Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: ricketts1 on 11/02/2010 00:39:41
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I friend found this rock in Bedford County, Virginia (Near Lynchburg) and we would love to know what it is. We appreciate any help! Thanks.
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I think you can rule out dinosaur bone, maybe fossilized coral ... http://www.thenakedscientists.com/forum/index.php?topic=16123.msg187221#msg187221
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Thats pretty interesting. It doesnt look like a natural texture that I am familiar with, so my first guess would be fossil. The geology around bedford county is pretty complex (at least for me...Bass or JimBob would make better sense of it), but I would imagine it is marine in origin and maybe Cambrian in age judging from the area it came from and primitivity of the organism (if it IS indeed an organism). Beyond that, I couldnt venture a guess.
JimBob?
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Contrariwise, I can't think of anything biological that would have produced such straight lines in such a collection of random orientations. Until one of our real geologists comments, I'd guess that we're seeing micro-fractures that have been subsequently been filled by hydrological deposition (or possibly intrusion). The location is a bit too far from the Chesapeake Bay impact crater for that to be the cause of the micro fractures, but then it is quite close to the Lewis range (and may have been brought further south from the northern extents by a glacier).
Purely guesswork though.
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It is actually an alien mewpaper manuscript stone I first encountered on one of the moons of Shazatar in the Elgordian System. Strange it should appear here on Earth. [;D]
Sorry I haven't been on for a while - tying to make my fortune and fight allergies.
AS FOR THIS:
Knox Group dolomite or limestone of Ordovician - and upper Cambrian - age.
Probable fossilized macrophytic filamentous algal strands These look like colonial algae that were the Cambro-Ordoviciian equivalent of today's grass. (No, not pot, Bass. I know that this is why you go to the "field" for "field work" all the time. got to tend that plot.)
Klep is a type of colonial algae.
This is the best guess I have.
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OK - I can't Stand it anymore!!!!
What you have is a vitamin D deficiency!
(rickets? - disease? Get it? Oh well.)
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JimBob, how'd you know? My uncle married my Dad's sister 60+ years ago. He use to say, "When I was a kid I had Rickets, when I grew up I married one".
Well, do you know what this fossil is JimBob?
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I presented the picture to my carbonate professor (it actually tied in with our lecture...amazing timing). He thinks they are indeed cracks (nice job LeeE...especially by a non-real geologist!), and they are marine in origin, though not from meteors or tectonism. He said they were likely dessication cracks in evaporite deposits on a tidal flat that were filled in and then flooded after a sea level rise. The carbonate that filled the cracks were preserved and the evaporites were dissolved in the process. This would have likely occurred during the Cambrian or Ordovician.
Its a pretty darned cool sample.
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Looks more like crossing strands than casts of cracks to me ...
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But I'm just "another non-real geologist".
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I thought the same thing RD, and still have my doubts about it being dessication cracks. The photo that I showed him was from my phone, so there was not much scale with which to see detail. I brought up the overlying strands, and he stated that he was about 90% certain that it was either differential depth in cracking or from multiple flood/evaporation events that occurred one atop the other. It was a texture that he was apparently very familiar with. Who knows. There are multiple interpretations for some features even among "real" geologists.
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It looks to me like a mat of crystals of the sort you sometimes get when you slowly evaporate a solution of some salts. What would I know- I'm a chemist rather than a geologist.
Incidentally, re. the title of the thread; fossils are natural rocks too.
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When the green guy - (AKA little green frethac) called to tell me what his professor said, my words were "I don't buy it."
I be with you RD and I are a real geologist.
BC, if it is a crystal grown from solution, why were the underlying ones not dissolved when the sub-strait was rehydrated?
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I don't know, but I could ask the same question about geodes.
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Geodes form from very hot, supersaturated waters. These "crystals" would need to be deposited in what we would think of as surface conditions. And it is evident from the photos that there are several different episodes of crystal formation - if these are solution derived features.
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Here's a closer image of the rock:
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it puts me in mind of a leaf, you know a decayed one, so fragile and delicate when all that is left is the bones and fine strands of the frame and nowt else. put a few of thoes ontop of each other and it could look like that
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OK - looks like crystals - BUT were the penecontemporaneous with formation or diagenetic?
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Am thinkin' y'all are a mite cerfused thar.
What you is a'seein is a petrificated string vest as worn by the famous Rab C. Nesbitt
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it puts me in mind of a leaf, you know a decayed one ...
Leaf skeleton ?
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Nah, rock pattern is not dendritic.
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Are we sure that those crystals arent clastics or spar?
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it puts me in mind of a leaf, you know a decayed one ...
Leaf skeleton ?
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Nah, rock pattern is not dendritic.
Leaves were not invented when this rock was laid down. And frethac, spar is crystalline by definition.
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JimBob, I think I was a little confused in the conversation. I thought you guys were considering that the lines were crystal growth.
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we were
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fair do's i understand that there were no leaves at that time ok but...... superimpose another leaf skeleton ontop of it and you get what i mean. it also puts me in mind af a piece of polystyrene thats been sprayed, the polystyrene melts the same as that.
as i have no understanding how crystals grow i can only gape in awe at what i would call a very cool rock.
good find that man