Show us your reworked fossils or fossil-bearing breccia/conglomerate

[FranzBernhard]

I am starting this topic because of this one:

Would you like to show off your examples of reworked fossils still located in younger matrix or conglomerate/breccia with fossil-bearing clasts. I am quite eager to see some nice examples.

 

I have only one, most of you may already know this :

One of the clasts contains Eifelian corals.

 

Thanks you very much!!
Franz Bernhard

[Tidgy's Dad]

Nice topic, but I don't think I have any. 

[FranzBernhard]

51 minutes ago, Tidgy's Dad said:

I don't think I have any. 

This stuff is not uncommon, but lets see how many specimens are in collections. I think only very few - I have only this one shown above in my collection*.

 

*Well, the rudist-bearing "Knödelbrekzie" of the Campanian nearby could be also considered as such an occurrence - older clasts in younger matrix, but the age difference between clasts and matrix is only a few million years.

 

Franz Bernhard

[Ludwigia]

Here's my one and only. From a block out of the Torrener Ache in Bluntautal by Gölling. Not all that far from your stomping grounds. It got washed down from the mountains but it's Toarcian. Couldn't id the ammos, though. I know its not exactly what you're looking for, but it's the best I could find.

 

 

[FranzBernhard]

Thanks, @Ludwigia! It all depends on the age difference between clasts and matrix , but it looks very good! Is there any reference to this kind of stuff?

 

Thinking about the subject, so called "transgression breccias/conglomerates" come to my mind. There are some of these here in Styria:

- The Permian Präbichl-formation, but with only some microfossils in some clasts and none in the matrix:

  Praebichl-Formation (wikipedia, in German)

- The Santonian/Lower Campanian Geistthal-formation. According to literature, there are many fossiliferous clasts of different age (Devonian to Triassic) in this formation, but I have not found a pic until know. Nor have I examined this rock very closely myself.

  Geistthal-formation (external site, small pdf)

 

Problem with these formations is, that they are all terrestrial*, so fossils in the matrix are rather scarce to non-existent. The holy grail would be specimens with both older and younger macrofossils side by side...

 

* The "Eggenberger Brekzie" shown above does not contain fossils in its calcitic matrix. Age determination is by lateral correlation, but one clast of silicified wood was also found in this breccia (Taxodioxylon sequoianum):

Wood in Breccia (external site, pdf, in German)

 

Franz Bernhard

[Ludwigia]

3 hours ago, FranzBernhard said:

Is there any reference to this kind of stuff?

The only refernce I have is in Gero Moosleitner's well-known book "Fossiliensammeln im Salzburgerland".

I've just remembered another interesting piece where at least the provenance is interesting. The "Goniatitenkalk" in which the Goniatites are imbedded is a silty limestone of Early Carboniferous origin. They are to be found in tectonic clefts within the Late Devonian Reef Limestone at the quarry in Winterberg by Bad Grund, Lower Saxony. Just google "Goniatitenkalk Bad Grund" and you'll come up with some literature about it.

 

 

[CornelDumitru]

4 out of 5 confirmed (top left rock not cleared yet):

 

First (lower- left) investigated in :

 

 

 

Do they count? Only millimetric/centimetric fossil specimens can be found.