|Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥2,900,000 (Direct Cost: ¥2,900,000)
An early stage of the present project, developmental efforts for Re-Os analyses were made. The Re mass spectrometry was usually disturbed by filament blank, but finally successful measurements were attained. However, the contribution of filament Re is still large, and our efforts must be given to reduce such effect.
The Re-Os dating method were applied to several kinds of samples such as Permian Akasaka limestones, late Jurassic mudstones from Tamba group, Miocene mudstones from Shimane Prefecture, present-day river and marine sediments. Those data indicate two important aspects: (1) Most of the limestones and mudstones undergone severe thermal event during diagenetic processes are not suitable for Re-Os dating. Re might tend to be mobilized during such processes. (2) However, relatively young mudstones, which did not undergo thermal damage, can yields reasonable age, and thus are suitable for Re-Os dating.
Finally, although application of Re-Os method to sedimentary rocks might be restricted to relatively young rocks, this method must deserve attention for further geological investigations.