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| Titel |
39Ar groundwater dating of a coastal aquifer in the Nam Dinh Province, Vietnam |
| VerfasserIn |
Christoph Gerber, Roland Purtschert, Flemming Larsen, Hoan V. Hoang, Long V. Tran, Luu T. Tran, Nhan Q. Pham, Jürgen Sültenfuß |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081177
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| Zusammenfassung |
| In the south of Nam Dinh Province, Red River Delta, Vietnam, fresh Pleistocene groundwater
has been identified to exist next to brackish pore waters in the Red River area (WAGNER et al.
2011). Extensive exploitation of the fresh water results in decreasing groundwater
heads and migration of brackish water towards the freshwater (WAGNER et al.,
2012).
In order to understand the dynamics and origin of the fresh and saltwater and to predict
the future evolution of the resource an extensive investigation using environmental tracers has
been carried out. 39Ar, 85Kr, 3H/3He and stable noble gas measurements have been used for
groundwater dating. Stable isotopes and other geochemical parameters (stable isotopes of the
water molecule, water chemistry and gas composition) provide crucial information about the
genesis of the water.
Groundwater ages are modern in the recharge area and increase to > 1000 years towards
the coast and northwards based on the 39Ar data (T1-2: 269 years). Depleted stable noble gas
concentrations correlate with high concentrations of dissolved methane suggesting degassing
due to the high methane partial pressure. Physical modelling of the degassing process
(AESCHBACH-HERTIG et al., 2008) supported by concentrations of accumulated radiogenic
4He indicates that diffusion controlled the observed degassing at a late stage of the
groundwater evolution path.
References
Aeschbach-Hertig, W., El-Gamal, H., Wieser, M., Palcsu, L., 2008. Modeling excess air
and degassing in groundwater by equilibrium partitioning with a gas phase. Water Resour Res
44:W08449.
Wagner, F., Trung, Ð. T., Phúc, H. Ð., Lindenmaier, F., 2011, Assessment of Groundwater
Resources in Nam Dinh Province, Final Technical Report, Part A, Improvement of
Groundwater Protection in Vietnam.
Wagner, F., Ludwig, R. R., Noell, U., Hoang, H. V., Pham, N. Q., Larsen, F.,
Lindenmaier, F., 2012, Genesis of economic relevant fresh groundwater resources in
Pleistocene/Neogene aquifers in Nam Dinh (Red River Delta, Vietnam). EGU 12. European
Geosciences Union, Vienna |
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