Solar Astronomy in the Prehistoric Southwest
1. The Anasazi World:
To varying degrees, nearly every known ancient human civilization has been preoccupied with the heavens. For a farming-based society, such as that of the Anasazi of the ancient American Southwest, the Sun is usually an object of central importance, and often plays a pre-eminent role in religious practices. The Anasazi1 were but one of three large cultural groups that flourished in the Southwest. Their sphere of cultural influence centered on the so-called four-corner region, which we identify today with the meeting point of the states of Colorado, New Mexico, Utah and Arizona. For the Anasazis, however, it would be more appropriate to define it in terms of the drainage basin of the San Juan river, shown on the map in the center of the slide. To get a sense of distance, note that Chaco Canyon (labeled 1) and Mesa Verde (labeled 3) are separated by 160 km. The San Juan basin cuts through high desert plateaus; Chaco Canyon is about 1900m above see level, Mesa Verde 2200m, and Hovenweep 1650m. Most tributaries of the San Juan dry up in the summer, with the only perennial streams found in the northernmost regions, at higher elevations. The sites listed on the map represent but a small subset of prehistoric towns and dwellings to be found in the region. They are the sites we will encounter in the following slides. The surrounding photographs show the Casa Rinconada area in Chaco Canyon (top left), Holly House Ruins in Hovenweep (top right), White House Ruin in Canyon de Chelly (bottom right), and the twin towers of Chimney Rock (bottom right).
The San Juan basin was inhabited by sedentary farming population at least since the beginning of the modern era. Living first in subterranean rooms known as pit-houses, by approximately 500 A.D. the population became increasingly concentrated in villages of above-ground dwellings. By 700 A.D. stone masonry was becoming increasingly common, and by the mid-900s the Anasazi lived in large multi-rooms, buildings, now referred to as pueblos, on canyon floors and mesa tops. The Anasazi exploded, culturally and socially, in the following three and a half centuries. Figure 1 gives a timeline of important events in the Anasazi world of 1000-1300 A.D., together with a few astronomical events of importance.
In the late 1000s and early 1100s the Anasazi culture radiated far beyond the four corners region, with Chaco Canyon (next slide) becoming the dominant social and cultural center. For reasons not yet properly understood, by the mid-1100s the Chacoan system collapsed, leading to the abandonment of Chaco Canyon. Some Chacoan relocated North to what are know Aztec and Salmon Ruins, in Northern New-Mexico, but this was short-lived. The Anasazi continued to prosper in the Northern San Juan basin, notably at Mesa Verde, but by the end of the late 1200s the region was rapidly abandoned, most likely in response to a long period of severe drought.