3he cosmogenic nuclide age dating
3he cosmogenic nuclide age dating - dating in southport
Many of these processes occur so rapidly and unexpectedly that they have daunting consequences.We are poorly equipped to predict their nature and possible impacts due to the lack of scientific understanding.
Within landslide studies, NGU applies TCN dating to determine ages of rockslide events and the age of sliding surfaces in order to determine past long-term displacement rates Earth is constantly bombarded with cosmic rays that are high-energy charged particles.The principles of dating sliding surfaces are more explained in the publication on the Oppstadhornet slide on Otrøya. 16.6 to 14.2 kyrs ago and past long-term displacement rates are in the order of 2 mm/yr.Displacements rates measured today by differential Global Navigation Systems Satellite Systems (GPS) indicate the same velocity suggesting that the rockslide has been moving nearly constantly over the past 14 thousand years.Although dating with this method is expensive and the entire process takes a long time, TCN dating has the advantage that the dateable material is produced by the rockslide event itself by exposing fresh material surfaces to the cosmic rays.With the accuracy of modern instruments general every surface older than about 1000 years can be dated and the uncertainty limits today lie below 10% of the age.Our research interests cover a wide spectrum of earth scientific disciplines and include timing of ice ages, subglacial erosion rates, uplift rates of Pleistocene terraces, and a better understanding of the production systematics of cosmogenic nuclides.
We apply the full spectrum of cosmogenic nuclides, including the routine extraction of A 3-dimensional model of the Mont Fort and Sivier glacier system, showing well-preserved 'Egesen' and 'pre-Egesen' moraine systems that are studied to understand the glacier and climate changes during the Late Glacial Period (14.5 - 11 ka ago) in the Swiss Alps.
The basic principle is that these radionuclides are produced at a known rate, and also decay at a known rate.
Accordingly, by measuring the concentration of these cosmogenic nuclides in a rock sample, and accounting for the flux of the cosmic rays and the half-life of the nuclide, it is possible to estimate how long the sample has been exposed to cosmic rays.
In NGU's projects on unstable rock slopes in Norway, TCN dating is used to date 1) rock-avalanche deposits and 2) sliding surfaces.
Ages of rock avalanche deposits throughout Norway cluster in the first few thousand years after deglaciation, however ages throughout the entire Holocene have also been obtained.
These particles interact with atoms in atmospheric gases (and thereby producing northern lights) and the surface of Earth.