Wrapped fossil leaves

[FranzBernhard]

Hello,

 

I have found a site with wrapped fossil cretaceous leaves. The are in a silty-sandy bed several cm thick, extenting for several meters in strike. In some parts, the leaves are flat lying in the bedding plane (as expected), in some parts they are wrapped. That means, they are regularly bend (no kinks) up to about 90° (or even more?). In that way, they partly truncate the general bedding or, in other words, that part of the sediment containing the wrapped leaves is not well layered, more massive.

 

Has anybody encountered that kind of wrapped leaf preservation also? Does anybody know any literature about this subject?

 

Well, these leaves are supposed to be Credneria, which is somewhat notorious for enrolled preservation! German Wikipedia gives the following explanation (g. translation):

"In addition, the leaves from the Blankenburg quarry are usually rolled up at the edge or completely like a bag. This led to the assumption that they were twisted by drying out and were thus embedded in sand dunes."

 

The environment "my" leaves are found in are not dune sands, judging from published data and own observations.

 

Thank you very much for your help!
Franz Bernhard

[jpc]

I have seen similar preservation in the late Cretaceous here in Wyoming.  Usually in sand bar deposits.  No pix available

[Ludwigia]

Hi Franz. Looks like you've already found mine here.

[FranzBernhard]

12 hours ago, jpc said:

Usually in sand bar deposits.

Thanks for your reply! Highly interesting.

These sand bars are strictly or by definition subaquatic? Do you know of any literature, reports etc. describing this leaf occurrences? Thank you!

Meanwhile, I have taken a few oriented specimens from the leaf-outcrop. It appears, that leaves are embedded in the rock mostly with the open side roughly upwards, that means, they look somewhat like boats. This is also reflected in the shape of bigger, multi-leaf specimens, which are "convex" at the bottom side and "concave" at the top side. But this is all veeeery preliminary. There are also spots within this bed with more or less flat leaves throughout or flat leaves on top of the wrapped leaves.

The matrix of the wrapped leaves is quite sandy (0.x mm grain size) and "clean". The matrix of flat leaves appears somewhat finer-grained, still with sand particles, but more clayey and thinly, but not very well, laminated.

Franz Bernhard

Edited August 25, 2022 by FranzBernhard

[rocket]

We had some in Westfalia, see (PDF) Wittler, F., Kaplan, U. & Scheer, U. (1999): Zwei stratigraphisch bedeutsame Aufschlüsse im Santon (Oberkreide) des westlichen Ruhrgebietes.- Dortmunder Beiträge zur Landeskunde, naturwiss. Mitt., 33: pp 133-136. (researchgate.net)

I add one leaf, we had several...

 

[rocket]

[Ludwigia]

It appears to me that sandstone is conducive to such preservation.

[rocket]

In Westfalia it was very special. Seems to be algue, beach, storm. Combination of this was the interpretation of the site.

We started to write a hugh paper about the site and the "nodules", but never finished.

I am curious about seeing the leaves and fossils from FranzBernhard and the ones from jps coming from Wyoming. Would you post some?

We have the old material from Gelsenkirchen stored in our collection, I can do more pics if necessary

Edited August 25, 2022 by rocket

[FranzBernhard]

Thanks so much @rocket for the paper. "Plants wrapped around nodules" - quite spectacular!

My fossil friend has photographed all the specimens, but I don´t now, if he included wrapped ones. Have to look through the 8 GB of pics. If I find something, I will pm you.

I will try to photograph one newly found specimen myself, which is not only regularly enrolled by about 90°, but also has a kink with about 60°, perpendicular to the axis of enrolling.

Meanwhile, here is large, rather flat specimen photographed myself and a somewhat bend and wrinkled specimen from the discovery day. These specimens have been stuck in a tree ball.

 

Just adding a view of the outcrop. The leaf bed is at the lower end of the screwdriver and just below the red object (which is about 12 cm high), extending to the left and right. General lithology of the outcrop is sandstone. This "quarry" was not dug by man, but by a falling tree .

Franz Bernhard

Edited August 25, 2022 by FranzBernhard

[rocket]

wow, great site, lovely plants! Thanks for sharing, never seen!

Are there any other fossils to find like insect, vertebrate-fossil-remains or other?

Our nodules contained everything "from the beach", including fish-remains, crinoid-parts, early mammal- and dino-teeth and more

 

[FranzBernhard]

40 minutes ago, rocket said:

Are there any other fossils to find like insect, vertebrate-fossil-remains or other?

Well, the several hundred meter thick succession in this general area is considered to be "distal alluvial facies" in a PhD thesis from 1995. Composed of sandstones, siltstones and local m-thick conglomerate beds. Fossil leaves are also found at some other sites in this facies, but much less abundant. The area around this leaf site contains several occurrences of oncolites, stratigraphically below and above this particular leaf site. My fossil friend found a Trochactaeon snail several years ago in a conglomerate bed in this area. A small reptile skull was found about 2 km away, also in the alluvial facies. Nothing published about that skull yet, unfortunately.

In this particular leaf bed, nothing else besides plants was found yet. Unidentifiable plant debris is abundant, perhaps some small seeds, but this is not certain. No animal remains of any kind yet.

Here is the official geo map of the area, plant fossil site is within the large oncolite area, proximal and distal alluvial facies not distinguished (alluvial Geistthal-formation). The more yellowish areas are clastic marine Afling-formation. The small greenish areas are lacustrine St. Pankrazen-formation, mostly somewhat bituminous marls:

 

40 minutes ago, rocket said:

Our nodules contained everything "from the beach", including fish-remains, crinoid-parts, early mammal- and dino-teeth and more

Nodules with yummy cores - that´s something really special.

 

Franz Bernhard

 

Edited August 25, 2022 by FranzBernhard

[rocket]

3 hours ago, FranzBernhard said:

 

Nodules with yummy cores - that´s something really special.

 

Franz Bernhard

 

 

I will add some next days, know where the boxes are in our fossil-lagerstätte 

[jpc]

I would love to add some pix, but I think I only have one specimen at home.  I say I would love to add a photo, but if you notice how long it is taking me to get additional photos of traveling Sara up... it may be a while.   Any others I have collected might be in the U of Wyoming collection, but we were collecting mammals and may not have collected the leaves.  Memory is weak as that was 30 years ago.  

[FranzBernhard]

Here is one of those wrapped leaves. It bends quite regularly parallel to its main axis by about 90°. Additionally, its kinked near the tip by about 50° in another direction. Leaf is photographed probably upside down (It was found in a loose block).

@rocket, @jpc

Franz Bernhard

 

[rocket]

wow, cool one, the Crednaria..., wrapped like the westphalian ones

I took some of your collection in the photo-room, hope to find time today or tomorrow for good pics

[Sjfriend]

My local Miocene plant location often produces leaves that are bent / partially rolled. The matrix grain varies from sandy to very fine silt / mud . The bent/rolled leaves can be found mixed in the same layer as flat specimens. The deposition appears to be mostly slow flowing to still water freshwater environments. Often I find the bent leaves in localized (less than 10cm) filled depression looking spots within the plane. None have ever looked exactly like tracks but it often resembles what I've seen when I've stepped in a muddy spot with leaves but on a smaller scale.

 

Currently can't provide photos as I'm away from home. 

[Opabinia Blues]

I have seen exactly this in the mudstones of the Metseetsee Formation at the Big Cedar Ridge site in Wyoming. It makes the fossils very difficult to split out intact.