by Kathy Hedges
SOCORRO, N.M., July 19, 2006 – Dr. Kent Condie, professor of geochemistry at New Mexico Tech, was one of the organizers of the recently held Penrose Conference, an annual event of the Geological Society of America. This year’s conference, held in Lander, Wyoming, from June 13 – 18, 2006, discussed the topic “When Did Plate Tectonics Begin on Earth? Theoretical and Empirical Constraints.”
The conference was the subject of a news feature in the journal Nature, written by Alexandra Witze. According to Witze, the early Earth is difficult to study because “there aren’t many old rocks to look at, and those that are around are often so altered, chemically and physically, as to be nearly indecipherable.”
The specific aim of the meeting was to try to fix a date for the onset of plate tectonics, the movement and recycling of Earth’s crust. Conference attendees proposed beginning dates for the process ranging from shortly after the Earth formed, 4.5 billion years ago, to a mere 1 billion years ago. By the end of the meeting, a majority of the attendees voted for plate tectonics having started between 3 billion and 4 billion years ago, although some favored an “intermittent approach” in which the process started and stopped several times throughout history.
Condie, a longtime professor at New Mexico Tech, is the author of numerous scientific papers, books, and articles on the history of the Earth. He is especially known for the textbook Earth as an Evolving Planetary System.