PD Dr. Michael W. Rasser

The Steinheim Basin (Steinheim am Albuch) is a meteorite impact crater formed ca. 15 Ma b.p. In this basin, a long-lived lake developed that existed over several hundred thousands of years. This lake contains a low-diverse snail fauna with Gyraulus being the dominant genus. The ubiquitous form Gyraulus kleini settled in an early lake stage. It is the founder species of a flock with 17 endemic forms. Several aberrant forms are known from this flock, ranging from small, fragile shells that are secondary uncoiled like a cork screw, and on the other side very large, trochiform shells with thick shells and knobs. The topic of this project is to reconstruct the factors that controlled this unique shell evolution.

Freshwater snails are among the main biogenic components in the Miocene of SW Germany. These include fossil lagerstaetten of the Swabian Alb (Randeck Maar, Steinheim Basin), as well as numerous localities in the North Alpine Foreland Basin, also know as Molasse Basin. The aims of this project are twofold: First, the snails of the particular localities are recorded and documented systematically. Based on this data, the snails are used as palecological proxies in order to reconstruct Miocene continental ecosystems.

Several non-marine aquatic deposits occur in the Miocene of the North Alpine Foreland Basin. I am currently focusin on three of them: (1) The Steinheim Basin (see my other topic), an impact crater with purely carbonate sediments and microbial bioherms, (2) the Randeck Maar, a volcanic crater with unusual fine-laminated sediments, (3) A kilometer-long lake district along the southern margin of the Swabian Alb, known as Silvana limestone. The aim of this topic is to reconstruct the lakes as paleoenvironments, using multiple methodological approaches, including microfacies analyses, stable isotopes, and geophysics.

Rhodoliths are nodules formed by calcareous red algae. The are lying on the substratum, are unattached, and therefore reflect the ecological conditions of their living/depositional environment.  This makes them valuable palecological proxies for fossil environments. Pliocene and Quaternary rhodoliths are studied in cooperation with partners from Acores and Lisbon. Of particular interest is Cabo Verde, where rhodoliths are preserved within tsunami sediments. Using actuopaleontological methods, we aim to analyze, how tsunamis affect shelf and coastal areas.

(DFG RA 1597/3-1 „Rhodoliths from the Cape Verde Archipelago: insights into climate change and megatsunami sediment dynamics”)

Over the last hundred thousands of years, huge travetine bodies have formed along the Neckar valley during different time-slices. Intercalated are tools from early humans, most probably Homo heidelbergensis. This project aims to reconstruct the paleoenvironments and the factors that have controlled the formation and depositional rhythms of this deposit.