Origin of carbon dioxide occurrences in Central Anatolia (Turkey)

The occurrence of carbon dioxide (CO2) in Central Anatolia has been well-known for 50 years. Four gas producing fields (Bozkar, Guneygaz, Karbogaz, and Terra) are located in the region. The aim of this study was to define the composition of these gas occurrences and to determine the gas origin. For this purpose, the molecular and isotopic composition of gas samples from production wells were investigated and interpreted. Gases from the region are rich in CO2 (>80%). Carbon dioxide concentrations were found to vary from 80.7 to 94.3%. The total amount of methane components (CH4+) was less than 0.1%. The isotopic composition of CO2, with values between -1.76 and 1.02 parts per thousand, indicated abiogenic origin from limestone. The generation of CO2 could largely result from the decarbonation of limestone. Helium isotopic values indicated that a minor amount of CO2 originated from the mantle. delta C-13 values for methane from the Karbogaz Field suggested that the origin of the Aksaray Field methane is thermogenic

The properties of Can Basin coals (Canakkale-Turkey): Spontaneous combustion and combustion by-products

The goals of this study were to investigate the susceptibility of Can Basin (Canakkale-Turkey) coals to spontaneous combustion and to determine the composition of the gas produced from the coal during combustion. Coal properties were determined using burned and partly burned coal samples; gas samples were analyzed for their composition. The mineralogical variations of burning coals were also investigated. Our results indicated that the pyrite content of Can Basin coals is a significant factor for promoting combustion in addition to rank and moisture. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses indicated that the coal samples contained pyrite, quartz, cristobalite, tridymite, kaolinite, amorphous matter, and gypsum. Fumarolic minerals (sulfur blooming and ammonium chloride) forming on the surface of coal seams were monitored. Elements including beryllium, fluorine, scandium, vanadium, cobalt, nickel, copper, zinc, arsenic, selenium, zirconium, molybdenum, tungsten, mercury, tantalum, lead, and uranium were found to be higher in can coal samples than the world average. The concentration of arsenic (max. 3319.7 mu g/g) was relatively high and is the major hazardous element in the region

Microbial Community Structure in a Serpentine-Hosted Abiotic Gas Seepage at the Chimaera Ophiolite, Turkey

The surface waters at the ultramafic ophiolitic outcrop in Chimaera, Turkey, are characterized by high pH values and high metal levels due to the percolation of fluids through areas of active serpentinization. We describe the influence of the liquid chemistry, mineralogy, and H-2 and CH4 levels on the bacterial community structure in a semidry, exposed, ultramafic environment. The bacterial and archaeal community structures were monitored using Illumina sequencing targeting the 16S rRNA gene. At all sampling points, four phyla, Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria, accounted for the majority of taxa. Members of the Chloroflexi phylum dominated low-diversity sites, whereas Proteobacteria dominated high-diversity sites. Methane, nitrogen, iron, and hydrogen oxidizers were detected as well as archaea and metal-resistant bacteria