Rock and Block Tour - Day Two - Desert Conveyor
We woke this morning in our rock and log cabin, deep in the gorge of Zion National Park. Outside the snow was frozen and the sun was hours away from getting to us. At breakfast in the lodge, originally built in 1924, we watched the sunlight slowly descending the west facing cliffs. It took the Virgin River about a million years to mine 2000 vertical feet of red sandstone and carry it down to the Colorado River. Colorado. Much of this red sand must now be in southern Arizona and the Gulf of California.
Today was all sandstone. 285 road miles. Utah 9 east to US 89 south to Arizona 98 east to US 160 east to Indian Route 59 to US 191 south to Indian Route 7 to Canyon de Chelly National Monument. Canyon de Chelly is a thousand feet deep. Grand Canyon is 6000 feet deep. The Colorado Plateau, Permian and Jurassic stratigraphy is 130,000 square miles. That is a lot of sandstone. If you haven’t taken a road trip through Navajo country, put it on your list.
A surprising number of the rivers that flow through the Colorado Plateau carve canyons straight through the mountains rather than taking the easy path around them. This confused a lot of people, including geologists, for a long time until someone came up with the Great Exhumation Theory. Exhumation: The uncovering or exposure through erosion of a former surface, landscape, or feature that had been buried by subsequent deposition (answers.com).
The Rocky Mountains were buried up to their peaks throughout the Miocene. Water (and wind) unburied them. Rivers flowing on the broad, flat plain 10 million years ago took no notice of the mountains below the surface. But slowly, all throughout the Pliocene, they carved their way down through the mountains, starting at the top, just like the Virgin River carved the gorge at Zion.
Turning left onto US 160, basically still in the middle of nowhere, we started paralleling a new railroad line - new ties on clean, level ballast and electric lines suspended over the tracks on new, straight pine poles. Very unusual. Up ahead, about ten miles, we saw three huge concrete silos. They must have been two hundred feet high, and leading to them was the longest conveyor belt I had ever seen. Imagine my delight. As we got close, we saw that we were only looking at the feeding conveyor. It was connected to absolutely the longest conveyor belt I had ever seen because it not only crossed the highway on a bridge but ran south for at least a mile until it disappeared over the ridge.
New rail line, new silos, new HUGE conveyor? What gives?
I got to talking to two Navajo youths in hoodies selling jewelry out in front of the Sinclair gas at the next junction about what the silo and train was about. Coal, they said. The government mines their coal to make electricity at the new power plant at Page, next to Glen Canyon Dam, and “we don’t get nothin”. Peabody Energy, the world’s largest private sector coal company, leases land on Black Mesa near Kayenta from the Navajo. The coal is extracted from open pit mines, crushed, and then carried 97 miles to the Navajo Generating Station at Page, Arizona.
The plant is capable of generating 2250 megawatts of power. For comparison, the Alta Wind Energy Center which we saw yesterday at Tehachapi Pass, the largest wind farm in the world, has a capacity of 1320 megawatts.
During the Carboniferous period (300 million years ago), the entire region was classic Jurrasic Park, and when the dinosaurs, the swamps, and the palm trees got covered in thousands of feet of volcanic ash, the coal began to take shape.
I had to find out more about Peabody and the Kayenta mine: They process 7.5 million tons of coal annually and the conveyor is actually 17 miles long.