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The impact of hydrogeological settings on geochemical evolution of groundwater in karstified limestone aquifer basin in northwest Sri Lanka

Thilakerathne, Asanka and Schüth, Christoph and Chandrajith, Rohana (2015):
The impact of hydrogeological settings on geochemical evolution of groundwater in karstified limestone aquifer basin in northwest Sri Lanka.
In: Environmental Earth Sciences, Springer, pp. 8061-8073, 73, (12), ISSN 18666299, DOI: 10.1007/s12665-014-3962-6, [Online-Edition: http://link.springer.com/10.1007/s12665-014-3962-6],
[Article]

Abstract

© 2014, Springer-Verlag Berlin Heidelberg.The geochemical and isotope analysis of groundwaters from the Murunkan basin in north western Sri Lanka was carried out to examine their evolution and recharge sources in order to shed light to enhance the current knowledge of the hydro-geochemical processes in a karst geological setting. A total of 40 water samples from ground and surface water bodies were collected from the Miocene limestone terrain, nearby metamorphic and from unconsolidated Quaternary terrains for major anions, cations and environmental isotopes ratios (δ18OVSMOW and δ2HVSMOW). Distinct geochemical differences were noted between waters from limestone terrain and nearby metamorphic terrain indicating the modification of groundwater flow paths. Bicarbonate-chloride rich water is dominated in the limestone terrain in which water flows through a less mineralized aquifer system and is modified by the sea water intrusion. Groundwater in the metamorphic terrain is modified by dissolving of Caâ��Mg rich mineral phases and subsequent ion exchange processes. The environmental isotopes of groundwater from both limestone and metamorphic terrains vary from â��0.38 to â��6.68 â�° and â��2.41 to â��42.3 â�° for δ18OVSMOW and δ2HVSMOW, respectively. However, slightly enriched isotope signatures and low d-excess values from limestone terrain indicate an excessive evaporation compared to that of the metamorphic terrain where rapid infiltration occurs through the overlying highly permeable grumusols soil layers.

Item Type: Article
Erschienen: 2015
Creators: Thilakerathne, Asanka and Schüth, Christoph and Chandrajith, Rohana
Title: The impact of hydrogeological settings on geochemical evolution of groundwater in karstified limestone aquifer basin in northwest Sri Lanka
Language: English
Abstract:

© 2014, Springer-Verlag Berlin Heidelberg.The geochemical and isotope analysis of groundwaters from the Murunkan basin in north western Sri Lanka was carried out to examine their evolution and recharge sources in order to shed light to enhance the current knowledge of the hydro-geochemical processes in a karst geological setting. A total of 40 water samples from ground and surface water bodies were collected from the Miocene limestone terrain, nearby metamorphic and from unconsolidated Quaternary terrains for major anions, cations and environmental isotopes ratios (δ18OVSMOW and δ2HVSMOW). Distinct geochemical differences were noted between waters from limestone terrain and nearby metamorphic terrain indicating the modification of groundwater flow paths. Bicarbonate-chloride rich water is dominated in the limestone terrain in which water flows through a less mineralized aquifer system and is modified by the sea water intrusion. Groundwater in the metamorphic terrain is modified by dissolving of Caâ��Mg rich mineral phases and subsequent ion exchange processes. The environmental isotopes of groundwater from both limestone and metamorphic terrains vary from â��0.38 to â��6.68 â�° and â��2.41 to â��42.3 â�° for δ18OVSMOW and δ2HVSMOW, respectively. However, slightly enriched isotope signatures and low d-excess values from limestone terrain indicate an excessive evaporation compared to that of the metamorphic terrain where rapid infiltration occurs through the overlying highly permeable grumusols soil layers.

Journal or Publication Title: Environmental Earth Sciences
Volume: 73
Number: 12
Publisher: Springer
Uncontrolled Keywords: Groundwater recharge,High grade metamorphic terrain,Ionic ratios,Limestone aquifer,Seawater intrusion,Stable environmental isotopes
Divisions: 11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Earth Science > Hydrogeology
11 Department of Materials and Earth Sciences
Date Deposited: 17 Apr 2018 12:40
DOI: 10.1007/s12665-014-3962-6
Official URL: http://link.springer.com/10.1007/s12665-014-3962-6
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