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Patterns in shale... Are these geologic fossil records?


CAtoPA

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Hello Pros!

While hiking along Indian Creek Trail in Northampton, PA, (southeastern PA)... I noticed that some of the shale along the river looked like it was once a river bank, or the shore along a beach. It's all stone, but looks like water is moving sand/silt into those little mounds you see anytime you're at a water's edge.

Does anyone know what era this would be from? I took photos, as the pieces were probably around 500# or more, soooo... about 5xs my weight! I wanted to carry it home, though! It looks really beautiful.

post-22024-0-35032700-1469111141_thumb.jpg

post-22024-0-94932400-1469111154_thumb.jpg

Thanks in advance for any info you all can give me! I just want to understand the area better.

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This is a trace fossil(?) called ripple marks. They form under water or at the water's edge.

I do not know why they are considered a fossil since they are not a structure created by the action of a biological critter.

Others should be able to narrow the age.

Tony

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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If they are ripple marks,you can't use them for dating,as a matter of definition.They're not confined to (a) particular (part of) the stratigraphical column.

They're non-biogenic sedimentological structures.

And: a very COOL FIND :D

Edited by doushantuo

 

 

 

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If they are ripple marks,you can't use them for dating,as a matter of definition.They're not confined to (a) particular (part of) the stratigraphical column

This is true, but they can be dated by the formation if it is known.

Tony

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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If they are ripple marks,you can't use them for dating,as a matter of definition.They're not confined to (a) particular (part of) the stratigraphical column.

They're non-biogenic sedimentological structures.

And: a very COOL FIND :D

Thanks! I thought they were interesting. :)

This is true, but they can be dated by the formation if it is known.

Tony

I'm not sure how to find out about the area. I'm going to need to join a geology or fossil club in this area!!

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I'm not sure how to find out about the area. I'm going to need to join a geology or fossil club in this area!!

You can look at some geological maps of the area to try and find the ages/formations in the area.

Tony

PS Joining a local club is a good idea, because they often have collecting trips to good locations. and lots of members to help ID things.

Edited by ynot

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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Search your location (e.g. your county) on the US Geological Survey. For example:

maverick county texas usgs

I always check wiki, though doushantuo disapproves. ;-)

https://en.m.wikipedia.org/wiki/Paleontology_in_Pennsylvania

I mean, here's but one example of priceless knowledge from the above wiki article.

"Local Delaware people used to smoke mixtures of fossil bones and tobacco for good luck and to have wishes granted."

I am going to test this scientifically right now. Not sure I have any tobacco, though. Or fossil bones.

Edited by CraigHyatt

Info: Craig Hyatt, retired software/electrical engineer

Experience: Beginner, fossil hunting less than a year

Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert

Formation: Escondido, Marine, Upper Cretaceous

Materials: Sandstone, Mudstone, Shale, Chert, Chalk

Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus

Reference: http://txfossils.com/Txfossils.html

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The overall picture looks like wave ripple marks. On closer examination, I see small patterned gouges that are telling me more like sedimentary mud flutes.

In New York Upper Devonian Shales, we see a lot of sedimentary structures from simple Ripple marks to complex submarine activity. Commonplace rock have very curious features that one can get to recognize quickly. Using Google Image you will see examples of things like: Turbidites, Seismites, Convolutes, Cross Bedding, Load casts, Flute casts, Ripple marks, Septarian nodules. All these things make for an interesting walk along creeks looking for fossils or traces.

Edited by fossilcrazy
  • I found this Informative 2
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Thanks, Doushantuo! The first document is very interesting! The second one is cool, but hard to read, ha ha. Thank you so much!! I'll check out the last one, too... I do live in the Lehigh Valley, so this should be very informative!! I appreciate your help!!

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This is a trace fossil(?) called ripple marks. They form under water or at the water's edge.

I do not know why they are considered a fossil since they are not a structure created by the action of a biological critter.

? I have not heard that ripple marks are called fossils or even trace fossils, since as you say they are not created by a living critter.

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? I have not heard that ripple marks are called fossils or even trace fossils, since as you say they are not created by a living critter.

You are correct Wrangellian, in that the "fossils" are not Biological in origin, and would not fit the definition of fossils. We can cut some slack for the folks just familiarizing themselves with our topic. I for one have called "fossil raindrops" knowing darn well they would not be fossils or even Pseudofossils. It's unscientific, but we all understand jargon or folklore terms for natural items having been described and a formal nomenclature been assigned. I laugh at myself for ideas and concepts I held while an ignorant newbie. It wasn't being an idiot, it was using what I knew to explain what I didn't know. I guess after all, that is kind of what science does.

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Yes, I know lots of things are called fossil-this or fossilized-that, but I thought Tony (or the source he might be quoting) was beyond just familiarizing himself with the topic...

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Yes, I know lots of things are called fossil-this or fossilized-that, but I thought Tony (or the source he might be quoting) was beyond just familiarizing himself with the topic...

Personally, I consider it jargon. Not technically correct, but gets the point across without being unwieldy. Sort of like when people talk about their "disc drive" being full even when it's solid state and has no discs or drive. But that's just me.... not a big stickler for precision as long as everybody gets the gist and has a good time. :-)

Info: Craig Hyatt, retired software/electrical engineer

Experience: Beginner, fossil hunting less than a year

Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert

Formation: Escondido, Marine, Upper Cretaceous

Materials: Sandstone, Mudstone, Shale, Chert, Chalk

Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus

Reference: http://txfossils.com/Txfossils.html

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? I have not heard that ripple marks are called fossils or even trace fossils, since as you say they are not created by a living critter.

I have seen "Park guides" call them (and things like sand dunes) "fossils" of an ecosystem. (It never made sense to Me).

Yes, I know lots of things are called fossil-this or fossilized-that, but I thought Tony (or the source he might be quoting) was beyond just familiarizing himself with the topic...

That is why I put a question mark in the sentence. Thank You for clarifying the matter!

It is one of the drawbacks to never having taken a course in geology or paleontology, I have to trudge through the mud of misinformation out there.

Tony

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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some etymology:

a Fossil is (original meaning): "anything dug up".

So:anything coming out of the ground.

and remember ,we humans are lazy: "fossil" as an adjective is shorter than "fossilized"

A turbidte is a km-sized structure*,so you can't see it unless you're standing miles away from it.

*or even tens of kilometers

The individuals Bouma units can't be recognized in the field by themselves,they can only be seen in context.

Edited by doushantuo

 

 

 

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I have seen "Park guides" call them (and things like sand dunes) "fossils" of an ecosystem. (It never made sense to Me).

Yes, I guess you can expect anything from a park guide! And maybe they are trying to use terms that Joe Public will understand too..

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I think the park guides are correct in their phraseology.

Edited by doushantuo

 

 

 

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Rather than fossil(ized) I think a better term would be "lithified evidence of the ecosystem".

OK, but I think saying "petrified water" would be going too far.

:D

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