thumbnail

Evidence for prolonged El Nino-like conditions in the Pacific during the Late Pleistocene: a 43 ka noble gas record from California groundwaters

Quaternary Science Reviews

By:
, , ,
DOI: 10.1016/j.quascirev.2009.05.008

Links

Abstract

Information on the ocean/atmosphere state over the period spanning the Last Glacial Maximum - from the Late Pleistocene to the Holocene - provides crucial constraints on the relationship between orbital forcing and global climate change. The Pacific Ocean is particularly important in this respect because of its dominant role in exporting heat and moisture from the tropics to higher latitudes. Through targeting groundwaters in the Mojave Desert, California, we show that noble gas derived temperatures in California averaged 4.2 ?? 1.1 ??C cooler in the Late Pleistocene (from ???43 to ???12 ka) compared to the Holocene (from ???10 to ???5 ka). Furthermore, the older groundwaters contain higher concentrations of excess air (entrained air bubbles) and have elevated oxygen-18/oxygen-16 ratios (??18O) - indicators of vigorous aquifer recharge, and greater rainfall amounts and/or more intense precipitation events, respectively. Together, these paleoclimate indicators reveal that cooler and wetter conditions prevailed in the Mojave Desert from ???43 to ???12 ka. We suggest that during the Late Pleistocene, the Pacific ocean/atmosphere state was similar to present-day El Nino-like patterns, and was characterized by prolonged periods of weak trade winds, weak upwelling along the eastern Pacific margin, and increased precipitation in the southwestern U.S.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Evidence for prolonged El Nino-like conditions in the Pacific during the Late Pleistocene: a 43 ka noble gas record from California groundwaters
Series title:
Quaternary Science Reviews
DOI:
10.1016/j.quascirev.2009.05.008
Volume
28
Issue:
23-24
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
2465
Last page:
2473
Number of Pages:
9