Topic description:
Stromatolites are layered marine carbonates that were directly precipitated from ancient seawater in the presence of microorganisms and are the oldest so far known geological remnants of microbial life on Earth. During the course of the KLI colloquium talk, I will highlight the application and the potential of geochemical proxies, in particular the Rare Earth Elements (REE) and radiogenic Sm-Nd isotope systems, in marine chemical sediments to evaluate the physico-chemical conditions of ancient environments, i.e. potential habitat in which the earliest life on Earth may have thrived and established. Setting the reconstructed habitat in relationship to suggested biochemical models of the origin of life is essential to evaluate, if the stromatolite environment or similar habitats may be suitable for the origin establishment of life on our Earth.

Biographical note:
Sebastian Viehmann studied geology/palaeontology at the Rheinischen Friedrich-Wilhelms Universität Bonn and focused on the geochemical characterisation of 3.8 and 2.7 billion year old marine chemical sediments during his diploma thesis. He built up on this topic during his PhD at the Jacobs University Bremen and reconstructed the physico-chemical conditions of the atmosphere and hydrosphere on Earth in the time frame between 3.8 billion years ago until 534 million years ago. In summer 2017, he moved to the University of Vienna to merge the topics of biochemistry and geochemistry. He will apply geochemical analyses of stromatolites, i.e. marine layered carbonates that were precipitated in the presence of the microorganisms, to further understand the environmental conditions and habitats of the earliest life that is preserved in the geological rock record.