Abstract

Oxygen isotope records of cushion-plant peat cellulose from the southern central Andes capture evidence for significant environmental changes. We observe that the delta O-18(cell) peatland record from Cerro Tuzgle (24 degrees S) is in high conformity with the respective Lagunillas peatland record (27 degrees S). During the late Holocene, two significant fluctuations occurred and are interpreted as regional moisture signals with increased precipitation amounts indicated during multi-centennial phases from 1,530 to 1,270 cal. yr BP and from 470 to 70 cal. yr BP. These fluctuations can be best explained by changes in the strength of the South American summer monsoon (SASM). This interpretation is further supported by consistency with northern Andean paleoclimate records (10-13 degrees S) and very high correlation (R-2 = 0.76) with the Southern Oscillation Index. The congruent precipitation signals suggest the persistent climatic control of the SASM-strength in this latitudinal band during the last 1,800 years.