Show Rocks, Minerals, Fossils and Gems

[ivoire]

A bit of a stretch?

Rock Man3 by Michael Wolf, on Flickr

 

[D7k1]

Deep Water (very fine sedimate matrix), 22-30 MYO

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[PacNWMike]

Famous thrust fault.

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Creag a' Chnocain (Knockan Crag)

 

[D7k1]

Fossil Mold, 12.5 MM long, Keasey Formation (25-30 MYO)

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Have not been able to make a cast of this mold yet, so am not sure of family or species.

 

[D7k1]

Can anyone ID the inclusion in this Deep Water Mudstone from the Keasey formation? The Mollusks are about 50 mm accross. Stone is 15 CM longest direction. This pieces comes from a very large section that fell about 100'. Several other pieces have similar inclusions. Close up shows structure.

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Is it Mineral or Biological? The pieces that have this inclusion type are identical, perhaps a coral?

 

[D7k1]

So I have found a significant "load" of mostly bivalves in a very deep water mudstone. This mudstone is very hard, when it fractures it is a lot like obsidian, extremely sharp and extremely hard. The specimen in this image is 3 x 5mm. The calcium shell has very little identifiable structures, yet the cast part seems "fair" crisp. If the shell was removed perhaps shell parts would be shown in the cast for ID. Would you remove the shell (if so how? acidic acid?). Any ideas on how to soften this mudstone, it is as hard but not as brittle as any shale I have seen. G picks don't see to do anything but an 8 pound sledge works





Imaging done with a Panasonic G9 and Olympus 60mm macro lens using focus stacking.

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[D7k1]

This specimen was found in the Pittsburg Bluff formation (Oligocene) in loosely consolidate sandstone. Due to the large opening and smooth shell I believe it to be a Neverita. Although the location is near the town of Pittsberg Oregon, I can't recommend it for the faint of heart (you are about 4' from the traffic which is mostly log trucks going > 55 MPH). However that being said the talus at the bottom of this formation is a marine invertebrate hunters gold mine. There was one piece of the sandstone that was fairly large (over a meter long) and it and every stone beneath had fossils. Most of the rocks in talus were covered with mud and water. This was only 2 days ago, so I have barely start to ID stuff. Here is my first find, just like this laying in talus covered with mud and water. Speciman is 5mm wide by 10mm long.



Quite happy with location and the condition of the fossils.

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[Harvey Melvin Richards]

This specimen was found in the Pittsburg Bluff formation (Oligocene) in loosely consolidate sandstone. Due to the large opening and smooth shell I believe it to be a Neverita. Although the location is near the town of Pittsberg Oregon, I can't recommend it for the faint of heart (you are about 4' from the traffic which is mostly log trucks going > 55 MPH). However that being said the talus at the bottom of this formation is a marine invertebrate hunters gold mine. There was one piece of the sandstone that was fairly large (over a meter long) and it and every stone beneath had fossils. Most of the rocks in talus were covered with mud and water. This was only 2 days ago, so I have barely start to ID stuff. Here is my first find, just like this laying in talus covered with mud and water. Speciman is 5mm wide by 10mm long.



Quite happy with location and the condition of the fossils.

View attachment 869855

Nice find. Maybe go on a Sunday or whenever the trucks aren't running.

 

[D7k1]

They run all week long

Loggers have to haul when the logs are waiting. I've ridden with a few loggers and can tell you the ride is not for the faint of heart.

 

[D7k1]

I always work through my smaller rocks when I get home. Taken with the G9 and the Oly 60. As I am working my way through the Keasey rocks looking for fossils, I was gathering up the shards and small pieces and I notice a small piece of shell in the deep water piece I was working. Kept it just to check it out. as you can see the gastropod (I think, closest shells with the ribbing and rings are Bruclarkia columbiana and Solenosteira macrospira (does not seem to have been found in the Keasey Fm.)) The rest of the matrix is very hard and the dental picks won't scratch what is left. I think the center shows this is definitely a Gastropod but only a partial shell and one that is really small. Know this is not much to go on but anyone want to take a guess as to what it is? The shell is very small, 2mm at most across and the top is missing but there maybe more bottom of the shell in the very hard matrix. Took a while to get it out of the 10 x 6mm sliver it was encased in.

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[D7k1]

So, yesterday I was doing some work on some talus and near the end I picked up two rocks (one sandstone from the Pittsburg Bluff formation (PBF, Miocene) and the other deep water shale (>1000') from the Keasey Formation (Eocene), each only have a shell piece showing on the outside. The Sandstone (PBF) is consolidated but all it take is a gentle tap from the Gpick while the Shale (KF) is extremely fine grained and very, very hard. I was going to toss both since I have some very good casts and molds of these formations bivalve molluscs.
Then I thought why not at least break them in half(both were between 6" and 8" on the longest dimension). The sandstone split and much to my astonishment there was a cast and a mold of a mollusc (wide dimension: 30mm) with lots of details in the mold and cast. Enough that I will take the time and ID it (lots of mollusc species in the PBF). The image I have attached of it shows clearly the none symmetric shape and other ID points. Am going to leave it in the matrix as I like the look.
The PDB has significantly more marine fossils than does the KF in my experience. The Keasey shale being deep water is a made of very fine particulate matter that is extremely hard to break, even with my 3 pound hand sledge hammer. When I hit this piece of shale, the first time it broke a small sliver off and the second time a four inch piece flew off. Like the rest of the piece just a bit of shale was in the 4". However in the voild left was a 10mm smooth sided Dentalium. I have found in a different layer of the KF some large ribbed Dentalium. But in the site from where this one came from this is the first one I've found there. All of the other Dentalium have been a ribbed species leaving me very interested to ID this one. Again I will leave it in the matrix as due to its size, the hardness of the shale, and the fact that this might be rare in this specific locality I will wait until I contact a few folks who have studied this formation in case they are interested. Images shot with Panasonic G9, Olympus 60mm macro lens, and an electronic flash.

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[PacNWMike]

I do custom cabinetry and have seen some pretty amazing countertops made out of this stuff

 

[ABFoz]

Interesting thread. Anyone who has access to a free-to-sample fossil palace that's around 600m is just lucky.

Is it Mineral or Biological?

Fossil mineralisation is dependent on temperature and pressure. I have seen some Eocene fossils that have completely mineralised into zeolite while some of our fossils here that are of the same age still have plenty of carbon-based materials left.

Would you remove the shell (if so how? acidic acid?)

Which formation is this from?

It's hard to tell from the photos but it seems that the shell has a certain degree of mineralisation but it's still the shell itself. If you want to make a cast, you can remove the shell but it's better to do it on a different, more complete sample.

Getting the complete complete fossil can be very tricky but you can study the fracturing patterns and planes based on your existing samples.

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This, for example, is a good find as you have the whole shebang. I would leave it like that, though, as the surroundings tell a lot about the fossil's paleoecology. Cheers.

 

[D7k1]

Interesting thread. Anyone who has access to a free-to-sample fossil palace that's around 600m is just lucky.


Fossil mineralisation is dependent on temperature and pressure. I have seen some Eocene fossils that have completely mineralised into zeolite while some of our fossils here that are of the same age still have plenty of carbon-based materials left.


Which formation is this from? Anything with shale is Keasey Formation (Eocene), Anything with sandstone is Miocene (early) Pittsberg Bluff (sometimes put in late Eocene).

It's hard to tell from the photos but it seems that the shell has a certain degree of mineralisation but it's still the shell itself. If you want to make a cast, you can remove the shell but it's better to do it on a different, more complete sample. Yes some have a combination and it makes for removal of the matrix somewhat hard.

Getting the complete complete fossil can be very tricky but you can study the fracturing patterns and planes based on your existing samples.

This, for example, is a good find as you have the whole shebang. I would leave it like that, though, as the surroundings tell a lot about the fossil's paleoecology. Cheers.

I am using a combination of reports from the Oregon government, Google Earth, and some scientific and hobbyist reports to find locations. These marine deposits are located with in a hour of the house. Here in Oregon you can't dig without a permit but talus and surface stuff as long as not significant (who knows what that means but I think any bones) are fair game. The very best stuff here in Oregon is in the federally protect John Day Fossil beds which are amazing to walk through. Oregon is made up of Islands that the plates pushed together and we range from Jurassic to recent stuff mostly. You just never know what you will find and yes I am very lucky to have an interest in marine stuff that is so close to where I live. Thanks for looking.

 

[PacNWMike]

John Day Fossil beds which are amazing to walk through.

not just "marine stuff" there.

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[D7k1]

Mike: have you been to the new museum there? I belong to the rose city astronomers and we can take long hikes in the beds - never know what you are going to sea. Most of the stuff is amazing. But it is a "no touch" location reserved for the PROs. . University of Oregon has 2 warehouses full of stuff but no funds or people to prep or curate I understand.

 

[PacNWMike]

The one at the Sheep Rock Unit? No, we've never been there when it's been open. The actual cat fossil is in the museum there. My photo is of the cast in sitio. We've noticed that the marine fossil section doesn't get nearly as much attention as the colorful hills.