MSirmon Posted April 3, 2017 Share Posted April 3, 2017 Need some help from the micro fossil experts. I am going through some mud samples from Terkingua TX and found this item. Appx 1/16" long and ribbed. Doesn't look like wood so was thinking something along the lines of a dental plate. I was told it was part of the Aguja formation but am not sure so am trying to pinpoint the actual formation on this map. How far off base am I? Link to comment Share on other sites More sharing options...
Rockwood Posted April 3, 2017 Share Posted April 3, 2017 Just a cautionary note. There is a mineral, related to tourmaline I think, that has a similar crystalline structure. Link to comment Share on other sites More sharing options...
Rockwood Posted April 3, 2017 Share Posted April 3, 2017 Tourmaline pyrite is what I'm thinking of. I don't know if it would be seen in fractals on this scale or not. Link to comment Share on other sites More sharing options...
Plax Posted April 3, 2017 Share Posted April 3, 2017 very small cylindracanthus frag? just guessing of course... Link to comment Share on other sites More sharing options...
Fossildude19 Posted April 3, 2017 Share Posted April 3, 2017 I've got nuthin'! Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
Troodon Posted April 3, 2017 Share Posted April 3, 2017 The Ajuga Formation is definitely found in the area around Terlinga, it's Campanian in age, but I've only see it marked in maps of Big Bend park. Any chance you can sharpen your photo. Link to comment Share on other sites More sharing options...
EMP Posted April 3, 2017 Share Posted April 3, 2017 5 hours ago, Rockwood said: Just a cautionary note. There is a mineral, related to tourmaline I think, that has a similar crystalline structure. Tourmaline rarely forms in sedimentary rocks, especially schorl (which I think you're referring to?). It's more indicative of metamorphosed and igneous rocks. It could be a fragment of a schorl eroded down into the rock, but it appears to have a slight greenish tint to it, which could make it elbaite. Tourmaline's a tougher mineral and could resist the weathering and erosion, especially if the earlier bedrock formed in the area was metamorphosed igneous rock. it could also be a piece of bone/jaw calcium phosphate. We'll need better pictures. Link to comment Share on other sites More sharing options...
MSirmon Posted April 3, 2017 Author Share Posted April 3, 2017 2 hours ago, Plax said: very small cylindracanthus frag? just guessing of course... That is very interesting Don. Looking at some online photos it looks like it. So now the big question is how to differentiate between the two? Link to comment Share on other sites More sharing options...
EMP Posted April 3, 2017 Share Posted April 3, 2017 8 hours ago, Rockwood said: Tourmaline pyrite is what I'm thinking of. I don't know if it would be seen in fractals on this scale or not. It could appear as fractals at this size. In fact, there's an entire sub-sect of mineral collecting called micro mounting devoted to small crystals like this. The problem is pyrite would have likely oxidized into an iron oxide or hydroxide between deposition in the Cretaceous to now. Link to comment Share on other sites More sharing options...
Rockwood Posted April 3, 2017 Share Posted April 3, 2017 These have been in limestone since the Ordovician. Link to comment Share on other sites More sharing options...
MSirmon Posted April 5, 2017 Author Share Posted April 5, 2017 Let's see if these are more discernible. I dissolved the mud and found a few more items. I am attaching pictures. Link to comment Share on other sites More sharing options...
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