GREELEY AND GUEST: A PIONEERING DUO IN PLANETARY VOLCANOLOGY

Ron Greeley and John Guest first met and started collaborating during the Mariner 10 mission to Mercury in 1974. This led to a successful collaboration in planetary volcanology and geologic mapping that span decades and several worlds, from choosing the Viking 2 landing site and publishing the first comprehensive map of the eastern equatorial region of Mars to researching volcanism on the Moon, Io and Earth. They published one book together, Geology on the Moon (1977, Wykeman Geology series), geologic maps of regions on Mercury, Mars, and Io, and numerous research papers and book chapters. Both loved field research and actively worked on Kilauea and Mount Etna, sharing interests such as the formation of lava tubes and the origin of Kilauea’s Great Crack. Their partnership included helping one another’s students, who greatly benefitted from the attention of these two great mentors, whose remarkable talent as teachers were complemented by their mentorship in navigating political waters, their ruthless editing and even their practical jokes, usually designed to teach students not to believe everything their advisors said. Both Greeley and Guest were winners of the GSA’s G.K. Gilbert award. They passed away within months of one another. This paper will review their joint contributions to planetary geology.