Back into the Early / Lower Eocene of Mississippi

[Rock Hound]

It was too cool and windy, for 2 hours of walking and looking for surface finds in a great wide open area 2-4-24; but I guess I heard that old siren's call again?

 

 

 

Edited February 5 by Rock Hound

[Paleoworld-101]

Awesome haul! What formation are these from? 

[Rock Hound]

1 hour ago, Paleoworld-101 said:

Awesome haul! What formation are these from? 

The Wilcox Group

[MarcoSr]

7 hours ago, Rock Hound said:

It was too cool and windy, for 2 hours of walking and looking for surface finds in a great wide open area 2-4-24; but I guess I heard that old siren's call again?

 

 

 

 

That is a large number of surface finds for 2 hrs.  The Eocene, Nanjemoy Formation in Virginia is very acidic.  As the teeth in the formation expose, the acid in the formation along with the exposure to air and water cause the teeth to turn whitish, and they look very much like your specimens.  However, the teeth still completely encased in the formation matrix are usually pristine.  Do you have formation remaining where you are collecting?  Have you tried breaking it down to see if there are pristine teeth in it?  For the Nanjemoy Formation (Note I am on private property with owner permission) I dig out 8 five gallon buckets of formation during typically 3 hrs at the site and break down the formation in a sieve with window screen under it in a stream.  I pick out the larger specimens from the sieve and bring home the residue that falls through the sieve into the window screen.  I usually bring home 2 half filled 5 gallon buckets of residue, which I completely break down at home and then search.  In a single trip, I usually find hundreds of shark, ray and bony fish teeth (mostly micro teeth), hundreds of shark, ray and bony fish vertebrae, a couple of thousand coprolites, croc, snake and turtle specimens, much less common bird bones, and rarely mammal specimens.  The Nanjemoy Formation has a lens with a very high fossil density where I collect.  Where you are searching may also have a high fossil density in the formation matrix based upon the number of teeth that you found in 2 hrs, or it could be that nature just sorted out a large number of teeth from a very large amount of formation matrix.

 

Marco Sr.

[automech]

@MarcoSr It's interesting how the enamel is flaking off. Is that from being exposed to the elements?

[MarcoSr]

12 minutes ago, automech said:

@MarcoSr It's interesting how the enamel is flaking off. Is that from being exposed to the elements?

 

In the Nanjemoy Formation of Virginia, water combined with a lot of pyrite in the formation leads to sulfuric acid creation, which attacks a lot of the teeth that become exposed in addition to the elements.  This acid bleaches the teeth white (sometimes also turns the enamel blue by reacting with chemicals in the enamel) and attacks the enamel, cracking, flaking and disintegrating it.  Being exposed just to the elements (sun, heat, water etc.) can bleach teeth and cause enamel flaking, but I wouldn't expect almost all the teeth looking affected unless an acid was also involved.

 

Marco Sr.

[Shellseeker]

1 hour ago, MarcoSr said:

 

In the Nanjemoy Formation of Virginia, water combined with a lot of pyrite in the formation leads to sulfuric acid creation, which attacks a lot of the teeth that become exposed in addition to the elements.  This acid bleaches the teeth white (sometimes also turns the enamel blue by reacting with chemicals in the enamel) and attacks the enamel, cracking, flaking and disintegrating it.  Being exposed just to the elements (sun, heat, water etc.) can bleach teeth and cause enamel flaking, but I wouldn't expect almost all the teeth looking affected unless an acid was also involved.

 

Marco Sr.

I was hunting a Miocene site last week,  finding mostly marine fossils. I has broken thru a layer and most small shark teeth finds were dull and worn..  One of the few mammal fossils was this Gomph tooth tip.  However , this flaking was very unusual and none of my other finds had anything similar.

[Rock Hound]

4 hours ago, MarcoSr said:

 

That is a large number of surface finds for 2 hrs.  The Eocene, Nanjemoy Formation in Virginia is very acidic.  As the teeth in the formation expose, the acid in the formation along with the exposure to air and water cause the teeth to turn whitish, and they look very much like your specimens.  However, the teeth still completely encased in the formation matrix are usually pristine.  Do you have formation remaining where you are collecting?  Have you tried breaking it down to see if there are pristine teeth in it?  For the Nanjemoy Formation (Note I am on private property with owner permission) I dig out 8 five gallon buckets of formation during typically 3 hrs at the site and break down the formation in a sieve with window screen under it in a stream.  I pick out the larger specimens from the sieve and bring home the residue that falls through the sieve into the window screen.  I usually bring home 2 half filled 5 gallon buckets of residue, which I completely break down at home and then search.  In a single trip, I usually find hundreds of shark, ray and bony fish teeth (mostly micro teeth), hundreds of shark, ray and bony fish vertebrae, a couple of thousand coprolites, croc, snake and turtle specimens, much less common bird bones, and rarely mammal specimens.  The Nanjemoy Formation has a lens with a very high fossil density where I collect.  Where you are searching may also have a high fossil density in the formation matrix based upon the number of teeth that you found in 2 hrs, or it could be that nature just sorted out a large number of teeth from a very large amount of formation matrix.

 

Marco Sr.

 

@MarcoSrThank you, for the detailed explanation of why the environment is bleaching these teeth white.  I had associated the poor condition of the tooth enamel, with harsh environmental conditions; but had not associated it with the acidity of the soil.  That explains it.

 

I have done no digging at the site.  The ground has been worked over and spread around, by human activity.  This has created the surface exposure, which has not been completely taken over by natural grasses yet.  This is a developed property, if you will.  Digging with a shovel, might quickly end my access to the site.

Edited February 5 by Rock Hound

[MarcoSr]

1 hour ago, Shellseeker said:

I was hunting a Miocene site last week,  finding mostly marine fossils. I has broken thru a layer and most small shark teeth finds were dull and worn..  One of the few mammal fossils was this Gomph tooth tip.  However , this flaking was very unusual and none of my other finds had anything similar.

 

The layer where "most small shark teeth finds were dull and worn" sounds like a reworked layer, probably caused by a marine transgression or regression.  Specimens in these reworked layers can get really beaten up by the water action.  If your Gomph tooth tip came out of that reworked layer, the reworking could easily cause the flaking.

 

Marco Sr.

[MarcoSr]

1 hour ago, Rock Hound said:

 

@MarcoSrThank you, for the detailed explanation of why the environment is bleaching these teeth white.  I had associated the poor condition of the tooth enamel, with harsh environmental conditions; but had not associated it with the acidity of the soil.  That explains it.

 

I have done no digging at the site.  The ground has been worked over and spread around, by human activity.  This has created the surface exposure, which has not been completely taken over by natural grasses yet.  This is a developed property, if you will.  Digging with a shovel, might quickly end my access to the site.

 

The sites we dig are in heavily wooded stream areas a good distance away from the owners' houses.  So the owners don't have any problem with us digging.

 

Marco Sr.

[Rock Hound]

Please forgive my slipup.  I meant to say Early / Lower Eocene; not Upper Eocene.

 

I am human, after all.

[Bjohn170]

5 hours ago, MarcoSr said:

 

The sites we dig are in heavily wooded stream areas a good distance away from the owners' houses.  So the owners don't have any problem with us digging.

 

Marco Sr.

Lucky you! Sounds like an amazing spot to collect at!

[MarcoSr]

10 minutes ago, Bjohn170 said:

Lucky you! Sounds like an amazing spot to collect at!

 

Multiple amazing spots.  I have known the landowners in this area for over 25 years, which is why I have permission to collect.  One landowner's brother built my house in 1999.  Another landowner put in my driveway and septic system.

 

Marco Sr.

[Bjohn170]

3 minutes ago, MarcoSr said:

 

Multiple amazing spots.  I have known the landowners in this area for over 25 years, which is why I have permission to collect.  One landowner's brother built my house in 1999.  Another landowner put in my driveway and septic system.

 

Marco Sr.

I got to work on my networking 

[Tidgy's Dad]

Nice finds.

 

[Rock Hound]

1 hour ago, Tidgy's Dad said:

Nice finds.

 

Thank you, sir.

[patelinho7]

Very interesting. I've been collecting the Maastrichtian Severn Formation in MD. The site I've been visiting has teeth a lot like yours. The preservation is really hit or miss, and many of the teeth are split and peeling at the enamel like yours. Funny thing is that there are two categories of teeth: ones like yours, where the features are crumbling off and the tooth is highly unstable, and others that have been preserved in phosphatic concretions and are jet black and incredibly hard but are so worn they lack almost all details. 

[Rock Hound]

3 hours ago, patelinho7 said:

Very interesting. I've been collecting the Maastrichtian Severn Formation in MD. The site I've been visiting has teeth a lot like yours. The preservation is really hit or miss, and many of the teeth are split and peeling at the enamel like yours. Funny thing is that there are two categories of teeth: ones like yours, where the features are crumbling off and the tooth is highly unstable, and others that have been preserved in phosphatic concretions and are jet black and incredibly hard but are so worn they lack almost all details. 

 

It has puzzled me, why almost every find at this location; is being attacked so aggressively by the environment it's in?  The explanation that the soil is acidic, and that every time it rains the fossils are bathed again in fresh acid; seems logical, to me. 

 

I feel like I have rescued some fossils, at the last minute; before they were completely destroyed, by their harsh environment.  A testimony of sorts, to what was once there.

Edited February 8 by Rock Hound

[patelinho7]

46 minutes ago, Rock Hound said:

 

It has puzzled me, why almost every find at this location; is being attacked so aggressively by the environment it's in?  The explanation that the soil is acidic, and that every time it rains the fossils are bathed again in fresh acid; seems logical, to me. 

 

I feel like I have rescued some fossils, at the last minute; before they were completely destroyed, by their harsh environment.  A testimony of sorts, to what was once there.

 

It could also be the depositional environment. In my case, it's a mixture of both soil environment as well as depositional environment. Certain exposures are just compromised from the very point of when sediments cover the organisms. Or, a human effect: dredging out material which gets more erosion and sunlight than it can handle.

Edited February 8 by patelinho7