ABSTRACT
This chapter explores an hypothesized linkage between the episodic occupation of the Picacho Reservoir dune field and changes in the global thermal regime. It proposes that some ill-behaved fluctuations in the output of solar radiation during the past 5000 years created global thermal maxima which may have affected the habitability of a small, relatively unproductive patch of the Sonoran Desert for Archaic hunter-gatherers and later horticulturalists. The chapter provides some background on the archaeological investigations and the radiocarbon dates which elicit the long-term pattern. It attempts descriptively to recreate the explanatory conundrum posed by the archaeological, stratigraphic, and geomorphological data, all of which point to occupation associated with increased water availability. Temperature and water only account for the timing and association of certain aspects documentation of very different adaptive systems in the Middle Archaic, the Transitional, and the Hohokam periods underscores the potential diversity of human responses in the Picacho area.
