Deterioration of tuffite and andesite stones monuments in urban areas (Niğde, Central Turkey)

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Yalçin M. G.

Niğde Şehir merkezindeki tüf ve andezitlerden inşa edilmiş sanat yapılarında görülen yıpranmalar), Prof.Dr.Servet YAMAN özel sayı, Geosound, 52, 21-41, (2008). (İngilizce baskı), sa.52, ss.21-41, 2008 (Hakemli Dergi)

Özet

The aim of this work is to investigate the pollution characteristics and the source of pollution on tuffite and andesite walls of 15 historical monuments which were built in various dates in several parts of the Niğde city in central Turkey. In this respect, surface of walls were sampled to represent the general structure of stone monuments. Mineralogical features and structural-textural determinations of rock samples were conducted on thin sections with optical microscopy. The heavy metal accumulations on wall surfaces were measured with Spectro-Xepos Benchtop X-Ray Fluorescence Spectrometer. XRD (x-ray powder diffraction) analyses were also carried out on the same samples. The metal concentrations of the samples were evaluated with coefficient correlation, element coefficient correlation dendogram, hierarchical cluster, model summary and anova analysis statistical methods.

On thin sections, minerals are extensively altered. Chloritization, sericitization, prophylitization, carbonization and limonitization occur on the rock surfaces. Iron oxide is detected along the fracture and fissures. Green, black, yellow, red and brown color changes are seen on the rock surfaces, depending on structural and textural alterations and deterioration. Gypsum also occurs on rocks in association with contamination.

As a result, it was determined that different types of pollutants are involved in pollution of stone monuments. Pollution on the stone monuments has been expedited by polluted air of the city of Niğde, SO2 in atmosphere, suspended particular material and exhaust wastes of vehicles. Strong positive correlations were determined among some metallic elements. The elements with positive correlations are thought to have the same source. Determined pollution on tuffite and andesite wall samples from the stone monuments are due to anthropogenic and atmospheric effects. In order to minimize the degree of pollution on stone monuments, necessary measurement should be taken.