Origin & Evolution of Life: August 2008

Members of NAI's University of Wisconsin, Madison team have a new paper in Earth and Planetary Science Letters presenting their analyses of 4.35 - 3.36 billion year old detrital zircons from the Jack Hills, Western Australia. Their data reveal relatively high lithium abundances compared to other zircons, as well as lithium isotope ratios that are similar to continental crust weathering products rather than ocean floor basalts. The results support the hypothesis that continental-type crust and oceans existed by 4.3 billion years ago, and suggest that weathering was extensive in the early Archean.