Thursday, September 14, 2017

Zion National Park, Utah

The drive into Zion National Park is via Hwy 9, which starts at Hwy 89 in Mt. Carmel, Utah, and runs west to Hurricane, Utah on the west side of the state. Hwy 9 is actually a main route and part of the highway just happens to go through Zion National Park. We drove in and got to Springdale, which is the first city south of the park, near the south entrance; stopped in the city to have lunch and visit the Visitor's Center, and then headed back into the park. The road into the heart of the park is called Zion Canyon Scenic Drive and can only be accessed by shuttle. The park has free parking and to ride the shuttle is also free. We did not do this as it was really crowded, so we opted to just drive in and back out, taking pictures along the way. 

The formation on this mountain is called Checkerboard Mesa. This famous formation was originally named Checkerboard Mountain by Preston P. Patrow, the 3rd superintendent of Zion. Standing at 6,670 feet, it was named for its checkerboard appearance caused by the horizontal cross-bedding of ancient sand dunes and vertical cracking due to expansion and contraction of the sandstone during winter.

Temple Cap Formation

The holes in the two above pictures are actually light holes for the tunnel that runs 1.1 miles through the mountain. It was completed in 1930 and is named the Zion-Mt. Carmel Tunnel.

North of Zion rain fell on the 11,000 foot high Colorado Plateau and raced downhill, slicing Zion's soft layers, and pushed its debris off the Plateau's southern edge. This edge is not abrupt, but it steps down in a series of cliffs and slopes known as the Grand Staircase. Above Zion, topping the Staircase, Bryce Canyon's crenellated edges form as water trickles off the Plateau. Below Zion, Grand Canyon forms the lowest rung int which 90% of Colorado Plateau waters run. Zion's gathered waters, known as the Virgin River, traverse Mojave Desert lands and join the Colorado River in Lake Mead's handmade basin before completing their Pacific-bound journey. 

Long before today's landscape even appeared, streams, oceans, deserts, and volcanoes deposited thousands of feet of mud, lime, sand and ash. The immense pressure and heat of accumulating sediments turned lower layers to stone. Later, underground forces uplifted the Colorado Plateau, a 130,000 square mile mass of rock, over 10,000 feet above sea level. Rain then worked into the Plateau's minute cracks, loosening grains and widening fractures - and eroding today's mighty canyons. This process still continues and eventually this beautiful canyon will melt away and others will form.

These are many layers in the rocks of Zion. The very top are temple cap formations, then Navajo sandstone. Under that is the Kayenta formation, mudstone featuring dinosaur tracks. Then comes the Moenave formation, lower testify to pooling waters, upper ones indicate swift-moving floods. The Chinle formation shales are soft and contain petrified wood. The Shinarump conglomerate is composed of varied sizes of eroded Moenkopi rubble. The Moenkopi formation records a shallow sea withdrawing, so the marine fossils differ in its bottom and top layers.

People have occupied this area for thousands of years. Zion's first residents tracked mammoths, camels, and other mammals through open desert and sheltered canyons. These animals died out 8,000 years ago. Hunters adapted by hunting smaller animals and gathering food, and adjusted to suit their location. One desert culture, evident here still, evolved over the next 1,500 years as a community of farmers now known as Ancestral Puebloans. On the Colorado Plateau, crops grow best between 5,000 and 7,000 feet of elevation, which makes Zion's elevations nearly ideal. But drought, resource depletion and migrations eventually decreased the Ancestral Puebloans' dominance. The Southern Paiute people who followed brought traditions suited to the harsh desert climate and thrived here. 

Westward expansion eventually brought new settlers to the canyon. In the 1860s, early Mormon pioneers came to the region and built small communities and farmed the river terraces. Through hard work and faith, the new residents endured in a landscape where flash floods destroyed towns and drought burned crops. The same threats exist today, but Zion draws new explorers to experience the beauty and the sanctuary of this place that countless generations have considered home.

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