New Identity of the Kimberlite Melt: Constraints from Unaltered Diamondiferous Udachnaya – East Pipe Kimberlite, Russia - Advances in Data, Methods, Models and Their Applications in Geoscience - page 189

(a) (c)

(b)

(d) (e)

(f)

(h) (i)

(g)

Fig. 7. Back-scattered electron images of olivine-II crystals demonstrating different types of
zoning and core and rim relationships. Scale bars represent 100 µm

3.3 Olivine-II: Compositional variation
The inner parts (“cores”) of olivine-II are strongly variable in Fo content (85.5 - 93.5 mol%),
although the compositions 90.5-93 mol% Fo are most common (69%, Fig. 6b). The cores
display relatively wide range of NiO (0.13-0.44 wt%, Fig. 6b), CaO (0-0.08 wt%), MnO (0-0.15
wt%), and Cr2O3 (0-0.09 wt%) contents. NiO contents are the highest and almost constant at
Fo >89.5, and then gradually decrease in less magnesian olivine (Fig. 6b).
The outer parts (“rims”) of olivine-II, although representing significant volumes of this
population, have very constant Fo content 89.0 ± 0.2 mol% (Fig. 6b). In contrast, the trace