Research Interests
Kent C. Condie, Professor of Geochemistry

One of my major areas of active research is the study of the earth's oldest rocks. Such studies take us back to about 4 Ga and into some of the most remote parts of the continents: southern Greenland, South Africa, the deserts of western Australia, and the Arctic areas of Siberia and Canada. Some of the oldest rocks we are currently studying are sedimentary rocks including sandstones, carbonates, and shales and associated volcanic rocks. In the past few years, my graduate students have done field work in such places as South Africa, southern India, and northern China. Our results are exciting and suggest that although plate tectonics probably operated on Earth more than 3 Ga, mantle plume activity was considerably more important in the Archean than it is today. Continents didn't appear until the Earth cooled enough for granite magmas to form, and it appears that the first major period of continental growth was between 3 and 2.5 Ga, when the first supercontinent formed.

Another important and exciting research problem that we are working on is the composition and evolution of the lower continental crust and mantle lithosphere. Here we work with metamorphic petrologists and geophysicists. Has the upper and lower continental crust grown synchronously through time or have significant volumes of the lower crust been added by magmatic underplating? Are the mantle lithosphere and continental crust coupled and in what tectonic setting did they form? To begin to answer these and related questions, we are geochemically studying xenoliths of the lower crust and upper mantle brought to the Earth's surface during recent volcanic eruptions, in such areas as the Navajo Volcanic Field in the Four Corners area of the Southwest.

Another question of major interest today is the role that mantle plumes may have played in the evolution of our planet. Could the Earth have been more like Mars and Venus during the Archean some 3 Ga?  Instead of cooling principally by plate tectonics as it does today, did the Archean Earth cool chiefly by rising mantle plumes?  How do we identify the effects of mantle plumes in the geologic record? Did plumes have a role in the growth of continents? Are large mantle plume events recorded in the geologic record, and if so, what were the consequences of these events in terms of our atmosphere, oceans, and biosphere?