MINOR ELEMENTS IN MARJALAHTI OLIVINE

Precise microprobe determinations of minor elements in olivine from Marjalahti show averages of 0.067% CaO; 0.0211% Cr₂O₃; less than 0.0045% TiO₂; 0.288% MnO; and 30 ppm Ni. The calcium is as high as in some terrestrial plutonic olivines (e.g. Stillwater) but lower than in terrestrial nodule (high-temperature mantle?) olivines, consistent with very slow cooling to low temperatures. The chromium is discrepant with some earlier determinations, and possibly chromium is zoned in most pallasitic olivines. The Ti, Mn, and Ni data are consistent with previous determinations.