Radiocarbon evidence of paleo-recharge (pre-Saraswati period) of potential deep aquifer in Thar desert

• Published in: Journal of the Geological Society of India Vol. 77; no. 3; pp. 239 - 242
• Main Authors: Reddy, D. V., Nagabhushanam, P., Rao, M. R., Mitra, D. S., Tripati, B. M., Sinha, S. K., Bhadu, B.
• Format: Journal Article
• Language: English
• Published: India Springer-Verlag 01.03.2011; Springer Nature B.V
• Subjects: Aquifers; Carbon dating; Deserts; Earth and Environmental Science; Earth Sciences; Geology; Groundwater; Hydrogeology; Natural gas; Paleoclimate science; Radiocarbon dating; Recharge; Stable isotopes; Total dissolved solids; Water depth; Well water; Thar Desert; India, Rajasthan; India, Rajasthan, Thar Desert; India; Radiocarbon; Groundwater; Aquifer; Paleo-recharge; Rajasthan
• ISSN: 0016-7622; 0974-6889
• DOI: 10.1007/s12594-011-0030-7

The Oil and Natural Gas Corporation Limited (ONGC), India, embarked upon exploration and exploitation of deep groundwater under the project named as “Saraswati” in arid Thar desert, Rajasthan, with a societal mission of providing water to the local people and cattle. A 555 m deep well drilled by the ONGC near Jaisalmer town in 2006 encountered a potential aquifer at a depth of 450–500 m. Radiocarbon dating of this well water indicated paleorecharge to be >40,000 yr BP (uncorrected) (Before Present with respect to 1950 AD), while the medium depth (∼200 m) well waters around that area showed an age range of ∼9,000 to 17,000 yr BP (uncorrected). These waters represent pre-Saraswati era recharge, because the mighty Saraswati flowed in this region between 7000–4000 yr BP. The stable isotope (δD and δ 18 O) and Total Dissolved Solids (TDS) data of these waters clearly indicated absence of communication between the two aquifers (deep and medium depth). However, the extension of this deep aquifer needs to be determined.