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Frontiers
Grand Canyon Rocks Reveal Continent's Past
July/August 1998
One of the most beautiful and pristine sites in America
is challenging a team of researchers eager to decipher its mysterious clues.
The team hopes to learn about the formation and breakup of a theorized supercontinent
that existed hundreds of millions of years ago.
Through a series of expeditions to the famed Grand Canyon, Karl Karlstrom,
professor of geology at the University of New Mexico in Albuquerque, and
his Grand Canyon Project team are collecting and studying the Canyon's rock
and sediment. They are confident that what they are finding will allow a
greater understanding of how the continents evolved, why certain land masses
formed, broke up and re-formed the way they did, and how the Earth's past
geologic activity relates to its current, albeit slow, shifting and re-formation.
The team is focusing on geologic events that occurred 1,800 to 600 million
years ago during the pre-Cambrian era. Toward the later part of this period,
much of the Earth's land mass was assembled in a supercontinent called Rodinia.
By studying the Grand Canyon's multiple layers of rock, the researchers
hope to learn, among other things, how and when Rodinia was assembled and
broken apart and the proposed correlation of the breakup to the first burgeoning
life forms.
The researchers' discovery process requires time-intensive techniques to
study the rocks and extract evidence about their layering patterns. They
also analyze fossil fragments, minerals and volcanic ash particles to obtain
their data. The NSF-funded effort is a collaborative one involving researchers
from the Massachusetts Institute of Technology, Harvard University, the
University of Massachusetts, and the New Mexico Institute of Mining and
Technology, in addition to Karlstrom and other geologists from the University
of New Mexico.
"For geologists, the Canyon represents an open book with a two billion
year history and a spectacularly exposed geologic story to be told," says
Karlstrom. "We are only beginning to read that story."
Next year, results and on-going research from the Grand Canyon Project
will be on display for park visitors through the "Trail of Time" exhibit,
a one-kilometer walking trail along the south rim of the Canyon. Currently
in development, the trail will be marked with informative displays and interactive
models designed to represent the history of the continent and the Canyon
region through geologic time. The idea for the exhibit was proposed by Karlstrom
and Michael Williams, a structural geologist and associate professor of
geosciences at the University of Massachusetts, as a way to increase and
expand on the geologic information currently displayed at the park.
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