The eastern Grand Canyon was about half-carved (to the level of the red cliffs above the hiker) from 15 million to 25 million years ago, an analysis published Sunday suggests. But the inner gorge was likely scooped out by the Colorado River in just the past 6 million years.
Credit Laura Crossey / University of New Mexico
Recent analyses suggest that this stretch of the Grand Canyon (Marble Canyon, near Cape Solitude) was beneath more than a mile of layered rock until 6 million years ago, when a mighty river came through and scooped it out.
In recent years geologists have hotly debated the age of the Grand Canyon. Some think it's young (just 6 million years old), while others argue that it dates back 70 million years — to the days of dinosaurs.
Now one group says the Grand Canyon is neither young nor old. Instead, these geologists say, it's both.
Ten years ago, NASA's rover, optimistically named Opportunity, landed on Mars on what was to be a three-month mission. But Opportunity is still going strong today, still searching the Red Planet, sending data and images back to NASA. To celebrate Opportunity's decade of life, we called Jim Bell. He's an astronomer at Arizona State University. Welcome to the program.
JIM BELL: Great to be here.
MARTIN: So, take us back, Jim. What was Opportunity originally designed to do?