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Some Rudists from the Campanian St. Bartholomä-formation, Gosau group, Eastern Alps (St. Bartholomä, Styria, Austria)


FranzBernhard

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FranzBernhard

From time to time, I would like to post specimens from the Campanian St. Bartholomä-formation in Styria, Austria, in this thread.

 

For the first specimen, I was motivated by this thread:

http://www.thefossilforum.com/index.php?/topic/91459-is-this-a-rudist-fossil/

 

So the first specimen is a fragment of a large Vaccinites alpinus, with only two pillars - and not much else.

VaccinitesAlpinus_Fragment_25_3962_kompr.thumb.jpg.c13c60b13736e1f1b6c96f1fa87bb98a.jpg

 

Franz Bernhard

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Great! 

I look forward to following this thread! :)

 

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FranzBernhard
Just now, Tidgy's Dad said:

I look forward to following this thread!

Thanks! Will take some time...

Franz Bernhard

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On 1/11/2019 at 10:47 AM, FranzBernhard said:

Thanks! Will take some time...

Franz Bernhard

No hurry!

:popcorn:

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FranzBernhard

This is a serial section through a specimen with two Hippurites colliciatus, the rudists are mostly surrounded by fossiliferous limestone. The series of pics consists of three pieces, cut from one specimen. AN4119 (0 mm) is the lowermost piece, apical view. Its an end piece and the polished surface is very near the lower end of the left rudist, where it has been broken some time after his death. The other two pieces are slabs, each about 10 mm (AN4120) and 11 mm (AN4121) thick. These slabs are polished on both sides, and I have flipped the adapical views, to have them the same orientation as the apical views (for better comparison).

 

This series, presenting about 3 cm of height within two rudists, demonstrates two things:

1. The filling of rudists can change within centimeters. From nearly the same stuff as the matrix (fossiliferous limestone, the topmost two sections), to sparry calcite (the lowermost two sections, right rudist) to some younger, greenish sediment, introduced into the rudist during its redeposition within a debris flow, resulting in a rock called deprite (in an english paper) or "Knödelbrekzie" (in a german paper). 

2. It strongly depends on where you are sectioning a rudist, if you can see the position of teeth and muscles. In this specimen, position of teeth and one muscle can be clearly seen in the section at 14 mm (left rudist) and in the section at 18 mm (right rudist). Preservation of teeth and muscle positions depend especially on the timing of the loss of the upper valve and the timing of the dissolution of the inner, aragonitic shell. 

AN_HippuritesColliciatus_25_AN4119bisAN4121_kompr.thumb.jpg.00ec4636d159a83af9f328aa7b1e236a.jpg

 

Franz Bernhard

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Very informative and great photos. :)

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FranzBernhard

This is my display of hippuritid rudists from St. Bartholomä. All specimens were collected from July 2017 to October 2018. Nearly all are from point 25 east of Kalchberg, except Nr. 3 (from point 38 east of Kalchberg) and Nr. 8 (from point 36 west of Kalchberg). Specimen 4a is about 20 cm high, specimen 10 is about 10 cm high.

1: Hippurites colliciatus, pseudocolony, not very well preserved.

2: H. colliciatus, strongly bend individual.

3: H. colliciatus, pseudocolony of two individuals.

4: H. nabresinensis, one individual consisting of two parts, 4b with partial preserved upper valve. The story behind this specimen is already presented in my blog:

    http://www.thefossilforum.com/index.php?/blogs/blog/179-rudist-digging-at-point-25-st-bartholomä-styria-austria-campanian-gosau-group/

5: Vaccinites vesiculosus, somewhat bend, large specimen. The two parts were found about 0.5 m apart, but at the same day (in contrast to Nr. 4 ;)).

6: V. vesiculosus, large, strongly bend fragment.

7: V. alpinus, large, straight fragment.

8: V. alpinus with apex, slowly growing in diameter with height.

9. V. alpinus, short fragment with apex, fast growing in diameter with height.

10. V. cf. sulcatus, with supposed natural upper end (but no upper valve).

Hippuritide_Austellung_1.thumb.jpg.e0dd2c8d814202f20b6e1994177845d5.jpg

Franz Bernhard

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Beautiful collection! :wub:

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This is wonderful, Franz!

Thanks for sharing these. :) 

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FranzBernhard
12 hours ago, Tidgy's Dad said:

Beautiful collection! 

 

11 hours ago, Fossildude19 said:

This is wonderful, Franz!

 

11 hours ago, abyssunder said:

Nice collection!

Thanks for all your appreciation!
Franz Bernhard

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FranzBernhard

In this post, I am presenting one of the heaviest (> 5 kg) and maybe also the most spectacular rudist specimens from my hunting trips in the St. Bartholomä-formation.

It has a short, but rather funny story to it: I was running out of time during one of my hunting trips and so I took a short cut. Well, that was the reason why I stumbled upon "The Pipe Organ". It was simply lying around in the litter on the trail, just waiting for me. I don´t know, how long it has been waiting... Exceptionally, I am posting also some field pics of this find in this thread. The specimen is near the read pocket knife and as found, pics from 04/02/2018. I have collected and dug in this area several times later on, found other some nice rudists, but not another "Pipe Organ". The site is still very, very far away from being exhausted, so maybe... And, my January FOTM entry is also from this site (point 36).

36_Zusammenstellung_02042018_kompr.thumb.jpg.68471e91165e97de2192bf773bae54ba.jpg

 

HippuritesNabresinensis_36_E_kompr.thumb.jpg.59c25b9b781e5a0e72195c97a1180b46.jpg

Franz Bernhard

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A nice piece, and a nice beech tree forest, too. They look the same here, now (beech tree forests). Not an ideal place to hunt fossils, though, as leaf litter covers everything. Good eagle eye, Frantz.

 

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Great find! :)

And what a monster! 

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FranzBernhard

Two Hippurites colliciatus and a radiolitid rudist (Radiolides angeiodes?) loosely grown together. The two slabs are about 3 mm apart. Upright position of the H. colliciatus can be discerned from the arrangement of the pillars, upright position of the radiolitid (L = ligamentary pillar) from its outer shape.

T = Position of one of the theeth of the radiolitid. It is very uncommon, that a tooth position is documented by the green, younger sediment in this specimens. It seems, that in an early stage, sediment had filled the narrow gap between the tooth and the inner shell. Later on, tooth and inner shell were lost and the resulting void filled with greenish, younger sediment. The filling of the two H. colliciatus is also mostly of the younger type (judging from the quartz grains it contains), despite its atypical color.

Lb = Two Lithophaga borings.

All three rudists contain "geologic levels" (or "fossil levels"), one of them a rather complex one, all of them slightly inclined to the lower left.

AN4129_AN4130_kompr.thumb.jpg.f667d102370adbdacdc92971939c126d.jpg

Franz Bernhard

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DeepTimeIsotopes

Very nice! This is a great thread you’ve got going.:dinothumb:

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Informative, beautiful and great photos.:)

Again.

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FranzBernhard

Radiolitid rudist transverse sections, about 3 mm apart. This specimen seems to be disintegrating in a very strange way, don´t know what exactly happens here.

A small part of the rudist is filled with younger, green sediment, everything else is filled with quite homogeneous, fossiliferous limestone.

T could be the position of a former tooth. This would mean, that the part of the inner shell, that is now filled with the green sediment, was lost rather late in the rudist´s history.

AN4124_AN4125_kompr.thumb.jpg.13a3389d0673d50f2d7a67730c1b420b.jpg

Taxonomically, I am at a loos with the radiolitids... 

 

For comparison, I am posting an upper valve and a transverse section of the lower valve of more completely preserved radiolitids from the literature (Skelton, 2013).

Radiolitid_Skelton2013_Detail.thumb.jpg.9ea04a25596520bff92506f29e41c09d.jpg

 

Franz Bernhard

 

 

 

 

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These were such odd creatures! :headscratch:

Thank you for taking the time to post these and teach us about them. :) 

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FranzBernhard
On 14.1.2019 at 5:23 PM, Quer said:

A nice piece

Thanks, this one was really a big surprise. 

On 14.1.2019 at 5:23 PM, Quer said:

Good eagle eye

No, no, normal eyesight with glasses, but nearly blind without ;). But one gets used to some fossils and its typical patters. For rudists, the longitudinal ribbing/structure is typical and can be spotted from several meters away. Sometimes, it turns out to be a piece of sandstone, tough...

 

On 14.1.2019 at 9:03 PM, Tidgy's Dad said:

Great find!

Thanks!

On 14.1.2019 at 9:03 PM, Tidgy's Dad said:

And what a monster! 

Yes, it´s somewhat monstrous, at least for this formation.

 

On 16.1.2019 at 3:55 PM, UtahFossilHunter said:

Very nice!

So someone is enjoying it? ;);) Thanks!

 

On 16.1.2019 at 7:58 PM, Tidgy's Dad said:

Informative, beautiful and great photos.

Thanks!

 

11 hours ago, Fossildude19 said:

These were such odd creatures!

Yes, they are! It´s really a pity, that they are extinct!

11 hours ago, Fossildude19 said:

Thank you for taking the time to post these

You are welcome! I am just sharing my humble specimens :).

11 hours ago, Fossildude19 said:

teach us about them.

I am teaching mainly myself ;). I have to take a closer look while posting them and I am learning always something new, when looking closely at them. And describing the observations in English is really difficult for me. But that is good, in this way I have to think a little bit more.
Franz Bernhard

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FranzBernhard

From the outside, this specimen is rough, pitted, butchered and cracked and with a rather large amount of fossiliferous limestone attached to it, but it was clear, that it is a bi-valve radiolitid with its apex preserved - nothing that is super-abundant. I decided to cut off the apex first (to see if there is a L-pillar, yes, there is one, but not very well visible in the pic) and then cut it vertically.

The vertical sections clearly show the different structures of the two valves: The lower valve is cellular, the upper valve massive-lamellar (When I think about it, this difference seems to be a very strange "behavior" ;).) This results in some borings of clionid sponges in the upper valve, in contrast to the lower valve, which is devoid of such borings. (I have read somewhere, that the cellular structure of the lower valve has evolved to avoid such borings - ?)

The rudist is filled with sparry, somewhat drusy calcite and fossiliferous limestone (quite similar to the limestone outside of the rudist). The sparry calcite may result, at least in part, from recrystallization of the inner shell. I think, the position of the teeth (T) can still be recognized.

Radiolitid_AN3936_AN3937_kompr.thumb.jpg.76ec40c2f8369d2a5aab6855882419bc.jpg

Franz Bernhard

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FranzBernhard

From the outside, this radiolitid specimen is as ugly as the above one. But it has also the apex preserved and is also a bi-valve one. On cutting vertically, it shows a nice cellular lower valve and a thin, but massive upper valve with abundant clionid borings.

 

But it has a totally different infill, consisting of different clasts of fossiliferous limestones, a clast of a finely cellular fossil (What could this be?) and a light greenish marl clast (at the apex), embedded in greenish, younger sediment. How can this happen, the rudist appears to be closed? Well, there is big hole in the upper valve, where the clasts had no problem entering the interior of the rudist. A small part of this hole can be seen in the middle part of the upper valve of the right specimen. So the infill of this specimen is a small-scale example of the "Knödelbrekzie" (which contained this rudist), with the exception, that the infill is matrix-supported unlike the mostly clast-supported, normal "Knödelbrekzie".

 

The lower valve has cracks filled with greenish, younger sediment; this infill indicates, that this crack may have formed during or shortly after redeposition of the rudist into the "Knödelbrekzie" (= debrite).

 

At the outside, the lower valve has some small patches of fossiliferous limestone as well as the greenish, younger sediment attached to it. The first one indicates, that the rudist has not grown immediately before it was transported and deposited within the "Knödelbrekzie", but that it was once part of the fossiliferous limestone, and that it was largely, but not completely, freed from matrix before its redeposition.

 

To make things a little bit more clear, I have attached an abstract of a paper dealing with a similar Gosau occurrence in Carinthia, Austria. The situation in St. Bartholomä appears to be quite similar. My hippuritid species names depend on this paper, too.

 

I think, that´s all for the moment... :headscratch:

AN_Radiolitid_AN4055_AN4056_kompr.thumb.jpg.0bacb87c8738ddfc7eb747af9f3a3247.jpg

 

Wietersdorf.jpg.d6b4301fe12116c34984096faee0de5d.jpg

 

Franz Bernhard

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FranzBernhard

This is a one-of-a-kind find. Its from my digging at point 25 east of Kalchberg. No prep involved, just cleaning with a soft brush and water.

Its a pseudocolony of 3 radiolitid rudists, two of them are nearly empty, the left one is about 3 cm deep. The upper valve of this one is preserved as a ring, firmly attached to the lower valve. The right one has also some traces of the upper valve. All three have a ligamentary pillar, especially visible at the left one. As in most cases, the lower valve is cellular (visible at the right rudist) and the upper valve is massive-lamellar.

 

It´s a somewhat eye-catching specimen in person (pic is not very good), at least if one knows all the other dozens and dozens of butchered and broken rudists from St. Bartholomä. But nothing to compare with @Quer´s superb rudist specimens:). And it is also not really educative, but one for the display shelf ;).

Radiolitid_25_3963_kompr.thumb.jpg.1e4fd10d6615243c27d647212b8dfe92.jpg

Franz Bernhard

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Nice to catch up with this thread. 

I rather like that last one, very nice as a display piece. :)

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  • 2 weeks later...
FranzBernhard

After a break, the next one :).

Polished serial section of a Hippurites colliciatus, somewhat oblique cut, firmly embedded in fossiliferous limestone with several radiolitid fragments. The Lithophaga boring makes this specimen somewhat special.

25 mm (topmost section). Nothing very special, part of the rudist´s shell is missing, both pillars are present.

14 mm: Oops, one pillar is lost and something strange is going on...

11 mm: Oh, now are both pillars there again, but only the half of each. A Lithophaga (some shell is preserved) was boring around, removing filling, pillar and shell substance of the rudist. It seems that the pillars are somewhat wrapping around the Lithophaga, but the don´t, they are sharply cut by the boring. Maybe there is also a smaller Lithophaga and there are also some geologic levels present.

0 mm (lowermost section): One pillar is completely missing again, but unfortunately, the H. colliciatus is completely filled with younger, greenish sediment, erasing all evidence of the Lithophaga boring at this level.

AN4067_AN4068_kompr.thumb.jpg.76ead10d654afecf7b0df0b045505d71.jpg

Franz Bernhard

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