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UtahFossilHunter

Wellsville Mountain Rock Formation Layers

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UtahFossilHunter

Can anyone point me to a map or article or paper on the Wellsville Mountains rock layers? I'm trying to identify a mystery mineral and I need to what the matrix is. I can post pictures later if somebody wants to take a guess at it.

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tylosaurus

I don't know of any good maps, but I know the rocks. Where did you find it?

The big cliffs above Brigham City are made of the Geersten Quartzite. Above that is a lot of limestone and dolomite, with a thin layer of the Spence Shale. Post a picture, I'll look at it. I live in the area if you want someone to look at it in person.

Edited by tylosaurus

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UtahFossilHunter

I found it in one of the rock slides that went up almost to the top. Unfortunately the rocks were pretty well mixed up seeing as I had found the Spence shale trilos along side. I

post-15927-0-80740900-1439771898_thumb.jpg

post-15927-0-79095900-1439771921_thumb.jpg

post-15927-0-32808600-1439771933_thumb.jpg

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UtahFossilHunter

One more

post-15927-0-50420500-1439771991_thumb.jpg

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UtahFossilHunter

I don't know of any good maps, but I know the rocks. Where did you find it?

The big cliffs above Brigham City are made of the Geersten Quartzite. Above that is a lot of limestone and dolomite, with a thin layer of the Spence Shale. Post a picture, I'll look at it. I live in the area if you want someone to look at it in person.

Unfortunately, I don't live near the Wellsville Mountains and don't have the time to make a trip up there soon. :( I have had a couple people take a look at it and they came up with either epidote or spinel but they were uncertain as well.

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trilobite tim

Pretty sure this started life as a Galena crystal and then was replaced/altered by an iron mineral. Similar material can be found in the wheeler shale down in the house range, which is similar to Wellsville formations (some, anyway). Will a magnetic stick to it a little bit? That will confirm the iron content.

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UtahFossilHunter

Pretty sure this started life as a Galena crystal and then was replaced/altered by an iron mineral. Similar material can be found in the wheeler shale down in the house range, which is similar to Wellsville formations (some, anyway). Will a magnetic stick to it a little bit? That will confirm the iron content.

Thanks for replying. It does not stick to a magnet.

Edited by UtahFossilHunter

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Castle Rock

Looks a bit like a Limonite pseudomorph after pyrite…my 2 cents……dave

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UtahFossilHunter

Looks a bit like a Limonite pseudomorph after pyrite…my 2 cents……dave

After searching pics on limonite pseudomorphs, many of them look really similar. We may have an answer to this now. Thanks!

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BrokenTrowel

Looks a bit like a Limonite pseudomorph after pyrite…my 2 cents……dave

I thought the same exact thing as Dave.... limonite after pyrite. Definitely reminiscent of a number of specimens I've collected of this pseudomorph before (although none from this area, all of mine came from Magnet Cove, Arkansas).

Edited by BrokenTrowel

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UtahFossilHunter

I thought the same exact thing as Dave.... limonite after pyrite. Definitely reminiscent of a number of specimens I've collected of this pseudomorph before (although none from this area, all of mine came from Magnet Cove, Arkansas).

Two votes for limonite pseudomorph, I guess this is settled then.

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cojo

I'll give a 3rd vote for limonite pseudomorph over pyrite - or "Goethite" as I've always (possibly erroneously?) called it. Here's some of mine from the Lehi, UT area. Not my best finds, just the ones within arm's reach 😉

post-8535-0-96021200-1454784153_thumb.jpeg

post-8535-0-28736700-1454784168_thumb.jpeg

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