Quelccaya is located at 13°56'S; 70°50'W and has a summit elevation of 5670m a.s.l. Ice cores to bedrock were drilled in 1983 
using the first solar - powered drill. The cores were dated precisely (+/- 2 years at A.D. 1500) using a combination of seasonally 
varying dust concentrations and 18O, visible dust layers deposited each year during the dry season, and identification of ash 
from the A.D. 1600 eruption of Huaynaputina. Numerous paleoenvironmental records for this remote region have been extracted 
from these cores as reflected in the selected references below. The delta18O record from a core drilled at the summit in 1976 
is compared with that from one drilled in 1991 and reveals that the isotopic seasonal signal is no longer preserved and that 
the isotopic average is enriched by 2o/oo.

Thompson, L.G., E. Mosley-Thompson, P. Grootes, and M. Pourchet. 1984. 
Tropical glaciers: potential for paleoclimatic reconstruction. 
Journal of Geophysical Research, 89 (D3), 4638-4646.

Thompson, L.G., E. Mosley-Thompson and Benjamin Morales Arnao. 1984. 
Major El Niņo/Southern Oscillation events recorded in stratigraphy of the tropical Quelccaya Ice Cap. 
Science, 226 (4670), 50-52.

Thompson, L. G., E. Mosley-Thompson, J. F. Bolzan and B. R. Koci. 1985. 
A 1500 year record of tropical precipitation recorded in ice cores from the Quelccaya Ice Cap, Peru. 
Science, 229(4717), 971-973.

Thompson, L.G. and E. Mosley-Thompson. 1987. 
Evidence of abrupt climatic change during the last 1,500 years recorded in ice cores from the tropical Quelccaya ice cap, Peru. 
Abrupt Climatic Change - Evidence and Implications, NATO/NSF Workshop volume. D. Reidel Publishing Co., 99-110.

Shimada, I., C.B. Schaaf, L.G. Thompson and E. Mosley-Thompson. 1991. 
Cultural impacts of severe droughts in the prehistoric Andes: Application of a 1,500-year ice core precipitation record. 
World Archaeology: Archaeology and Arid Environment, 22(3), 247-270.

Brecher, H.H. and Thompson, L.G. 1993. 
Measurement of the retreat of Qori Kalis in the tropical Andes of Peru by Terrestrial Photogrammertry. 
Photogrammetric Engineering and Remote Sensing, 59(6), 1017-1022.

Thompson, L.G., M.E. Davis and E. Mosley-Thompson. 1994. 
Glacial records of global climate: A 1500-year tropical ice core record of climate. 
Human Ecology, 22(1), 83-95.