The Hiking and Camping Guide to Colorado's Flat Tops Wilderness. Al Marlowe
Читать онлайн книгу.
would. Still, the second largest wilderness in the state offers challenges. A visitor could spend a season and not hike every path. From a distance, the Flat Tops Wilderness lives up to its name. Traveling along State Highway 131, between the communities of Toponas and Yampa, you view the plateau to the west, appearing nearly flat. Here and there, incisions were made in the massive block, formed by stresses deep within the earth during the formation of the Rocky Mountains. Rivers and creeks that drain the land enlarged and deepened the cuts.
Along the west flank of the White River Uplift, the geologic name for the Flat Tops, sedimentary rocks have been folded. Solid rock and overlying sediments deposited by ancient seas were pushed upward by forces of plate tectonics. The sediments conformed to the core rocks in the same way a bedspread drapes a bed. At the edges, the rocks were folded. At a rate imperceptible in a single lifetime, the exposed sediments eroded, and then were swept away by wind and rain, leaving only remnants of folds along the west flank of the Flat Tops. You will find this uplifted, folded, and eroded structure, known as the Grand Hogback between State Highways 13 and 325 near Rifle Gap Reservoir north of Rifle. Along Interstate 70 between Glenwood Springs and New Castle, red sediments sloping steeply to the south give additional testimony to the forces that built the Flat Tops.
The Forest Service estimates that more than 170,000 visitors come to the Flat Tops each year to enjoy the wilderness. They come in all seasons for a variety of reasons. Some visit the excellent mountain lodges. Many come for the fishing and hunting. Backpackers and horsemen travel the trails in the backcountry. And while the number of visitors seems large, as in many places in the backcountry, if you get any distance from edges and trailheads, you encounter fewer people, allowing each individual or group the privacy desired.
History
The written record of the Flat Tops is sparse. Early Spanish explorers traveled the southern and western areas of the state. The Pike Expedition (1806-7) and Long Expedition (1819) explored east of the Rockies. The Western emigration that began following the exploration of the Louisiana Territory took several routes, all of which passed either north or south of the Flat Tops. Very little if any record exists of early American or European explorers venturing into the area other than a few fur trappers.
It is thought by some that humans first used the area about ten thousand years ago. Ute Indians were the most recent Native Americans to inhabit the Flat Tops. For more than two centuries, they traveled and hunted from southern Wyoming to as far south as Taos, New Mexico. Having acquired horses by 1740, they could easily have ventured into the plateau to hunt.
Whites settled the region in the mid-nineteenth century. In 1878, Nathan Meeker was appointed agent for the White River Agency, located near the town that bears his name. His ambitious but ill-advised plan to reform the Ute Indians, changing them into farmers rather than hunters, ended in disaster. Chief Douglas and 25 to 30 Utes set fire to the agency on the White River on September 29, 1879, killing Meeker and 10 other men. Major Thomas T. Thornburgh brought a small force of 153 soldiers from Fort Steele, Wyoming, too late to protect the agency. Near Milk Creek, northeast of town, Chief Colorow and nearly 400 Ute Indians ambushed the force, killing Thornburgh and 12 soldiers. Even though the Indians won the battle, they lost the war when the Army moved them to a reservation in Utah three years later.
Just as a historian pores through old writings, putting together a story, the geologist studies the record of the Flat Tops in the rock. The story tells of the history; how this area came into existence, what makes it unique. It begins nearly three billion years ago.
Viewing the Flat Tops, one could easily believe it is a permanent fixture on the land. Yet, a close look reveals countless streams, draining countless hillsides. Each of these creeks removes tiny particles of rock, eroded by constant weathering. Before our eyes, the mountains that appear so solid are destroyed a grain of sand at a time. This process of building mountain ranges and reducing them to rubble has occurred several times in this area.
The same events that have created the Earth’s present form were also at work in molding and sculpting the Flat Tops. Scientists have long speculated that the continents we now know were once united in a single landmass called Pangea. This single, massive continent began to break apart by a process called plate tectonics.
As the single, massive continent began to dissociate, the sea moved into the rifts created. Several times, warm seas covered the lowlands east of the Flat Tops as Pangea crumbled.
The theory of plate tectonics suggests that continents, or plates, not only “drift” around over the Earth’s surface, moving apart, they also collide. When two plates crash together, the result is similar to that of two cars bumping—that is, if the collision takes place over eons rather than milliseconds. Fenders bend—sheet metal tears. Land compresses—rock shears.
Continents pushing against each other create tremendous stresses in the land. Compression forces build mountains in a similar way a child might squeeze toy blocks together. The resulting forces fracture solid rock. Continued pressure moves some blocks of rock upward, some are shoved down.
Once blocks of rock are lifted, perhaps several thousand feet above sea level, nature goes to work tearing them down. Freezing and thawing cycles break apart solid rock. Rain and snowmelt remove eroded bits and pieces. Wind scatters small particles of sand. Over hundreds of millennia, once-high mountains are worn into nonexistence. Eroded sediment eventually comes to rest on the ocean floor. Mountains have risen and fallen several times in the Flat Tops region.
Another phenomenon controlled by plate tectonics is volcanism. Oceanic plates are denser than continental plates. On colliding, one oceanic plate moves beneath the other. The denser rock moves deeper, contacting a zone of intense heat, melting the rock. As in a pot of boiling water, bubbles move from the bottom at the heat source, the molten rock boils up, seeking escape. As it rises, continental crust is fractured, creating a path for the liquid magma to spew out and cover the land.
Eruptions away from the plate edges are usually mild, not violent as was Mount St. Helens. Basalt, a thick, black, molten rock coming from deep within the Earth, flows and spreads out over the land in the same way chocolate frosting covers a layer cake. Mount Kilauea in Hawaii, while located on an ocean plate rather than a continent, is such a volcano. The volcanoes of the Flat Tops were similar in activity to Kilauea.
In the past twelve million years, ten or more mild eruptions spread basalt over the plateau. After spreading out over the surface, the basalt cooled, giving the Flat Tops its tabletop appearance. Deep Lake, in the southeast quadrant of the area, was once a volcano on the Flat Tops.
This U-shaped valley gives evidence of the glaciers that formed drainages in the Flat Tops.
Glaciers have also had a part in sculpting the area. During the most recent Ice Age, ending about ten thousand years ago, they worked on the many fractures in the uplift. Gorges were deepened. Deep Creek and the South Fork of the White River had their streambeds carved by glacial action. The thick sheet of ice carved the Chinese Wall near Trappers Lake.
Rubble was pushed ahead of the advancing ice wall. As the climate warmed and the glaciers melted, ridges of rock left behind formed dams creating lakes here and there. Glaciers dammed Trappers Lake more than once.
The Ice Age ended as the Earth’s climate began to warm. Volcanoes no longer pour out smoke and lava. The region has experienced geologic activity, however, over the past ten millennia. Near the town of McCoy, an eruption occurred eight thousand years ago. Just over four thousand years ago, about a mile north of Dotsero, the most recent volcanic eruption in Colorado occurred. The resulting lava flow dammed the Eagle River, creating a shallow lake. Through the ensuing centuries, the river slowly eroded the basalt barrier. The only remaining evidence of the pond you will find is the scattering of black boulders between Interstate 70 and the river, rock that once formed the low dam.
The forces that built the Flat Tops also created an ideal environment for life. The waters contain an abundance of life-sustaining minerals for fish. The vegetation is rich in calcium, enabling elk to grow massive antlers. The land supports the largest deer and elk herds