fossils4fun Posted September 5, 2014 Share Posted September 5, 2014 Hi, I found this and thought it was interesting. The rock is sandstone and the sunken spot is very smooth. Any input will be great. My pictures aren't very good, sorry, thanks Link to comment Share on other sites More sharing options...
Fossildude19 Posted September 5, 2014 Share Posted September 5, 2014 Pictures look good to me. Where was this item found? Regards, 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...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 In Arkansas I don't know how old it is. Link to comment Share on other sites More sharing options...
fossilized6s Posted September 5, 2014 Share Posted September 5, 2014 (edited) That looks like a piece of Softshell Turtle shell, but it's SO THICK!! I've never seen a Softshell turtle frag so thick. Let's see what others say. Edit: here's a link http://www.empireoftheturtle.com/Fossils/apalone.htm Edited September 5, 2014 by fossilized6s ~Charlie~ "There are those that look at things the way they are, and ask why.....i dream of things that never were, and ask why not?" ~RFK ->Get your Mosasaur print ->How to spot a fake Trilobite ->How to identify a CONCRETION from a DINOSAUR EGG Link to comment Share on other sites More sharing options...
tmaier Posted September 5, 2014 Share Posted September 5, 2014 The surface is exactly like Trionyx, but the flatness, thickness, and lack of structure in the cross section makes me think it is more likely ripple patterns in mud. Cross section of Trionyx... Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Wow, that really looks similar, thanks for the link! It is very thick, you are right. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Someone else said it was ripples in mud and that makes sense too, what about the smooth sunken spot? Link to comment Share on other sites More sharing options...
tmaier Posted September 5, 2014 Share Posted September 5, 2014 At first I was going to say the flat spot was a chip-out from a percussion to the side of the rock, but it shows no percussion ripples. Also, notice that the mud ripples follow the curve of the depression. That seems to indicate that the depression was there at the time when the mud was wet. So I think the depression was made by a very tired allosaur who sat down to catch his breath, and that is an impression of his butt cheek. Look very closely at the surface for signs of other things that you may find at the beach, such as embedded shell or trails of animals crossing the mud. If it is a mud ripple surface, it's a nice one. I'd keep it. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Thanks, I have included a picture of the back, it does have a tiny something. Also, I don't know if you can see it but the side is kind of shiny. Link to comment Share on other sites More sharing options...
Auspex Posted September 5, 2014 Share Posted September 5, 2014 I think they are ripple marks, and I think that this slab was oriented face-down; a cast of the original marks, formed in the overlying layer of sediment. This would make the smooth dimple a raised object, perhaps a water-smoothed cobble exposed in the rippled mud. A very low-energy deposition, in any case, and very cool! "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...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Thanks Link to comment Share on other sites More sharing options...
tmaier Posted September 5, 2014 Share Posted September 5, 2014 The last item that would round out the cool factor is to find out the approximate age of it. The ripples were probably made all in one day back millions of years ago, so that is cool. Then you could buy some of that felt with sticky on one side, apply it to the back, and it becomes a table decoration and conversation piece. Write "ancient mud ripples from Cretaceous period" or whatever period it is from on a label on the back. And I'm really disappointed that Auspex didn't agree with my allosaur theory. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 That is cool, I feel really dumb asking this but how do you find out the age? Link to comment Share on other sites More sharing options...
Carl Posted September 5, 2014 Share Posted September 5, 2014 I agree that is more sedimentary than biomorphic but I can't see them as ripple marks. They exhibit more disarray than do ripple marks. I don't really have an alternative suggestion, not being a sedimentologist, but I feel like I've seen examples like this called something else. Either way, it is an extremely beautiful and interesting piece! Link to comment Share on other sites More sharing options...
squali Posted September 5, 2014 Share Posted September 5, 2014 I agree the lack of symmetry is not indicative of ripple marks. It kind of looks like a cast of weathered bryozoan formed as Auspex suggested. A narrower location than just Arkansas may help with the ID. It is a very interesting piece. It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Thank you, I love all these comments. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Well it is in Northwest Arkansas in Washington County. Link to comment Share on other sites More sharing options...
tmaier Posted September 5, 2014 Share Posted September 5, 2014 Ripple marks are formed by water movement, and convoluted rippled are formed by convoluted water movement. When the wave source is unidirectional you find those parallel ripples. A veering wind creates surface waves that break up the pattern and you can get some very complex pattern forms. Here's a collection of ripples... http://natureinfocus.wordpress.com/2014/06/13/more-about-joggins-fossil-cliffs/ Link to comment Share on other sites More sharing options...
Auspex Posted September 5, 2014 Share Posted September 5, 2014 ...I'm really disappointed that Auspex didn't agree with my allosaur theory. You overlooked the fact that there are no feather impressions. "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...
squali Posted September 5, 2014 Share Posted September 5, 2014 http://libinfo.uark.edu/aas/issues/2002v56/v56a12.pdf this is a link to the university of Arkansas library pdf with the most recent geology of the West Fork Quadrangle Washington County It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Thanks for the link, very informative. Link to comment Share on other sites More sharing options...
Auspex Posted September 5, 2014 Share Posted September 5, 2014 Ripples like these are the result of gentle omni-directional sloshing. A positive clay impression would look more natural, with broad, round-bottom valleys and narrow, sharper ridge tops. "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...
tmaier Posted September 5, 2014 Share Posted September 5, 2014 Well it is in Northwest Arkansas in Washington County. Oh-oh, this calls for another trip in the Way-Back Paleoportal... Please adjust your goggles and hang on. Keep arms and legs inside the vehicle at all times. http://www.paleoportal.org/index.php?globalnav=time_space We dial in Arkansas and find... http://www.paleoportal.org/index.php?globalnav=time_space§ionnav=state&name=Arkansas ... we are back in the Carboniferous, about 360 million years in the past. Our Official Tour Guide from Paleoportal tells us " During the Early Carboniferous, limy sediments accumulated in a shallow sea that covered what is now northern Arkansas. This sea was home to brachiopods, crinoids, and bryozoans. Deeper waters covered the central and southern portions of the state at this time. As rivers and streams eroded the continent, clastic sediments began to accumulate on top of the shallow water deposits, further reducing the water depth. Fossils of ammonites and of plants that washed in from the land, as well as trace fossils, can be found in these rocks. By the Late Carboniferous, the sea receded, exposing new land drained by numerous rivers. These rivers washed sand and mud into the deeper water that remained over what is now central and southern Arkansas. The sandstone and shale that formed from these sediments contain rare ammonites, plant fossils, and trace fossils. South America collided with Arkansas during the Late Carboniferous. This tectonic activity caused the folding and faulting of earlier-formed rocks into the Ouachita Mountains in central Arkansas." So it's kind of swampy... keep your boots on. OK, the ride is over... time to go home. Everybody OK? Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 Squali, Thanks for the link, it talks about Cane Hill which is close to me. I love it. This will make for some very interesting reading. Link to comment Share on other sites More sharing options...
fossils4fun Posted September 5, 2014 Author Share Posted September 5, 2014 tmaier, Thanks so much, I have been looking for a map like this for a long time. This info is great, thanks again! If anyone wants to send me anything it is greatly appreciated, I love to learn about the fossils in my area. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now