Which species or family are these corals?

[PaleoOrdo]

Happy new year to all members!

Today I would like to present some of my finds of tabulate corals. I am grateful if anyone can help to identify the family, genus or species. First I will present corals from the Kalvsjøen formation, late Ordovician in Hadeland, Norway. I think rock 3-8 have the same species.

Rock 1 and 2 are most puzzling so I present those first. I see several kinds of corals in them and not only corals. Can you also see the nautiloid?

 

 

 

 

Next, some rocks which I believe have the same kind of coral:

Rock 3 - the biggest coral I found in the area, more than 50 cm broad (still in situ), worthy to be in a museum:

Rock 4, very smooth surface, maybe rounded by the glacier or river:

 

Rock 5 - size is same for the diameter of the coralittes:

Rock 6 - same size of coralites

Rock 7:

Rock 7 

Rock 8- in situ:

 

 

 

 

 

[oyo]

This is not in absolute my comfort field, but couldn't those first specimens be some kind of sponge?

Edited January 1, 2022 by oyo

[PaleoOrdo]

On 1/1/2022 at 6:52 PM, oyo said:

couldn't those first specimens be some kind of sponge?

I do'nt know if you are right or wrong. I thought they are some kind of corals, but I guess not only corals have circular patterns. I hope someone with more knowledge than me can present their opinions. 

[Ludwigia]

They look like corals to me, but I've no idea on them. @TqB ?

[TqB]

I'm not sure about 1 - it's ringing a bell but I can't remember where I've seen it.

 

The others (including the smaller circles of no. 2) look like the tabulate Sarcinula (order Sarcinulida) which has characteristic corallites joined by horizontal platforms, well known from the U. Ordovician of Norway. 

Edited January 3, 2022 by TqB

[FranzBernhard]

You have got a lovely bunch of very old corals up there! Thanks for sharing!

 

On 12/31/2021 at 12:00 PM, PaleoOrdo said:

maybe rounded by the glacier or river:

 

Not necessarily, weathering in the soil zone can do that, too. Have a look at all the other rooks: All are quite rounded and smooth.

Franz Bernhard

[PaleoOrdo]

11 hours ago, FranzBernhard said:

You have got a lovely bunch of very old corals up there! Thanks for sharing!

You are welcome, hope you enjoyed!

11 hours ago, FranzBernhard said:

Not necessarily, weathering in the soil zone can do that, too. Have a look at all the other rooks: All are quite rounded and smooth.

Yes, that may be right. Moreover, I read somewhere that these corals was somehow rounded originally.

Edited January 3, 2022 by PaleoOrdo

[PaleoOrdo]

13 hours ago, TqB said:

The others (including the smaller circles of no. 2) look like the tabulate Sarcinula (order Sarcinulida) which has characteristic corallites joined by horizontal platforms, well known from the U. Ordovician of Norway. 

Yes, I can see the horizontal platforms in some of my rocks. Thanks a lot for the help. It is a great pleasure to know the order and genus name of my finds.

I found some information online on Sarincula which states that this genus we only can find in the Ordovician, and as I understand this genus is later in Ordovicium that other genus in the same order.

Why are the rings or corallittes so bright white in color? It the reason that they are preserved as calcite, while oriinally made of aragonite? I read somewhere that all corals in Palaeozoicum was made of aragonite.

Concering some of the first pictures, it is puzzling that the size of the coralittes in the same rock is not the same.

My finds of corals in the location includes also some chain corals and other tabulates which I will present in my next post.

Edited January 4, 2022 by PaleoOrdo

[PaleoOrdo]

Some chain corals from the same formation, which genus I not know:

 

[PaleoOrdo]

 

Concerning the above circular unknow coral, to the right side, with some other things, I took this photo with microscope:

 

Then there is this petoskey-like rock. Maybe a kind of rugose corals?

 

[FranzBernhard]

3 hours ago, PaleoOrdo said:

Then there is this petoskey-like rock. Maybe a kind of rugose corals?

Overall, it looks very much like the tabulate coral Thamnopora boloniensis of the middle Devonian (Eifelian) Plabutsch-Formation around me. Sure its not the same . Length of largest coral is ca. 49 mm.

 

Here are some more:
Thamnopora boloniensis (link to my personal homepage)

 

6 hours ago, PaleoOrdo said:

I read somewhere that these corals was somehow rounded originally.

For sure! Its possible to have the original roundish growth form preserved if the colonies were embedded in "mud" after their life.

If they were encased in pure limestone, they tend to form a "unity" with the host rock. On "smashing" (naturally or by man), you will get angular fragments, later rounded by different kinds of exogene actions.

Of course, you can also have a combination.

 

Very nice chain corals, it seem, you are having a coral dream land nearby .

 

Have you ever tried polishing small (< 5 cm), ugly or scratched specimens?

Franz Bernhard

[TqB]

9 hours ago, PaleoOrdo said:

I read somewhere that all corals in Palaeozoicum was made of aragonite.

It is Mesozoic and later corals (scleractinians) that are aragonite. Rugose and tabulate corals were probably mostly calcite, hence their usual good preservation.

[PaleoOrdo]

3 hours ago, TqB said:

It is Mesozoic and later corals (scleractinians) that are aragonite. Rugose and tabulate corals were probably mostly calcite, hence their usual good preservation.

Thank you for the explanation.

[PaleoOrdo]

7 hours ago, FranzBernhard said:

Overall, it looks very much like the tabulate coral Thamnopora boloniensis of the middle Devonian

Yes, it is quite similar in shape. Very nice speciemen in your homepage. Thanks for showing it. Is a Thamnopora boloniensis favosite or "rugose colonial"? If so, my speciemens should also be.

I find it difficult to see the difference between the rugose and the small colonial corals, as in this speciemen where it is two similar but different corals, in the middle to the left side in the photo (the rock is too big to bring home, so it is still in situ). One colonial and one rugose here?

7 hours ago, FranzBernhard said:

Very nice chain corals, it seem, you are having a coral dream land nearby

Indeed! It seems that in Late Ordovician corals are abundant, especially in this formation. 

7 hours ago, FranzBernhard said:

Have you ever tried polishing small (< 5 cm), ugly or scratched specimens?

So far I only clean the fossils with water and a toothbrush. The surface of the limestones are easily destoyed even if I use hot water. You have any advice of how to polish limestones? 

[FranzBernhard]

38 minutes ago, PaleoOrdo said:

Thamnopora boloniensis

This is a tabulate coral.

 

38 minutes ago, PaleoOrdo said:

The surface of the limestones are easily destoyed even if I use hot water.

Yes, same here! The weathering brings out the details and the contrast between fossil and host rock. Even a good scrub can destroy this surface layer.

Polishing should only be done on ugly specimens (scratched etc.). Just pieces you would not collect in the first place .

 

Usually, "my" Eifelian specimens give very poor contrast upon polishing and are very dark, nature is much better in doing that. Here is a usual example, with contrast quite strongly enhanced after scanning:

 

Here is an exceptional specimen, the only one of this colorfull and rather bright type I have:

 

Concerning polishing, you may check this out

 

and this:

 

You may also check out youtube, many vids about rock polishing there!

Franz Bernhard

Edited January 4, 2022 by FranzBernhard

[PaleoOrdo]

6 minutes ago, FranzBernhard said:

Usually, "my" specimen give very poor contrast upon polishing, nature is much better in that.

That is often the case, as in this rock from Ordovician, some small corals in it, which may be not so interesting, but the rock is sliced as if it was done by a machine and polished by nature into a straight very smooth surface and colored. It looks as if you look into the a painting or the Ordovician water:

 

 

Thanks a lot, Franz, for your very nice photos, advices and links for polishing!

[PaleoOrdo]

Another Sarincula tabulate coral I found show more clearly the shapes. It is found another place, and I wounder if this is a limestone or a sandstone? It would be helpful to know, because I not sure of the formation, if it is silurian or ordovician, the sandstones in the area being silurian.

Edited January 21, 2022 by PaleoOrdo