Timeline of Chacoan history

A timeline of Chacoan history includes Chaco Culture National Historical Park, Aztec Ruins National Monument, Twin Angels Pueblo, Casamero Pueblo, Kin Nizhoni, Pierre's Site, and Halfway House.

Paleo-Indian Period

 * 11000 BC: First foragers?

Archaic Period

 * 6000 BC-800 BC: Hunter-gatherers

5th century

 * 490: Basketmaker farming begins

6th century

 * 500: Turquoise beads and pendants appear; offerings in great kivas (sites 29SJ423, Shabik' eshchee Village)

7th century

 * 600-800: La Plata Black-on-White ceramic
 * 700: Population of Chaco Canyon between 100 and 201 people

9th century

 * 800-900: Builders use piñon, juniper, and cottonwood trees that grew close by


 * 850-925: Large construction projects.


 * 875-1040: Red Mesa Black-on-White ceramics

10th century

 * 900-1150: Large buildings, mounds, roadways, great kivas, and tri-walled structures are built throughout the San Juan Basin.


 * 900-1125: Construction of Penasco Blanco


 * 900: Emergence of the Chaco Anasazi


 * 900: Chetro Ketl pueblo begun


 * 900-1025: Chaco Wash in erosional cycle and cut a paleo-channel.


 * 925-1130: Stable environmental conditions favorable to dry farming throughout the Colorado Plateau. Human populations also stable.


 * 950: Keet Seel, second largest cliff dwelling. is inhabited
 * 950: Nonlocal ponderosa is the dominant beam timber; spruce and fir increase

11th century

 * 960-1020: Unpredictable rainfall. Little building at Pueblo Bonito


 * 1000: "Chaco phenomenon" acceleration of cultural development


 * 1000-1075:Great House construction, and roads expanded. The first usage of chocolate further than central Mexico was first used in ceramic cylinders for rituals.


 * 1000-1140:Escavada Black-on-White ceramics


 * 1025-1090: Depositional period during which time the paleo-channel was filling. There is some historical, anecdotal evidence that the inhabitants of Chaco Canyon may have constructed a dam at the west end of the canyon.


 * 1030:Chacoans seek trees at higher altitudes


 * 1040: Increased rainfall


 * 1040-1050: Building resumes at Old Bonito. Pueblo Bonito construction stage II


 * 1050-1070: Pueblo Bonito becomes more complex. Pueblo Bonito construction stage III


 * 1050: Imports of copper bells, Macaws, and shells (origin unknown)


 * 1054: ~July 4 - Cliff painting near Penasco Blanco consisting of three symbols: a large star, a crescent moon, and a handprint, may portray the sighting of SN 1054, the Crab Nebula supernova.


 * 1064, 1066: Sunset Crater volcanic eruptions; volcanic debris blankets Jemez Mountains and Bandelier area.


 * 1080-1100: Great North Road construction.


 * 1080: Salmon Ruin established.


 * 1080: Construction of Pueblo Alto begins.


 * 1090: Drought

12th century

 * 1075-1123: Pueblo Bonito constructed at Chaco.


 * ?: Five astronomical observatories are built


 * 1100: Peak of Chaco culture.


 * 1100-1104: Tree felling at Pueblo del Arroyo


 * 1106-1125: Aztec Ruins built.


 * 1130: Pueblo Bonito is four stories tall and contains 800 rooms


 * 1130-1180: Fifty-year drought in the Southwest. Rain and snow cease to fall. Alluvial groundwater declines, floodplain erosion occurs. Dry-farming zone reduced, crop production potential decreased.  Severe arroyo cutting and depression of alluvial groundwater. Severe environmental stress.


 * 1140–1150: Collapse of the Ancestral Puebloan culture at Chaco Canyon.


 * 1150: Great Houses empty


 * 1180: Sunset Crater erupts for the second time.

16th century

 * 1539: Marcos de Niza erroneously describes the pueblo of Háwikuh as the Seven Cities of Gold.

17th century

 * 1680-1692: The Pueblo Revolt of the Pueblo people against Spanish colonists in the New Spain province.


 * 1774: Don Bernardo de Miera y Pacheco identifies the Chaco Canyon area as "Chaca" on a map. The term, a Spanish translation of a Navajo word, is thought to be the origin for "Chacra Mesa" and "Chaco".

19th century

 * 1844: Josiah Gregg refers to the Chaco pueblos in his book Commerce of the Prairies, making its first appearance in popular culture.


 * 1849: Lt. James H. Simpson leads the Washington Expedition, a military reconnaissance team which surveys Navajo lands and records cultural sites in Chaco Canyon. Illustrations created by the Kern brothers are included in a government report.


 * 1877: Artist and photographer William Henry Jackson participates in the Hayden Survey of the Western United States, producing maps of Chaco Canyon, but no photographs due to technical problems.


 * 1888: Richard Wetherill and Charlie Mason find the Cliff Palace, Spruce Tree House and Square Tower House.
 * Chaco Canyon is surveyed and photographed by Victor and Cosmos Mindeleff of the Bureau of American Ethnology


 * 1896: Richard Wetherill begins excavating Chaco Canyon


 * 1896-1899: George H. Pepper from the American Museum of Natural History leads the Hyde Exploring Expedition in excavating Pueblo Bonito

20th century

 * 1901: General Land Office special agent S. J. Holsinger recommends creating a national park to preserve archaeological sites in Chaco Canyon


 * 1907: Chaco Canyon National Monument is established.


 * 1928-1929: American astronomer and University of Arizona professor A. E. Douglass participates in a National Geographic Society research project exploring Chaco Canyon. Using his newly invented technique of dendrochronology, Douglass dates Chetro Ketl and dozens of Chacoan sites


 * Expedition under Neil Merton Judd to collect dendrochronological specimens to date habitation of Chaco Canyon


 * 1937: A Civilian Conservation Corps of Navajo stonemasons repairs Chacoan buildings in Chaco Canyon. A previous group built soil conservation devices, planted trees, and improved roads and trails.


 * 1941: Heavy rains cause Threatening Rock to fall, destroying ~60 rooms at Pueblo Bonito.


 * 1960: Floors excavated at Una Vida


 * 1971-1982: The Chaco Project, conducted by the National Park Service and the University of New Mexico, surveys and excavates Chaco Canyon


 * 1976-1978: Fourteen rooms at Pueblo Alto excavated by the Chaco Project


 * 1980: Chaco Canyon National Monument is renamed Chaco Culture National Historical Park with 13,000 acres (53 km2) added. The Chaco Culture Archaeological Protection Site program is created to protect Chacoan sites.


 * 1982: NASA's Thermal Infrared Multispectral Scanner (TIMS) detects over 200 miles of a prehistoric (AD 900 or 1000) road system in Chaco Canyon, as well as walls, buildings, and agricultural fields.


 * 1983: Dean and Warren estimate 200,000 trees were used to build great houses.


 * 1987: Chaco Culture National Historical Park is designated a UNESCO World Heritage Site.

21st century

 * 2001: Two-thirds of large roof timbers traced to Chuska Mountains and one-third to San Mateo Mountains.