Project: Comparative Planetary Taphonomy
The quest for the discovery and characterization of habitable worlds motivates our looking outward, to explore the cosmos, but it also inspires looking inward, to search for vestiges of Earth’s earliest biosphere. This requires understanding the evolution and environmental characteristics of planetary systems as well as the history of microbial life, including taphonomy — the science of organism fossilization. Fossils are so interesting because they are so rare, and it takes an unusual convergence of factors to create a taphonomic window of preservation. It is essential to understand how biologic materials become recorded in Earth’s rock record — including modes of organism decomposition — and how to interpret ancient environmental conditions. This is particularly relevant for early Earth and even more so for Mars: if you want to find something significant, you have to know where to look.
The primary objective of the proposed research is to decipher the key factors that resulted in preservation of organic materials in very ancient rocks on Earth and to compare and contrast these factors with similar rocks that may also occur on Mars. The Mars Curiosity rover provides an unprecedented capability to characterize rocks on Mars, including their geochemical and mineralogical attributes, which have been shown to be important factors in creating favorable taphonomic conditions on Earth. This may ultimately lead to a more refined search paradigm in exploration for biosignatures preserved in ancient rocks on rocky planets like Mars and Earth.
Bio: John Grotzinger is a professor of geology and geobiology, and the division chair for Geological and Planetary Sciences at the California Institute of Technology (Caltech). He received his B.S. from Hobart College, M.S. from the University of Montana and Ph.D. from Virginia Polytechnic Institute and State University (Virgina Tech), and was a postdoctoral fellow at Columbia University. Prior to moving to Caltech in 2005, he spent 18 years as a member of the faculty at the Massachusetts Institute of Technology, where he was named Waldemar Lindgren Distinguished Scholar and Robert R. Shrock Professor of Geology.
At Caltech, his research group studies the co-evolution of surficial environments on Earth and Mars. Field-mapping studies are the starting point for more topical laboratory-based studies involving geochemical, geologic and geochronological techniques. He served as the chief scientist for the Mars Curiosity rover mission from 2007 to 2015. He is a member of the National Academy of Sciences and a recipient of NASA’s Distinguished Public Service Medal, and he received the Charles Doolittle Walcott Medal in 2007 for the elucidation of ancient carbonates and the stromatolites they contain and for meticulous field research that has established the timing of early animal evolution.