To: zedex who wrote (1515 ) 3/30/1999 11:04:00 PM From: Jesse Read Replies (1) | Respond to
Sensible thinking, Bruce, but no, alluvial diamonds are considered secondary deposits. This pyroclastic-body discovery is a primary... :>Message 8264960 the bedded deposits referred to in the recent Ashton release are almost certainly pyroclastics, i.e. "hot grainy rocks", which were dumped at or near their current location after being blown out of the vent. They certainly may have been re-sorted a bit by water action but they are essentially in the same place they were a few minutes or hours after they were blown out and fell back to the sea floor. In current cross section, they probably resemble grey or brown clay-rich "sandstones" interbedded with darker mudstones (i.e. shales). When they are less altered to clays (i.e. weathered) the kimberlitic components consisting of micas and olivine give them a medium- to dark-green colour. The tonnage potential of these bedded deposits in a place like Alberta are orders of magnitude higher than for pipe deposits and their geometry is amenable to "Alberta-style" mining, that is, gigantic scale mining operations using draglines."PS ,"Major diamond deposits and resources thoughout the world are
