Vertebrate fossils of east texas

[Jared C]

I've noticed that despite finding loads of petrified wood deep in East Texas (around Jasper, just east of Lake Sam Rayburn), I've never heard of any vertebrate material being uncovered in the area. 

 

I specifically spend a lot of time hunting petrified wood on the catahoula formation ( which is Oligocene) when I'm there, and there's definitely no shortage of said petrified wood. If so many trees are fossilized, shouldn't there be fossils of the animals that lived along side them too?

[Uncle Siphuncle]

You’ll do better in marine deposits for verty stuff.

[Jared C]

2 hours ago, Uncle Siphuncle said:

You’ll do better in marine deposits for verty stuff.

Thanks for the reply - we have property there, so none of our trips out there are for the sole purpose of fossil hunting. I was just wondering the odds of finding mammalian material, if there is even any. Would it be reasonable to assume that my chances are comparable to finding mammal material in, say, central Texas? 

[Uncle Siphuncle]

For Pleistocene mammal stuff, focus on areas mapped Pleistocene terrace deposits.  Mammal matl outside of Pleistocene is pretty rare in TX.

[BobWill]

A perspective from a non-geologist so someone correct me if it's wrong:
Part of the problem with trying to find vertebrate fossils from times after the Mesozoic is the lack of deposits. In marine environments sedimentation is pretty well constant everywhere. In terrestrial environments it generally occurs in stream beds or wind-blows sands of deserts so is far less common The quantity of terrestrial fossils in the Permian "basin" of west Texas on the other hand are enhanced by the material deposited into that region from erosion coming from mountain ranges on both sides. This was not the case for material now exposed in east Texas.

[Jared C]

54 minutes ago, BobWill said:

A perspective from a non-geologist so someone correct me if it's wrong:
Part of the problem with trying to find vertebrate fossils from times after the Mesozoic is the lack of deposits. In marine environments sedimentation is pretty well constant everywhere. In terrestrial environments it generally occurs in stream beds or wind-blows sands of deserts so is far less common The quantity of terrestrial fossils in the Permian "basin" of west Texas on the other hand are enhanced by the material deposited into that region from erosion coming from mountain ranges on both sides. This was not the case for material now exposed in east Texas.

All sound reasoning. I do wonder though how there's such an abundance of petrified wood in the area - does wood mineralize under different conditions than bone?

[JohnJ]

On 8/16/2021 at 4:57 PM, Jared C said:

I specifically spend a lot of time hunting petrified wood on the catahoula formation ( which is Oligocene) when I'm there, and there's definitely no shortage of said petrified wood. If so many trees are fossilized, shouldn't there be fossils of the animals that lived along side them too?

 

According to published literature, vertebrate fossils can be found, but they are rare.

[erose]

On 8/17/2021 at 10:23 AM, Jared C said:

All sound reasoning. I do wonder though how there's such an abundance of petrified wood in the area - does wood mineralize under different conditions than bone?

I had read somewhere that the large deposits of petrified wood in east Texas may be the remains of huge blow downs by hurricanes that then accumulated in back bays or oxbows. 

[Jared C]

9 hours ago, erose said:

I had read somewhere that the large deposits of petrified wood in east Texas may be the remains of huge blow downs by hurricanes that then accumulated in back bays or oxbows. 

That would do well to explain why so much of the wood  looks do be in decomposing state. It may be superficial, but I have noticed before that much of it looks like it was rotten before petrifying.

Edited August 28, 2021 by Jared C

[DPS Ammonite]

On 8/17/2021 at 7:26 AM, BobWill said:

Part of the problem with trying to find vertebrate fossils from times after the Mesozoic is the lack of deposits. In marine environments sedimentation is pretty well constant everywhere. In terrestrial environments it generally occurs in stream beds or wind-blows sands of deserts so is far less common

The Tertiary deposits are there; they are not mostly exposed yet. To get organisms preserved a traumatic event such as a flood is often needed following by deposition into a sediment accumulating: subsiding basin. Most oceans are accumulating basins hence the commonality of marine fossils. Then you need to erode or lift the basin. The newer basins have not had time to uplift or erode and expose the fossils.

Edited August 29, 2021 by DPS Ammonite

[erose]

12 hours ago, DPS Ammonite said:

The Tertiary deposits are there; they are not mostly exposed yet. To get organisms preserved a traumatic event such as a flood is often needed following by deposition into a sediment accumulating: subsiding basin. Most oceans are accumulating basins hence the commonality of marine fossils. Then you need to erode or lift the basin. The newer basins have not had time to uplift or erode and expose the fossils.

Good explanation. I would just add this one caveat: by "oceans" we are talking really about the near shore continental shelves or the epicontinental seas.  The deep ocean bottoms are almost always subducted and whatever fossils existed there destroyed.  The fossil record is not nearly as complete as many think.  WE have almost no record of things that lived in the deepest oceans or the highest peaks.