报告题目：Biosignatures on the early Earth and possibly on Mars
Dr. Papineau's main research interests are aimed at understanding the origin and evolution of life during the first four billion years of Earth history in order to predict what might be found on other planets and planetary bodies with liquid water and volcanism. He's interested in knowing: 1) how biochemistry can arise from pre-biotic geochemical evolution; 2) how micro-organisms form communities that affect or are affected by the biogeochemical cycles of C, N, S, and P; 3) how the atmosphere and oceans became oxygenated and led to the rise of multicellular organisms in the late Paleoproterozoic and compartmentalized early animals in the late Neoproterozoic. He believe that a solution to these scientific problems will help to unify Earth Sciences and give the necessary basis to explore other ancient planetary surfaces for biosignatures. The dream of finding extra-terrestrial life is a ‘raison d’être’, an outcome of the evolution of consciousness on this planet, and potentially a way to bring peace on Earth, since private wars for money become irrelevant if we all realize that we are unified as a single animal species on one of many inhabited planets.
In the search for extraterrestrial life, it is critical to have an understanding of the origin of life and of biosignatures from the early Earth. This presentation will review different types of biosignatures and micro-analytical techniques useful in astrobiology. Selected examples of well-documented biosignatures preserved in minerals from the Precambrian sedimentary rock record will be discussed, with an emphasis on some of the oldest sedimentary rocks, from more than 3.7 billion years old. This was a time when Mars also had an ocean of liquid water on its surface along with an evolving pre-biotic carbon cycle. Future sample return mission and particularly manned missions to the red planet will reveal whether pre-biotic chemistry on Mars led to the emergence of a second genesis of life.