Applying scores of multivariate statistical analyses to characterize relationships between hydrochemical properties and geological origins of springs in Taiwan

Abstract

This work used scores of multivariate statistical analyses, factor analysis (FA) and discriminant analysis (DA), to characterize relationships between hydrochemical properties and geological origins of springs in Taiwan. Factor analysis was first used to examine major hydrochemical patterns of springs. Moreover, according to springs emerging from acid-sulfate and neutral-sulfate igneous, metamorphic and sedimentary rocks, DA was then adopted to establish a linear classification model using hydrochemical data on springs. Finally, scores of FA and DA were applied to explore statistically common hydrochemical features of springs based on their geological origins. Key components of hydrochemical parameters, which were capable of differentiating among geological groups, were proposed to interpret likely formation processes of springs. The analyzed results indicate that spring waters emerging from neutral-sulfate igneous rock contain abundant Ca 2+ concentrations and obviously differ from those from the other rocks owing to the process of dedolomitization. Spring waters emerging from acid-sulfate igneous rock are high temperatures, large quantities of aqueous SiO 2 and low pH. Spring waters emerging from sedimentary rock are rich in Cl −, HCO 3 − and Na + concentrations and low temperatures. Furthermore, spring waters emerging from metamorphic rock contain less ions than those from the other rocks do, except for HCO 3 −.