Geologic timescapes

 

When the explorers, artists and scientists of the Hayden Survey crossed over what they called Lake Creek Pass — better known now as Independence Pass — in 1873, they encountered a mountain range incomparable to anything they had been documenting in Colorado.

 

A web-based project released in August highlighting the drawings and photographs produced through the work of the Hayden Survey in Colorado from 1873 through 1876 includes much discussion of the Elks and their unique characteristics.

 

Thomas Huber, a University of Colorado at Colorado Springs geography professor, spent more than a decade putting together “Hayden’s Landscapes Revisited: The Drawings of the Great Colorado Survey.” It is freely available on the web at www.haydenslandscapes.com through the University Press of Colorado. Huber went to the vantage points that survey members used in creating their drawings to take panoramic photos showing how the scenes had changed, or not.

 

For his section on the Central Elks — one of 19 on the website devoted to specific survey regions — Huber hiked to a 13,370-foot-high point above Buckskin Pass in the Maroon Bells-Snowmass Wilderness. It was the same spot where, during a summer field expedition 143 years ago, William Henry Homes drew a landscape extending from Castle Peak to Mount Sopris.   

 

Holmes’ frame shows a remarkable mix of geology. The most noticeable feature of the Maroon Bells and surrounding peaks is the rust-colored sedimentary rock, but looking west, one sees the hard granite making Snowmass Mountain appear lighter in comparison.  

 

Geology had only been a specific scientific field for about 100 years in the 1870s and it would be decades before the full story of the Elks’ origins would be understood. Despite not having carbon dating and other more modern tools at their disposal, the surveyors led by Ferdinand Vandeveer Hayden did a good job documenting the unique features of the Maroon Formation, Huber writes. The survey’s 1874 Annual Report notes how much additional study the Central Elks warrant.

 

Scientists now know that the rocks that make up the Maroon Formation were once part of the Ancestral Rockies, a 300-million-year-old mountain system that included two ranges roughly where today’s Front Range and San Juan mountains are located, with a flat lowland in the middle. Huber explains in the Central Elks section of Hayden’s Landscapes Revisited that as the Ancestral Rockies eroded, sediment filled this lowland. These rocks compressed became the Bells during a mountain building episode about 65 million years ago. A similar process is responsible for the geology of the Garden of the Gods in Colorado Springs, Huber said.

 

Other rock forms intruded into the Maroon Formation, such as the harder granite visible on Snowmass Mountain. Huber, a professor at the university since 1981, said the hike up to Buckskin Pass is unique in the state for all the different rock types on view.

 

“No mountain range lasts forever,” Huber writes in the project’s introduction. “Even as you read these words, the relentless act of erosion is bringing down the current Rockies. This happens slowly but inevitably. Much of the eroded rock will eventually be deposited again to become new rock in the ever-spiraling cycle of erosion, deposition, uplift, erosion, deposition. …  In a few million years, more or less, the mountains we know of as the Rockies will be just a memory unless other vertical movements intercede.”

Giving shape to dreams

The Hayden Survey was one of the four great surveys of the West funded by Congress beginning in 1867, the others being the King, Wheeler and Powell surveys. Powell became famous in 1869 for leading the first expedition through the canyons of the Colorado River in the Southwest.

 

Hayden’s survey work was the most prolific, and besides his studies of Colorado, expeditions he led documenting the Yellowstone River helped in the creation of the country’s first national park in 1872.

 

Colorado — especially the Front Range and Arkansas River — had been explored by Americans beginning in 1806. Mining camps in Blackhawk and Central City were well established by the 1850s. But the surveys of the late 1860s and 1870s were the most extensive effort to date to map and understand vast unsettled swaths of the West.  

 

“[Hayden] and his scientists and topographers looked at the land in all its varied facets,” Huber writes in the introduction. “They described water resources, energy potential, agricultural promise, tourism attraction, and esoteric natural history phenomena. … They mapped the land and gave shape to many a dream.”

 

The survey team included a few dozen men who would spend the summers in the field, with annual reports presented to Congress each year.  

 

The four surveys were competing for limited funding, but Hayden’s work always got the most, Huber said, owing to Hayden’s efforts to make his reports understandable to the layperson.

 

“He thought [his knack for simplification] was he greatest strength and other scientists thought that was his greatest weakness,” Huber said.

 

The presence of artists and photographers on the survey team was part of the effort in bringing the realities and wonders of the West to the general population.

 

Mount Holy Cross, for example, had already captured the public’s imagination, thanks to a cross-shaped snowfield on its northeast face. The Hayden Survey in 1873 made it its mission to document this feature and did so with a photograph by William Henry Jackson and a drawing by Thomas Moran.

 

Jackson’s photography is particularly remarkable, Huber said, because he needed to haul around some 600 pounds of gear, including a portable darkroom, to make his photos possible. Glass plates needed to produce photographs were limited and cumbersome, and there was little room for error.

 

Living in the wild for months at a time, traveling in areas with no roads and eating mainly for survival was certainly more difficult than Huber’s 21st century quest to gather photographic recreations of the vistas captured by Hayden’s men, Huber noted. The survey teams were true trail breakers, Huber said, and the members racked up numerous first ascents of Colorado peaks.

 

The mystery of the Sawatch debris

The Hayden Survey was especially taken with the Sawatch Range, just east of the Elk Mountains and home to the state’s highest concentration of 14ers. Giant glacial moraines — debris piles left when glaciers retreat — mark the foothills of the mountains and are the subject of much discussion in Hayden’s annual report. The size of the moraines is among the evidence the team considered in reaching the conclusion that the Sawatch Range has been subject to massive erosion over the eons, and that in the past the summits were perhaps thousands of feet taller.

The team was incorrect, however, in its conclusion that the Arkansas River, which forms the valley east of the Sawatch, carried away all that sediment, Huber writes. Huber writes that later scientists, equipped with a better understanding of plate tectonics, discovered that until recently — in geologic terms — the Arkansas River was connected to what’s now the San Luis Valley and the Rio Grande Basin, before a mountain-lifting episode created separate drainages with the establishment of what is now Poncha Pass, south of Salida.

 

“More dramatically, the Arkansas Valley, the San Luis Valley, and the Rio Grande Valley into New Mexico are all part of an extended Miocene-Pliocene-age tectonic rift zone in the crust of the earth,” Huber writes in the section on the Sawatch Range and Clear Creek.

 

Twin Lakes in Hayden’s day was one of the Central Rockies’ best known landmarks, with two natural dams created by glacial moraines forming the lakes. A larger dam was built in the 1930s to allow the lakes to store more water. They are now officially know as reservoirs and are a key point in the system that collects water from the headwaters of the Roaring Fork basin and transports it through tunnel underneath the Continental Divide toward the North Fork of Lake Creek. That water is mostly consumed in Pueblo, Colorado Springs and on Eastern Plains farms.

curtis@aspendailynews.com