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 183

80 o E 140 o E

Laptev Sea

Ta i m yr
Fold Belt

Russia

70 o N

Anabar

Norilsk Verkhoyansk

Fold Belt

Udachnaya



Yakutsk

Aldan

Baikal
Fold Belt

Kimberlite fields
Archaean shields

Fig. 1. Map of the Siberian Platform showing the major kimberlite fields after Pearson et al.
(1995).

et al., 1976). At deeper levels (> 400 m) of the kimberlite body the amount of serpentine in
the groundmass gradually decreases and the amount of carbonate in the groundmass
increases. Intensive mining of the Udachnaya pipe revealed widespread chloride minerals
(mostly halite) as dispersed masses in the groundmass and massive multi-mineral
segregations of halite, serpentine, anhydrite, carbonates and hydrous iron oxides (Pavlov &
Ilupin, 1973). The amount of chloride minerals in the groundmass increases with depth, and
recently a large number of chloride-carbonate “nodules” were recovered from ~470-500 m
depths of the mine.
The studies Udachnaya-East kimberlites are dark massive rocks with porphyroclastic
fragmental textures. They are exceptionally olivine-rich (Fig. 2, 12a), a feature shared by the
majority of known kimberlites, excluding rare aphanitic kimberlites, such as those from
Kimberley, South Africa (Edgar et al., 1988; Edgar & Charbonneau, 1993; le Roex et al., 2003;
Shee, 1986) and Jericho, Canada (Price et al., 2000). The large abundance of olivine (45-60
vol%) is reflected in the high MgO content of the bulk rock compositions (28-36 wt%).
Olivine is set in a fine-grained matrix of carbonates (Fig. 2, calcite, shortite Na 2 Ca 2 (CO 3 ) 3 and