Miket Posted May 14, 2018 Share Posted May 14, 2018 Found this in Western South Dakota, someone suggested it might be Stromatolites? Anyone know? Thanks! 1 Link to comment Share on other sites More sharing options...
GeschWhat Posted May 14, 2018 Share Posted May 14, 2018 Welcome to the forum. I don't know what it is, but I'm sure someone here will. Very interesting! Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
DPS Ammonite Posted May 14, 2018 Share Posted May 14, 2018 Welcome to the Fossil Forum. It is not a stromatolite since they are solid layered structures that are not likely to fall apart and create the little bits and pieces that you see. Where is the rock from? A specific locality will help with ID. Are the white areas calcite or quartz? A good guess based on overall folded "cornflake" shape: Phylloid algae. http://www.lakeneosho.org/King1Pic157-Tech.html https://en.m.wikipedia.org/wiki/Stromatolite 2 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
Miket Posted May 14, 2018 Author Share Posted May 14, 2018 I'll try to get a better picture, I believe the white areas are calcite- I'm fairly new to all of this so I'm not really sure. I do know that it isn't quartz. I found it in Fairburn, SD, actually. Out looking for Fairburn Agates and it caught my eye. As can be seen from the photos, the top part is raised and very textured, it's super interesting... I'll also research the Phylloid algae, thanks! 1 Link to comment Share on other sites More sharing options...
abyssunder Posted May 14, 2018 Share Posted May 14, 2018 It reminds me of Coquina . (Coquina jasper/agate ?) 1 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted May 14, 2018 Share Posted May 14, 2018 Hello, Mike, and a very warm welcome to TFF from Morocco! Looks like mineral banding to me.. if it's not part of the famous agates from around that area then some calcitic layering or it may be coquina as abyssunder suggests. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
ashcraft Posted May 14, 2018 Share Posted May 14, 2018 You can test for calcite by dropping vinegar on it. Calcite will fix. Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
ynot Posted May 15, 2018 Share Posted May 15, 2018 3 hours ago, ashcraft said: Calcite will fix. Calcite will fizz. Can You scratch it with a knife? Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
FranzBernhard Posted May 15, 2018 Share Posted May 15, 2018 This one sprang immediately to my mind, coquina made of congeria bivalves from Fohnsdorf, Styria, Austria (Carpatium). Wide of polished specimen 14 cm. (Just for comparision and to show off a nice local fossil-rock ). Franz Bernhard 2 Link to comment Share on other sites More sharing options...
Miket Posted May 15, 2018 Author Share Posted May 15, 2018 That does look similar, I haven't had a chance to try vinegar or a scratch test yet... Link to comment Share on other sites More sharing options...
DPS Ammonite Posted May 15, 2018 Share Posted May 15, 2018 1 hour ago, FranzBernhard said: This one sprang immediately to my mind, coquina made of congeria bivalves from Fohnsdorf, Styria, Austria (Carpatium). Wide of polished specimen 14 cm. (Just for comparision and to show off a nice local fossil-rock ). Franz Bernhard @FranzBernhard Franz, I think that you have a very interesting rock (much more interesting than a coquina) and would love to know more about it. I am having a hard time seeing the shells since you call it a coquina. I find it hard to understand how shells could be folded into S shaped folds without breaking into pieces. I think that it looks like a layered rock (shale and carbonate?) that was deformed before the layers were lithified. It is also known as soft sediment deformation. See: https://www.sciencedirect.com/science/article/pii/S2095383616300530 1 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
abyssunder Posted May 15, 2018 Share Posted May 15, 2018 for comparison: Coquina jasper 1 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
FranzBernhard Posted May 16, 2018 Share Posted May 16, 2018 @DPS Ammonite, I don´t unterstand it, too! In my picture, the S-shaped forms are made of carbonate, some black parts in beween are shale or coal. Google for "Fohnsdorfer Muschelkalk", you will find a specimen with more (carbonatic) matrix. Matrix can be shaley or carbonatic, the rock forms an up to 3 m thick layer immediately above a thick subbituminous coal seam and was used as building stone. Very rarely, you can find thin coal layers betweeen the shell layers (unfortunately not a very good photo, wide of specimen ca. 7 cm). Addition: Here is a paper about the area, unfortunately in german: http://www.sediment.uni-goettingen.de/staff/dunkl/zips/Sachsenhofer-et-al-2010.pdf For the rock in question, see pages 32 and 34. Franz Bernhard 1 Link to comment Share on other sites More sharing options...
supertramp Posted May 16, 2018 Share Posted May 16, 2018 What’s the size of the specimen? It resembles some of the so many “marble” known in Italy as “lumachella”, which actually are bioclastic limestones; don’t know if it corresponds to the spanish coquina https://www.google.it/search?q=lumachella+ancient+rome&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjgksCvhorbAhVFWxQKHb-wA5cQ_AUICigB&biw=1517&bih=707#imgrc=DU4PqSBZUgFxvM: ciao Link to comment Share on other sites More sharing options...
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