Gallia ist omnis divisa in partes tres…. erh, stop, that’s not quite the story I wanted to tell – although I have to admit that the longer I think about it, the more details come to mind, and the longer the series of posts I plan gets. And that’s something I do not wish to subject anyone to, least of all myself. I’ll instead try to KISS, and details be damned!
Let’s start with a very quick overview of the geology of the area I want to talk about, sprinkled with a few fossil pics for the less geologically and more zoologically minded. Here’s a geological map of the state of Baden-Württemberg, photographed at the Urweltmuseum Hauff, a museum that will play a big role in these posts.
As you can see on the map, the region is dominated by the Upper Rhine Valley in the west (the yellow stuff, see here), and a south-east tilted sedimentary region east of it. All the way on the flanks of the Rhine Graben, the Black Forest consists of a lot of granite basement rocks (pink), but its eastern flank is already made up of Triassic rocks (oranges). Those are overlain by the famous Swabian Jurassic (Lias, Dogger, Malm are the regional terms for Lower, Middle, and Upper Jurassic; green-violet-brown-blue on the map) – and that’s all there is of the Mesozoic. The foreland basin of the alps is filled in with (dinosaur-free, thus stinkin’) Tertiary stuff, the yellow on the map. YUCK! Along its northern border runs the Danube (again, roughly). There’s quite a lot of volcanic stuff, too, as you can see on the section, but I won’t delve into that at all.
This series of sediments you hit if you go NW-SE has harder and softer layers, and tilts very gently. As a consequence, especially the Jurassic part forms Schichtstufen (cuestas, in English geology speak): sharp rises leading onto tilted plateaus. This landscape includes the famous Schwäbische Alb (Swabian Jura – not Alps!), and that’s where most of the fossil come from that I am going to show you. The Triassic is also choke-full of fossils, but aside from my beloved Plateosaurus I have little photos to show, and admittedly comparatively little interest. it’s all non-dino stuff. YUCK again!
I was born in Tübingen (center of map), grew up in Stuttgart (a tad to the right and above Tübingen), and thus was exposed to fossils especially from the Jurassic early on. Ichthyosaurs are all over in regional museums. I previously showed a monster panorama of a Eurhinosaurus, here’s some more now.
Both at the Urweltmuseum Hauff, more on them later.
The Jurassic of the region is famous for its ammonites, too, which are wonderful playthings for geologists interested in stratigraphy. Because the layers are consecutive and choke-full of the little fossils, and because the species turn-over of ammonites was quick but not too quick, you can get a wonderful biostratigraphy. Friedrich August von Quenstedt, professor at Tübingen, worked on them a lot, and there is a really cool site that has high-resolution scans of all the plates of Quenstedt’s big work Die Ammonites des Schwäbischen Jura (Ammonites of the Swabian Jura). Check it out, the artwork is beautiful!
Enough for now; next post will describe some key fossiliferous layers a bit and get into some serious fossil-photo dumping!