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Foraminifera In A Pleistocene Lake?


PleistoGuy

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Hi!

I've found this fossils within a lake fossil deposits from central Mexico, I cant' figure out what they could be. A friend of mine tell me they seems very much like a foraminifera, but I've read that those fossils are only marine.

Indeed, the lake (in central Mexico) is a little bit brackish and exists at least from Miocene/Pliocene. It contains fossils from the Blancan and Rancholabrean with volcanic activity causing the fossils to be black for the iron and manganese on them. The common fossils are mammoths, horses, camels, etc.

If you can help me with this I'll be so grateful!

THANKS FOR YOUR TIME!

PICS

post-5845-0-75482200-1322410450_thumb.jpg

post-5845-0-36181400-1322410510_thumb.jpg

post-5845-0-68029700-1322410480_thumb.jpg

post-5845-0-33171600-1322410490_thumb.jpg

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It's so hard to tel from the pics what they are.. Maybe

if you added the size and got a close-up pic of just one,

cropped with only the fossil in natural light.. I think I see ridges

or small spine-like areas in the last pic but just can't tell.

Welcome to the forum!

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There are apparently over 50 discovered fresh water or brackish water species of foraminifera nowadays, so I guess they had to start somewhere in the past. Do a bit of googling.

http://en.wikipedia....ki/Foraminifera

Thanks I'll try to get better pictures!! (http://www.biani.unige.ch/msg/files/pdf/Holzmann_JEM2003_50_210.pdf)

THANKS for your time... :D :D :D

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It's so hard to tel from the pics what they are.. Maybe

if you added the size and got a close-up pic of just one,

cropped with only the fossil in natural light.. I think I see ridges

or small spine-like areas in the last pic but just can't tell.

I'll promise to take better photos, these was taken with a iPod... but they are on a stereoscopic microscope, the fossils are very small, maybe 1-2mm across... maybe they just are sommething else...

I've found this and these authors points to freshwater Foraminifera living on lakes and rivers... (http://www.biani.uni...2003_50_210.pdf)

THANK YOU!!

PS. I attach this file on which I have draw lines remarking the big ones...

post-5845-0-40353100-1322615767_thumb.jpg

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I don't know much about Foraminifera but there are other members

on this forum that do.. What I can see from you images (pics 2 & 3)

are raised edges neatly going around the south part of those two

fossils.. I don't see it in the first image..

Hopefully someone will jump in that knows these types of fossils

better.. I wish I could help.. Hang in there.. :)

Welcome to the forum!

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In my opinion, it appears to be a foram with the spiral shape and the apparent suture lines of growth. Is there an opening (aperture) at the end of the outer swirl? You may need to use a small wetted paintbrush to pick up and rotate the specimen in order to look for the aperture. If it has an aperture, I'd be more sure that it was a foram.

Let us know what you find out.

Collecting Microfossils - a hobby concerning much about many of the little

paraphrased from Dr. Robert Kesling's book

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