Multivariate statistical analyzing of chemical parameters of thermal and non-thermal springs of Mahalat area in Iran

Abstract

In this study multivariate statistical analysis are used to characterize relationships between hydrochemical properties of<br />thermal and non-thermal springs. Four factors for thermal waters and two for non-thermal springs were extracted based<br />on factor analysis. In thermal springs, the first factor showed high loading on Ca, Mg, Na and K and this factor was<br />interpreted as leaching of cations in the rocks by meteoric thermal water. The second factor showed high loading on SO4<br />and it was assumed to be extracted from gypsum dissolution. The third factor showed loading on HCO3 and it was<br />interpreted to be caused by dissolution of limestone. The forth factor showed high loading on SiO2 and it was supposed to<br />be result of alteration of silicate minerals. The δ18O-enrichment with respect to the meteoric water line (MWL), confirms<br />that thermal waters have been diluted by shallow waters with meteoric origin. Comparison of the chemistry of thermal<br />and non-thermal springs and other evidences are indicative of an immature hydrothermal water system in Mahalat.<br />Quartz and Chalcedony geothermometery show the range of 96oC to 131 oC temperature for the Mahalat reservoir.