Scientists who proposed three years ago that a meteorite from Mars holds evidence of primitive martian life are thrilled by new research that sets the age of carbonate mineral deposits in the rock to 3.9 billion years old. The dating research, headed by Lars Borg, a geochemist at the Institute of Meteoritics at the University of New Mexico, is being lauded as the first to establish a reliable age for mineral processes that occurred after the formation of a meteorite. The research is published in this week’s issue of the journal Science.