With the opportunity to travel to Germany last year, I couldn’t help but include some time for geotourism in my schedule. Thankfully, due to the ever-present nature of geology on the solid earth, there is rarely a location without some feature of interest to explore. I present the following highlights in reverse-geochronological order, as a sort of stratigraphic column tour of the places I visited.
Nördlinger Ries Impact Crater
14.4 Ma (Miocene)
Evidence of shock metamorphism in local rocks provided evidence pointing towards the meteor impact formation of this valley, rather than volcanism as previously thought. The shock metamorphosed rock includes sub-millimeter sized diamonds formed from graphite deposits being subjected to the intense heat and pressure of the meteor impact. The 15 mile diameter crater remnant is also unique on Earth for its rampart morphology, with ejecta (material thrown out from the surface due to the impact) flow giving evidence for a water saturated or shallow marine environment at the time of impact. The nearby Steinheim crater, also notable for its central peak, suggests that the impacts that formed these two features was caused by a binary object, or one that separated into two objects soon before near-simultaneous impact.
Siebengebirge Columnar Basalt
28-15 Ma (Cenozoic)
Volcanism accompanied the European Cenozoic Rift System, some of which continued into the Quaternary. At Siebengebirge, the only remnants of past fiery activity are the columnar basalts, heavily utilized in local stone construction, and folklore of the dragon and its legendary defeat at Drachenfels.
European Cenozoic Rift System
33.9-23 Ma (Oligocene)
Spanning central Europe southwest to northeast, from France to the Czech Republic, this rift system could have formed in response to the formation of the Alps, their orogeny. The Rhine river follows some of the major rifts (bearing the river as their namesake as the Upper and Lower Rhine Grabens) from its headwaters in the Alps, through western Germany and the Netherlands eventually into the North Sea. An eastern member of this rift system, the Eger Graben runs parallel to the Ore Mountains that form a portion of the border between Germany and the Czech Republic, adjacent to the Elbe Sandstone Mountains.
140-66 Ma (Late Mesozoic)
The Alps are a member of a continent-spanning orogeny (mountain formation events), ranging from the Pyrenees and Atlas Mountains in the west, to the Himalayas and Sumatra in the east. As the African, Arabian, and Indian plates collided with the Eurasian plate, the mountain forming processes uplifted former seafloor sediments, closing much of the Tethys Ocean. The basins of the Mediterranean, Black, and Caspian Seas stand as remnants of this ancient ocean.
The Elbe Sandstone Mountains
140-66 Ma (Late Mesozoic)
Formed within the Alpine-Himalayan orogeny, these ocean sediments were uplifted and eroded into stunning sculptures and forested mesas now cut by the winding Elbe river.
The Rhine Gorge
420-360 Ma (Devonian)
The fosiliferous sediments that constitute the Rhenish Facies of this region were deposited in a shallow marine environment 400 million years ago. Later uplift and subsequent erosion by waters flowing from the newly formed mountains carved the gorge that is seen today, centered on the confluence of the Mosel with the Rhine at Koblenz.
Apollo 16 Moon Rock
~4000 Ma (Pre-Imbrian)
The Rieskrater Museum in Nördlingen features a Moon rock from the anorthositic lunar highlands, brought back by the Apollo 16 astronauts – a gift from NASA following geological training for the Apollo missions around Nördlinger Ries.