Cosmogenic dating ppt
Cosmogenic dating ppt - Adult vieo random chat
12PBe at SLHL 5.1 0.3 atoms/g/yr PAl at SLHL 31.1 1.9 atoms/g/yr??????????? 13PBe at SLHL 5.1 0.3 atoms/g/yr PAl at SLHL 31.1 1.9 atoms/g/yr???????????
lat.) z 20003500 m (670800 g/cm2) 11,000 yr exposure (from 14C dating).
Cartoon illustrating cosmogenic nuclide exposure ages. A glacier transports an erratic boulder, and then recedes, exposing it to cosmic rays.
Spallation reactions occur in minerals in the rocks upon bombardment by cosmic rays.
Material giving rise to these enhanced exposures has become known as naturally occurring radioactive material (NORM).
NORM is the acronym for Naturally Occurring Radioactive Material, which potentially includes all radioactive elements found in the environment.
| Using cosmogenic nuclides in glacial geology | Sampling strategies cosmogenic nuclide dating | Difficulties in cosmogenic nuclide dating | Calculating an exposure age | Further Reading | References | Comments | Cosmogenic nuclide dating can be used to determine rates of ice-sheet thinning and recession, the ages of moraines, and the age of glacially eroded bedrock surfaces.
Cosmogenic nuclide dating uses the interactions between cosmic rays and nuclides in glacially transported boulders or glacially eroded bedrock to provide age estimates for rock at the Earth’s surface.
It is an excellent way of directly dating glaciated regions.
It is particularly useful in Antarctica, because of a number of factors: Cosmogenic nuclide dating is effective over short to long timescales (1,000-10,000,000 years), depending on which isotope you are dating.
By sampling the rocks and separating certain minerals (such as quartz or pyroxene) and calculating the amount of these minerals (as a ratio to other, stable, minerals), we can work out how long the rock has been exposed on the earth’s surface.
Cosmogenic nuclides are rare nuclides that form in surface rocks because of bombardment by high-energy cosmic rays.
Different isotopes are used for different lengths of times.