Teres Posted July 23, 2012 Share Posted July 23, 2012 I use muiratic acid, but.. I would rather one of the professionals here advise you on strength and usage. It only takes a few drops, still...there's a thread somewhere (I think) that deals with the specifics. I'll look later if no one chimes in. Link to comment Share on other sites More sharing options...
Auspex Posted July 23, 2012 Share Posted July 23, 2012 Vinegar will do, if you look closely for any reaction, and is very safe. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Roadrunner Posted July 23, 2012 Author Share Posted July 23, 2012 (edited) Vinegar will do, if you look closely for any reaction, and is very safe. Yes, I use vinegar to "clean up" some fossils. So, if I get any kind of reaction (bubbling) what will that tell me? And should I just use an eye dropper, or drop the whole piece in vinegar? Edited July 23, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
Bullsnake Posted July 23, 2012 Share Posted July 23, 2012 (edited) I would think drops on as pure a sample as possible, thinking that if there is any calcitic matrix residue, it will fizz. Having said that, I'm wondering (for my own learning as well) what the acid test is for, if she has determined hardness greater than calcite. Another reactive mineral, or to substantiate if it's calcified, or not? Edited July 23, 2012 by Bullsnake Steve Link to comment Share on other sites More sharing options...
Missourian Posted July 23, 2012 Share Posted July 23, 2012 BTW, the next clue I have is that the little piece I have will easily scratch glass - but will not scratch a quartz crystal. So that piece of material is between 5.5 (plate glass) and 7 (quartz) on the Mohs scale. Sounds like at least some of the stuff is silicified. Crystalline quartz should hold up to chert rock pretty well. It looks kind of 'cherty' to me as well. Context is critical. Link to comment Share on other sites More sharing options...
Herb Posted July 23, 2012 Share Posted July 23, 2012 If the hardness is near 6+ there is not too much that will fizz anyway. It looks like it's predominately chert. It is in several layers, the striated layer ( that I can't explain) and under that a bumpy/dimpled layer that resembles Stromatoporid layering. Did you see any growth lines in the edges? "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
Teres Posted July 23, 2012 Share Posted July 23, 2012 "Sounds like at least some of the stuff is silicified. Crystalline quartz should hold up to chert rock pretty well. It looks kind of 'cherty' to me as well" Thanks Missourian "cherty" was the word I was looking for . I wasn't sure if the scratch test was sufficient to determine if it was silicified or not. Link to comment Share on other sites More sharing options...
Roadrunner Posted July 24, 2012 Author Share Posted July 24, 2012 (edited) If the hardness is near 6+ there is not too much that will fizz anyway. It looks like it's predominately chert. It is in several layers, the striated layer ( that I can't explain) and under that a bumpy/dimpled layer that resembles Stromatoporid layering. Did you see any growth lines in the edges? The picture below (from the 3rd page in this thread) shows that the striated layers repeat themselves, as do the spongy or "dimpled" looking layers. Growth lines assume an organic source and to me the layers look that way because they seem to alternate between the striated and dimpled layers - but of course, that can also be a geologic / fossilization process. Sometimes growth lines are measured in microns, and that is something I can't see without equipment. Then there are these areas in the picture below, that look to me like the inside of a brachiopod - especially when you look at the middle area and see 2 circles within the outter concentric circles. I didn't hear from the museum today, but also don't know if my contact works every day of the week. So if I don't hear from him in a day or two I'll try reaching him again. Edited July 24, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
Herb Posted July 24, 2012 Share Posted July 24, 2012 Curioser and curioser ! Those lines look like fracture lines to me. "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
Roadrunner Posted July 24, 2012 Author Share Posted July 24, 2012 Curioser and curioser ! Those lines look like fracture lines to me. Are you referring to the first picture in the 2 above? Link to comment Share on other sites More sharing options...
glacialerratic Posted July 24, 2012 Share Posted July 24, 2012 The picture below (from the 3rd page in this thread) shows that the striated layers repeat themselves, as do the spongy or "dimpled" looking layers. Based on this photo, I'd agree with Teres -- stromatoporoid. I have a few pieces from MI. that are smooth on one surface and bumpy on the other. Here's another link: http://www.ucmp.berkeley.edu/porifera/stromatoporoids.html There are two main groups of fossil stromatoporoids that lived in different eras, the Paleozoic and the Mesozoic. The fossil record of the earlier group begins in the Ordovician and persists until the Early Carboniferous. After their appearance, the Paleozoic stromatoporoids quickly became dominant reef builders, and persisted as such for over 100 million years. They are absent in the fossil record between the Early Carboniferous and the Late Permian. The second group of stromatoporoids, from the Mesozoic, may represent a distinct group with a similar growth form. The Mesozoic stromatoporoids are again important contributors to reef formation, especially during the Cretaceous. Link to comment Share on other sites More sharing options...
Roadrunner Posted July 24, 2012 Author Share Posted July 24, 2012 Based on this photo, I'd agree with Teres -- stromatoporoid. I have a few pieces from MI. that are smooth on one surface and bumpy on the other. Here's another link: http://www.ucmp.berk...atoporoids.html That's what I keep coming back to, also. And I did find more marine fossils around there - not in the immediate area, but meters from there. It is a pretty interesting area, and I did confirm that it is not private property. Link to comment Share on other sites More sharing options...
Herb Posted July 25, 2012 Share Posted July 25, 2012 Are you referring to the first picture in the 2 above? no, I was thinking of the second picture. The lines look almost like an impact ctater. (looks like,not is) "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
Roadrunner Posted July 26, 2012 Author Share Posted July 26, 2012 (edited) OK - quoted from a palentologist from the Albuquerque Museum of Natural History, via e-mail. "Thank you for sending me all the photos. What you have in the photos is completely silicified---looks like it is totally replaced by chalcedony or opaline. I would like to see a broader shot of the whole boulder, like the jpg 721--but even farther out. i am puzzled by the wavy or corrugated lines in the chert--this looks like a impression of a fossil, something like Chaetetes, which is a bizarre sponge-like critter. So, send me a few more photos--shoot a bit farther way, and keep the rock hammer in there---and i will try and tell you more." I don't find a whole lot on Chaetetes, even on googlescholar.com, but I'm not giving up. And it sounds like the Chert opinion was right! If anyone finds out anything on these things, please advise. I will also let you know of any additional information that I get. Again - thank you, everyone! Edited July 26, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
Auspex Posted July 26, 2012 Share Posted July 26, 2012 LINK "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Roadrunner Posted July 27, 2012 Author Share Posted July 27, 2012 (edited) LINK Thanks - I'd seen those, but when I click on them there isn't a whole lot of information there, unless I'm missing something. Most of them are about books for sale on the subject. Edited July 27, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
Missourian Posted July 27, 2012 Share Posted July 27, 2012 If that indeed is Chaetetes, it would likely place the rock within the middle Pennsylvanian (upper Desmoinesian Stage of the Midcontinent). Context is critical. Link to comment Share on other sites More sharing options...
Auspex Posted July 27, 2012 Share Posted July 27, 2012 Thanks - I'd seen those, but when I click on them there isn't a whole lot of information there, unless I'm missing something. I thought the photos in THIS ONE might be interesting. Forms to compare, and perhaps to look for. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Roadrunner Posted July 27, 2012 Author Share Posted July 27, 2012 (edited) I thought the photos in THIS ONE might be interesting. Forms to compare, and perhaps to look for. Yes - I had examined those. Of course nothing will look exactly like what I've found but what I noticed on the pictures were that most of the striations were inside some other layer and/or had a predictable pattern - while the one I'm looking at the striations are on top and around the boulder - even in sometimes different directions. We had a deluge of rain yesterday - over an inch in a very short time (much needed), but it even uprooted trees so it may be a little longer than I'd planned to get back out there since I do have to travel down a deep arroyo. I must say it is strange to have more water in the dog water bucket than when I left it only a few hours ago, especially in NM. Thank you all for the continued help and support - I'll keep you updated. Edited July 30, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
TqB Posted July 27, 2012 Share Posted July 27, 2012 With Chaetetes, you might expect to see some pore structure, like a tabulate coral (which is what it was once thought to be). I think my money's on stromatoporoid at the moment... This is a partially silicified Chaetetes from the Namurian (= upper Mississipian) of northern England. Scale bar in 2nd pic = 1mm. Tarquin Link to comment Share on other sites More sharing options...
Auspex Posted July 27, 2012 Share Posted July 27, 2012 ...what I noticed on the pictures were that most of the striations were inside some other layer and/or had a predictable pattern - while the one I'm looking at the striations are on top and around the boulder - even in sometimes different directions... All objective observations are valuable. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Roadrunner Posted July 27, 2012 Author Share Posted July 27, 2012 All objective observations are valuable. You're absolutely right! Link to comment Share on other sites More sharing options...
Teres Posted July 27, 2012 Share Posted July 27, 2012 With Chaetetes, you might expect to see some pore structure, like a tabulate coral (which is what it was once thought to be). I think my money's on stromatoporoid at the moment... I'm not an "ologist" of any sort but I agree with TqB! Link to comment Share on other sites More sharing options...
Roadrunner Posted July 27, 2012 Author Share Posted July 27, 2012 (edited) I'm not an "ologist" of any sort but I agree with TqB! I'm even less qualified, and tend to agree. Yet the only porous looking material is underneath the striated material, which is also what seemed to somewhat confound the paleontologist. Thumbnail pictures; I'll go for more pics - probably on Sunday since I have to travel some tomorrow. Edited July 27, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
Roadrunner Posted July 28, 2012 Author Share Posted July 28, 2012 (edited) A close-up of the flat side; Thumbnail; Edited July 28, 2012 by Roadrunner Link to comment Share on other sites More sharing options...
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