Dating sites in antarctica
| 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.We are hereby presenting a new dating method based on inverse techniques, which aims at calculating consistent gas and ice chronologies for several ice cores.The proposed method yields new dating scenarios simultaneously for several cores by making a compromise between the chronological information brought by glaciological modeling (i.e., ice flow model, firn densification model, accumulation rate model), and by gas and ice stratigraphic constraints.Data collected as part of this project will also be used to obtain a better understand how ice flows in general using state-of-the-art inverse techniques to measure important but poorly-constrained flow properties of ice. Satellite image showing the SW Ronne Ice Shelf region with the Fowler, Korff, Henry and Skytrain ice rises labelled and the routes of our two skidoo traverses shown in red (2013/14 season) and green (2014/15 season).Inset shows the regions location in West Antarctica.This method enables us to gather widespread chronological information and to use regional or global markers (i.e., methane, volcanic sulfate, Beryllium-10, tephra layers, etc.) to link the core chronologies stratigraphically.Confidence intervals of the new dating scenarios can be calculated thanks to the probabilistic formulation of the new method, which takes into account both modeling and data uncertainties.
This long period of applicability is an added advantage of cosmogenic nuclide 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.During two field seasons (Figure 1) we used a unique BAS ice-penetrating radar to measure the internal deformation of these ice rises in unprecedented detail.
We are now combining these data with radar observations of structures that form within the ice rises due to the peculiar way in which ice deforms in these locations.
Krypton is produced by cosmic rays bombarding the Earth and then stored in air bubbles trapped within Antarctic ice.