Stalk?

[Mareczek]

Hi, it's my first post here.

I found some fossils like this and asked about this on polish forum and i got help - it's a probably stromatoporoids.

On one of them it's a something what looks like stalk. I don't know but probably is only core/internal layers (rest decay). It is possible that something gather inside (alga)?

Found in southern Poland - Layer; middle or late jurrasic period.

What do you think? (sorry for my english).

Edited July 13, 2015 by Mareczek

[ZiggieCie]

Welcome to the Forum.

Could it be from an area that it might be driftwood?

[Pumpkinhead]

I find stuff like that around stromatoporoid fossils around the silurian rocks where I am sometimes too. I'll be interested to see what they are

[Auspex]

These are very interesting! I, too, would like to learn what they are.

Welcome to the Forum

[abyssunder]

In my opinion, they are fossilized(crystallized) branches of trees or something like that,the first one have a leaf on the external surface.

[Mareczek]

Thanks for your response,

Wood - Branch was my first thought. But i don't show you all. In one of these fossils collector who helped me, identified a belemnite phragmocone interior.

http://postimg.org/image/5o20aadcf/

I found in this place subfossil wood but it's look totaly otherwise (probably different period).

Edited July 13, 2015 by Mareczek

[abyssunder]

Looking at your last picture, I have to change my opinion.What you show there is a Belemnitida(Belemnites) with the conical shaped phragmocone(containing the chambers and the siphuncle) pointed into the rostrum`s posterior part.The rostrum of the belemnoid is bullet-shaped.A transverse section of the rostrum (wich could be round or oval in shape) reveals radiating fibrous structure,and sometimes visible concentric structure. Here is one of my belemnites in transverse section with the concentric structure visible:

The morphology of Belemnoidea is shown in this picture:

In conclusion I would say,that your specimens presented are belemnites fragments,and in the first picture on the external surface is not a fossilized leaf but could be a mineralization/chrystalization pattern (Aragonit?).

[Auspex]

I find Abyssunder's analysis to be compelling, based on the physical evidence.

[Mareczek]

Thanks for images Abyssunder! Between radial structure [X] and concentric structure [O] is big difference. I wonder if it depends on the species or the mechanism of fossilization.

[abyssunder]

As I mentioned,in a transverse section of a belemnite rostrum coexist the radial(prisms of calcite) and the concentric pattern (both visible in my exemple), the radial due to the mineralization process in time and the concentric due to the growth of the belemnite. Like in a petrified wood the rings are the growth rings. In longitudinal section the rostrum has a cone-in-cone structure(visible very well in your last photo - a beautiful example).

"In 1951,when H.C.Urey and his collaborators carried out the first application of the paleothermometry method using a Jurassic belemnite, they took advantage of the particularly simple microstructure of this fossil: the massive conical rostrum(Fig.2.11a) in which prisms of calcite are radially arranged (Fig.2.11b).Thin sectioning or etching shows that the concentric growth layering is also preserved (Fig.2.11c and2.11d).Through regularly spaced sampling of carbonate material along a radius of the section (Fig.2.11b), they were able to measure the O16/O18 and C12/C13 isotope ratios that had been recorded in the superposed growth layers produced by this belemnite during its lifetime. In a few lines, they described precisely the living conditions for the animal that built this rostrum about 150 million Years ago." Biominerals and Fossils Through Time - Jean Pierre Cuif,Yannicke Dauphin,James E. Sorauf.

H.C.Urey document is here: https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Isotopes-and-paleotemperature/more/Urey-et-al-1951.pdf

Hope all these helps.

[Herb]

I believe it is a Belemnite also.

[Carl]

Sorry folks, I'm getting a strictly geoloigic vibe here. It doesn't look like the belemnites I am familiar with at all.

[Plax]

do they react to mild acid (vinegar)? I agree with Carl for what they aren't. Am thinking broken and worn cave deposits? Mareczek could rule this out by telling us if they were broken out of solid rock or found loose. Your english is very good!

[Guguita2104]

Yes, it doesn't seem a belemnite phragmocone. I have lots of belemnites shells and some phragmocones, because they are very common in Portuguese geological formations ..

They are usually like that (these aren't mine):

Edited July 15, 2015 by Guguita2104

[Auspex]

On closer examination:

This, and the exterior shape and texture, are wood-like.

[donnyjoe]

I vote for wood as well.

[DPS Ammonite]

I also think that it is wood that has been compressed into an oval shape. Most of the belemnites that I have seen keep their circular cross section because they were hard when they were deposited. I also don't see the tapering points and smooth sides that belemnites usually have.

[Mareczek]

do they react to mild acid (vinegar)? I agree with Carl for what they aren't. Am thinking broken and worn cave deposits? Mareczek could rule this out by telling us if they were broken out of solid rock or found loose. Your english is very good!

I use vinegar and hear quiet "tsss" - react. I didn't have to dig! It's lay on the ground. I found this on the top of mining heap, in my area were iron ore mines. Phragmocone-like part i found on another heap than rest of parts (heaps are spaced 3km). In this place I found other fossils like that (right side - probably part of Reineckeia Amonite).

Edited July 16, 2015 by Mareczek

[Auspex]

Ah, I misunderstood, and thought that the phragmocone was in the same matrix. I an much more comfortable now in thinking that the 'stems' are petrified wood.

[abyssunder]

I agree.

[Herb]

I change my vote to wood also.

[Mareczek]

Hi all,

I found the answer. I get another one - these dendritic lines are a strong radial partitions.

If the incremental layer (concentric) degrades we can see it on surface.

Edited August 1, 2015 by Mareczek

[abyssunder]

Definitely they are not Belemnites.Nice finds.Thank you for the update.

[abyssunder]

Just want to add to this topic, after years, what I think is interesting in the realm of iron:

 

reference: D. Ashkenazi et al. 2016. Brass-iron couple and brass-iron-wood ternary system of metal objects from the Akko 1 shipwreck (Israel). Corrosion Science 110:228-241