Hydrogeochemical Characteristics of Geothermal Waters from Mesozoic Formations in the Basement of the Central Part of the Carpathian Foredeep and the Carpathians (Poland) Using Multivariate Statistical Methods

Joanna Jasnos

doi:10.3390/en14134022

Abstract

The subject of this study is the chemical composition of potentially geothermal waters of the Mesozoic basement of the central part of the Carpathian Foredeep and the Outer Carpathians regions. The research objectives were: (1) to identify statistically significant differences between the chemical composition of waters from the Cretaceous, Jurassic, and Triassic aquifers, and between the waters of both regions; and (2) the discovery of zones indicating active water exchange—attractive due to the operational efficiency of wells. Knowledge of the chemical composition of water allows for the preliminary identification of areas of interest for the exploitation of water for recreational, healing, and heating purposes. The research methods used were: (1) statistical tests and (2) methods of multivariate data analysis, such as the Kruskal–Wallis test and Principal Component Analysis (PCA). The performed tests and statistical analyses allowed us to draw conclusions about significant differences between the chemical composition of waters from the Cretaceous, Jurassic, and Triassic aquifers, and the basement of the Carpathian Foredeep and the Outer Carpathians. They indicated the existence of a zone with symptoms of active water exchange. Before establishing the fact of active exchange of waters in this zone, further research should be undertaken.

Highlights

The geological structure of the area in question naturally influences the significant differences in the chemical compositions of the waters
This paper presents chemical composition of the potentially geothermal waters from statistical point of view and pointing out the hydrochemicaly anomaly zone
Significant differences were found between the concentrations of most of the main ions, the TDS, and the density of water in the groups mentioned

Summary

Introduction

The chemical composition can have a diagnostic role for many phenomena occurring in the rock mass. It can contribute to or impede the optimal exploitation of geothermal water for different purposes, such as recreation and balneotherapy and district heating. Recreational purposes require waters with mineralization of up to 35 g/L, and therapeutic purposes up to 50 g/L [15,16]. In both cases, it is imperative that the waters have a chemical composition suitable for human contact. District heating cells place emphasis on the amount of water stream per time unit during exploitation from the borehole (borehole capacity). A favorable chemical composition of the waters, so as not to cause corrosion and precipitation, is desirable

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Discussion

Conclusion