Affiliations: Department of Science and Technology, Uva Wellassa
University, Badulla, Sri Lanka | Geosphere Research Institute, Department of Civil
Engineering, Saitama University, 255 Shimookubo Sakura Ku, Saitama, 338-8570,
Japan | Department of Geology, University of Peradeniya, Sri
Lanka
Abstract: The geochemistry of regional groundwater has been utilized worldwide
to discover subsurface mineral deposits, though it has not yet been practiced
in Sri Lanka. The present study focuses on utilizing geochemistry of
groundwater in the Udawalawe area of south-central Sri Lanka where two
serpentinite bodies exist within the high-grade crystalline basement. This area
is in the proximity of the litho-tectonic boundary between two metamorphic
complexes. Thus, the scope of the study is to uncover geological and
geochemical anomalies of potential mineralization. Mode of occurrences and
petrography of exposed serpentinite bodies and physico-chemical properties of
groundwater were investigated to establish a relationship between regional
groundwater geochemistry and geological anomalies. The pH and electrical
conductivity of groundwater were measured in-situ and concentrations of Al, Ba,
Be, Cs, Cu, Fe, Li, Mn, Pb, Rb, Sr and Zn were analysed using atomic absorption
and emission spectroscopy. The present study reveals that concentrations of
these elements are significantly higher close to serpentinite bodies with Cu
and Zn having the highest concentrations. Elevated concentrations of Al, Ba,
Be, Fe, Li, Pb, Rb and Sr were also noted. Relatively higher concentrations of
Be, Cu, Li, Mn, Pb, Rb and Zn in groundwater in the area between the two
exposed serpentinite bodies indicate the possible occurrence of a subsurface
mineral deposit in the area. These results indicate the importance and
feasibility of the application of regional groundwater geochemistry as a tool
for uncovering subsurface mineral deposits. Detailed observations of
groundwater flow patterns, facies changes, and associated element mobility
could effectively help in accurate demarcation of the lateral extents of
mineral deposits.
Keywords: Mineral exploration, groundwater geochemistry, heavy metals, trace elements, serpentinite
