24 April 2013
Native copper from the Catoctin Formation
Posted by Callan Bentley
Another new insight from last week’s visit to the Outdoor Lab was that they have several fine examples of native copper found in float of the Catoctin Formation on their property. Here are a few examples:
Classic examples – a bit of malachite in there too, it looks like.
I wasn’t totally shocked when I saw these items, since just a month or two ago, I was shown a similar sample from further north, just across the state line in Pennsylvania. One of the people who attended my January Smithsonian class loaned me a sample for macro GigaPan imaging. It’s a lovely thing:
So: there is native copper in the Catoctin greenstone. Is this Neoproterozoic copper? Or did it form during metamorphism (accompanying Alleghanian mountain building)? Anyone know of other copper deposits in the area?
What do you mean by “float”?
It’s a term for loose rocks – i.e., not “in situ” bedrock.
Thanks, now I know! Even with some knowledge of geology I hadn’t heard ‘float’ used in a geological sense before.
Callan, It is much further south than the MD/PA border region, but I believe that the Hightop Copper Mine NW of Lydia, VA is in the Catoctin Greenstone Formation. Azurite and Malachite have also been found there there as well, not surprisingly