Kimberlite pipes |
Kimberlite pipes |
Feb 28 2012, 10:41 AM
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#1
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Rock Bar! Group: Members Posts: 426 Joined: 6-February 04 Member No.: 84 |
Here's a little item I found on another forum.
http://www.sciencenews.org/view/generic/id...onds_to_surface This thin slice of a kimberlite rock from northern Canada, seen through a microscope and in polarized light, shows colorful minerals caught up in magma that rose from deep within the Earth. Leonard |
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Feb 8 2021, 04:18 AM
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#2
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Shovel Buster! Group: Members Posts: 118 Joined: 22-December 10 From: USA Member No.: 7,480 |
Musk Rat,
Kimberlite is a very peculiar rock once exposed to oxygen for a few million years it changes from hard rock to a yellowish sand like structure very similar to sandstone in colour. (weathering)... hence the term yellow ground. It will react with oxygen and the slightest water movement will wash the material down any close-by gully's ditches rivers etc... now the name changes to Alluvial material and this material can travel for hundreds of miles downriver.... Many of these ancient deposits are mined in SA and around the world. So Kimberlite weathers when oxygen is introduced..... it releases the Pyrope garnets G-10, Chromium Diopside diamonds Spinel etc etc.... all these are called diamond indicators. But Kimberlite comes to the surface from 150km down in the Earth.... as a big hot lava flow and collects quite a few different rocks on the way up. So you will find strange rocks in it nothing out of the ordinary. Good luck with your hunt. DD PS there are lots of different garnets.... but only One counts!! |
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