup file, including a help file, test data files and graphic files, which are designed to produce a high-quality printout of the related plotting software. We developed a Windows program, called WinTcac, for calculation and classification of tourmaline-supergroup based on the current IMA-2011 scheme.The program calculates tourmaline-supergroup minerals according to 31 O atoms for complete tourmaline analyses.Electron-microprobe-derived tourmaline analyses are carried out based on site occupancy by using the stoichiometric B2O3 and H2O (wt%) contents.WinTcac generates and stores all the calculated results in an Excel file for further data manipulation and plotting.The program enables the user to display over 80 binary and ternary plots for classification, environmental, miscellaneous, and substitution diagrams.

MINERALOGICAL AND CHEMICAL PROPERTIES AND THE ORIGIN OF TWO TYPES OF ANALCIME IN SW ANKARA, TURKEY

Authigenic analcimes were observed in different amounts in Miocene units in central Anatolia, Turkey. Two types of analcime occurrences were defined: (1) as continuous but inhomogeneous concentrations varying from 3 to 75 wt.% in lacustrine sedimentary rocks; and (2) as low concentrations (between 3 and 20%) and discontinuous components in the tuffs and claystones intercalated with tuff. The type 2 analcimes have been investigated by many researchers while the origin and properties of the sedimentary analcimes, which are widespread in different parts of Turkey, have not been clarified. The present study focused on the genesis and the mineralogical and geochemical properties of both types of analcime. The analcimes were investigated using X-ray diffraction, optical microscopy, scanning electron microscopy, and chemical analytical methods. In the first type, other than volcaniclastic material, analcime is the only zeolite mineral. The first type of analcime was associated mainly with montmorillonite, dolomite, and feldspar and sometimes with calcite, and rarely with illite and kaolinite. The second type of analcime was found as an accessory mineral accompanied by montmorillonite, feldspar, and heulandite/clinoptilolite, and more rarely by erionite, kaolinite, and mica. The pyroclastic rocks are chemically classified into two subgroups, dacitic and andesitic rocks, with an intermediate to high silica content and a high percentage of alkali cations. Analcime in the pyroclastics intercalated with clay layers commonly replaced early-formed zeolites, such as clinoptilolite or volcanic materials. The first type of analcime was not formed from precursor zeolites and had a different origin than the second type. Type 1 analcime contains larger amounts of Si (34.19 to 34.68 Si per unit cell) and less Al and Na than in theoretical analcime. The theoretical structural formula of analcime is Na16(Al16Si32O96)H2O. The strongly decomposing feldspar and clay minerals (in particular montmorillonite and partially illite) of the older formations and the dissolution of halite and also soda minerals, e.g. thenardite and glauberite, allow the authigenic formation of type 1 analcime, dolomite, K-feldspar, and montmorillonite in a saline and highly alkaline environment such as the marginal part of Lake Tuzgölü. Type 2 analcime may have been precipitated directly from solution, pyroclastic material, or precursor zeolite minerals in saline and alkaline lake water.

A Windows program for chlorite calculation and classification

A Microsoft Visual Basic program, WinCcac, has been developed to calculate the structural formulae of chlorite. WinCcac classifies rock-forming chlorite group minerals based on 14 oxygens for complete chlorite analyses. For electron-microprobe-derived chlorite analyses site occupancy can be estimated by using the stoichiometric H2O (wt%) and Fe2O3 (wt%) contents. The program is created to predict cation site-allocations at the different structural positions such as the tetrahedral, octahedral, and interlayer sites. Furthermore, various chlorite geothermometers based on an empirical approach are carried out to specify the condition of formation temperature. WinCcac allows the user to enter and load multiple chlorite analyses in its own data entry window, to edit and load Microsoft Excel files in estimating and classifying chlorite data, and to generate and store all the calculated results in the output of Microsoft Excel file for further data evaluation and graphing purposes. A Windows program (WinCcac) has been developed to calculate chlorite analyses.WinCcac classifies rock-forming chlorites based on 14 oxygen equivalents.The program provides the stoichiometric H2O (wt%) and Fe2O3 (wt%) contents.WinCcac estimates various chlorite geothermometers based on an empirical approach.

Hydrothermal Alteration of the Saplica Volcanic Rocks, Sebinkarahisar, Turkey

A widespread, intense hydrothermal alteration zone has developed in the Cretaceous Saplica volcanics as a result of the intrusion of Late Cretaceous-Paleocene granitoids. The propylitic, phyllitic (sericitic), and argillic alteration along with hematite, silica polymorphs, and two types of tourmaline mineralization developed under a wide range of Eh and pH conditions. Alunite, kaolinite, and silica are abundant in the argillic alteration, whereas sericite dominates in the phyllic alteration. Most of the major alunite deposits are located along the periphery of the Saplica volcanic rocks and in addition contain alunite, kaolinite + quartz ± opal ± cristobalite. Illite and pyrite, barite, and gypsum also occur in small amounts. Major and trace elements are concentrated in, or were leached from, the volcanic rocks, depending upon the alteration types. In general, Al + K and Mg + Ca + Fe were enriched in the alunitic + sericitic and propylitic alteration types, respectively. On the other hand, Ca, Mg, and Fe were leached during argillic alteration, and Fe was concentrated in hematite formation. Strong leaching of Na was determined for alteration types. Silica generally decreased in argillitic (kaolinitic and alunitic) alteration zones. Most trace elements were mobile during hydrothermal alteration. Y, Sc, Mo, Cr, Co, Ni, and Zn tend to be mobile in acid aqueous systems, and thus are nearly absent in these alunitic alteration zones. In the surrounding kaolinitic envelope, these elements are present at background (average) or slightly higher concentrations. Rb and Sr contents are high in the alunitic and kaolinitic zones. Barium is highest near the alunite zone because of the relative insolubility of barite in acidic solutions. Pb and Cu contents increase in the propylitic zone. Such hydrothermal alteration zones can be used effectively in the exploration and evaluation of mineral resources of the eastern Black Sea region.

Kaolin Occurrences in the Erenler Dagi Volcanics, Southwest Konya Province, Turkey

Mainly calc-alkaline, andesitic, and dacitic volcanics from different late Miocene-Pliocene eruption centers crop out WSW of Konya, and locally are interbedded with lacustrine sediments. Hydrothermal alteration within these rocks is widespread. In addition to kaolinite, other major alteration products include halloysite, alunite, cristobalite, quartz, illite, montmorillonite, and zeolitegroup minerals. Based on the cristobalite-quartz relationship, the kaolinization temperature is estimated as ∼100°C. The samples were mineralogically and chemically examined using XRD, SEM-EDS, IR, DTA-TG, and XRF. The crystallinity of the kaolinite is moderate, and shows structural disorder. Both the kaolinite and halloysite are almost stoichometric. Kaolinization generally led to Al2O3 increases and release of alkalies, alkaline earths, most of the Fe2O3, and SiO2. SiO2 and Al2O3 contents are low, and LOI is very high for halloysite deposits relative to kaolin occurrences. The kaolinite-alunite assemblages indicate that pH of the altering solutions initially was ∼4. SEM investigation demonstrates that kaolinite has booklet texture, whereas halloysite is acicular to needleshaped. The chemical, mineralogic, and firing properties of the kaolin deposits are appropriate for use as refractory raw material. The Erenler Dagi kaolin deposits are excellent examples of the acid-sulfate type of hydrothermal alteration. The findings of the study may be useful in exploration for similar hydrothermal mineral occurrences worldwide.

GEOLOGY AND CONDITIONS OF FORMATION OF THE ZEOLITE-BEARING DEPOSITS SOUTHEAST OF ANKARA (CENTRAL TURKEY)

The pyroclastic sediments studied here contained varied amounts of zeolite and were formed in the saline alkaline Tuzgölü Basin following the alteration of dacitic volcanic materials during the Early to Late Miocene. The present study focused on the geological-geochemical properties of the zeolites and describes their formation. Mineralogical and chemical compositions were determined by X-ray diffraction, scanning electron microscopy, optical microscopy, and inductively coupled plasma mass spectrometry. Results indicated that the zeolitic tuffs consisted mainly of heulandite/clinoptilolite (Hul/Cpt), chabazite, erionite, and analcime associated with smectite. Smectite, calcite, and dolomite are abundant in the clay and carbonate layers which alternate with the zeolitic tuffs. K-feldspar, gypsum, and hexahydrite (MgSO4·6H2O) were also found in some altered tuffs and clay-marl layers as accessory minerals. The zeolite and other authigenic minerals showed weak stratigraphic zonation. Some vitric tuff layers contained no zeolite minerals and others were found to consist of almost pure Hul/Cpt and chabazite layers with economic potential. The rare earth elements (REE), large ion lithophile elements (LILE), and high-field strength elements (HFSE) in the Hul/Cpt-rich tuffs and vitric tuffs were enriched or depleted relative to the precursor rock, while many major elements were slightly or significantly depleted in all zeolitic tuffs. The amounts of REE in the chabazite- and erionite-rich tuffs were generally smaller than those in the precursor rock. The middle and heavy REE (MREE and HREE, respectively) were abundant in the Hul/Cpt-rich tuffs, tuffs, and smectitic bentonites. Chondrite-normalized REE values of the sample groups are characterized by sub-parallel patterns with enrichment in LREE relative to HREE. The mineral assemblages and geological setting indicated that zeolite diagenesis occurred in a saline-alkaline basin. The δ18O and δD compositions of the Hul/Cpt, chabazite, and smectite indicated that the minerals formed at low to moderate temperatures and that some of the zeolitization occurred due to diagenetic alteration under closed-system conditions that varied according to the nature of the basin and with the composition and physical properties of the volcanic materials.

Radioactivity concentrations and dose assessments of therapeutic peloids from some Turkish spas

Abstract The activity concentrations of natural radionuclides in peloids were studied to assess the radiologic hazard from 18 Turkish spas. The peloids are mainly used for therapeutic treatments, rheumatic diseases and aesthetic purposes. The concentrations of the natural radionuclides 226Ra, 232Th, 40K and 137Cs were determined with a gamma ray spectrometer using a HPGe detector. The average activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the peloids studied were 110.69, 71.52, 576.48 and 0.447 Bq/kg, respectively. The radium equivalent activities in the peloid samples ranged from 63.3 to 766.77 Bq/kg. The absorbed dose rate (Dout) varied between 37.52 and 330.67 nGy/h and most of the observed spa doses are greater than the worldwide recommended values. The annual effective dose values range from 0.26 to 2.78 μSv/y. The annual gonadal dose equivalents of the samples vary from 224.07 to 2283.55 with a mean of 821.99 μSv/y.