A  very interesting session is devoted to life and the conditions for life on the very young Earth, only a few hundred million years after its formation. Some exciting new evidence appears to hint that early biotic and abiotic processes were intimately linked.

Two recent developments have stimulated interest in the way the Hadean to Archean Earth functioned. The first is the continuing geochemical investigation of Hadean zircons from Jack Hills, which appear to show that 4.4 Ga ago, the Earth's surface was cold and wet. The second is the flood of new information bearing on the origin of life - where and how if first appeared and how it evolved. Other important issues are the rate and manner in which the continental crust formed; geodynamics of the Archean mantle and the nature of oceanic crust; the onset of subduction and the characteristics of Archean subduction zones; deformation of Archean continental lithosphere; changes in the temperature and composition of the oceans and atmosphere.

Some of the papers and posters presented in this session:

• Franck, S.; Bounama, C.; von Bloh, W. Geodynamics and the Archean carbon cycle
  "[Our] model for the global carbon cycle ... coupled to a mantle convection model ... give[s] a rather hot as well as a freezing climate on the early Earth (Hadean and early Archaean)."
• Nisbet, E.; Grassineau, N. Archaean microbial evolution: The age of Rubisco
• Rosing, M. T. H₂ - feasible fuel for photosynthesis?
  The last topic was the subject of a recent article in New Scientist "And life created continents...".
• Cnossen, I; Favata, F; Sanz-Forcada, J; Witasse, O; Zegers, T. The Habitat of Early Life: Solar X-ray and UV Radiation at Earth’s Surface 4-3.5 Billion Years Ago
  ".... any form of life that might have been present at Earth’s surface 4-3.5 Ga, must
  have been exposed to much higher levels of damaging radiation than at present."
  

Session: BG1.01 Geodynamic and Metabolic Cycles of the Young Earth | >>programme

Unfortunately, Minik Rosing cannot make it to Vienna. He has to stay at the Geological Museum in Copenhagen, but he agreed to answer questions about his work.
Dr Minik Rosing This e-mail address is being protected from spam bots, you need JavaScript enabled to view it phone 45 35 32 23 68 / cell +45 51 50 60 68