Origin of Magnesite in Turkey, a Stable Isotope Study

This thesis is concerned with the problem of the genesis of the various types of cryptocrystalline magnesite deposits found in western Turkey. Veins and stockworks of cryptocrystalline magnesite deposits are found within the discontinuous ultramafic belts of western Turkey. Sedimentary-hydrothermal lacustrine magnesites and presently forming hydromagnesite deposits lie above these ultramafic rocks. A hot-spring calcite deposit at the northern edge of a Menderes graben is also considered. From the stable carbon and oxygen isotopic signatures of the magnesite, hydromagnesite and calcite formations of western Turkey, three end-members can be distinguished End-member-1: represents the cryptocrystalline, vein-type of magnesite deposits. Decarboxylation of organic-rich sediments may have provided about two thirds of the carbonate in the vein-type of Koyakci Tepe magnesite deposits, Konya, which have ~-13 and ~+27 % of delta13C and delta18O respectively. Stockwork deposits at Helvacibaba, Yunak and Kozagac, all in Konya, have slightly heavier delta13C and delta18O values indicating more involvement of atmospheric carbon dioxide (as bicarbonate in the circulating meteoric water) compared to those of Koyakci Tepe. End-member-2 : represents carbon dioxide of atmospheric origin. Presently forming hydromagnesite deposits at Saida lake, Yesilova, Burdur reflect such a carbon dioxide origin with of delta13C of ~+4‰PDB and delta18O of ~+36‰SMOW. End-member-3 : represents the carbon dioxide of metamorphic origin. Present-day, hot-spring travertine (calcite) deposits at Pamukkale, Denizli, have the heaviest delta13C (~+6 %o,PDB) and extremely light delta13C (~+20‰SMOW) values and these values are probably the result of decarbonation and/or dissolution of limestone formations beneath travertines. Sedimentary magnesite deposits at Hirsizdere, Denizli and stockwork magnesite deposit at Arapomer Deresi have unexpectedly heavy delta13C (~+2 and 0‰PDB respectively), and these deposits probably gained their carbonates from decarbonation and/or dissolution of limestones. The extremely low REE contents of magnesite, hydro magnesite and ultramafic host- rocks indicate that the magnesium is derived from the ultramafic rocks. The Saida lake hydromagnesite deposits are being formed by a microbial community in the lake itself. In terms of isotopic signatures, physical features and geological environment, Saida's hydromagnesite deposits are comparable with the Miocene, lacustrine, sedimentary magnesite deposits elsewhere, perhaps especially to Bela-Stena in Serbia. Therefore Saida's hydromagnesites may be a precursor of magnesite

Some Geological Features of Limestone Aggregates Produced From Central Anatolian Carbonate Formations

F or the last fifteen years, there has been extensive motorway and railway constructions in Turkey. This requires enormous amount of road-fillers and aggregates, and the construction companies open many open-pit limestone quarries to fulfill their aggregate needs. The partly double four lines , partly one-way double line motorway of KonyaHüyük have recently been enlarged and partly re-constructed. During this construction, a total of five limestone quarry were opened to produce limestone aggregate. The Bozlutepe Limestone member of Asmalıtepe Formation near the town of Selki HüyükKonya, central Anatolia were used for this demand, and it has been operated for the last 6 years. The limestone member is approximately 200 m thick at most and mostly made of three type of minerals and these are dolomitic limestone, crystalline limestone and quartz-bearing crystallized limestones. All the minerals are crystallized and the minerals locally dominate at the quarry. The produced aggregates have relatively flat granulometry curve indicating most of the grains are of thin and have clay-silt sized particles. Our studies revealed that Bozlutepe Limestones are formed in carbonate facies in shallow marine environments during Permian-Carboniferous times. The member most likely have low-grade metamorphism during Paleozoic and Mesozoic era

TOPRAKTEPE-BEYŞEHİR (KONYA) KROMİTLERİNİN YÜKSEK ALAN ŞİDDETLİ YAŞ MANYETİK AYIRMA İLE ZENGİNLEŞTİRİLMESİ

In this work, optimum enriching possibilities of Topraktepe-Beysehir (Konya) chromitesfrom abondoned mine (mined by ADO Mining Inc.) were searched. Enriching method employed. In thisresearch study was high intensity wet magnetic separation (Boxmag Rapid LHWL type). Magneticseparation tests were carried out by using 250 g samples of – 0.106+0.075 mm, -0.075+0.053 mm, -0.053+0.038 mm, -0.038 mm particle fractions. Effects of current intensity applied through magneticseparator to Cr2O3 grade and recovery for each particle size were researched in detail. In the tests,current intensity of 5, 10, 20 amperes and voltages of 40, 90, 185 volt were applied to selected fourparticle fractions. According to test results, it was observed that the best results were obtained by using20 ampere of current intensity. As a result of tests, it was showed that concentrates could be producedwith a Cr2O3 grade of 51.06 %, recovery of 86.67 %, weight of 69.37 % in -0.106+0.075 mm particlefraction, Cr2O3 grade of 51.74 %, recovery of 86.55 %, weight of 77.32 % in -0.075+0.053 mm particlefraction, Cr2O3 grade of 50.13 %, recovery of 60.14 %, weight of 57.18 % in -0.053 +0.038 mm particlefraction, Cr2O3 grade of 49.79 %, recovery of 69.74 %, weight of 39.75 % in -0.038 mm particle fractionusing 20 ampere current intensity in all tests.Bu çalışmada, ADO Madencilik A.Ş. tarafından işletilmiş ve daha sonra terkedilmiş olanTopraktepe-Beyşehir (Konya) kromitlerinin “Boxmag Rapid LHWL” tipi yüksek alan şiddetli yaşmanyetik ayırıcı ile optimum koşullarda zenginleştirilebilme olanakları araştırılmıştır. Manyetik ayırmadeneyleri, -0.106+0.075 mm, -0.075+0.053 mm, -0.053+0.038, -0.038+0.000 mm boyutlarında 250 gramlıknumuneler ile yapılmıştır. Her bir boyut için ayrı ayrı akım şiddetinin ve voltaj değerlerinin Cr2O3tenörüne ve verimine etkisi incelenmiştir. Deneylerde dört ayrı fraksiyon aralığında 5, 10, 20 amperlikakım şiddeti ve 40, 90, 185 volt değerleri test edilmiştir. Yapılan deney sonuçlarına göre, 20 amper akımşiddetinde en iyi sonuçların alındığını görülmüştür. Bu sonuçlara göre, -0.106+0.075 mm fraksiyonunda20 amper akım şiddetiyle % 69.37 ağırlık oranında, % 86.67 verim ile % 51.06 Cr2O3 tenörlü konsantre, -0.075+0.053 mm fraksiyonunda 20 amper akım şiddetiyle % 77.32 ağırlık oranında, % 86.55 verim ile %51.74 Cr2O3 tenörlü konsantre, -0.053+0.038 mm fraksiyonunda 20 amper akım şiddetiyle % 47.18 ağırlıkoranında, % 60.14 verim ile % 50.13 Cr2O3 tenörlü konsantre, -0.038 +0.000 mm fraksiyonunda 20 amperakım şiddetiyle % 39.75 ağırlık oranında, % 69.74 verim ile % 49.79 Cr2O3 tenörlü konsantre, eldeedilmiştir

Radon Gas Variations in Soil Gas on Ilgın Active Fault Zone, Konya, Turkey

Soil gas radon concentrations have been studied in an active fault zone of Ilgın, Konya, Turkey. At this seismically active fault zone 20 km long, 3-5 km width in the study area there are two faults and a graben in between them. The maximum radon and thoron concentrations are 32601 Bq/m3 and 17628 Bq/m3 , while the minimum values are 170 Bq/m3 and 103 Bq/m3 respectively. At 15 sampling points for radon the obtained values are higher than the average values. There has been a clear visibility of both 222Rn radon and 220Rn thoron anomalies in the area. The 222Rn and 220Rn have no positive or negative correlation at sampling points in the field

MINERALOGICAL AND CHEMICAL CHARACTERISTICS OF THE AMPHIBOLE MINERALS FROM THE METAMORPHIC SOLE ROCKS OF THE LATE CRETACEOUS-AGED HATIP OPHIOLITIC MÉLANGE IN THE KONYA AREA (CENTRAL SOUTHERN TURKEY)

In the Konya area, the Neotethyan assemblage is represented by Late Cretaceous aged Hatıp Ophiolitic Mélange, in where the metamorphic sole rocks crop out as thin slices beneath the sheared serpentinites and harzburgites, and Çayırbağı ophiolite. This study aims to characterize the mineralogical characteristics and chemical composition of the amphiboles in the metamagmatic sole rocks of the Hatıp Ophiolitic Mélange. The main rock types in the metamorphic sole rocks are amphibolite (amphibole up to 90.3 %); epidote-amphibolite (65.3% amphibole); zoisite-amphibolite (amphibole 52.2%) and amphibole-quartzite (amphibole 28.5%) with nematoblastic to porphyroblastic texture. The microprobe analyses of the amphiboles suggest that the amphiboles have crystallized from a wet magma in medium pressure condition (≤ 7 kb), and are magnesiohornblende, pargasite and edenite in composition.  The obtained data also reveal that the Neotethyan assemblage has experienced a regional metamorphism in greenschist facies conditions, which resulted in no chemical changes in the amphiboles

GEOLOGICAL AND GEOMECHANICAL PROPERTIES OF SOME CARBONATE MARBLES AND BASALT STONE FROM MOROCCO

The natural rocks used today as well as in the history for a variety of purposes were a subject of different alteration, weathering and deterioration conditions. These conditions are strictly controlled by environment and nature of rock varieties (marble and stone). This study is a first approach to understand the relation between some geological features and behavior against salt (Na 2SO4) decay of Moroccan marbles and stones. For this purpose, widely used four dolomitic limestones, two crystalline limestones, one limestone and one basalt sample (total 8) were chosen from Morocco. Extra attention paid to choose locations being a representative of all Moroccan country. The carbonate samples (limestone and dolomite) consist of mainly dolomite and calcite with micritic and sparitic cement. The sole, non-carbonaceous sample is basalt of Khenifra containing mainly plagioclase and pyroxene. In general, both bulk-dry and powder density values of the studied rock samples are homogeneous. The limestone of Bir Jdid has the highest (10.81 %) effective porosity and dry weight loss value (4.61 %). The loss on ignition value of the Khenifra basalt has the lowest value with 1.26 %. The loss on ignition values are also relatively uniform. The obtained data indicate that outdoor uses (especially in coastal areas) of limestones of Bir Jdid and dolomitic limestones of Taza are more risky than the others

GEOLOGICAL AND GEOCHEMICAL FEATURES OF THE KIZILDAĞ (AKSEKİ- ANTALYA) CHROMITE OCCURRENCES

The study area is located at 20 km southwest of Seydişehir (Konya) and the chromites are cropped out in the dunitic rocks of the Kızıldağ ultramafics. The chromites are found as banded, schliren and massive occurrences and their chemical composition have a features of Alpine type chromites. These chromites can be classified as Al- rich and ferric chromites and their Cr/Fet is between 2.77 and 3.28 (mean 2.99). In the Cr/Cr+AlMg/Mg+Fe +2 binary diagram, r/Cr+Al values covers a festricted area while Mg/Mg + Fe+2 ratios distrubuted in a wider range. There is a strong negative correlation between Cr and Mg and negative (not too strong) correlation between Cr and Al