Why Do Pennsylvanian Rock Formations Appear as Strips?

[Ms Music]

and now find myself sitting on top of an enormous fossil bed.

Lucky!

I have 4 days off work, (Thurs - Sun) so I will either a/ forget this thread completely, or b/ remember and post some pictures. Is it okay to post pictures of collections in this thread even though it is called "fossil and rock IDENTIFICATION"? Or should I use the old thread?

Evo, your swimming yams reminds me of one day at the ocean. There was a walkway cut through a small sand dune, and part of the dune also had collapsed to show the interior. Although it was sand, there were these orange clam looking blobs in the sand same as your picture. I always wondered how you could get orange blobs of sand mixed with normal sand. Probably completely different, but they look the same as your picture, none the less.

 

[Evo]

Lucky!

I have 4 days off work, (Thurs - Sun) so I will either a/ forget this thread completely, or b/ remember and post some pictures. Is it okay to post pictures of collections in this thread even though it is called "fossil and rock IDENTIFICATION"? Or should I use the old thread?

Collections are definitely ok.

Evo, your swimming yams reminds me of one day at the ocean. There was a walkway cut through a small sand dune, and part of the dune also had collapsed to show the interior. Although it was sand, there were these orange clam looking blobs in the sand same as your picture. I always wondered how you could get orange blobs of sand mixed with normal sand. Probably completely different, but they look the same as your picture, none the less.

I wonder what they are?

 

[cousin it]

This looks like a textbook example of 'tafoni' weathering in rocks. This type of weathering pattern occurs in 'case hardened' rock where the hardened outer surface is somewhat more reisitant to weathering than the softer interior. Nice example.

That is not "tafoni" weathering. I agree with the earlier respondent that it is some kind of cnidarian. Take a hammer and give it a good whack... let us see a fresh surface.

 

[cousin it]

A ventral and a dorsal of an asaphid trilobite(Isotelus gigas).
Ordovician of Kentucky
http://www.flickr.com/photos/30726183@N05/5423389797/

 

[Evo]

That is not "tafoni" weathering. I agree with the earlier respondent that it is some kind of cnidarian. Take a hammer and give it a good whack... let us see a fresh surface.

Definitely not a sponge (cnidarian).

http://www.google.com/search?aq=&rl...ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi

 

[phlip180]

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?

 

[Evo]

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]

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]

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.

 

[Evo]

Bigger pics? You can send me the files.

 

[dlgoff]

Bigger pics? You can send me the files.

Done. Thank you.

 

[Evo]

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]

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.

 

[Andre]

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]

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.

 

[Evo]

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.

 

[chemisttree]

Is the fracture surface also light?

 

[dlgoff]

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.

 

[chemisttree]

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?

 

[dlgoff]

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]

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?

 

[ngruman]

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".

 

[Evo]

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]

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.

 

[dlgoff]

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

I need a spectrometer Andre. I did a "flame test" with a propane torch directed on a small area of the edge; no change in flame color.

 

[Andre]

I need a spectrometer

I just happen to know that Lisab has one; working with it daily.

 

[dlgoff]

I just happen to know that Lisab has one; working with it daily.

Really? I would send the rock to her if she were interested. What a deal.

 

[dlgoff]

When I was a kid I, boxed and stored some of my rocks at my parents house. I discovered them a couple of days ago while going through an old shed; hence the bump.

The boxes where still taped as I had left them and since I hadn't seen then for a long time, it was like opening Christmas presents. Here a couple pic I just took.

http://imageshack.us/a/img41/5697/q84a.jpg

http://imageshack.us/a/img69/6713/atgl.jpg

 

[Evo]

Oooh, very nice rocks and fossils! They are digging near here ( 2 blocks away) and have a mountian of fossil rock and with the cooler weather that's hit, I'm going to go down there and do some fossil picking.

 

[dlgoff]

Do you know what this fossil is? A plant or a fish?

http://img11.imageshack.us/img11/5614/08hz.jpg