Tritiogenic 3He in shallow groundwater

Schlosser, Peter; Stute, M.; Sonntag, Christian; Münnich, K. O.

doi:10.1016/0012-821x(89)90144-1

Cited by 222 publications

(189 citation statements)

References 7 publications

Supporting

Mentioning

181

Contrasting

Unclassified

Order By: Relevance

“…[15] Groundwater radiogenic 4 He concentrations (computed by subtracting atmospheric helium from the measured value [see Schlosser et al, 1989]) indicate a trend of increasing concentration with depth, with the maximum 4 He rad concentration occurring within the clay till at both sites (Figure 4). Radiogenic helium is not detectable at the water table, increases to a maximum within the clay, and then decreases within the aquifer and underlying bedrock aquitard.…”

Section: Groundwater 4 He Concentrationsmentioning

confidence: 99%

Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario

Sheldon

Solomon

Poreda

et al. 2003

Water Resources Research

View full text Add to dashboard Cite

[1] Profiles of 4 He in pore water were measured in clay aquitards in SW Ontario. The 4 He distributions are consistent with groundwater velocities that are <6 mm yr À1 , and thus diffusion is the dominant transport mechanism for 4 He. Modeling indicates that the effective diffusion coefficient for 4 He is 6.3 ± 1.6 Â 10 À6 cm 2 s À1 . Furthermore, the profiles are consistent with the internal release of 4 He from aquitard sediments at a rate of 0.03-0.13 mcc(STP) kg À1 yr À1 . These rates are also consistent with laboratory release experiments and, on average, are 600 times greater than the production of 4 He from U/Th decay. Modeling and the ratio of 21 Ne to 4 He within the sediments indicate that although the aquitards were deposited about 13 kA BP, the sediments released >70% of initial 4 He for 50 to 60 kA prior to incorporation into the till.

show abstract

Section: Groundwater 4 He Concentrationsmentioning

confidence: 99%

Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario

Sheldon

Solomon

Poreda

et al. 2003

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…Vários autores tratam da implementação de técnicas isotópicas para datação das águas e elucidações sobre as condições hidrogeológicas locais, quase sempre associadas às análises de 3 H- 3 He em conjunto com outras ferramentas de datações (Tolstikhin & Kamenskiy 1969, Schlosser et al 1989, Eckwurzel et al 1994, Szabo et al 1996, Solomon et al 1993. As abordagens quantitativas, utilizando-se as concentrações de 3 H (trítio), tornam-se difíceis quando não se dispõem das séries completas de concentrações nas águas de precipitações da área pesquisada.…”

Section: Figura 2 -Perfi L Construtivo Dos Poços De Coleta Para As Anunclassified

Estudos isotópicos em águas subterrâneas do Distrito Federal: subsídios ao modelo conceitual de fluxo

Lousada

Campos

2011

RBG

View full text Add to dashboard Cite

Revista Brasileira de GeociênciasArquivo digital disponível on-line no site www.sbgeo.org.br 355 41(2): 355-365, junho de 2011 Estudos isotópicos em águas subterrâneas do Distrito Federal: subsídios ao modelo conceitual de fl uxo O variam entre -5,71‰ e -5,19‰, os quais equivalem à média global do vapor atmosférico e precipitação nos oceanos. Portanto avalia-se que as águas subterrâneas analisadas não sofreram processos signifi cativos capazes de modifi car a composição isotópica. Os valores de trítio (UT) apresentaram-se relativamente elevados para águas rasas, indicando idades mais jovens. As águas do fraturado apresentaram valores mais baixos, associadas a épocas de recargas mais antigas. A avaliação por CFC-11 e CFC-12 corroborou as interpretações com trítio, porém possibilitou uma abordagem quantitativa. Em análises do CFC-12 para o primeiro ponto amostrado (EL1-fraturado e EL2-poroso) obtiveram-se idades aproximadas, associadas ao período de 1990 a 1997. No segundo ponto, as amostras EL3 (fraturado) e EL4 (poroso), apresentaram variação temporal de 20 anos entre as águas analisadas, associadas ao período de 1969 a 1989, respectivamente. As amostras EL5 (poroso) e EL6 (fraturado) também mostraram valores com variação em intervalo de 15 anos para épocas de entradas das águas de precipitação nos aquíferos, associados ao período de 1974 e 1989. O resultado das análises isotópicas confi rma a aplicação do modelo hidrogeológico considerado, pois os dois meios avaliados mostram intervalos de tempo que variam de 15 a 20 anos para a infi ltração das águas. Esse resultado converge para a existência de dois níveis potenciométricos distintos, uma vez que o retardo para a transferência das águas dos aquíferos rasos para os profundos determina a signifi cativa diferença de idades entre os diferentes meios. Palavras-chave: isótopos, água subterrânea, modelo de fl uxo.Abstract Hydrochemical studies in ground water of the Federal District: subsidies to the fl ow conceptual model. This paper refers to hydrochemical studies for a fl ow model characterization proposed to the Federal District region, Brazil. The "Two Potenciometric Surfaces Model" has been proposed by Campos & FreitasSilva (1988) H and gases CFC has been developed in shallow and deep groundwater samples for tree points located on Jardim River watershed. The δ 18O values vary from -5,71‰ to -5,19‰, which is related to global mean atmospheric vapor and ocean rains, it shows that the groundwater was not submitted to signifi cant process able to modify the isotopic composition. The values in tritium units (UT) were relatively high for shallow groundwater, indicating young ages. Groundwater in fracture fl ow showed low values, indicating old recharge. The CFC-11 e CFC-12 values corroborate the tritium interpretations, and turn feasible the quantitatively evaluation. Analyzing CFC-12 for the fi rst point (EL1 -fracture aquifer and EL2 -shallow groundwater) was obtained similar ages, associated to 1990-1997 period. For the second point, the sample EL3 (fracture)...

show abstract

“…Precipitation that incorporates CFCs, and SF 6 , and 3 H from the atmosphere infiltrates into the ground and carries a particular chemical or isotopic signature related to atmospheric conditions at the time of recharge to the UFA. The CFC, 3 H/ 3 He trit , and SF 6 dating methods assume that gas exchange between the unsaturated zone and air is fast, but that shallow groundwater remains closed to gas exchange after recharge (Schlosser et al 1989;Plummer and Busenberg 1999;Busenberg and Plummer 2000).…”

Section: Dating Spring Watersmentioning

confidence: 99%

“…However, by measuring tritiogenic helium-3 ( 3 He trit ), the stable daughter product of 3 H decay that has accumulated in groundwater systems, the dating range and precision can be enhanced Cook and Böhlke 1999). Combined measurements of 3 H and its daughter product of radioactive decay, 3 He trit , define a relatively stable tracer of the initial 3 H input to groundwater, which can be used to calculate the 3 H/ 3 He trit age from a single water sample (Schlosser et al 1988(Schlosser et al , 1989Solomon and Sudicky 1991). The 3 H/ 3 He trit ratio yields the following equation for the piston-flow assumption in which the apparent age (T, years) can be expressed as (Torgersen et al 1979)…”

Section: Tritium and Tritium/helium-3mentioning

confidence: 99%

“…A He-isotope mass balance is used to calculate the amount of tritiogenic and non-tritiogenic 3 He in the sample. Non-tritiogenic 3 He (which generally is negligible in a shallow aquifer with local recharge) is corrected for by using measured concentrations of 4 He and neon (Ne) in the water sample and assuming solubility equilibrium with air at the water temperature measured during sampling (Schlosser et al 1988(Schlosser et al , 1989. It is assumed that 3 H and 3 He trit concentrations in groundwater are not affected by contamination, sorption, and microbial degradation processes that can alter the concentrations of other transient tracers such as CFCs ).…”

Section: Tritium and Tritium/helium-3mentioning

confidence: 99%

See 1 more Smart Citation

Mixing of shallow and deep groundwater as indicated by the chemistry and age of karstic springs

Toth

Katz

2006

Hydrogeol J

View full text Add to dashboard Cite

Large karstic springs in east-central Florida, USA were studied using multi-tracer and geochemical modeling techniques to better understand groundwater flow paths and mixing of shallow and deep groundwater. Spring water types included Ca-HCO 3 (six), Na-Cl (four), and mixed (one). The evolution of water chemistry for Ca-HCO 3 spring waters was modeled by reactions of rainwater with soil organic matter, calcite, and dolomite under oxic conditions. The Na-Cl and mixed-type springs were modeled by reactions of either rainwater or Upper Floridan aquifer water with soil organic matter, calcite, and dolomite under oxic conditions and mixed with varying proportions of saline Lower Floridan aquifer water, which represented 4-53% of the total spring discharge. Multiple-tracer data-chlorofluorocarbon CFC-113, tritium ( 3 H), helium-3 ( 3 He trit ), sulfur hexafluoride (SF 6 )-for four Ca-HCO 3 spring waters were consistent with binary mixing curves representing water recharged during 1980 or 1990 mixing Résumé D'importantes sources karstiques du Centre-Est de la Floride aux USA, ontétéétudiées par multitraçage et par des techniques de modélisation géochimique, pour mieux comprendre les directions de l'écoulement souterrain et les mélanges entre les eaux souterraines phréatiques et profondes. Les eaux de source sont du type Ca-HCO 3 (six), Na-Cl (quatre), et mixte (une). L'évolution de la chimie des eaux du type Ca-HCO 3 aété modélisée par réactions entre l'eau de pluie et la matière organique des sols, la calcite et la dolomite, dans des conditions oxydantes, et par mélange avec des proportions variables de l'eau saline de l'aquifère du Bas-Floridien qui représente 4 a 53% du débit total de la source.Les Resumen Se estudiaron manantiales kársticos grandes en la parte centro-oriental de Florida, USA utilizando técnicas de modelizado geoquímico y multi-trazadores para un mejor entendimiento de trayectorias de flujo de agua subterránea y la mezcla de agua subterránea profunda y somera. Los tipos de agua de manantial incluyeron Ca-HCO 3 − (seis), Na-Cl (cuatro), y mezclada (una). Se modelizó la evolución de química de agua para las aguas de Hydrogeology Journal (2006) los manantiales Ca-HCO 3 − mediante las reacciones de agua de lluvia con la materia orgánica del suelo, calcita, y dolomita bajo condiciones anóxicas. Los manantiales con Na-Cl y mezclados se modelizaron mediante reacciones ya sea de agua de lluvia o agua del acuífero Floridano Superior con materia orgánica del suelo, calcita, y dolomita bajo condiciones anóxicas y mezclando con distintas proporciones de agua salada del acuífero Floridano Inferior, lo cual representó entre 4 y 53% de la descarga total de los manantiales. Los datos de trazadores múltiples [clorofluorcarbono CFC-113, tritio ( 3 H), helio-3 ( 3 He trit ), hexafluoruro de azufre (SF 6 )] para cuatro manantiales Ca-HCO 3 − fueron consistentes con curvas binarias de mezclado que representan agua recargada durante 1980 o 1990 que se mezcló con un componente más viejo libre de trazadores (reca...

show abstract

Tritiogenic 3He in shallow groundwater

Cited by 222 publications

References 7 publications

Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario

Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario

Estudos isotópicos em águas subterrâneas do Distrito Federal: subsídios ao modelo conceitual de fluxo

Mixing of shallow and deep groundwater as indicated by the chemistry and age of karstic springs

Contact Info

Product

Resources

About