Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: JDMcGee on 21/11/2008 23:18:57
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Hello fellow earth scientists and enthusiasts!
I would like to say I have been on this forum for roughly five minutes now, and I have high hopes for this place. An internet forum where I can converse with people interested in the same subjects as myself is very exciting to me. That aside, time to get down to my question(s).
Has anyone on this forum done extensive study on this formation? If so, would you be willing to share your knowledge on the subject?
If anyone else is interested in this formation, or just the Cumberland Plateau in general, feel free to post in this topic.
-James
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Welcome to the forum!!
Hard-rocker though I may be, I'll take a fling at this. I do have some familiarity with Cumberland Plateau, having spent my undergraduate years in Nashville and living for a year in Quebec, TN on the western edge of the plateau. If I recall, the Suwannee Conglomerate is lower Pennsylvanian, and composed mostly of quartz pebbles in a medium-grained sandstone matrix. Serves as a cap rock in several areas if my memory hasn't faded completely.
But extensive study- no.
The Cumberland Plateau is an amazing place. Spent several years on rivers there (including several trips down the Obed) and more time than I should have fooling about in caves.
What is your interest in the Suwannee Conglomerate and the Cumberland Plateau?
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Hey Bass thanks for the welcome!
Your memory for the most part serves you correctly my friend. As always, the formation is more complex than we think it is at first. Important features in the formation include (typically) eroded clay intraclasts, intermittent coal layers, as well as the lisegang banding present in both the Sewanee and the Warren Point Sandstone. It is a cap rock in areas around the University of the South, which is (for the most part) where I am conducting my study.
As for the Plateau, it is an amazing place haha :D. I love it up here, all the caves are loads of fun when I have spare time.
My interest in the Sewanee Conglomerate is both personal and educational. I am working on a study of the area from the perspective of a sedimentologist. I am looking specifically at diagenetic features, provenance, and whatnot. It is going to take me a few weeks to get all the data I have been assembling for the past few months into some coherent form. This thread is both to inform others as well as to receive input from anyone interested in the topic with experience to share.
-James
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Sounds like an interesting investigation- keep us up to date on your research, it's always fun to learn something new.
Back in ye olde triassic days, when I was a wet-behind-the-ears geology undergrad, I did a study on the Ft. Payne formation- trying to correlate the chert layers with appalachian volcanic eruptions. Age dates at that time were not accurate enough to make the correlation, but I always wondered if the chert may have been from silica-shelled organisms that might have flourished during active volcanism. Saw a Ft. Payne specimen from Lookout Mtn area with what appeared to be pumice fragment. With 30+ years experience, though, I might view it differently now??
And pay no heed to JimBob, the poor guy was born sometime in the Proterozoic and tends to drift a bit when he forgets his Alzheimers pill.
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James - Jim Here - very glad to see you on the forum and a hearty WELCOME! (I need more sedimentologist to compete with this hard hock now-it-all, Bass. by the way, I am the resident curmudgeon here as well, so that spot is take. GERRRRRRR!)
I held some Suwannee Conglomerate in my hand this September. I asked the geologist I was with "what is this?" and his answer was - oh, a conglomerate we find all over the place. Nothing special." Looking at the rock I couldn't have agreed less. And Bass, even with Alzheimers I can still recognize pumice and you are correct. There could be some in it. The problem being that pumice was in the Suwannee Conglomerate. Now the poser here is that to the northwest, near London, Ky where I was, the Fort Payne Chert is no more just chert, but becomes in part a conglomerate itself, possibly being of tubiditic origin as suggested by Johnson, Krissek, and Ausich, 2003. Thus, the Miss. pumice would have had to have floated into the area or incorporated in some other way into the shale and carbonate matrix, and redeposited in the Suwannee Conglomerate I found it in and picked up. I didn't have room in my luggage to bring it back with me on the plane or I would have kept it.
BUT all is not lost! It is possible I may be going back up to Kentucky to further evaluate and plan exploitation of some of the potential Rome Trough gas fields that the geologist I was visiting with has leased. This would occur, if it happens, about a week from Monday. If I can't get a sample, I'll get a picture - if I can remove enough snow to get to the rocks. The area around London has a considerable amount on the ground, I understand.
F.Y.I, BASS, I was born during the Cryogenian System of the Neoproterozoic Era. It is why I am so well preserved (get it? Ice , all that? oh well, back to my cell.)
(sighs and drags his ball and chain to his cell)
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Haha well then Jim I hope you get a good sample of conglomerate in SE Kentucky. I would really like to know what it is like up there. Could you bring your Braunton compass (I assume you have something suitable if not a Braunton) and marble along with a field notebook? Some paleocurrent readings would be appreciated. Also if you find some scour surfaces or lag deposits take pictures. I hate to convert you into my field agent, but I don't have the time or opportunity to head up to Kentucky at the moment. If you do go up there take a bunch of pictures of the Sewanee. I would appreciate it if you sent 'em to my email, or posted them up here or whatever. The prospect of more data is very exciting to me. I have good evidence supporting an orogenic provenance, as some of the zircons I have seen are from at least 1 bya, likely from up in the Canadian Shield. As you are probably aware, there was a massive braided fluvial system that ran up against the Apps roughly 300 ma, when they were bigger than the mighty Himalayas. But that is the neat part. If that zircon analysis is correct, the Appalachians were a recycled orogen already 300 ma!
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So no one cares about the Cumberland Plateau and the conflicting interpretations of its environment of deposition? There are really only 4 that I know of, and of those 4, the only truly plausible models are the littoral model and the view I believe is most likely (due to the prevalence of unimodal paleocurrent directions and the lack of marine fossils), the braided stream model. Some sources on the subject if you are interested:
Bergenbeck, R.E., 1987, Carboniferous depositional environments in the Southern Cumberland Plateau: Tennessee Division of Geology, Report of Investigations 37, p. 63-86.
Bergenbeck, R.E., 1993, Lower Pennsylvanian-Upper Mississippian deposystems, Monteagle Mountain, Tennessee: Journal of the Tennessee Academy of Science, V. 68, No. 3, p. 94-98
Hurd, S.A., and Stapor, F.W., 1997, Facies, stratigraphy, and provenance of the Warren Point Sandstone (Pennsylvanian), Cumberland Plateau, Central Tennessee: Southeastern Geology, V. 36, No. 4, p. 187-201
Milici, R., 1974, Stratigraphy and depositional environments of Upper Mississippian and Lower Pennsylvanian rocks in the Southern Cumberland Plateau of Tennessee: Geological Society of America Special Paper 148, p. 115-133
I have more if you want, but most people probably don't have access to these unless they reside in the SE USA or live near a university library that has an EXTENSIVE periodicals section.
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You will get over it, JD. There are so many cool things in geology and sedimentology you will learn that if you get this wrapped up in one thing then you will exhaust yourself endlessly.
HOWEVER! - This is the type of passion you needed to do a graduate thesis or dissertation so don't let go of it for that one special project that no one has answered to anyone's satisfaction.
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Sorry that it's taken a while to get back to you JDM-
You've got a fascinating project going, and I agree that the braided stream model is most compelling- especially with the Allegheny orogeny shedding copious sediments off to the west. Provenance would be particularly interesting, especially in light of the continuing debate surrounding continent-to-continent vs possible exotic terrain collision that initialized the Allegheny orogeny.
Clay interclasts? Coal seams? Almost seems an oxymoron for such an active system as braided streams. 1000 million yr old zircons do present a provenance problem- any sedimentological evidence for source rocks from the north or northeast?
Haven't had the chance to check your references, but will get to the library one of these days. Keep us informed on your progress- intersting stuff.