Sm---Nd ages for norwegian garnet peridotite

Sm---Nd results for ga-WR-cpx from garnet Iherzolite in Almklovdalen, western Norway, define an isochron with age of 1703 ± 29 Ma and /ge_t = + 4.7 ± 0.7 (2/gs) which falls on a depleted mantle curve. Garnet websterite from the same peridotite body falls close to the Iherzolite isochron. Minerals from the websterite, however, define a younger age of 1040 ± 30 Ma.

The age of 1703 Ma is interpreted to date formation of the peridotite body and crystallisation of the garnet-bearing assemblage. The younger age from the websterite may record an uplift stage in the history, or alternatively may only reflect secondary disturbance of the isotopic systems in this sample.