Keasey Formation item in carbonate concretion

[OregonFossil]

So I am driving on RT. 47 which leads to Vernonia and Mist, Oregon and a road cut that looks very similar to the Keasey locations I have been picking talus and for the first time it appears dry (seems to be a seep at the the top). In Oregon unless on private or in special circumstances BLM land you can not dig, you have to surface troll. I found a safe parking space and then crossed the road to enter the ditch. Once again close to traffic but people on this somewhat used road either slowed or pulled over, except for the truck who stopped and gave me directions to "a secret" place:), now that's cool.

 

I had stopped here during winter but it was really wet and I left after finding a mollusc taking an image so I had the GPS. This day it was very different quite a few concretions had fallen out of the formation. These are very, very had carbonate concretions. So I decided to pickup 3 or 4 and see what I could find.

There are lots of sociological items on this piece. However the object of interest in the focus of these images. I have an assumption (I'll post mine after a day or two) of what this is due to the formation (if I am right and the location of this outcrop in relationship to Vernonia and Mist, Oregon). That being said what is your best guess?

 

 

 

Edited May 10, 2021 by OregonFossil

[Myrmica]

My guess:  'teredo' burrows in what-was a chunk of wood.  Those are relatively common finds in Washington and Oregon Cenozoic sites.  

[OregonFossil]

3 hours ago, Myrmica said:

My guess:  'teredo' burrows in what-was a chunk of wood.  Those are relatively common finds in Washington and Oregon Cenozoic sites.  

The late Eocene–early Oligocene Keasey Formation (32-35 my( in Northwestern Oregon contains a unique fauna of deep-water (>200 m) marine bivalves preserved in sparsely fossiliferous massive tuffaceous siltstone as well as in several distinctive cold-seep limestone bodies and carbonate layers.

 

No teredo worms or wood ever found in this formation.

 

Now if this formation turns out to be Pittsberg formation (shallow water in some levels of the stratas) then it could be teredo worms. However, I am pretty sure that this is Keasey.

Edited May 11, 2021 by OregonFossil

[jpc]

impression of teredo wood was my guess as well.  Hmmm

[OregonFossil]

I have several species of Mollusc and Scaphopoda from the concretion location that I will try and identify which should resolve Keasey or Pittsberg as there was an extinction event between them. This outcrop is within 1/4 mile of another Keasey outcrop and they look very similar.

Edited May 11, 2021 by OregonFossil
add info

[Myrmica]

It could be a chunk of wood that sank.  It will have been drifting at sea at some point.  It really does look like ship-wormed wood.

[OregonFossil]

My guess is a disarticulated Isocrinus Oregonensis. If you look at this internet image (which was very small), the upper left in the full image is an articulated Oregonensis and as you can see from the enlargement it appears very similar to this UI specimen. Since it is in the same formation as the famous Mist Keasey Crinoid layer, I suspect that is a disarticulated, further degraded crinoid (various parts).  I could/may/sometimes am wrong:). But the small size of the piece and the distance it would have had to float to reach the 200 to 2000 meter depth would make this a highly unusual occurrence vs the remains of an animal known to live in this location. Occam's Razor.

 

IsocrinusOregonensis-Enhanced2.tif

Edited May 11, 2021 by OregonFossil

[Wrangellian]

Occam's Razor notwithstanding, I have to say it doesn't look like any crinoid part that I have seen, and have to throw my hat in with the teredo wood explanation. My collecting area up here is said to be a deeper marine shale or mudstone facies, with lots of marine fauna including crinoids, and fairly common plant/wood pieces also. (It is certainly not chockablock full of fossils, I would guess moderate depth/distance from shore.) The plant material must have floated out to sea some distance, became waterlogged and sunk. Your sediments may be deeper/further from shore than mine are but that doesn't mean the occasional bit of wood could not make its way out there.

For that matter, your rock doesn't look like it was formed very far from shore. I think I can see ichnofossils (burrows) in there, indicating near-shore.

Edited May 12, 2021 by Wrangellian

[OregonFossil]

9 hours ago, Wrangellian said:

Occam's Razor notwithstanding, I have to say it doesn't look like any crinoid part that I have seen, and have to throw my hat in with the teredo wood explanation. My collecting area up here is said to be a deeper marine shale or mudstone facies, with lots of marine fauna including crinoids, and fairly common plant/wood pieces also. (It is certainly not chockablock full of fossils, I would guess moderate depth/distance from shore.) The plant material must have floated out to sea some distance, became waterlogged and sunk. Your sediments may be deeper/further from shore than mine are but that doesn't mean the occasional bit of wood could not make its way out there.

For that matter, your rock doesn't look like it was formed very far from shore. I think I can see ichnofossils (burrows) in there, indicating near-shore.

I am finding lots of "burrows" both in the Pittsberg (near shore, some maybe even alluvial fan stuff) and the deepwater Keasey. I know a person who if there is time might look. If it wood that actually makes it more special because how often is wood found that deep? Very cool thank you for the participation.

[Oregon1955]

I believe you are correct that those exposures between highway 26 and Vernonia on 47 are Keasey. I also fall into the teredo wood camp. 50 years ago at the exposures of Keasey near the tunnel on highway 26 I found a pinecone in a concretion on a school outing. If a pinecone can make it to deeper waters I suspect so can a piece of wood.

Nice find though and keep up the good work.

[Wrangellian]

7 hours ago, OregonFossil said:

I am finding lots of "burrows" both in the Pittsberg (near shore, some maybe even alluvial fan stuff) and the deepwater Keasey. I know a person who if there is time might look. If it wood that actually makes it more special because how often is wood found that deep? Very cool thank you for the participation.

I doubt that your chunk was deposited in very deep water or far from shore. It appears to be sandstone, with ichnofossils, which both point to a shallow/near-shore environment. I can't say exactly how near to shore, but not too far or deep. In my area, as I said, there is (mainly) deeper-water shale or mudstone, but in the same area I can find lighter-colored sandy material with more plant bits, burrows, etc. - very similar to yours, and these would have been shallower water. All part of the same formation.

[OregonFossil]

Over laying GPS on a geological map of the area and then using Google Earth I can say that this is definitely the Pittsberg Bluff Formation (red dot on map is location). Teredo wood is now my guess as well as many areas in the PBF were shallow. Interestingly enough it is less  than a 1/4 miles from a Keasey formation out crop that is about 300' higher in elevation. I should have done the hour or so of research to find this information. It is not in any of the Oregon guides on fossils, so here in Oregon you've got a map right to it. As you can see on the map, these two formation do in fact abut in this area.

 

 

Edited May 13, 2021 by OregonFossil

[Wrangellian]

There you go.

Yes, it is often difficult to find the info you need, or else it is actually easy but you didn't think of it or needed someone to point you in the right direction.