What is surrounding this Crinoid stem?

[TqB]

Crinoidal rock where the stem calcite has been dissoved to leave both external and internal moulds is often colloquially called "crinoid screw stone". Worth searching for images.  

(Many crinoids don't have such wide lumens - I think it's largely Palaeozoic ones that do but please correct me if that's not the case.) 

[DPS Ammonite]

The Daily Mail published an article about a group claiming the screws were proof of a 300 million year old alien society on Earth. 
 

Isn’t getting your science news from the Daily Mail sort of like getting your medical news from the National Enquirer?
 

https://www.dailymail.co.uk/sciencetech/article-3030781/amp/Is-300-million-year-old-screw-Group-claims-proof-aliens-living-Earth-scientists-say-s-just-fossilised-sea-creature.html

 

[solidus]

8 hours ago, DPS Ammonite said:

The Daily Mail published an article about a group claiming the screws were proof of a 300 million year old alien society on Earth. 
 

Isn’t getting your science news from the Daily Mail sort of like getting your medical news from the National Enquirer?
 

https://www.dailymail.co.uk/sciencetech/article-3030781/amp/Is-300-million-year-old-screw-Group-claims-proof-aliens-living-Earth-scientists-say-s-just-fossilised-sea-creature.html

 

Ahh Daily Mail. Always gives me a good laugh.

[Rockwood]

Anyone who thinks that's a thread has already signed on as a nut. 

No offense intended to anyone who had trouble with the photos. 

[solidus]

Is anyone able to direct me to info or explain here more or less how we can determine the age of something like this?

[Ludwigia]

Since this is probably, as you have already suggested, a glacial erratic, one would need to be able to recognize the type of stone which makes up the matrix, determine the species, or at least the genus of the fossils contained within it and then perhaps thereby be able to extrapolate it's origin and age. This involves a lot of knowledge and research, so in your case, I would suggest taking it to your nearest natural science museum or university geology department and showing it to a resident geologist/paleontologist.

[solidus]

3 hours ago, Ludwigia said:

Since this is probably, as you have already suggested, a glacial erratic, one would need to be able to recognize the type of stone which makes up the matrix, determine the species, or at least the genus of the fossils contained within it and then perhaps thereby be able to extrapolate it's origin and age. This involves a lot of knowledge and research, so in your case, I would suggest taking it to your nearest natural science museum or university geology department and showing it to a resident geologist/paleontologist.

Makes sense. So essentially we would need to know the type of rock and where it originated so that we can figure out how deep the sediment was when the fossil formed, correct?

[Ludwigia]

4 minutes ago, solidus said:

Makes sense. So essentially we would need to know the type of rock and where it originated so that we can figure out how deep the sediment was when the fossil formed, correct?

 

Yup. Plus, like I said, identifying the fossils if possible, since they are also stratigraphical indicators.

[solidus]

8 minutes ago, Ludwigia said:

 

Yup. Plus, like I said, identifying the fossils if possible, since they are also stratigraphical indicators.

So since I know that all of the land itself was formed only 21,000 years ago via the glacier it is therefore impossible for any sedimentary fossil containing rocks to have originated from here, correct? I guess what confuses me is even though there was no land here there was ocean and obviously an ocean floor. So is it not possible that sedimentary rock on that old ocean floor could contain fossils that now wash up on my beaches? Is it just that all of those fossil bearing sediments are simply under the ocean floor and never have an opportunity to become surface rocks?

Edited August 31, 2023 by solidus

[Rockwood]

7 minutes ago, solidus said:

Makes sense. So essentially we would need to know the type of rock and where it originated so that we can figure out how deep the sediment was when the fossil formed, correct?

Although the depth of the rock that contains the fossil generally records the relative age it can not be thought of in the same way as calendar or tape measure. Many factors have to be considered for it to be used as an indication. 

[Ludwigia]

18 minutes ago, solidus said:

So since I know that all of the land itself was formed only 21,000 years ago via the glacier it is therefore impossible for any sedimentary fossil containing rocks to have originated from here, correct? I guess what confuses me is even though there was no land here there was ocean and obviously an ocean floor. So is it not possible that sedimentary rock on that old ocean floor could contain fossils that now wash up on my beaches? Is it just that all of those fossil bearing sediments are simply under the ocean floor and never have an opportunity to become surface rocks?

Your first question is correct. And it is also possible that sedimentary rocks from the ocean floor, if they are there in your general area, could wash up on the shore. But you would need to research what kind of rocks are there and how old they are.

[solidus]

3 minutes ago, Ludwigia said:

Your first question is correct. And it is also possible that sedimentary rocks from the ocean floor, if they are there in your general area, could wash up on the shore. But you would need to research what kind of rocks are there and how old they are.

Makes sense. Thanks so much. Learning a ton here

[Rockwood]

14 minutes ago, solidus said:

 I guess what confuses me is even though there was no land here there was ocean and obviously an ocean floor. So is it not possible that sedimentary rock on that old ocean floor could contain fossils that now wash up on my beaches?

Land that was formed by tectonic activity is usually a chaotic jumble of volcanic islands and micro continents. The plates deform greatly during the process adding to the confusion. So, yes it seems quite possible that you are finding fossils from that ocean floor.

[solidus]

Just now, Rockwood said:

Land that was formed by tectonic activity is usually a chaotic jumble of volcanic islands and micro continents. The plates deform greatly during the process adding to the confusion. So, yes it seems quite possible that you are finding fossils from that ocean floor.

Thats what I always thought. But its very commonly said that Long Island simply has no fossils (clearly untrue because I have found 2) Additionally that we have no real crystals besides some quartz. I think I need to read a bit more about the geological history in order to understand why this is the case.

[Ludwigia]

7 minutes ago, solidus said:

Makes sense. Thanks so much. Learning a ton here

You're welcome. I should also perhaps mention, and I hope this doesn't get you confused, that underlying the sedimentary layers on Long Island, the bedrock is composed of very old (4-500mya) metamorphic rocks, which contain no fossils. It's apparently possible to find garnets there, but probably not all that common.

[solidus]

2 minutes ago, Ludwigia said:

You're welcome. I should also perhaps mention, and I hope this doesn't get you confused, that underlying the sedimentary layers on Long Island, the bedrock is composed of very old (4-500mya) metamorphic rocks, which contain no fossils.

Right, and I think this is what sort of confused me. On top of that rock there was eventually sediment, which could have formed fossils at pretty much any time in history. So why wouldnt there be just as much likelyhood of finding fossils on my beaches than anywhere else? I know the land itself that we live on is only about 21000 years old... But all of the surrounding oceans and bays were always there, and filled with life. There must be something specific about the area that causes locally formed fossils to be rare/non existant. Even then 21000 years is enough time for fossils to form as well right, although they would be relatively young.

[Rockwood]

17 minutes ago, solidus said:

Thats what I always thought. But its very commonly said that Long Island simply has no fossils (clearly untrue because I have found 2) Additionally that we have no real crystals besides some quartz. I think I need to read a bit more about the geological history in order to understand why this is the case.

There is likely a book titled roadside geology of Newyork. It would be a good place to start.

[solidus]

21 minutes ago, Rockwood said:

There is likely a book titled roadside geology of Newyork. It would be a good place to start.

Yea its old and a bit pricey but I am going to grab it. Thanks!

[Ludwigia]

3 hours ago, solidus said:

Right, and I think this is what sort of confused me. On top of that rock there was eventually sediment, which could have formed fossils at pretty much any time in history. So why wouldnt there be just as much likelyhood of finding fossils on my beaches than anywhere else? I know the land itself that we live on is only about 21000 years old... But all of the surrounding oceans and bays were always there, and filled with life. There must be something specific about the area that causes locally formed fossils to be rare/non existant. Even then 21000 years is enough time for fossils to form as well right, although they would be relatively young.

 

It helps to know that only a very small percentage of all sedimentary stones actually have been able to preserve fossils over time, be it, geologically speaking, long or short. A large portion of sediments never held fossilized remains since the creatures either did not die and become deposited in the region, or the remains dissolved or eroded away quickly before they could be preserved, which is actually usually the case. Special circumstances are necessary in order for flora and fauna remains to be preserved and also for them to become exposed at the surface where they can be reached. I would suggest, if the subject interests you, to find some books which deal with sedimentology and the preservation of fossils and study them in depth. There are a good number of basic books dealing with the question of how fossils are formed to choose from.

[Randyw]

Plus don’t forget that the glaciers moving through removed some layers of rock and moved them to other locations even as they were depositing stuff from other locations to yours…

[solidus]

35 minutes ago, Ludwigia said:

 

It helps to know that only a very small percentage of all sedimentary stones actually have been able to preserve fossils over time, be it, geologically speaking, long or short. A large portion of sediments never held fossilized remains since the creatures either did not die and become deposited in the region, or the remains dissolved or eroded away quickly before they could be preserved, which is actually usually the case. Special circumstances are necessary in order for flora and fauna remains to be preserved and also for them to become exposed at the surface where they can be reached. I would suggest, if the subject interests you, to find some books which deal with sedimentology and the preservation of fossils and study them in depth. There are a good number of basic books dealing with the question of how fossils are formed to choose from.

Makes sense. I am going to look for literature on this as I am very interested. I've been going through some basic geology courses but they're of course very generic and talk about everything from plate tectonics to fossils, but I would like to try to hone in on this specific subject in particular to try to understand what makes certain places rich in fossils and crystals while where I live relatively barren

[solidus]

37 minutes ago, Randyw said:

Plus don’t forget that the glaciers moving through removed some layers of rock and moved them to other locations even as they were depositing stuff from other locations to yours…

This in particular is what I'm interested in understanding about my location. Are these fossils that I'm finding pieces of stone that were pushed over here from the glaciers...Or were they always in my nearby waters and just finally made it up to the surface eventually. My best bet is likely to talk to someone who studies this stuff locally.

Edited August 31, 2023 by solidus

[Mahnmut]

Hi,

just from the information provided in this thread, I think I have got a general idea why you are not on prime fossil territory:

The bedrock is to old and metamorphic, which means no recognizable fossils. The layers above that are quite young (21ka you say) which means they could contain fossils, but only very select ones from that young age.

Glacial and other erratics may bring some exceptions to that, like your finds possibly.

All the mesozoic rocks and more that could contain dinosaurs, ammonites and whatever else makes us forum members happy either never formed in your region or eroded away before the young sediment formed.

https://en.wikipedia.org/wiki/Unconformity

Best Regards,

J

[solidus]

39 minutes ago, Mahnmut said:

Hi,

just from the information provided in this thread, I think I have got a general idea why you are not on prime fossil territory:

The bedrock is to old and metamorphic, which means no recognizable fossils. The layers above that are quite young (21ka you say) which means they could contain fossils, but only very select ones from that young age.

Glacial and other erratics may bring some exceptions to that, like your finds possibly.

All the mesozoic rocks and more that could contain dinosaurs, ammonites and whatever else makes us forum members happy either never formed in your region or eroded away before the young sediment formed.

https://en.wikipedia.org/wiki/Unconformity

Best Regards,

J

This is so helpful, but of course brings more questions…. Even if the bedrock is metamorphic and old, would there not have been sand and other loose material sitting on top of that on the sea floor? I always imagined the sea floor would have the sort of material that would slowly become sedimentary rock over time, and that organisms dying there would potentially fossilize. I guess I am imagining that long before the land itself formed 21kya, the sea floor would have accumulated fossils. But I am likely misunderstanding the contents of the sea floor

[Mahnmut]

As Ludwigia said, not all seafloor is full of fossils. Think of a modern beach, there are spots with lots of shells, but also wide stretches with barely any, and only very occasionally a bone or other vertebrate remains. Depending on depth, oxygen- and nutrient content the seafloor is even emptier than the average beach. And depending on acidity and other factors, not all calcitic remains get preserved. In low pH sand, there are hardly any bones left when graves are dug up after 30 years.

There are places where shells and other fossils make up the better part of tall rocks, but it all depends on many factors.

Best Regards,

J