This specimen is thought to be over 2.5 billion years old. Bacteria and algae appeared at this time in the water. Volcanic activity produced increased atmospheric pressure and temperature. The higher temperature caused serpentization of the sediments thus the green color. In between the layers the micro stromatolites (like algal mats).
This fossil was found in southern Africa's Greenstone Belt. Its green color definitely matches the formation name. Unique about the fossil material is it is called butterstone dated to the geologic eon Archean.
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In addition, here are pictures of oolitic agate formed on a Wyoming seafloor during the Eocene. Check it out on eBay: CLICK HERE
4 comments:
Mike--
I don't think there was any seafloor in (or anywhere near) Wyoming during the Eocene. See Ron Blakey's paleogeographic maps, here: http://cpgeosystems.com/nam.html
Cheers,
--Howard
Hi Howard,
Thanks for the feedback.
You have a point as that map shows the area absent of water. I was going off the label provided with that specimen. Will investigate and update the posting with my findings.
Thanks as always for showing me a mystery to work on. I agree that the Wyoming Eocene does not appear to be sea covered, instead the specimen might be from the Middle Jurassic of Wyoming.
Regards,
Mike
Mike--
Yes, I'd say Jurassic is much more likely. From my subsurface work in southern Saskatchewan, I know that oolitic limestone is quite common in the Jurassic rocks there, and the same seaway looks to have extended south through Wyoming.
--Howard
Howard,
The evidence is pointing to the Jurassic as I found an image of cut oolitic material at this web site: http://www.minersgallery.com/index.php?categoryID=175
The material in between the oolites on the specimen will fluoresce a weak yellow-golden color under LW UV light.
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