The Abandoned Lands...A Journey Through the Colorado Plateau: The Rise and Fall of Empires, Part 2

We had reached the heart of the Abandoned Lands, having done the journey somewhat in reverse, by first finding the descendants of the Ancestral Puebloans at their present day homes along the Rio Grande and other nearby regions (Acoma and Taos), and then checking out one of their 'intermediate' settlements at Bandelier National Monument. We had also seen one of their recently abandoned pueblos at Pecos.

But now we had crossed the desert and had reached Chaco Culture National Historical Park, which for around 300 years constituted the center of the Ancestral Puebloan world. We had arrived on the evening of the summer solstice, and had experienced a kind of eerie night and beautiful solstice sunrise.

How do we know that Chaco was so important to the Ancestral Puebloans? Their descendants, for one, say so in their oral traditions. And then there is the sheer size of the complex at Chaco Canyon, something like fourteen major villages ("Great Houses") within a few square miles. There is the evidence of advance planning, as many of the building complexes are carefully aligned with the cardinal directions and astronomical and seasonal markers. And then there are the roads...

Source: http://en.wikipedia.org/wiki/File:San_Juan_Basin_Prehistoric_Roads.jpg

 

We have heard the expression that "all roads lead to Rome", but we don't usually associate roads with Native Americans. But if you look at the map above you can see that a system of straight roads led directly to the Chaco Canyon complex. The Puebloans cleared rocks and added berms in places, and when the roads encountered cliffs or other barriers, they built stairs (below). I don't think OSHA was consulted on this stairwell...

Below is a stretch of the Great North Road. The roads weren't for wheeled vehicles of course, but were instead pathways for pilgrims, and efficient routes for transporting supplies and materials, especially wood beams. The nearest forests were 40-50 miles away.

 And another set of steps...

The Great Houses also reveal their spiritual or political importance in the fact that they were not designed primarily for habitation. The complexes are huge, some with 700 rooms and originally standing four stories high, but not so many hearths for warmth, for instance (and winters are cold in this region despite the desert conditions). Wandering among the ruins, one can see the thinking of the planners and architects: this place was meant to engender a feeling of overwhelming power and awe in the visitor.

The major complexes at Chaco were built between around 850-1150 AD, and it is remarkable how well they have survived the elements for the last 900 years. These are not cliff dwellings, protected in alcoves and the like. They are out in the open and exposed to intense weathering from wind, ice and rain. Unlike many other unfortunate archaeological sites, Chaco Canyon today is in a remote location, so the buildings have not suffered as much the trepidations from vandals and early would-be "archaeologists". In addition, most of the complexes have never been excavated, and are thus protected beneath their own debris (having the walls exposed at the excavated ruins leads to rapid degradation; it is a cost associated with making a place interesting and educational to visit while trying to preserve the evidence of the past).

They had geological engineers in their midst, these Puebloans. Pueblo Bonito, the Great House we are touring in these pictures today, was tucked up against a cliff of the Cliff House Sandstone. The Cliff House Sandstone sits on top of a much weaker layer, the Menefee formation, and is often undercut by erosion so that large blocks of the sandstone will often tumble down the slopes into Chaco Canyon.

It was clear to the builders that a huge rock threatened the edge of the pueblo (we called the rock "Threatening Rock" in a fit of creativity). The Puebloans built a berm to try and stabilize the rock, and apparently they did a good job. It didn't collapse until 1941 (the pieces can be seen in the picture above).

Pueblo Bonito is a fascinating place to explore, being the most completely excavated of the Great Houses. It had 700 rooms, two great kivas, and a high outer wall that enclosed an area of two acres. The level of sophistication is such that no buildings in North America exceeded this complex in size until the 19th century.

It was uncomfortably hot wandering around the ruins on this particular day, which got me thinking about water at Chaco Canyon. There isn't any to speak of. The climate is very dry with an average rainfall of 8 or 9 inches. What did the Ancestral Puebloans do for water?

In the picture below, we can see the south wall of the complex...

One of the Great Kivas at Pueblo Bonito can be seen below. It was big enough that I couldn't fit the whole thing in a single shot. It took some major engineering to keep a ceiling over this space.

The wood used in the door beams and floors of the complex provided the means of dating the Chaco Canyon structures. Dendrochronology could be used to establish when the trees were cut down. The trees were not at all local; they came from mountains 50-70 miles away. Estimates are that 200,000 mature conifers were used in the construction of the Great Houses.

This has been just one of the fourteen Great Houses at Chaco Canyon. I'll look at a few others and deal with the question of why they were abandoned in the next post...and throw in some geology, too.

The Cretaceous Parks of the Colorado Plateau: The Green Table

The Mancos Shale of the previous post is also an important component of the geology at one of the nation's premier national parks, Mesa Verde (tr: "green table"). The park is tucked away in the far southwest corner of Colorado adjacent to the Ute Reservation and the towns of Cortez and Mancos (from which the shale takes its name). The high mesa (8,000 feet +) slopes south towards the desert region of Four Corners and the Navajo Reservation, and is dissected by a series of deep canyons which also drain towards the desert.

The mesa lies at the east end of the "fertile crescent" mentioned previously here and here, where conditions were ideal for growing squash, beans and corn. At Hovenweep and Canyons of the Ancients, the soils formed on the surface of the Dakota Sandstone. At Mesa Verde, the Mancos covers the Dakota, and is in turn covered by three formations that represent the receding shorelines and river floodplains that lined the Western Cretaceous Seaway, the Cliff House Sandstone, the Menefee Formation, and the Point Lookout Sandstone. The formations are found elsewhere, with different names, but the three together are usually referred to as the Mesa Verde Group. The sandstones are resistant to erosion and form prominent cliffs wherever canyons have been carved. Water moves freely through the sands until it reaches a clay rich layer (like the Mancos) and then moves sideways until it can drain into the canyons as springs. The cement holding the sands together is easily dissolved at such sites, and as the sand washes away, prominent alcoves have developed (the National Park Service has a nice review of the geology here).

Although the region is steeped in beautiful scenery, Mesa Verde was established as a national park in 1906 for the purpose of protected the spectacular cliff dwellings of the Ancestral Pueblo people. The mesa, as mentioned before, was a good site for agriculture. It was sort of a compromise; low enough to have a long growing season, but high enough to receive sufficent moisture in most years.

Nomadic peoples had moved through the area over thousands of years hunting and foraging, but the region was not settled in a permanent way until about 550AD (see here for a nice NPS review of the archaeology). It is not usually recognized, but for 500 years the Puebloan people did not live in cliff dwellings at all. They first lived in pit houses on the mesa surface, and later built small villages, also on the mesa surface. Looking at the semiarid forest of pinon and juniper that covers the surface of the plateau today, it is hard to believe that at one time, most of the park area was under cultivation. The farmers built reservoirs and check dams to prevent soil erosion, and most of the land was being used to support the population. The cliff dwellings for which the park is most famous were generally built during the final century of habitation, from around 1190 to 1270 AD. The dwellings certainly look defensive in nature, and when they were abandoned, so was the entire region. The reasons are not clearly known, but drought, resource depletion, warfare, or disease may have played a part. The survivors moved south and west to Arizona (the Hopi) and New Mexico (the Pueblo people) where they live today.

Something like 4,700 archaeological sites have been identified in the park, of which 600 are the popular cliff dwellings. Many sites were exposed in the last decade or so when something like two-thirds of the park burned in a series of intense fires. Although the fires severely damaged many sites, others were found for the first time. Many of the sites were severely vandalized by pot-hunters before the park was established, and the park service is vigilant about protecting what remains. Most of the dwellings and village sites are closed to visitation, but numerous pullouts on park roads allow visitors to look down into the alcoves. A number of the mesa-top sites can be accessed from the park roads. Spruce Tree, Cliff Palace, Long House and Balcony House are four of the larger alcove villages that can be toured (reservations required for the last three). Speaking from personal experience, Balcony House is one of the best tours, as you get a real sense of the inaccessibility of the villages: you must climb several tall ladders to get into the alcove, and must crawl through a few passageways to see the entire village.

If you visit the area with a geology crew, the park has a nice campground which is rarely crowded, with showers and a grocery store nearby. Motels and supplies are available in Cortez, Mancos or Durango. Oh, and try the Navajo Tacos at the Farview Lodge!