Grand Canyon – An Ancient Corridor



Like a corridor through time, the staggeringly magnificent Grand Canyon slices into the surface of the Earth, revealing layer upon layer of ancient rock whose glowing colours shimmer with the play of light. It is difficult to comprehend the immensity of the yawning chasm that is the Grand Canyon; it merits all superlatives and exceeds all expectations. This sprawling gash in the surface of the Earth, in the middle of the Arizona Desert, is some 280 miles (450km) long and plunges at its deepest point – Granite Gorge – to a depth of 1 mile (1.6km). At its widest it is 18 miles (29km) across, and beneath Toroweap Overlook on the North Rim it measures just under ½ mile (0.8km).

Layer upon layer of stone make up the striated walls of the canyon, whose deepest levels are formed of somber schist (metamorphic rock that splits easily) and fossil-rich granite. Stark, sheer buttes, looking amazingly like ruined temples, break up the landscape into a complex labyrinth of gullies and crevices. It is small wonder that in the 19th century some scientists believed the canyon could only have been created by a gigantic earthquake.

Around 60 million years ago in this region, the wide expanse of the Kaibab Plateau separated two waterways, the Ancestral Colorado River to the east and a river system called the Hualapai to the west. Over many centuries the Hualapai cut back into the plateau in a process known as headward erosion. Moving gradually but steadily, it met the Ancestral Colorado and combined with it to create the awesome modern Colorado River, which – until it was tamed by the Glen canyon Dam – surged through the plateau as an average of 20mph (32km/h), daily eroding millions of tons of rock and earth along its course.

The surface of the plateau once the floor of an ancient ocean, was the uppermost of many layers of sandstone, shale and limestone rocks deposited between 600 million and 250 million years ago in the Palaeozoic era. These rocks were laid down on top of even more ancient schist dating back 2000 million years to the Precambrian era. As the newborn Colorado rushed along, slicing through everything it encountered, upheavals in the Earth’s crust started to push up the rocks under its surging torrents, creating a large dome. Moving just a fraction of a millimeter a year, the plateau built up to 4000ft (1216m) in the next five million years.

Meanwhile, abrasive particles of rock and sand in the rushing river carved out the gorge inch by inch. And while the river cut downwards, other erosive forces began to work on the rock faces it had exposed, splitting their surface. Extremes of heat and cold caused the cracks to widen; winter storms and spring snowmelts loosened a steady stream of sandy gravel and debris and bulldozed them thr0ough the stone channels. Gradually meeting less resistance, the river battered the earth with increasing force, tearing away the base of the valley as the rocks continued to bulge upwards, causing the walls through which it flowed to mount higher and higher.

Although apparently immutable, this awesome canyon is continuously changing and growing. The building o he Glen Canyon Dam upstream from the Grand Canyon National Park in 1964 has drastically reduced the mighty Colorado’s power. But still the raging winter storms rip debris from the walls; plant roots find a foothold in crevices, and rocks still split and crash to the canyon floor.

Although the harsh landscape of the canyon appears dead and barren to the untrained eye, it is well endowed with plants and wildlife. The dry heat of the canyon floor supports a variety of desert creatures, including spotted skunks, yellow scorpions and whiptail lizards, and barrel cactus and mesquite flourish. The tassel-eared Kaibab squirrel is unique to the North Rim; the Abert squirrel prefers the warmer South Rim. The canyon’s cooler sidewalls provide homes for the Arizona grey fox and cliff chipmunks. Mountain lions also roam the rocks, but they are becoming increasingly rare. So, too, are the human inhabitants. Tourists, flying by helicopter into Havasu Canyon to view the Havasupai in one of the most remote reservations in the United States, are seeing the last of the region’s indigenous people. Hunters were in the canyon at least 4000 years ago, and around AD 1000 Pueblo Indians lived there in cliff houses. They were succeeded about 150 years later by the ancestors of the present group.

Amazing Skywalk at the Grand Canyon West Rim

Possibly the first Europeans to set eyes on this fantastic landscape were Spanish caballero Francisco Vazquez de Coronado and his party of 300 men, who in 1540 ventured into the territory in search of gold. He sent one of his captains to investigate the roaring river that could be heard to the west, but the patrol wandered along the canyon rim for three days without finding a path down to the river. They would have been astonished had they reached it, since from above they had gauged its width at only 6ft (1.8m).

More than 300 years later, in 1858, Lieutenant Joseph Christmas Ives, leader of an exploratory expedition in north-west Arizona, steamed up the Colorado River from its mouth on the Gulf of California for two hot months. Finally the waters became so treacherous that he was forced to leave the ship and lead his soldiers overland. On the South Rim of what he called the ‘Big Canon of the Colorado’, Ives rode a mule along a ledge that was “within three inches of the brink of a sheer gulf 1000ft (300m) deep; while on the other side, nearly touching my knee, was an almost vertical wall rising to an enormous altitude”.

Chemical reactions of air and water on the minerals contained in the 20 or more different rock layers in the canyon walls give them their distinctive colours. Light playing upon the rocks brings a range of mysterious shapes out of the shadows, while revealing colours that range from black and olive to russet, orange, dusty pink and pale sandy cream.

A Beautiful Sunset at the Grand Canyon

Although the grandeur and dimensions of the Grand Canyon have since inspired every conceivable exclamation of wonder, Ives seemed somewhat unimpressed by what he saw, and wrote, “Ours has been the first, and will doubtless be the last party of whites to visit this profitless locality. It seems intended by Nature that the River Colorado, along the greater part of its lonely and majestic way, shall be forever unvisited and undisturbed”.

How wrong he was. Today the Grand Canyon is regarded as one of the most astounding visits in North America and, like US President Theodore Roosevelt, many consider it ’the one great sight which every American should see’.

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