Dteutsche Gesellschaft für Geowissenschaften, Hannover
Doi
Abstract
The Nördlinger Ries is a circular, flat depression of
22-24 km diameter separating the Jurassic limestone
plateaus of the Franconian and Swabian Alb in
Southwest-Germany. Its centre is located 110
km NW of Munich, 70 km SSW of Nuremberg and
110 km E of Stuttgart. The Ries basin was formed
approximately 15 Million years ago (Gentner & Wagner,
1969; Staudacher et al., 1982) by an impact of a
stony meteorite less than 1 km in size (Shoemaker &
Chao, 1961; Stöffler, 1977).
The Ries crater represents one of the best preserved
and best investigated impact structures on Earth
(Bayerisches Geologisches Landesamt 1969, 1974,
1977; Hüttner & Schmidt-Kaler 1999; Stöffler &
Ostertag 1983). It gained wide public attention (e.g.,
Metz 1974, Steinert 1974, Lemcke 1981, Kavasch
1985, Pösges & Schieber 1994; Schieber 2004) and
served as training site for Apollo 17 astronauts in
August 1970 (e.g., Margolin 2000).
However, apart from its impact nature, the Ries basin
offers a great opportunity to study fossil lacustrine
microbialites. Such lacustrine deposits within impact
structures are of increasing interest for understanding
the origin and evolution of early life on Earth, and
possibly other planets (Cockell & Lee 2002, Osinski
et al. 2005, Cabrol et al. 2001). Therefore, the focus
on this field trip is on microbial and algal build-ups,
their facies context, and the discussion of microbial
effects and lake water chemistry.excursionguid