Peru Ice

We have seen elsewhere ( see methane) how atmospheric concentrations of methane (swamp gas) during the Holocene (last 10,000 years) are related to the extent of wetlands especially at low (tropical) latitudes.

Here in the lowermost graph we see oxygen isotope ratios and nitrate for the Huascaran glacier in Peru, showing an abrupt cooling at about 5200 BP. Compare this with the graph of methane; the two are mirror images. For other climatic indicators see the paleoclimatic page.

Also shown on the upper graph are proxy paleoclimatic data from sediment cores in the Santa Barbara basin off the coast of California, sediment bioturbidity and snail form, also indicating a discontinuity, possibly abrupt cooling, at 5.2k yrs BP.


Kennett, JP and Ingram, BL, A 20,000 yr record of ocean circulation and climate change from the Santa Barbara basin Nature v 377 p 510 12 Oct 95.

Thompson et al Late Glacial Stage and Holocene Tropical Ice Core Records from Huascaran, Peru Science v 269 7 July 1995.

Copyright 1996 Kirribili Press. Return to Scientific Summary Chronological Index Ignatius Donnelly and the End of the World