Two Kyt-projects:

download report

Transcript Two Kyt-projects:

Two Kyt-projects:
GeochemM: U-migration and
retention in granitic rock
U in Water-rock Interaction
Independents
• Both at a regional scale with samples of
several sites from Finland and Sweden
• Two different approaches:
– GeochemM: U-mineralogy, migration paths
characterization and dating of U-minerals
– U in WRI: U-isotopes (U-234, U-238) and
activity ratios (U-234/U-238) distribution in
groundwaters
Same conclusion
• Glacial melt water intrusion deep in the
bedrock
Other investigations with a third approach:
I.D. Clarck et al. 2000. GROUND WATER
38 no. 5,735-742
- Melt water injected into the subsurface (700 m
depth) during ablation of the Laurentide Ice
Sheet at ca. 10 ka under conditions of high
hydraulic gradient (modelled and supported
by studies of Björnson (Nature 395, 771-774).
What so?
• Site investigation studies refer to the same
event (oxygen isotope values)
• What is the fate of radionuclides (products,
positon, migration rates, distances, and
paths):
– Need of mineralogical studies and
characterization of possible migration paths
Future prospects
• Main report (TKK-series) with last findings
and modelling approach
• Publications to referee journals:
– U-mineralogy (chemistry) and migration
– U-mineral dating and connection to glacial
cycles
– Modelling approaches (reactive models for
radionuclide migration in granitic rocks)