Search

Demirbilek, Mehmet ( Dumlupınar-Author), The effects of alteration on granites outcropping around Sivrihisar area within the Tavşanlı Zone (NW Turkey) were investigated considering minero-petrographical, geochemical, and geomechanical properties. For this aim, polarizing light microscope, scanning electron microscope, X-ray diffraction, chemical analyses, and geomechanical tests were conducted on the granitic samples. The new petrographic index, referred as feldspar alteration index, was developed from the quantitative ratios of total and altered constituents in feldspar minerals. Based on solution-precipitation processes, plagioclase and alkali feldspar were altered to smectite, sericite, and kaolinite along microfractures, cleavage, twinning, and zoning structure. Anorthite-rich core is more altered than the rim of zoned plagioclase due to higher solubility in water and selective alteration of calcic plagioclase. EDS studies indicate that Na, Si, and Ca decrease and Mg, Al, K, and Fe progressively increase. The normalized values of whole-rock chemical analyses of the granites show depletion of Si, Al, Na, and Ca reflecting the dissolution of plagioclase. Enrichment of Si, Al, Na, Ca, Mg, K, and Fe reveal precipitation of smectite, sericite, and kaolinite minerals during alteration. Minero-petrographical and geochemical changes led to an increase in water absorption and apparent porosity and a decrease in apparent density, P-wave velocity, Schmidt hammer rebound, and compressive strength. Significant relationships between FAI and geomechanical properties (R2 = 0.7116–0.8676), FAI and P-wave velocity index (Ivp) (R2 = 0.8676), and FAI and strength ratio (Rs) (R2 = 0.7614) demonstrate that FAI can be used to determine the alteration degree of granites

It is well known that radon is the main source of natural radiation exposure to the population. Indoor radon concentrations in an area are affected by ascending radon migration following the convection of groundwater and soil gas along fractures and faults in the bedrock sediments. There are various studies showing that positive radon anomalies in the soil gas are found to coincide with the locations of houses showing the highest concentrations. Moreover, soil gas radon levels and soil permeability are important factors in determining the radon potential of an area, because high permeability enables the increased migration of radon from the soil into houses. Since radon in homes originates mainly from soil gas radon, it is of public interest to study the correlation between soil gas radon and indoor radon in different geographic locations. In the present work, a correlation study was carried in conjunction with radon concentrations in soil gas and indoor environment of Afyonkarahisar Province. The provincial center was assumed to be divided into four regions according to the rock types and tectonic structure to show also the geological structure effect on radon concentrations. The indoor radon concentrations were measured in 74 dwellings using CR-39 passive nuclear track detectors, and the radon concentrations in soil gas were determined in 243 drilled holes using AlphaGUARD detector. The correlation coefficient of 0.97 was obtained between radon concentrations in soil gas and indoor environment of Afyonkarahisar Province. © 2018, Saudi Society for Geosciences. Khalifa University of Science, Technology and Research, KU Türkiye Atom Enerjisi Kurumu: A5.H1.P1.06 Funding information This work was supported by Turkish Atomic Energy Authority with the grant number A5.H1.P1.06 and Afyon Kocatepe University Science Research Projects Coordination Unit with the grant numbers 17.KARİYER.95, 14.FENBİL.08, and 12.FENBİL.14.