Grand Canyon, world’s largest gorge

October 8, 2015January 24, 2017 thawngno

By Thomas O’neill

President Theodore Roosevelt called it “one of the great sights which every American . . . should see.” Following the road signs, I drove across sagebrush desert and through forests of ponderosa pine. A marker indicated that I had only a mile to go. I stopped the car and began to walk. The horizon revealed nothing. Suddenly the ground fell away below me, and I found myself looking into the most astounding abyss that nature has to offer. I fumbled for a brochure and read some numbers: The Grand Canyon in northwest Arizona is 277 miles long, from 600 feet to 18 miles wide, and as much as a mile deep.

These figures could not begin to convey the overwhelming spectacle and scale of the canyon, the largest in the world. Below me lay an immense gash in the earth’s surface, broad enough to encompass a seemingly endless succession of peaks and buttes. It was as if a mountain range had once been buried within the earth and had slowly reemerged.

Geologist Clarence Dutton, who studied the Grand Canyon from 1875 to 1881 and named many of its features, marveled at the profusion of rock formations, especially the buttes. “There are scores of these structures,” he wrote, “any one of which, if it could be placed by itself upon some distant plain, would be regarded as one of the great wonders of the world. Yet here they crowd each other. . . . [and] the power and grandeur is quite beyond description.”

The canyon was changing colors in the late afternoon. First the rocks glowed orange and yellow as if a furnace burned inside. Then, as the sun sank lower, the walls turned a fiery red like live embers. Finally the rocks cooled and a deep purple stole over them as night fell.

Far below, a ribbon of green flecked with white appeared here and there in the inner gorge. It was the Colorado River, master builder of the canyon. For millions of years the Colorado has been steadily slicing through the Kaibab Plateau, creating this chasm. And the canyon keeps getting deeper—at an imperceptible but relentless rate, averaging a few inches every thousand years.

The Grand Canyon is, of course, only one of many natural marvels in North America. From the long list I chose seven wonders that represent for me the great diversity of the continent’s geography. Besides the Grand Canyon, my itinerary included Death Valley in California, the Everglades of Florida, the Bay of Fundy between Nova Scotia and New Brunswick, the Columbia Ice field and the Yellowstone geyser fields in the Rocky Mountains, and Mammoth Cave in Kentucky.

grand canyon mather point — Mather Point, Grand Canyon by MichaelMatti

Like the other wonders I would visit, the Grand Canyon offers not only stunning scenery but also startling evidence of the workings of nature. To stand on the rim and let your gaze drop slowly is to take in an expanse of rock representing almost one and a half billion years of the earth’s history. More than a dozen distinct layers of sedimentary rock appear as bands on the canyon walls. To geologists, these different colored layers of sandstone, limestone, and shale—all unveiled by erosion—are records of how this place looked and what lived here over an immense period of time. The various layers tell of tropical seas, deserts with high dunes, and lowlands covered with swamps and sluggish rivers.

When I first visited the Grand Canyon several years before, I rode a wooden dory down the Colorado, hurtling through its more than 150 rapids. The first person to lead a recorded expedition down this tumultuous river was John Wesley Powell, a one-armed former Civil War officer who later headed the U. S. Geological Survey. Setting off in 1869 with four boats and nine men, Powell encountered risk and hardship nearly every day in the Grand Canyon as he battled his way down the “Great Unknown” with its “mad white foam.” Now as many as 18,000 people run the Colorado rapids each year.

Instead of journeying by river, which can take anywhere from one to three weeks on the various tours, you can descend through time in the Grand Canyon simply by hiking from rim to fiver, which the hardiest among us can do in half a day. One morning in May, I joined seven other backpackers at Monument Point on the north rim for a week’s walk into the canyon. As we maneuvered along the switchbacks, we often reached out and touched the rock as if it were Braille and on it we could read some of the earth’s history. We ran our fingers over fossilized shell fragments of a clam-like invertebrate called a brachiopod, embedded in limestone that formed in a warm sea 250 million years ago. We traced on shale the labyrinthine paths of worms that had inched through mud 500 million years ago, when life was emerging from the seas.

We took two days to reach the desert-like floor of the canyon. As we approached the Colorado River, we hiked on a ledge above a narrow side canyon whose gleaming walls twisted and turned. Where the small canyon ended, a tall cascade – Deer Creek Falls – poured down a cliff, leading us to the river. Here we gazed upon rock 1.7 billion years old – the Vishnu Schist. Black and jagged, the rock jutted out of the water at a sharp angle. We struggled to comprehend its age, and the staggering fact that the schist formed the roots of an eroded mountain range that once was as high as the Himalayas. Like John Wesley Powell, we had come to “the depths of the earth . . . and we but pigmies, running up and down the sands or lost among the boulders.”