a1 Centre for Astronomy, James Cook University, Townsville, Queensland 4811, Australia email: firstname.lastname@example.org
a2 Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder CO, 80309, USA and Centre for Astronomy, James Cook University, Townsville, Queensland 4811, Australia email: email@example.com
Three architectural traditions with astronomical associations have been identified among the ‘Great Houses’ and ‘Great Kivas’ of Chaco Canyon, New Mexico. Great Houses and one Great Kiva built during the height of construction activity (AD 1020–1100), the Bonito Phase, include front-facing south-southeast (SSE) orientations, and cardinal north-south and/or east-west (NS/EW) alignments. We present ethnographic material supporting our previous proposal that the SSE orientation is probably linked to migration traditions and ancestor veneration. We also confirm that a majority of Late Bonito Phase Great Houses (built after A.D. 1100) exhibit a third astronomical tradition: five of the principal in-canyon Great Houses built at that time were positioned at or near observing locations that could have functioned as solstice calendrical stations. Through use of these locations for public ceremonies, the Chacoan elite could demonstrate astronomical knowledge and ritual power. These findings provide support for Van Dyke's hypothesis that construction during this period was intended to reinvigorate a faltering system. One ‘Chaco halo’ Great House, Bis sa'ani, incorporates all three traditions. We suggest that temporal analysis of these traditions improves understanding of migration paths and shifting balances of power and social dominance among ancestral Pueblo culture groups.
(Online publication July 26 2011)