CLIMATE VARIATION AND THE RISE AND FALL OF AN ANDEAN CIVILIZATION

Paleolimnological and archaeological records that span 3500 years from Lake Titicaca and the surrounding Bolivian-Peruvian altiplano demonst rate that the emergence of agriculture (ca. 1500 B.C.) and the collaps e of the Tiwanaku civilization (ca. A.D. 1100) coincided with periods of abrupt, profound climate change, The timing and magnitude of climat e changes are inferred from stratigraphic evidence of lake-level varia tion recorded in C-14-dated lake-sediment cores. Paleolake levels prov ide estimates of drainage basin water balance. Archaeological evidence establishes spatial and temporal patterns of agricultural field use a nd abandonment. Prior to 1500 B.C., aridity in the altiplano precluded intensive agriculture. During a wetter period from 1500 B.C. to A.D. 1100, the Tiwanaku civilization and its immediate predecessors develop ed specialized agricultural methods that stimulated population growth and sustained large human settlements, A prolonged drier period (ca. A .D. 1100-1400) caused declining agricultural production, field abandon ment, and cultural collapse. (C) 1997 University of Washington.