Silica Geothermometry Studies of Shallow Aquifer in Kelantan

Abstract

The study aimed to analyze the spatial and temporal distribution of silica concentrations in shallow quaternary aquifers across Kelantan, Malaysia. This assessment was crucial for understanding groundwater dynamics, including residence times and potential contamination sources. A total of 32 (29 groundwater and 03 surface water) samples were collected during both pre-monsoon and post-monsoon periods in 2016. Silica concentrations ranged from 6.3 mg/l to 23.4 mg/l pre-monsoon and 6.2 mg/l to 23.5 mg/l post-monsoon. Silica geo-thermometry, based on the chalcedony equation, estimated temperatures ranging from 3.09°C to 37.61°C pre-monsoon and 0.90°C to 37.79°C post-monsoon. Under typical geothermal conditions with an average heat flow of 30°C/km, these temperatures corresponded to depths ranging from 0.02 km to 0.32 km pre- monsoon and 0.01 km to 0.32 km post-monsoon. The shallow depths (less than 0.32 km) indicate relatively rapid groundwater circulation, which aligns with the observed low silica concentrations. These findings suggest minimal anthropogenic influence and short residence times, emphasizing recent meteoric input and surface water inflow as dominant factors shaping water quality in the area.