Published by the American Geological Institute of the Earth
Sciences About 75 experts assembled in Grand Canyon Village,
Ariz., June 7-9 for a meeting of the minds on the origin of the
Grand Canyon. They debated the evolution of the landscape,
formation of the canyon, age of Quaternary deposits and timing
of fault movements. Not since 1964, when the last organized
gathering of scientists debated the issue, has the geologic
marvel received such concentrated scrutiny. Interest in a Grand
Canyon meeting intensified at a Geological Society of America
conference two years ago. At an informal gathering, several
geologists decided that a reconsideration of new data was long
overdue. As a result, this year’s meeting focused on examining
the diverse data sets collected in recent years, including
extensive potassium-argon age dating. The majority of
professional researchers at the meeting agreed that the modern
Colorado River probably did not flow to the Gulf of California
until 4.5 million to 6 million years ago. Most