Water stable isotopes, radiocarbon, noble gases and krypton-81 study of thermal groundwater from Upper to Mid-Pleistocene recharge age in deep aquifers of Argentina.

Recharge environmental conditions and residence time, can be studied by the application of different tracers. Several tracers are useful as proxies of the environmental recharge conditions, such as water stable isotopes deuterium and oxygen-18, and the dissolved noble gases. Other tracers are applied in order to know when the recharge occurred. Carbon-14 dating is a widely applied method for dating old groundwater, having an application range up to around 30 ky. Noble gases, as non-reactive and water-soluble substances, constitute useful tracers for studying different processes in hydrologic cycles. One of the applications is dating very old groundwater beyond the range of 14C. It can be done in a semi-quantitative way by the accumulation of 4He, and quantitatively through the radionuclide 81Kr (t1/2 = 229,000 y), a more robust method for dating groundwater up to 1.3 million years.The province of Buenos Aires, Argentina, hosts three deep sedimentary basins, from north to south, Salado, Claromec&#243; and Colorado, with areas of 85,000 km2, 3,100 km2 and 125,000 km2, respectively. In these basins, a thick continental sequence of Neogene sediments contains confined thermal aquifers, at depths from hundreds meters to more than 1 km. The recharge conditions and the water age of the Neogene aquifers are studied through water stable isotopes, 4He and 81Kr tracers.&#160; 10 deep wells were sampled for &#948;2H, &#948;18O, 3H, 14C, for noble gases using clamped copper tubes, and for 81Kr with a gas extractor. 4He analyses were performed at the IAEA laboratory by mass spectrometry, and 81Kr at the ATTA laboratory of USTC.3H contents were not detectable in all of the cases, thus no young water components exist. By plotting the isotopic results in a &#948;2H vs &#948;18O diagram, four groups of samples can be recognized. Group 1 includes Colorado basin isotopically depleted samples (&#948;18O from -6.5 to -7.5 &#8240;) along a line parallel to the GMWL and the present LMWL, but with a higher deuterium-excess (d). Samples in G1 have a Ne/He ratio around 0.6. 14C and 81Kr ages were from 10 ky to 40 ky. Group 2 includes the samples of the borders of the Salado basin, being isotopically more enriched (&#948;18O from -3 to -4.5 &#8240;) and with a lower d than present precipitation, a Ne/He ratio from 0.2 to 0.8 and one sample with 81Kr age of 640 ky. Group 3 is formed by brines from the Colorado basin, a Ne/He ratio in the range of 1E-02 to 1E-04, and 81Kr in ages around 900 ky, and are along a line of slope 1.9, showing a 18O shift. Finally the Group 4 formed by samples at the axis of Salado basin, are isotopically enriched (&#948;18O from -0.5 to -3.7 &#8240;) along a line of slope 3.9 resembling and evaporation line. However, these samples of 81Kr ages of 1000 ky and Ne/He ratio of 2E-03, showed a high correlation Cl- vs &#948;18O, with increasing values from West to East. This suggest a mixing with a brine or&#160;an increasing water-rock interaction.

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87SR/86SR, δ18O AND NOBLE GASES AS TRACERS OF WATER-ROCK INTERACTION IN THE THEISTAREYKIR GEOTHERMAL FIELD

10.1130/abs/2020am-351406 ◽

2020 ◽

Author(s):

Marie Haut-Labourdette ◽

◽

Daniele Pinti ◽

André Poirier ◽

Marion Saby ◽

...

Keyword(s):

Noble Gases ◽

Geothermal Field ◽

Rock Interaction ◽

Water Rock Interaction

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Determination of oil charge timing in the Ordovician carbonate reservoir of the Tahe Oilfield, Tarim Basin, NW China

10.5194/egusphere-egu21-1547 ◽

2021 ◽

Author(s):

Jiaxu Chen ◽

Xiaowen Guo

Keyword(s):

Tarim Basin ◽

Sedimentary Basins ◽

Carbonate Reservoir ◽

Rock Interaction ◽

Tahe Oilfield ◽

Petroleum Systems ◽

Calcite Veins ◽

Homogenization Temperatures ◽

Two Phases ◽

Northern Tarim Basin

Determining the timings of oil charge in sedimentary basins are essential to understand the evolutionary histories of petroleum systems, especially in sedimentary basins with complicated tectonic evolution and thermal histories. The Ordovician carbonate reservoir in the Tahe Oilfield, which is located in the northern Tarim Basin, comprises the largest marine reservoirs in China with reserves up to 3.2&#215;108 t. This study aims to determine the timings of oil charge in the Ordovician carbonate reservoir in the Tahe Oilfield, Tarim Basin, which basin is subjected to multiple phases of tectonic deformations and oil charge. The phases of calcite veins that contain oil inclusions were systematically investigated by cathodoluminescence observation, in situ rare earth element, C, O, and Sr isotope analyses. The homogenization temperatures of aqueous inclusions that are coeval with oil inclusions were measured to determine the timings of oil charge by combining the burial and geothermal histories. Two phases of calcite veins were judged by the differences in cathodoluminescence color, Ce anomaly, &#948;18O, and 87Sr/86Sr values, which might be caused by variations in the water-rock interaction processes during different calcite phases. Primary oil inclusions with yellow fluorescence were observed in the two phases of calcite veins, suggesting two phases of oil charge. By combining the homogenization temperatures of aqueous inclusions with the burial and geothermal histories, the timing of phase I oil charge was inferred to be 336&#8211;312 Ma, and the timing of phase II oil charge was inferred to be 237&#8211;217 Ma.

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THE METABOLISM OF VALERATE-2-C14 BY UREDOSPORES OF WHEAT STEM RUST

Canadian Journal of Biochemistry and Physiology ◽

10.1139/y63-001 ◽

1963 ◽

Vol 41 (1) ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

H. Reisener ◽

A. J. Finlayson ◽

W. B. McConnell

Keyword(s):

Carbon Dioxide ◽

Glutamic Acid ◽

Specific Activity ◽

Tricarboxylic Acid Cycle ◽

High Specific Activity ◽

Water Soluble ◽

Buffer Solution ◽

Wheat Stem Rust ◽

Carbon 14 ◽

Water Soluble Extract

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-2-C14, about 88% of the radioactivity was removed from the buffer solution in a period of 3 hours. About 40% of the carbon-14 taken from the buffer was found in a water-soluble extract of the spores and about 15% was respired as carbon dioxide. The result is compared with an earlier report that carbon 1 of valerate is more extensively released as carbon dioxide and less extensively incorporated into spore components. Glutamic acid, glutamine, γ-aminobutyric acid, and alanine of high specific activity were isolated. It was estimated from partial degradation that more than one-half of the carbon-14 of glutamic acid occurred in position 4 and that carbon 5 was very weakly labelled. Citric acid was also of high specific activity and was labelled predominantly in the internal carbons.It is concluded that respiring rust spores utilize externally supplied valerate by β-oxidation, which releases carbons 1 and 2 in a form which is metabolized as acetate by the tricarboxylic acid cycle.

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