Fossil and rock identification


by Evo
Tags: evo, fossil, fossils, identification, rock
Evo
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#37
Oct12-12, 11:23 PM
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Quote Quote by phlip180 View Post
I can't tell if it's just the angle the picture is taken from, but it looks like the holes are more concentrated in certain areas than others. Is that an accurate assessment or am I just imagining things?
I'll try to get better pictures from all angles. Yes, the holes are not over the entire rock. I just found a large boulder that has a lot of little "pockmarks" all over it, but nothing like the holes on this rock, I'll get more pictures this week, we're expecting severe storms tomorrow.
phlip180
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Oct13-12, 10:59 AM
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I have seen a lot of rocks like that in Missouri. I've noticed they tend to be, or come from, large boulders. Since they're sedimentary and found in the midwest, I assume they were probably formed during the Mississippian Period, when the midwest was underwater. That's all I know about them so far, and you might have already known all that, or have a different theory. I'm going to a nature center this weekend, so I'll do a little research while I'm there.
dlgoff
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Nov5-12, 03:48 PM
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I was tamping the dirt around some fence post in preparation to re-stretch the wire when I heard a clank. This is what I pulled out of the ground. It's about 4 1/2 inches long and weights about 10 ounces. I checked with a magnetic, but it's not ferrous.



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tamprock1.jpg   tamprock2.jpg  
Evo
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Nov5-12, 09:33 PM
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Bigger pics? You can send me the files.
dlgoff
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Nov6-12, 09:27 AM
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Quote Quote by Evo View Post
Bigger pics? You can send me the files.
Done. Thank you.
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Nov6-12, 11:37 AM
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Quote Quote by dlgoff View Post
Done. Thank you.
I've seen that weird yellow-orange stuff coming out of rocks before, but I'll have to look again.

I'm so disappointed that so many fossils and fossil rocks posted online either have no pictures or just black and white drawings, many just have a written description, which is SO ANNOYING.
dlgoff
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Nov6-12, 01:24 PM
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Quote Quote by Evo View Post
I've seen that weird yellow-orange stuff coming out of rocks before, but I'll have to look again.

I'm so disappointed that so many fossils and fossil rocks posted online either have no pictures or just black and white drawings, many just have a written description, which is SO ANNOYING.
That yellow-orange stuff is very hard which was surprising to me and after looking even closer, could be something fossilized. And from the weight, I thought it surly had iron in it.

Thank you for looking.
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Nov7-12, 06:49 AM
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Quote Quote by dlgoff View Post
I was tamping the dirt around some fence post in preparation to re-stretch the wire when I heard a clank. This is what I pulled out of the ground. It's about 4 1/2 inches long and weights about 10 ounces. I checked with a magnetic, but it's not ferrous.



Any progress? The bluish greenish hue may indicate copper. Have you considered bornite or maybe chalcite

Just my
chemisttree
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#45
Nov7-12, 01:05 PM
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It looks like a fine-grained slate or shale but it could also be a basalt. The dark color of the fracture surface suggest it could be a mafic basalt or pyroxene. The orange could be manganese compounds (manganese oxide is orange) or iron oxides, both present in mafic basalts. If you look closely at a freshly fractured surface do you see small white veins of mineral? Just to the west of where I live near San Antonio is an intrusion of basalt that is richly veined with magnesium compounds. When mined and processed into gravel, piles of this material leach out the magnesium when it rains producing puddles of white magnesia everywhere.
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Nov7-12, 01:09 PM
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Quote Quote by chemisttree View Post
It looks like a fine-grained slate or shale but it could also be a basalt. The dark color of the fracture surface suggest it could be a mafic basalt or pyroxene. The orange could be manganese compounds (manganese oxide is orange) or iron oxides, both present in mafic basalts. If you look closely at a freshly fractured surface do you see small white veins of mineral? Just to the west of where I live near San Antonio is an intrusion of basalt that is richly veined with magnesium compounds. When mined and processed into gravel, piles of this material leach out the magnesium when it rains producing puddles of white magnesia everywhere.
DL sent me more pictures, they are actually light colored stones and the "blue" color was a problem with the camera lighting.
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Nov7-12, 06:37 PM
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Is the fracture surface also light?
dlgoff
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Nov7-12, 08:39 PM
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Quote Quote by chemisttree View Post
Is the fracture surface also light?
The light was from one of those CFLs causing is to appear bluer than it is. Here's two taken in sunlight.



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Nov7-12, 10:47 PM
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Now it looks like a fossilized rhino horn! So I take it the fresh fracture surface (facing down (!) in both pics) is light colored in the brighter light?
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Nov8-12, 10:26 AM
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Quote Quote by chemisttree View Post
Now it looks like a fossilized rhino horn! So I take it the fresh fracture surface (facing down (!) in both pics) is light colored in the brighter light?
Actually it's cross section is more triangular shaped.

Side 1



Side 2



Side 3 (bottom)

ngruman
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Nov8-12, 04:45 PM
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Quote Quote by Evo View Post
This is what I call "swimming yams". Any guesses?
Your "swimming yams" look like rip-up clasts from some sort of flow - based on how they are aligned. Do you happen to know what the matrix is surrounding the yams? And what are the yams made out of?
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Nov8-12, 04:54 PM
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Quote Quote by Evo View Post
Notice the empty indentations? That's where yams fell out.

Normally, the fossils are the usual hard white substance. But I have found a large number of rocks recently where the fossils are of a soft, crumbly orange substance. These are all from this area, both the white and the orange. I'm wondering what the orange yam like fossils could be.

Here's an orange fossil of possibly a crinoid?
You have a trace fossil here called a worm burrow where a critter crawled through the carbonate mud and the void space that was left was then subsequently filled by sand that has been loosely cemented. Unfortunately, it isn't possible to tell exactly which sort of critter made the burrow; however, more questions could be answered if it was possible to tell which direction was stratigraphically "up".
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Nov8-12, 05:31 PM
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Quote Quote by ngruman View Post
You have a trace fossil here called a worm burrow where a critter crawled through the carbonate mud and the void space that was left was then subsequently filled by sand that has been loosely cemented. Unfortunately, it isn't possible to tell exactly which sort of critter made the burrow; however, more questions could be answered if it was possible to tell which direction was stratigraphically "up".
This one is definitely a crinoid. I've found others that confirmed it.
Evo
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Nov8-12, 05:36 PM
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Quote Quote by ngruman View Post
Your "swimming yams" look like rip-up clasts from some sort of flow - based on how they are aligned. Do you happen to know what the matrix is surrounding the yams? And what are the yams made out of?
I'll verify the rock they're in tomorrow. The yams look like clay.


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