Lmshoemaker Posted December 29, 2012 Share Posted December 29, 2012 (edited) I come today with multiple questions. I don't know what formation these come from, but I am fairly confident in placing these in the new providence shale formation. I base this conclusion on numerous siderite nodules which are commonly found at the lower margin of the formation. My question is that I have no idea of the context in which these rocks were deposited, and this is what I am really curious about. I have a bit of information that might help if anyone here is good with paleoecology. In my back yard there is an exposure of clayey blue shales, many siderite nodules are present. No fossils present as far as I am aware. These rocks are overlain by a very thin layer of orange-ish brown chert which contains very sparse fossils, namely bryozoans and isolated crinoid ossicles. Overlaying this is a layer of what I think is limestone? It might be shale, see pictures. in this layer are sparse fossils, slightly more than the chert, and they are preserved as a thin brown crust? I haven't a clue as to why if you think you know please do tell? I have found the upper most layer elsewhere in a local forestry, I've found isolated ossicles in here, one siderite nodule containing a colony of bryozoans (picture soon). Also a layer of thick blue rock was found overlaying the layer in which I found the (skeletal) ossicles and bryozoan colony. When I fractured the rocks here there were massive amounts of crinoids, but they were preserved in the form of rust, the rust washes away very easily, it's almost like dust in a way. I have only two pictures, I shall get more when ever possible. Can anybody put this into paleoecological context? Edited December 29, 2012 by Cryptidsaurian Link to comment Share on other sites More sharing options...
piranha Posted December 29, 2012 Share Posted December 29, 2012 Can you provide limited locality detail (north, south, east, west) for the Indiana county you're collecting? Link to comment Share on other sites More sharing options...
Lmshoemaker Posted December 29, 2012 Author Share Posted December 29, 2012 (edited) Oh sure, southern indiana Jackson county. The forestry is called starve hallow, you should be able to find it on google maps. Edited December 29, 2012 by Cryptidsaurian Link to comment Share on other sites More sharing options...
Lmshoemaker Posted December 29, 2012 Author Share Posted December 29, 2012 Ok, I got them to finally upload to flickr, after having some technical issues: They are the top two images. http://www.flickr.com/photos/cryptidsaurian/ Link to comment Share on other sites More sharing options...
Lmshoemaker Posted December 29, 2012 Author Share Posted December 29, 2012 One other feature I forgot: It is common to find worm trails and worms themselves in the upper layers of these rocks. They kind of remind me of lobopods.. Link to comment Share on other sites More sharing options...
piranha Posted December 29, 2012 Share Posted December 29, 2012 I found a lot of open-access PDFs at google scholar searching for Borden Group + New Providence Shale: LINK A few of the papers could have valuable research info in the references. Hopefully it leads to something useful. Link to comment Share on other sites More sharing options...
Lmshoemaker Posted December 29, 2012 Author Share Posted December 29, 2012 I found a lot of open-access PDFs at google scholar searching for Borden Group + New Providence Shale: LINK A few of the papers could have valuable research info in the references. Hopefully it leads to something useful. Thanks, I'll have a look! Link to comment Share on other sites More sharing options...
Lmshoemaker Posted December 29, 2012 Author Share Posted December 29, 2012 (edited) So I've learned that the siderite nodules indicate low levels of oxygen, I can see how this would lead to few animals living in the water at the time these were deposited. At the same time I don't see why the fossils that are preserved are usually just traces and scraps... Edited December 29, 2012 by Cryptidsaurian Link to comment Share on other sites More sharing options...
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