Working on a profile

[Ludwigia]

I don't at all profess to be an expert at this. As a matter of fact, I've never done it before, but I've been thinking about trying this for quite a while. So this time when I visited my favorite site in the ditch at the side of the road in the Upper Danube Valley, I took along my camera, a pen and a few pieces of paper. I don't have a geologists compass and I forgot to bring along the measuring stick, so it was a pretty rudimentary first attempt. Starting at the base, I cleaned up the exposure where I'd previously been working over a stretch of about a meter's width and vertically up to the wall. Then I took a few photos, mostly using my hammer and a shovel as gauges. I needed 3 photos to get the whole profile in.

 

 

The hammer is at the bottom of the exposure, then there's a closeup somewhat higher up with the shovel in the photo above that and the pic at the top shows pretty well the whole exposure at a spot farther along the ditch, with the exception of the base, which was buried under rubble.

 

Continued...

 

 

 

[Ludwigia]

This site exposes the entire divisum zone in biostratigraphical terminology. It even reaches down to the next lower zone, the hypselocylum zone, which I discovered farther down the ditch a while ago, but most of it is still covered with debris, as is still the very bottom of the divisum zone, which I plan to dig up sometime in the future. But I'm in no great hurry to do that, since as far as I know, that part is practically free of fossils. These zones belong to the lithological Lacunosamergel Formation and the divisum zone, or Malm gamma, as it was called for generations, sits in the Crusoliensismergel, named after the Crussoliceras crusoliense ammonites which are quite common here. This section is the one that interests me the most, since that is where I've discovered the overwhelming majority of the fossils to be found here.

So I started methodically taking the horizons apart step by step. The base is composed of 3 horizons of argillaceous limestone (marl, or "Mergel" im German) approximately 20-30 cm. thick, each separated by a thin layer of soft clay marl which carries a lot of flatly pressed and friable fossils. Only the brachiopods survived 3-dimensionaly. I took some photos of these layers. You would think at first that you'd found something nice, but they are all only 2-dimensional.

 

 

Continued...

 

 

[Ludwigia]

The stone is harder in the middle of these horizons, and sometimes concretionary, which makes for well preserved fossils if you happen to hit the right spots, which I managed to do this time.

 

 

Continued...

 

[Ludwigia]

A few more.

 

The last and 4th limestone marl horizon is the hardest of all and can be extremely concretionary. This is where I first discovered that fossils could be found here and this time I pried out a block that was chock full of them and a couple of loose ones in the soft layer at the bottom.

 

 

That was, as I knew, the end of finding fossils for the day, but I continued on up with the profile.

 

Cotinued...

 

 

 

 

 

 

 

[Ludwigia]

Here is a photo showing the location between the two red lines of the marly limestone section which I have already described.

 

Above the marly limestone layers is a section of roughly 60cm. of soft marly clay which can be seen between the two red lnes in the following photo. A proper paleontologist would take some samples to sift through for microfossils, but I'm not that advanced. I have discovered two very large Pseudhimalayites uhlandi ammonites here during excavations, but they're extremely rare and anyway, I'm not digging closer in any more for fear of cliff collapse.

 

This is followed by increasingly hard marly limestone until a series of limestone banks interspersed with soft clay takes over, pictured above the red line.

 

Well, that's as far as I've gotten. Now I'll have to do some comparative studies on this formation in papers which have been published in the past from other sites and get this down on paper somehow. A nice private project for the winter months. One more thing I forgot to mention is that this section is in the middle of a sponge reef and sponges, although not always well enough preserved to keep, are extremely prevalent, almost rock-forming in parts.

By the way, I won't be able to prep the finds for a while. This time my air abrader got plugged up because my compressor was leaking oil, so now there are two things to get fixed this time.

 

 

 

[caldigger]

You found a fun place to play!

[Ludwigia]

2 minutes ago, caldigger said:

You found a fun place to play!

 

You said it!

[doushantuo]

wow,hi-res collecting by a member.

Me like,bigtime.

The Kimmeridge of Germany is of course known for its poriferan reefs

 

[doushantuo]

Schick's Gliederung und Typusprofil

http://www.naturkundemuseum-bw.de/sites/default/files/publikationen/serie-b/B346.pdf

(you'll probably already have that one,anyway)

[Ludwigia]

6 hours ago, doushantuo said:

Schick's Gliederung und Typusprofil

http://www.naturkundemuseum-bw.de/sites/default/files/publikationen/serie-b/B346.pdf

(you'll probably already have that one,anyway)

 

Thanks for your interest, but you're right. I've got that one and several others already. This isn't meant to be "bigtime". I'm just doing this for myself and learning as I go.

Another aside: I just learned that I might have to replace both abrader AND compressor

[doushantuo]

err actually,the "bigtime" is used adjectively here.

 

 

[PFOOLEY]

Inspirational.  Thank you for sharing.

[jpc]

very nice, ludwigia.  

Are those green ammonites I see in the last few pictures?!  Green!!??  or does the green come off with air abrasion? 

[tmaier]

The green ammonites aren't ripe yet, so you have to throw them back.

Man, that is great being able to have a profile in situ like that. Florida is fun to hunt, but most of what I end up finding are floats out of context, and that can be annoying. It is hard to tell the age and relationship between the fauna.

[Ludwigia]

4 hours ago, doushantuo said:

err actually,the "bigtime" is used adjectively here.

 

 

 

I actually figured on that with your Dutch sense of humor, but I thought I'd nevertheless set the record straight

 

2 hours ago, PFOOLEY said:

Inspirational.  Thank you for sharing.

 

Thanks, Mike, and you're welcome

 

2 hours ago, jpc said:

very nice, ludwigia.  

Are those green ammonites I see in the last few pictures?!  Green!!??  or does the green come off with air abrasion? 

 

The green is a fine layer of glauconite which, as you surmise, mostly disappears with abrasion, although sometimes a thin residue of color remains. Sometimes a bit of pyrite gets in there too. Did you get to the Gräfenberg quarry in Franconia when you were over here? It's famous for the "Grünlinge" which mostly retain the glauconite even after abrasion.

 

1 hour ago, tmaier said:

The green ammonites aren't ripe yet, so you have to throw them back.

Man, that is great being able to have a profile in situ like that. Florida is fun to hunt, but most of what I end up finding are floats out of context, and that can be annoying. It is hard to tell the age and relationship between the fauna.


 

 

Haha. Like green tomatoes, eh? You could still pickle them You're right about being able to find the fossils in their original context and reconstruct the paleogeographical circumstances. I know how frustrating it can be finding things in scree. Some forms and sculptures can continue in time through many zones and even stages, which can make identification extremely difficult.