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Zenmaster6

Basic Questions (Noob stuff)

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Zenmaster6

Hey everyone. Maybe someone could clear this is up for me. 
 

A. "When I look on a geologic map and see MzM (which means Mesozoic marine sedimentary rock.) Does that mean anything from Triassic to Cretaceous?
If so how can I be sure when I find a fossil which date it is from? (other than the obvious of course which is to identify the species and find what date its from)

B. I also see metasedimentary which is Precambrian and Silurian etc. Those rocks are "Meta" sedimentary which means they were sediments good for fossils but have been subjugated to high temperatures and pressures which Should destroy fossils. Do you think there are fossils in that metasedimentary rock or should I stick to just sedimentary. 

C. I found these fossils from the what I thought was the Eocene period on a hill (intermediate of hill and mountain) of a few clams and turritella inside a sedimentary rock. People who live in the nearby area talk about how millions of years ago the spot I collected at used to be a shallow prehistoric ocean. On the map it says tertiary (old word for Paleogene), which means 66 - 2.5 million years ago . 
When I use the website "(http://dinosaurpictures.org/ancient-earth#240)"  It shows that the spot I collected from was and remained land until 90 million years ago when became a shallow ocean. which would be cretaceous. The fossils I collected were all marine and were far from the real ocean. How is it that I found marine fossils in Paleogene sediment which was not shallow ocean since 90 million years ago. I would imagine a river or stream but these fossils look very "Ocean like" (I do know that's not a valid way to determine a fossils origin)

Anyways if anyone could help me out, that'd be great.

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Wrangellian
5 hours ago, Zenmaster6 said:

On the map it says tertiary (old word for Paleogene), which means 66 - 2.5 million years ago . 

 

Just a small correction: Tertiary was the old name for the Paleogene (66-23mya) and Neogene (23-2.5mya). They divided the Tertiary to make the 2 new periods.

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The Amateur Paleontologist
3 hours ago, Fossildude19 said:

Very old information here,

For some reason, there's something I really like about trawling through Kenney's datasets, however out-of-date they are :) 

-Christian

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Zenmaster6
5 hours ago, Fossildude19 said:

A. When terms like MzM are used, that usually indicates they are talking about a large area.A state like Washington is huge, and you would really need to look at the local Quadrangle maps to see what is actually there.  The USGS website may be useful in this regard.

 

From Wikipedia: 

During the early MesozoicTriassic pelecypods were common Washington inhabitants.[4] Jurassic and Cretaceous life left behind their fossils in the north-central and northwestern part of Washington.[5] By the end of the Mesozoic only about two thirds of the state's land mass had come together.[5] During the Cretaceous the region now occupied by the northern Cascade Mountains and the San Juan Islands were home to creatures like cephalopods with both coiled and uncoiled shells as well as pelecypods.[4] Only one known dinosaur fossil has been found in Washington.[6][7]

 

Very old information here, but may be helpful in research. 

 

You will have to research individual areas to figure out what Formations are there, and what they can possibly contain, fossil-wise.

 

B.  Chances are that any fossils that were there may have been destroyed by the metamorphic processes involved. Might still be worth a look, but I would focus elsewhere.

 

C.  There could be a number of explanations for this. 

Geologic maps show what the majority of the bedrock is made out of. That doesn't mean that there couldn't be pockets of outcrops of different aged rocks. 

 

I'm confused by this statement: 

"It shows that the spot I collected from was and remained land until 90 million years ago when became a shallow ocean. which would be Cretaceous. The fossils I collected were all marine and were far from the real ocean. How is it that I found marine fossils in Paleogene sediment which was not shallow ocean since 90 million years ago."

You would have to know when the ocean dried up or receded to figure this out.  You state it was " land UNTIL 90 mya", buy you don't say when it reverted back to land. :headscratch:

 

 

Keep in mind, there are such things as Estuarine and Lacustrine  sediments. ( Rivers and lakes)  Lakes have freshwater clams and snails, etc. 

 

Also, Glaciers. Glaciers could have deposited sediments from further away south when they were receding. 

 

You really need to study the geology of your area by reading up on what is available to figure this stuff out. Each area has a different geologic history.  :) 

This is part of the fun of Fossil collection. :D 

 

Hope this helps some.

 

 

 

 

Well, I do study the geology of my area quite intensely. I look into the small quadrangle maps on the Department of resources and found fossils already from tiny strips of sediment I saw on the maps. When I was looking at the large state map, I wasn't looking for anywhere in particular but  generally was looking on the eastern side (5 hours away) in order to plan out which direction on the highway I should go in the far future. Just for an idea of what was a dead volcanic / metamorphic zone and what had some kind of sediments. I know pretty much everything that's decent for fossils in a 1 hour radius of my house but haven't researched beyond that. 

To clear up my question,

I found marine fossils in spot A.

90 million years ago, Spot A, was indeed a shallow ocean.
60 million years ago it was not.

40 million years ago it was not

20 million years ago it was not

today it is not and far from it.

Like the Wikipedia article you posted saying the cretaceous left its fossils in the north western half of the state. That's my location
This further backs up that the fossils could be cretaceous. 

My main question is

Why do I have marine life in tertiary sedimentary rock if there was no ocean nearby for 90 million years (cretaceous) . 

Theory: it could have been lake or river. I will go back and look for more fossils to further identify whether it was the ocean or fresh water.

 


 

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Zenmaster6
2 hours ago, The Amateur Paleontologist said:

For some reason, there's something I really like about trawling through Kenney's datasets, however out-of-date they are :) 

-Christian

thank you. This website is awesome 

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Fossildude19
6 minutes ago, Zenmaster6 said:

Well, I do study the geology of my area quite intensely.

My main question is:
Why do I have marine life in tertiary sedimentary rock if there was no ocean nearby for 90 million years (cretaceous) . 
Theory: it could have been lake or river. I will go back and look for more fossils to further identify whether it was the ocean or fresh water.

 


 

Well then you are well on your way. :) 

 

Were these found as float, loose, laying around, or were they taken directly from an outcrop?

 

Not all geologic maps are entirely accurate, and little pockets or outcrops of other aged rocks could exist. 

You might have stumbled upon an unconformity, or some overlooked upthrust of bedrock.  

Sounds like you have the subject well in hand.  Good luck.  ;) 

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Zenmaster6
1 minute ago, Fossildude19 said:

Well then you are well on your way. :) 

 

Were these found as float, loose, laying around, or were they taken directly from an outcrop?

 

Not all geologic maps are entirely accurate, and little pockets or outcrops of other aged rocks could exist. 

You might have stumbled upon an unconformity, or some overlooked upthrust of bedrock.  

Sounds like you have the subject well in hand.  Good luck.  ;) 

These were buried in rock I needed to dig out with a geology pick. They weren't easy to bust out. 

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Zenmaster6
4 hours ago, Wrangellian said:

Just a small correction: Tertiary was the old name for the Paleogene (66-23mya) and Neogene (23-2.5mya). They divided the Tertiary to make the 2 new periods.

sorry, yeah I posted this at 2 in the morning. The admin had no idea what I was asking lol

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Zenmaster6
3 hours ago, The Amateur Paleontologist said:

For some reason, there's something I really like about trawling through Kenney's datasets, however out-of-date they are :) 

-Christian

judging by this, my location is not on here but the areas around it say Oligocene. I will look into this. Thank you : )

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