The last glacial maximum climatic conditions on Easter Island

Abstract

The aim of this paper is to refine previous estimates of last glacial maximum (LGM) climatic conditions for Easter Island. Samples were analysed for fossil pollen from the lower half of a 13.40 m sediment core (RRA5). This part of the core includes a time span from ca. 28,000–10,000 14C BP. The results show that during this period there were three different climatic conditions: first, a time span from ca. 28,000–23,200 14C BP with slightly cooler and probably drier conditions relative to present day. Second, a more cool and dry climatic condition from ca. 23,200–14,700 14C BP. The second time span had two peak points at ca. 22,100 and 17,150 14C BP. It seems that the coolest and driest conditions occurred at 17,150 14C BP. Third, a warm and wet climate started at ca. 15,000 14C BP and continued until the end of the period studied (10,000 14C BP). In all the time covered in this study, there was an inverse relationship between values of Palmae and Poaceae, while Poaceae and Tubuliflorae shrubs show similar variations. The temperature estimations that are presented by different authors based on oxygen isotopes are for approximately 4 °C cooling at the LGM. However, the empirical values derived from the pollen evidence suggest only ca. 1.9 °C cooling. This is in agreement with recently obtained values from tropical lowlands.