... of the Ekati diamond mine at Lac de Gras. The Ranch Lake kimberlite underlies Ranch Lake ( Fig. 2 ), which is c. 30 m deep. Access to the area is by air only. Fig. 1 Location of the Ranch Lake area, known kimberlites and regional ice flow patterns (from Dredge et al. 1997 ). Fig. 2 Aerial...

... production by value, from two separate mining operations. The mineral resources of Diavik Diamond Mines Inc. were discovered between 1993 and 1995. Four kimberlite bodies (A154N, A154S, A418, A21) are located within late Archean granitoid rocks beneath Lac de Gras, a large arctic lake in the Northwest...

... proxy reconstructions—of these maar infills remains ambiguous and requires refinement because of the large range in the age of kimberlites within the Lac de Gras kimberlite field. Existing constraints for the Giraffe pipe post-eruptive lacustrine and paludal maar sedimentary facies include a maximum Rb...

...F ig . 1. Location map of the Lac de Gras kimberlite field, Northwest Territories, Canada (after Pell, 1997 a ). Kimberlite occurrences are denoted by diamonds. The dashed line corresponds to the isotopically-defined boundary between two structurally different parts of the Slave Craton. ...

... mantle beginning at depths of ∼80–100 km. This lithospheric mantle conductor has electrical properties similar to those for the central Slave craton mantle conductor, which lies directly beneath the major diamond-producing Lac de Gras kimberlite field. While the Saskatchewan mantle conductor does...

.... (A) Peralkaline pegmatites of Lovozero (heavily dotted) and Murun (hatched); (B) Lac de Gras kimberlite. Also shown are compositional data for apatite-group minerals from diverse alkaline rocks of the Lovozero, Khibina, Inagli, Ilímaussaq, Bearpaw Mountains. and Gordon Butte ( Rønsbo 1989 , Pekov et al . 1995...