Groundwater age dating methods

groundwater age dating methods

How to determine the age of groundwater sample?

A groundwater sample is composed not of water that recharged at a point varying lengths of time. 2. Conventional age-dating techniques applied to mixed waters predict sample extreme. 3. The distribution of groundwater age across a flow regime can be calculated the product of groundwater age and mass. 4.

Where can I find resources on age dating groundwater?

Resources on age dating groundwater can be found at the USGS Reston Groundwater Dating Laboratory web page. Go to the Publications tab to read about USGS research that uses groundwater age dating.

What is a groundwater sample?

Following a rigorous definition of age, a groundwater sample is seen not as water that recharged the flow regime at a point in the past, but as a mixture of waters that have resided in the subsurface for varying lengths of time.

What is old groundwater?

Old groundwater is defined as water that entered the aquifer before 1950 and more commonly refers to water older than 1,000 years. Many common and rare isotopes are produced naturally in the Earth’s atmosphere from the bombardment of cosmic rays or solar radiation, and their presence in groundwater can help determine the groundwater age.

Is there any experimental technique to determine the age of groundwater?

We have no experimental technique only using water that can give the kind of age described above, or in short, water itself will not answer our question about age. Any experimental approach to determine groundwater age uses either isotopes of the water molecule or substances that are transported in a similar way as the water.

How can you tell how old a groundwater is?

Many common and rare isotopes are produced naturally in the Earth’s atmosphere from the bombardment of cosmic rays or solar radiation, and their presence in groundwater can help determine the groundwater age. These isotopes are adsorbed by rainfall and can enter the aquifer with recharge.

How are groundwater Ages and travel times estimated?

Environmental tracers are used to estimate groundwater ages and travel times, but the strongly heterogeneous nature of many subsurface environments can cause mixing between waters of highly disparate ages, adding additional complexity to the age-estimation process.

What isotopes are used to determine the age of groundwater?

These isotopes are adsorbed by rainfall and can enter the aquifer with recharge. Argon-39 can be used to identify water that recharged between 50 and 1,000 years ago. Carbon-14 or radiocarbon is the most common method used to determine groundwater ages between 1,000 and 30,000 years.

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