[meteorite-list] RE: Moqui Marbles and Meteor- Wrong contest from NewYears
From: E.L. Jones <jonee_at_meteoritecentral.com>
Date: Thu Apr 22 09:44:35 2004 Message-ID: <3A9EBD26.7D4E843B_at_epix.net> Hello All, This isn't the first time these have appeared on Ebay as alleged meteorites. This was the meteor-wrong ID contest I suggested around New Years. These "marbles" have had many local names applied to them, none of which I can remember at present. The primary collecting site in Utah has been closed to collecting. It was included in a National Monument designation under the first Clinton Administration. The guy who introduced me to them was a Native American from The Navajo Lands --he was also a trained geologist and seemed well informed, so I tend to go along with his expertise on their origins. I don't know why, exactly ,they have a rind of darker material. It may be subsequent replacement by calcium carbonate but originally it is believed to be seeps of very light crude oil/methane into a sand bed. When broken open, some still have loose sand grains and a few I have seen have secondary bubbles inside The origin of these artifacts is fairly unique to this locale and is theorized as follows: They started out as bubbles of hot, gas-ladden, petroleum globules which seeped up from cracks into loosely consolidated sands of a shallow sea. As these viscous yet water proof globules ascended, they expanded under the reduced pressure. Now this is a trick to do in solid stone, but in loose sand, it can be done by oozing around the grains and slipping the grains inside the bubble. When the sand inside the bubble filled the interior, the buoyancy was equalized and the bubbles stopped rising. They never reached the surface and there lay frozen until weathering released them. I was also told that the bubbles were naturally semi-sorted by diameter /size in layers where they are found in situ. I had not heard anything about them being found in limestone. As such they are not concretions in the traditional sense. Regards, Elton Received on Thu 01 Mar 2001 04:21:07 PM PST |
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