Rapid Vegetational and Sediment Change from Rano Aroi Crater, Easter Island

Previous pollen investigations by Flenley et al. (1991) suggest that the Rano Aroi Crater, Easter Island (27 08’ S, 109 26’W) contained a record of vegetational history that is greater than 35,000 C-14 years old. The environmental setting and modern vegetation is fully discussed by Flenley et al (1991). Rano Aroi Crater was selected for further work for two reasons. The first is that we were interested in a sediment record that spanned the transition from glacial to interglacial conditions. The second is that the peat composition might prove ideal for macrofossil analysis. Large fluctuations in pollen percentages characterize the stratigraphy, suggesting that this small subtropical island showed a major vegetational response to climate change. In order to add insight into the vegetational and sediment changes that took place, we re-cored the Rano Aroi Crater and are in the process of analyzing the core at 2-cm intervals for pollen and macrofossils in addition to sediment characterization and AMS C-14 dating. Our preliminary results here focus on the most striking lithological change in the core, Drive 3, between 200 and 300 cm depth.