Tritium age dating groundwater

Can tritium/3he dating be used to date groundwater?

Confinement of tritiogenic 3He Because 3He is a gas, the application of the tritium/3He method to dating of groundwater depends strongly on the degree of confinement of 3Hetritin the groundwater. The confinement of 3Hetritis mainly determined by the ratio of advection to dispersion in water parcels moving away from the water table.

What is the importance of age dating in groundwater?

These age-dating tracers can help water-resource managers to develop management strategies for shallow groundwater systems that contain mostly young groundwater. Old groundwater is defined as water that entered the aquifer before 1950 and more commonly refers to water older than 1,000 years.

What is the tritium-based age classification system?

This report presents a tritium-based age classification system for the conterminous United States based on tritium (3H) thresholds that vary in space and time: modern (recharged in 1953 or later), if the measured value is larger than an upper threshold; premodern (recharged pr

What is the half life of tritium?

Tritium ( 3 H, half-life of 12.43 years (Unterweger and others, 1980)) has provided an excellent tracer of young waters. Tritium input to ground water has occurred in a series of spikes following periods of atmospheric testing of nuclear devices that began in 1952 and reached a maximum in 1963-1964.

How is the tritium/3he method used to date groundwater?

Because 3He is a gas, the application of the tritium/3He method to dating of groundwater depends strongly on the degree of confinement of 3Hetritin the groundwater. The confinement of 3Hetritis mainly determined by the ratio of advection to dispersion in water parcels moving away from the water table.

What is the dating of tritium?

Tritium/ 3He dating. 1. Tritium ( 3H or T) is the radioactive isotope of hydrogen that decays with a half life of 12.43 years to its stable daughter 3He. Tritium is produced naturally in the upper atmosphere by interaction of nitrogen, and, to a lesser extent, oxygen with cosmic rays.

What is the deviation of the tritium/3 he age?

For the bomb tritium peak the deviation of the tritium/ 3 He age from the age determined by identifying the groundwater layer recharged between 1962 and 1965 is about 3 years (15%). The deviation can be explained by diffusive 3 He loss across the groundwater table and by flow dispersion.

How can tritium delivery be used to study water movement?

If the tritium delivery as a function of time can be reconstructed, this penetration process can be used for quantitative studies of water movement through identification of the bomb peak in certain ground water bodies.

What is the half life of tritium 2131?

Half-life of tritium 2131 A half-life value of 12.346 4- 0-002 yr is assigned to tritium. The probable error of 0002 yr represents the external consistency of the six determinations.

What is the amount of tritium that decays after 8 half-lives?

Amount of Tritium remaing after 8 half-lives = (½)^8 of the amount at the start = (1/256) × 256g = 1g. I must emphasize, that of the total amount of matter remaining in the sample would still be 256 g, of which 1 g would be tritium -3 and 255g of it would be He-3, the decay...

Can calorimetry be used to determine the half-life of tritium?

THE half-life of tritium has been measured and reportedtx-4) previously, but none of these determinations was made by calorimetry. High precision calorimeters developed at Mound Laboratory were used to follow the decay of a titanium tritide salt and a compressed gas sample.

What is the specific activity of tritium?

Tritiums specific activity is 9,650 curies per gram (3.57 × 10 14 Bq /g). Tritium figures prominently in studies of nuclear fusion because of its favorable reaction cross section and the large amount of energy (17.6 MeV) produced through its reaction with deuterium: