An another resource for Fine Diamonds:
As believed till
as recently as the late seventies that Kimberlite and Lamproite are the only
source rocks for diamonds, which stands untrue now. Consequently explorers have
discovered yet another source rock Komatiite, which yields excellent diamonds.
Initially discovered in Kazakhstan, Komatiite has subsequently been found at
other locations also, notably French Guyana, bearing gold as well. So far
Komatiite has yielded very high grade but only tiny, micro diamonds; but it is
strongly hoped that bigger diamonds of incomparable quality will also be
discovered from these rocks.
More recently very high-grade micro diamonds were found in strange volcanic
rocks in the South-central part of French Guyana. The rocks are profoundly
battered in the tropical Amazon forest. After some meticulous studies they were
found to be Komatiites a volcanic rock first found along the Komati River in
east of South Africa. Host nickel deposits in Australia and gold deposits in
Australia, South Africa and elsewhere in the world know the Komatiites. They
form part of the old volcanic belts called greenstone belts, well known for
their good potential for metal mineralisations. Guyana Komatiites are at least
1.9 billion years old and must have tapped their magnas from great depth. They
are different from kimberlite and lamproite.
Guyana Komatiite is situated at Dachine, about 170 km. South of Cayenne, the
capital of French Guyana. The Dachine property is located in the primary
equatorial forest and only accessible by boat or by helicopter. Guyanor is now
exploring the deposit. Guyanor, is now exploring the deposit. Guyanor, a
subsidiary of Golden Star Resources of the USA, has erected a tented camp, the
"Dachine Camp", on the north bank of the Inini River. In 1995, Guyanor decided
to have a re-look at the Inini diamond occurrences abandoned earlier. As a first
step, stream sediment samples were taken from the creeks, soil samples were
taken in the center of the BRGM anomaly and saprolite samples were taken in the
pits, which BRGM had excavated and were still open. The samples were found to be
very rich in micro diamonds. Gold was also found in the stream sediment
Gold has been found in the nearby rivers together with diamonds and locally
in soil samples (grades up to 2 g/t) on top of the talc rock. Gold flakes have
been seen in drill core samples of the talc schist. The Dachine talc rock is
therefore not only diamonds bearing, but also gold-bearing. The Dachine talc
schist is unusually rich in micro diamonds.
Komatiite expands over several hundreds of hectares and Guyanor hopes to find
parts where larger diamonds may occur in economic quantities. Recently, Rio
Tinto, the large mining group, has joined Guyanor in their exploration efforts
in French Guyana.