Jump to content
MarcoSr

Ostracods From The Paleocene Aquia Formation Of Virginia?

Recommended Posts

MarcoSr

I found a good number of these specimens looking through matrix from the Paleocene Aquia Formation (zone 4) of Virginia. They look like Ostracods to me. I don’t normally see Ostracods or Foraminifers in matrix that I’m looking through. Normally the chemicals that I use to break down the matrix, like acetic acid, dissolve them. This matrix was only washed in water. Any ideas on an id? These specimens are large for Ostracods being 2.5mm to 4mm.

post-2515-0-48115900-1380027165_thumb.jpgpost-2515-0-58969600-1380027175_thumb.jpgpost-2515-0-88645900-1380027188_thumb.jpgpost-2515-0-08815200-1380027203_thumb.jpg

Marco Sr.

Share this post


Link to post
Share on other sites
Al Dente

Marco

I don't think that is an ostracod but I don't know what it could be. Usually you will see a seam where the two shells meet on an ostracod. Here are some I found from the Pleistocene of North Carolina. You can see both halves, one always overlaps the other.

post-2301-0-03686900-1380105507_thumb.jpg

Edited by Al Dente

Share this post


Link to post
Share on other sites
MarcoSr

Marco

I don't think that is an ostracod but I don't know what it could be. Usually you will see a seam where the two shells meet on an ostracod. Here are some I found from the Pleistocene of North Carolina. You can see both halves, one always overlaps the other.

attachicon.gifGroup.Pleistocene.JPG

None of my specimens have a seam. The surfaces, however, are very similar to the Ostracods which you posted. I found several that are damaged and they are hollow inside. Your Ostracods are really nice. What is the size of your specimens? Hopefully someone on the Fossil Forum will recognize what my specimens are.

Marco Sr.

Share this post


Link to post
Share on other sites
squalicorax
MarcoSr

Thank you for the reference. I had ruled out Foraminifers because I knew that they were single cells and I thought that these specimens at 2.5mm to 4mm would be way too large for a single cell. However I just did some web research and found the following: "The size of the foraminiferal test typically ranges from 0.05mm to 0.5mm although some forams may be as large as several centimeters with a recorded maximum of 18cm in diameter. Foraminifera remain single-celled despite the large sizes they reach." After seeing the size they can reach I definitely think that these specimens could be Forams.

Marco Sr.

Edited by MarcoSr

Share this post


Link to post
Share on other sites
non-remanié

There are some pretty large forams in the paleocene Vincentown formation of NJ which correlates best with the age of the Piscataway member of the Aquia formation.

http://books.google.com/books?id=4erg9VxnMUAC&lpg=PA7&ots=Ln4MQxa4pk&dq=vincentown%20formation%20fossil&pg=PA1#v=onepage&q=vincentown%20formation%20fossil&f=false

Share this post


Link to post
Share on other sites
Al Dente

You might send Foram-Mike a message and ask his opinion if this is a foram. The Paleocene Moseley Creek Formation here in North Carolina is absolutely loaded with large forams but I've never seen one that looks similar to Marco's fossil.

Share this post


Link to post
Share on other sites
MarcoSr

There are some pretty large forams in the paleocene Vincentown formation of NJ which correlates best with the age of the Piscataway member of the Aquia formation.

http://books.google.com/books?id=4erg9VxnMUAC&lpg=PA7&ots=Ln4MQxa4pk&dq=vincentown%20formation%20fossil&pg=PA1#v=onepage&q=vincentown%20formation%20fossil&f=false

Steve

Thank you for the link and reference. I looked at the forams in the figures and couldn't find a good match for my specimens. However, it looks like there is a very high diversity in the Vincentown forams and the shape and size of the forams can be very different. Are you finding any ostracods or forams in the matrix that you are looking at from NJ?

Marco Sr.

Share this post


Link to post
Share on other sites
MarcoSr

You might send Foram-Mike a message and ask his opinion if this is a foram. The Paleocene Moseley Creek Formation here in North Carolina is absolutely loaded with large forams but I've never seen one that looks similar to Marco's fossil.

I sent a PM to Foram-Mike and two other members who may be able to help with the id. Hopefully one of them will recognize what my specimens are. I'm not looking for genus and/or species but just want to understand what my specimens are.

Marco Sr.

Share this post


Link to post
Share on other sites
Foram-Mike

Dear Marco Sr.

I would rule out forams, as at that size of 2,5-4mm they should have chambers/walls inside. You characterized them as being hollow inside.

In ostraodes commonly the 2 halves are clearly visible even if eroded. Furthermore a sample commonly contains also single halves.

I would consider plant/algae fruits/seeds as an option, but can't tell what to look for. I found some time ago egg-shaped microfossils, which turned out to be Charophytes. Yours are not - lacking the spire -, but there are so many other algae/plants out there :) Plant/algae fruit/seeds may only be found though close to the coast.

BTW you have a nice webpage at phatfossils, though forams are missing :) on which we may help you.

Share this post


Link to post
Share on other sites
non-remanié

Most of the Vincentown forams come from localized reef deposit horizons within the formation. Other formations generally do not produce any forams, definitely not in lag deposits at least. I have not encountered them anywhere except the Vincentown. Coastal plain sediments are ordinarily quite leached in NJ. There may be some forams in some of the shellbeds, but I would not know for sure.

Steve

Thank you for the link and reference. I looked at the forams in the figures and couldn't find a good match for my specimens. However, it looks like there is a very high diversity in the Vincentown forams and the shape and size of the forams can be very different. Are you finding any ostracods or forams in the matrix that you are looking at from NJ?

Marco Sr.

Edited by non-remanié

Share this post


Link to post
Share on other sites
Missourian
MarcoSr

Dear Marco Sr.

I would rule out forams, as at that size of 2,5-4mm they should have chambers/walls inside. You characterized them as being hollow inside.

In ostraodes commonly the 2 halves are clearly visible even if eroded. Furthermore a sample commonly contains also single halves.

I would consider plant/algae fruits/seeds as an option, but can't tell what to look for. I found some time ago egg-shaped microfossils, which turned out to be Charophytes. Yours are not - lacking the spire -, but there are so many other algae/plants out there :) Plant/algae fruit/seeds may only be found though close to the coast.

BTW you have a nice webpage at phatfossils, though forams are missing :) on which we may help you.

Foram-Mike

Thank you for the id help. These specimens are definitely hollow and I found over 50 of these so far without any evidence of 2 halves visible or without finding any single halves. So my specimens aren't forams or ostracods based upon what you have said.

The matrix is from a very near shore environment so plant/algae fruit/seeds are possible.

My sons don't look through real fine matrix at all. I do, but most of the matrix I search has been broken down using acid so forams would get dissolved. So we just don't find forams to add to phatfossils.

Marco Sr.

Share this post


Link to post
Share on other sites
MarcoSr

Share this post


Link to post
Share on other sites
MarcoSr

Most of the Vincentown forams come from localized reef deposit horizons within the formation. Other formations generally do not produce any forams, definitely not in lag deposits at least. I have not encountered them anywhere except the Vincentown. Coastal plain sediments are ordinarily quite leached in NJ. There may be some forams in some of the shellbeds, but I would not know for sure.

Steve

I don't see them either or don't recognize them.

Marco Sr.

Share this post


Link to post
Share on other sites
Herb

the only thing I can think of are Charophytes?? :popcorn:

Share this post


Link to post
Share on other sites
MarcoSr

the only thing I can think of are Charophytes?? :popcorn:

Herb

Thank you for the input.

Marco Sr.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×