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Yet Another Source for Fine Diamonds :
Kimberlite and Lamproite are not the only source rocks (mother rocks) for diamonds, as believed till as recently as the late seventies. Therefore researching explorers have discovered yet another source rock Komatiite which yields fine diamonds. Originally discovered in Kazakhistan, Komatiite has subsequently been found at other locations also, notably Frech Guyaan, bearing gold as well. So far Komatiite has yielded very high grade but only tiny, microdiamonds; but it is strongly hoped that bigger diamonds of exceptional quality will also be found from these rocks.
More recently very high grade microdiamonds were found in strange volcanic rocks in the South-central part of French Guyana. The rocks are heavily weathered in the tropical Amazon forest. After some detailed studies they were found to be Komatiites a volcanic rock first found along the Komati River in east of South Africa. The Komatiites are known to host nickel deposits in Australia and gold deposits in Australia, South Africa and elsewhere in the world. They form part of the old volcanic belts called greenstone belts, wellknown 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 located at Dachin, 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 samples.
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 in unusually rich in micro diamonds.
Komatiite extends 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.
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