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Gold/Mining/Energy : Kensington Resources Ltd. (V.KRT) * Diamond in the rough! -- Ignore unavailable to you. Want to Upgrade?

To: Zeev Hed who wrote (906)	12/24/1997 2:30:00 PM
From: maxed	Read Replies (1) \| Respond to of 5206

Happy holidays to all. Even you Shaun. Eddy.

To: Zeev Hed who wrote (906)	1/1/1998 4:48:00 AM
From: Francoise Kartha	Read Replies (1) \| Respond to of 5206

CHAMPAGNE CORKS... CHAMPAGNE BUBBLES... CHAMPAGNE GLASSES...The rough journeys of diamonds... A very true geological story with just a touch of festive twist Three scientists at Tohuku University, Sandai, Japan, are looking for the source of diamonds. For the last ten years, mineralogists are examining carefully diamonds brought up by kimberlites. They are particularly interested by impurities - inclusions - that they may contain. These impurities have probably penetrated in the diamonds when they were forming. They should provide informations on the zone in the mantle where they were formed. Many impurities contain peridotite, a rock found in the first 400 km of the Earth, so geologists had believed that diamonds are formed in that zone. But other diamonds contain a rare orange garnet. That orange garnet (sounds eclogitic to me) is very frequent in the compact rocks heated at lower depths: rocks of the ocean floors that have gone down along the subduction zones. Those diamonds originated at depths between 400 and 600 km. Subduction zone: The zone of convergence of two tectonic plates, one of which usually overrides the other. In subduction zones, along the volcanos that border the Pacific Ocean for example, the ocean floor sinks into the Earth mantle. It takes tens of million years to arrive at a depth of 660 km. Some scientists think that diamonds come from even further depths. Many inclusions contain sulphur, an element present in the Earth core. Those scientists defend the idea that diamonds are formed near the core of the Earth, at a depth of 2 900 km. Later, the diamonds join kimberlites and come straight up to the surface. The three Japanese scientists' idea is that, because of their buoyancy diamonds could behave like champagne corks. If their density is inferior to that of the molten surrounding rock, they go up; in the opposite case, they sink. Those scientists decided to create a model of the Earth's interior to see at what level a diamond would have to go up because of its density. After inserting a diamond into its surface, they compressed and heated a big piece of peridotite, a rock of the same composition as the Earth's mantle. The rock was subjected to a pressure of 20 Gpa (gigapascals) - 200 000 times the pressure of the atmosphere - and heated to 2 360 oC (conditions prevalent at a depth of 660 km). The sample was then cooled brutally to set the diamond and peridotite. No trace of the diamond, it had sunk. They started the process again at a pressure of 20.7 Gpa - equivalent to a depth of 680 km, in the lower mantle. The diamond had come back to the surface. The results occurred when the experiment was repeated at 22 Gpa - equivalent to a depth of 750 km. The scientists concluded that because of their density diamonds will come up to a depth of 660-670 km. Even if they form at the core of the Earth, they will accumulate at that depth until they find an elevator of kimberlite. Diamonds travel in kimberlite. To deliver intact diamonds, kimberlites must come up very fast. Otherwise, over a depth of 150 km, the gem would become graphite. Kimberlites are full of gases and very porous, thus they are very light. They come up very quickly like champagne in a bottle that has been shaken. Let the corks pop up, the champagne fill the glasses and 1997 be over... HAPPY, HEALTHY AND PROSPEROUS 1998 TO ALL!