Department Water Resources and Drinking Water

Measured He ages ranged from 8 to 61 Ma, and were reproducible to better than a few percent despite very large variations in [U] and [Th]. In all samples with internal stratigraphy or independent age constraints, the He ages honored the expected relationships. These data demonstrate that internally consistent He ages can be obtained on goethite, but do not prove quantitative 4He retention. To assess possible diffusive He loss, stepped-heating experiments were performed on two goethite samples that were subjected to proton irradiation to produce a homogeneous distribution of spallogenic 3He. The 3He release pattern indicates the presence of at least two diffusion domains, one with high helium retentivity and the other with very low retentivity at Earth surface conditions. Diffusive loss of 3He from the high retentivity domain is independent of the macroscopic dimensions of the analyzed polycrystalline aggregate, so probably represents diffusion from individual micrometer-size goethite crystals. This degree of retentivity is in excellent agreement with that independently predicted from the helium diffusion coefficients extrapolated to Earth surface temperature and held for the appropriate duration.

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We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon testing in the s and early s, based on essentially all available observations. The decline was largely due to radioactive tritium decay, which produced significant amounts of its stable daughter 3He. We present the scheme by which we separate the tritiugenic part of 3He and the part due to release from the sea floor terrigenic part.

Tritium can also be used to date groundwater samples using the 3H/3He dating technique, which utilizes daughter nuclide of tritium decay, tritogenic helium.

Constraining the age of young lavas, which generally fall outside the effective range of traditional geochronology methods, remains a key challenge in volcanology, limiting the development of high-resolution eruption chronologies. We present an in situ cosmogenic 3 He and 36 Cl surface-exposure chronology, alongside new minimum-limiting 14 C ages, documenting young eruptions at five sites in the Western Cordillera, southern Peru.

Four 3 He-dated lavas on the Nevado Coropuna volcanic complex hitherto thought to be dormant indicate that the central dome cluster is young and potentially active; two Holocene lavas on the easternmost dome are the youngest directly dated lavas in Peru to date. Two 3 He measurements confirm the Holocene age of these deposits and expand the chronology for one of the youngest major lava fields in Peru. These new data advance the recent Western Cordillera volcanic record whilst demonstrating both the considerable potential and fundamental limitations of cosmogenic surface-exposure methods for such applications.

This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Estudio del Cuaternario — Google Scholar. J Maps — J Volcan Geotherm Res — Ann Rev Earth Plan Sci — Andronico D, Lodato L Effusive activity at Mount Etna volcano Italy during the 20th century: a contribution to volcanic hazard assessment. Nat Haz —

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Cosmogenic 21Ne and 3He dating and geochemistry of young basaltic lavas from southern Mendoza, Argentina. Venera R. The ACBP lacks detailed chronological and geochemical information.

Author: Sültenfuß, J.; Genre: Conference Paper; Final published: ; Open Access; Title: Byproducts of 3H-3He-dating: use of radiogenic 4He to demonstrate.

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The Reston Groundwater Dating Laboratory

Help Contact us. Darling, W. George ; Gooddy, Daren C. Geochemical Journal , 51 5. An evaluation of the results from diffusion cell versus pumped tube sampling showed generally good agreement between the two techniques. Measurements of noble gas Ne, Ar, Kr and Xe concentrations revealed typically low amounts of excess air in the aquifer, with little variation around a mean of 1.

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The Christchurch earthquake series had severe consequences and surprised scientists for many reasons. Ground motions were extremely strong despite the relative moderate magnitudes of the quakes M W 5. The events happened on a system of hitherto unknown faults, some of which are located directly below Christchurch. Earthquake environmental effects EEE , especially liquefaction, were intense and widespread. It turned out that subsequent quakes reactivated the same feeder dikes of sand blows, showing that saturated sediments are susceptible of liquefaction no matter if they had been liquefied recently also see the paper of Quigley et al.

Another stunning lesson was the occurrence of intense rockfall in the vicinity of Christchurch.

Infiltration of river water to a shallow aquifer investigated with 3H/3He, noble gases and CFCs

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Schlosser and M.

We present a comprehensive account of tritium and 3He in the revealed by this new application of tritium-3He dating is considerable. We find.

The concept of neutron spectroscopy dates back to neutron discovery in Despite several attempts towards an efficient neutron spectroscopy system, such measurements remain cumbersome and detailed neutron spectra are sparse both in scientific laboratories and industrial sites. To-date the most widely used method relies on the 3He n,p 3H reaction, which – however – is more well suited for thermal neutrons and is particularly expensive, given that 3He is scarce.

The neutronSPHERE project will provide a unique alternative to 3He-based detectors for neutron spectroscopy by using the Spherical Proportional Counter SPC , a high-gain large-volume gaseous detector, filled with a nitrogen-based mixture. This breakthrough is enabled by novel developments in SPC instrumentation that the host has played a key role in demonstrating. The capabilities of the developed neutron spectroscopy system will be demonstrated in two application: Firstly, neutronSPHERE will provide the first high precision measurements of the neutron background spectrum in underground facilities.

These will provide a unique insight and will immediately inform direct searches for Dark Matter. Then, neutronSPHERE will measure in situ the neutron-induced dose during proton therapy treatments, which is a crucial element in hadron therapy treatment and planning. Veuillez activer JavaScript. Por favor, active JavaScript. Bitte aktivieren Sie JavaScript. Si prega di abilitare JavaScript.

Tritium/3He dating of river infiltration: an example from the Danube in the Szigetkoz area, Hungary

Tritium and helium are important tracers in hydrology, you can find actual examples in the projects section. The history of tritium 3 H and helium as tracers in hydrology began in the s and early s, when large amounts of tritium were released at the tests of thermonuclear bombs in the atmosphere. Soon it was discovered, that the radioactive superheavy hydrogen isotope 3H is an ideal tracer for hydrological processes of all kind, because it is readily incorporated in the water molecule to form HTO, and then takes part in the global water cycle e.

Begemann and Libby, ; Suess, These data form the basis for tracer applications of tritium.


JavaScript is disabled for your browser. Some features of this site may not work without it. This Collection. Login Register. View Usage Statistics. Antarctic glacial chronology : new constraints from surface exposure dating. Author Ackert, Robert P. Concept link. Metadata Show full item record. Location Marie Byrd Land, Antarctica. DOI Keyword Glaciers. Abstract Surface exposure dating, using the concentration of cosmogenic nuclides 3He, 21Ne, and 36Cl in moraine boulders, combined with mapping of glacial moraines from three key locations, is used to provide new constraints to Antarctic glacial chronology.

Paired 3He and 36Cl measurements are consistent with negligible surface erosion which is inferred from flow morphology.

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However, this method has rarely been applied to karstified aquifers and in particular to drip water in caves, despite the importance of the information which may be obtained. Besides the determination of transfer times of climate signals from the atmosphere through the epikarst to speleothems as climate archives, 3 H- 3 He together with Ne, Ar, Kr, Xe data may also help to give new insights into the local hydrogeology, e.

In order to check the applicability of 3 H- 3 He dating to cave drips, we collected drip water samples from three adjacent caves in northwestern Germany during several campaigns.

Once upon a if youre 3he Dating and diagnosed with breast cancer Start quotTheres really only one thing that the horror of and its how surgery was not guy not.

William J. Jenkins senior scientist, retired director of NOSAMS is a tracer geochemist whose research activities include the study of ocean circulation and ventilation, carbon and nutrient cycles, and the impact of climate change on them. He developed the use of tritium-3He dating to characterize water mass formation and ventilation, as well as oxygen utilization rates to determine biological production rates in the ocean.

Jenkins has also used the efflux of tritiugenic 3He to estimate subtropical ocean biological new productivity. He has also worked with noble gases in the shallow ocean as tools to determine air-sea gas exchange rates, as well as upper-ocean net community production. He has applied helium isotope measurements to submarine volcanic systems to study the long-term role of sea-floor spreading processes in affecting the chemistry of ocean waters, and to constrain abyssal ocean circulation.

More recently, Bill has been working on the influence of global climate change on the carbon cycle. In addition to illuminating broad-brush changes in ocean circulation and carbon cycle since the Last Glacial Maximum, these improvements may have significant benefits to archeology.

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