southern basin of Lake Titicaca (Lago Wiñaymarka) conTwo century-scale time series in northern Bolivia constrain the tains an incomplete Holocene record because it was almost ages of abrupt changes in the physical, geochemical, and biological completely desiccated prior to about 3500 C yr B.P. (Wirrcharacteristics of sediments obtained from lakes that formed durmann et al., 1990; Wirrmann and M...