Sunday, March 2, 2008

Weekend Fun again!

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I just spent two nice weeks in the south of Germany. That's the explaination for the total lack of activity here. Some things are just more important...
Anyways. On one of our sight-seeing tours I couldn't help but pick up some rocks. Here I show you one for this weekend's fun! I included a pencil for scale. I hope you will have some fun guessing, however, I think this one is pretty easy to get.

5 comments :

Silver Fox said...

Well, it looks a bit like ferricrete, though a few of the small fragments look a little like shells (fossils) - still, I vote for ferricrete.

And welcome back, I've been checking almost daily.

The Lost Geologist said...

Great to see that I have such active readers!

About the rock...I think you need to think about something else. ;)

Mel said...

Matrix supported conglomerate is my vote. Is the round ball an armored mudball? I don't really see armoring on it though. I've also seen volcaniclastic rocks that look like that.

Silver Fox said...

Okay, I'm going to have to go with either 1) some reddish, conglomeratic dirt or 2) some reddish concrete. Maybe it's one of those trick tests like they used to give in class! Otherwise, I'm stumped. That is, unless Mel already got the right answer.

The Lost Geologist said...

It is a piece of volcanic ash or tuff from the Phonolite complex of Singen-Hohentwiel that is surrounded by redish tuff erupted around 10 Ma ago. That's what you see. The tuff also contains lapilli (the round thing) of various sizes and volcanic bombs up to 80 cm across. I will make a more detailed description on the blog soon.