[edit]
See also: Timeline of Chacoan history
Archaic–Early Basketmakers[edit]
The first people in the San Juan Basin were hunter-gatherers: the Archaic–Early Basketmaker people. These small bands descended from nomadic Clovis big-game hunters who arrived in the Southwest around 10,000 BC. More than 70 campsites from this period, carbon-dated to the period 7000–1500 BC and mostly consisting of stone chips and other leavings, were found in Atlatl Cave and elsewhere within Chaco Canyon, with at least one of the sites located on the canyon floor near an exposed arroyo. The Archaic–Early Basketmaker people were nomadic or semi-nomadic hunter-gatherers who over time began making baskets to store gathered plants. By the end of the period, some people cultivated food. Excavation of their campsites and rock shelters has revealed that they made tools, gathered wild plants, and killed and processed game. Slab-lined storage cists indicate a change from a wholly nomadic lifestyle.
Ancestral Puebloans[edit]
  Anasazi sites in the Southwest
By 900 BC, Archaic people lived at Atlatl Cave and similar sites.
DNA evidence establishes the people of Picuris Pueblo once lived in Chaco Canyon. By AD 490, the descendants of those who lived in Chaco Canyon, of the Late Basketmaker II period, farmed lands around Shabik'eshchee Village and other pit-house settlements at Chaco.[citation needed]
A small population of Basketmakers remained in the Chaco Canyon area. The broad arc of their cultural elaboration culminated around 800, during the Pueblo I period, when they were building crescent-shaped stone complexes, each comprising four to five residential suites abutting subterranean kivas, large enclosed areas reserved for rites. Such structures characterize the Early Pueblo People. By 850, the Ancient Pueblo population had rapidly expanded: groups resided in larger, more densely populated pueblos. Strong evidence attests to a canyon-wide turquoise processing and trading industry dating from the tenth century. Around then, the first section of Pueblo Bonito was built: a curved row of 50 rooms near its present north wall. Archaeogenomic analysis of the mitochondria of nine skeletons from high-status graves in Pueblo Bonito determined that members of an elite matriline were interred here for approximately 330 years between 800 and 1130, suggesting continuity with the matrilineal succession practices of many Pueblo nations today.
The cohesive Chacoan system began to unravel around 1140, perhaps triggered by an extreme 50-year drought that began in 1130; chronic climatic instability, including a series of severe droughts, struck the region again between 1250 and 1450. Poor water management led to arroyo cutting; deforestation was extensive and economically devastating: timber for construction had to be hauled instead from outlying mountain ranges such as the Chuska mountains, more than 50 miles (80 km) to the west. Outlying communities began to depopulate and by the end of the century the buildings in the central canyon had been neatly sealed and abandoned.[citation needed]
Some scholars suggest that violence and warfare, perhaps involving cannibalism, impelled the evacuations. Dismembered bodies dating from Chacoan times were found at two sites in the central canyon. Yet Chacoan complexes showed little evidence of being defended or defensively sited high on cliff faces or atop mesas. Only several minor sites at Chaco have evidence of the large-scale burning that would suggest enemy raids. Archaeological and cultural evidence leads scientists to believe people from this region migrated south, east, and west into the valleys and drainages of the Little Colorado River, the Rio Puerco, and the Rio Grande. Anthropologist Joseph Tainter deals at length with the structure and decline of Chaco civilization in his 1988 study The Collapse of Complex Societies.
Athabaskan succession[edit]
Prehistoric roads and great houses in the San Juan Basin, superimposed on a map showing modern roads and settlements
Numic-speaking peoples, such as the Ute and Shoshone, were present on the Colorado Plateau beginning in the 12th century. Nomadic Southern Athabaskan-speaking peoples, such as the Apache and Navajo, succeeded the Pueblo people in this region by the 15th century. In the process, they acquired Chacoan customs and agricultural skills. Ute tribal groups also frequented the region, primarily during hunting and raiding expeditions. The modern Navajo Nation lies west of Chaco Canyon, and many Navajo live in surrounding areas.
Excavation and protection[edit]
The first documented trip through Chaco Canyon was an 1823 expedition led by New Mexican governor José Antonio Vizcarra when the area was under Mexican rule. He noted several large ruins in the canyon.
The American trader Josiah Gregg wrote about the ruins of Chaco Canyon, referring in 1832 to Pueblo Bonito as "built of fine-grit sandstone". In 1849, a U.S. Army detachment passed through and surveyed the ruins, following United States acquisition of the Southwest with its victory in the Mexican War in 1848. The canyon was so remote, however, that it was scarcely visited over the next 50 years. After brief reconnaissance work by Smithsonian scholars in the 1870s, formal archaeological work began in 1896 when a party from the American Museum of Natural History based in New York City—the Hyde Exploring Expedition—began excavating Pueblo Bonito. Spending five summers in the region, they sent more than 60,000 artifacts back to New York and operated a series of trading posts in the area.
In 1901 Richard Wetherill, who had worked for the Hyde expedition, claimed a homestead of 161 acres (65 ha) that included Pueblo Bonito, Pueblo del Arroyo, and Chetro Ketl. While investigating Wetherill's land claim, federal land agent Samuel J. Holsinger detailed the physical setting of the canyon and the sites, noted prehistoric road segments and stairways above Chetro Ketl, and documented prehistoric dams and irrigation systems. His report went unpublished and unheeded. It urged the creation of a national park to safeguard Chacoan sites.
The next year, Edgar Lee Hewett, president of New Mexico Normal University (later renamed New Mexico Highlands University), mapped many Chacoan sites. Hewett and others helped enact the Federal Antiquities Act of 1906, the first U.S. law to protect relics; it was, in effect, a direct consequence of Wetherill's controversial activities at Chaco (including amateur excavations, reuse of ruin materials for building, and a large livestock ranching operation). The Act also authorized the president to establish national monuments: on March 11, 1907, Theodore Roosevelt proclaimed Chaco Canyon National Monument. Wetherill relinquished his land claims.
A ceramic bowl excavated from Pueblo Alto, dating from AD 1030 to 1200
In 1920, the National Geographic Society began an archaeological examination of Chaco Canyon and appointed Neil Judd to head the project. After a reconnaissance trip that year, Judd proposed to excavate Pueblo Bonito, the largest ruin at Chaco. Beginning in 1921, Judd spent seven field seasons at Chaco. Living and working conditions were spartan at best. In his memoir, Judd wrote, "Chaco Canyon has its limitations as a summer resort". By 1925, his excavators had removed 100,000 short tons of overburden, using a team of "35 or more Indians, ten white men, and eight or nine horses". The team found only 69 hearths in the ruin, a puzzling discovery as winters are cold at Chaco. Judd sent A. E. Douglass more than 90 specimens for tree-ring dating, then in its infancy. At that time, Douglass had only a "floating" chronology. Only in 1929 did a Judd-led team find the "missing link". Most of the beams used at Chaco were cut between 1033 and 1092, the height of construction there.
In 1949, the University of New Mexico deeded over adjoining lands to form an expanded Chaco Canyon National Monument. In return, the university maintained scientific research rights to the area. By 1959, the National Park Service had constructed a park visitor center, staff housing, and campgrounds. As a historic property of the National Park Service, the National Monument was listed on the National Register of Historic Places on October 15, 1966. In 1971, researchers Robert Lister and James Judge established the "Chaco Center", a division for cultural research that functioned as a joint project between the University of New Mexico and the National Park Service. A number of multidisciplinary research projects, archaeological surveys, and limited excavations began during this time. The Chaco Center extensively surveyed the Chacoan roads, well-constructed and strongly reinforced thoroughfares radiating from the central canyon.
The richness of the cultural remains at park sites led to the expansion of the small National Monument into the Chaco Culture National Historical Park on December 19, 1980, when 13,000 acres (5,300 ha) were added to the protected area. In 1987, UNESCO designated the park a World Heritage Site. To safeguard Chacoan sites on adjacent Bureau of Land Management and Navajo Nation lands, the Park Service developed the multi-agency Chaco Culture Archaeological Protection Site program. These initiatives have identified more than 2,400 archeological sites within the current park's boundaries, only a small fraction of which have been excavated.
