Stable isotopes and carbon dating of groundwaters in the Tindall aquifer
Details:
Title
Stable isotopes and carbon dating of groundwaters in the Tindall aquifer,
Creator
Tickell, S. J.,
Collection
E-Publications,
PublicationNT,
E-Books,
12/2016,
Date
2016-05,
Location
Katherine,
Description
Made available via the Publications (Legal Deposit) Act 2004 (NT).,
Oxygen 18 and deuterium analyses and carbon dating of groundwater in the Tindall Limestone aquifer at Katherine were carried out in October 2015 and at two previous periods in 2011 and 1998. An assessment of all of the results found that the groundwater is primarily sourced from rainfall. Recharge only occurs where the aquifer is unconfined or semi-confined by direct downward infiltration. A proportion of the recharge occurs very rapidly via caves, sinkholes and macro-pores in the limestone. The groundwater also cycles rapidly to the discharge points in and along the river due to the karstic nature of the aquifer.
Contrasting with that, groundwaters in the confined areas are considerably older and appear to increase in age towards the basin axis to the south west. The likely source of the confined groundwater water is via slow lateral movement from the unconfined area.
The springs along the Katherine River act as drains for groundwater predominantly in the unconfined aquifer. Both the stable isotope compositions and carbon dates of the spring waters appear to fall in the mid-range of values of the bores, representing an “average” of all of the groundwaters in the unconfined areas.,