Eclogite xenoliths - alois12Hi,
I couldn’t find any other references or links to that site. But I did find the following info about the golf-ball sized eclogites and how rich they can be:
On p.1-2
https://web.utk.edu/~anandm/FLA_0084.PDF
All of the xenoliths studied are highly diamondiferous
(e.g., one 66 g eclogite contains 74 macro diamonds [>
1 mm], equivalent to 144,000 carat/ton). In Yakutia,
during the processing of the kimberlite, the ore is
crushed to ~5-6 cm size, washed, and passed along a
conveyor belt. These golf-ball-sized rocks are exposed
to X-rays, whereby any diamonds exposed at their sur-
face will fluoresce a bright blue. Sensed by a detector,
a shot of compressed air moves the rock off the belt
into a rubber bag. This diamondiferous sample is han-
dled carefully so as to recover the possibly large dia-
monds. The diamondiferous eclogites that our group
has been studying for several years are from these
suites of scientifically invaluable samples. One such
xenolith (UX-1) showing a diamond exposed on its
surface is shown in Fig. 1. There were more than 5
diamonds exposed on the surface of this xenolith that
were carefully removed during our detailed dissection;
another 69 diamonds were inside.
Shore Eclogite (from a dsel post):
Knowing then that eclogite has a world average of 23,000 carat/tonne in diamondiferous kimberlites, I did some DD to see if Shore had any. I found the following:
a) May 21, 2002 SHORE GOLD ANNOUNCES POSITIVE DIAMOND RECOVERY RESULTS FROM STAR 031RC
https://www.shoregold.com/newsrelease/may2102.html
Lakefield observed the presence of eclogitic minerals in the samples. This could be highly significant as eclogite may be richly diamondiferous and relatively minor amounts of diamondiferous eclogite in the mantle source region can lead to good or high diamond grades in the host kimberlite
Some links for eclogite garnet composition at some producing diamond mines, if you are interested in this sort of detail:
Letlhakane & Orapa eclogite garnet composition
https://www.geology.utoronto.ca/pub/geology/publications/Schulze/graphite.table.rtf
https://www.geology.utoronto.ca/faculty/schulze/carbon.isotope.data.html
Another link for info on eclogite vs peridotite garnets
https://hosting.soonet.ca/eliris/geoforum/diamonds.htm