Holocene Climate Variability of the Central Andes (Peru and Bolivia) Reviewed from δ18O Stratigraphy of Ice-Cores

Glacial ice cores are evidence of past environmental conditions through gases and elements trapped inside the drilled material. As Central Andes in the southamerican region are very sensitive to climate changes, a great history of temperature and precipitation variability could be found related to massive Ice Caps. Available oxygen isotope data from glacial ice cores conducted over the last three decades in the Central Andes are reviewed to analyze climate variability over the past seven millennia, a period characterized globally by remarkable climatic stability. The analysis allowed for the identification of climate cycles ranging from secular to millennial in time. These cycles have periods of 1.3, 0.87, 0.67, 0.46, and 0.25 kiloyears (ky.). A series of regional thermal minima and maxima are also defined. This variability in the Andean climate during the mid- and late Holocene is interpreted as being strongly controlled by changes in solar activity, in particular, the forcing of "grand solar minima" is recognized. Likewise, less frequent climate changes could be correlated with Bond cycles and increased or decreased activity of the thermohaline circulation.