PARENT SESSION
Contributed Oral Session 49: Climate and Vegetation Dynamics
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 520 C, Level 5, Palais des congrès de Montréal

Limitations of wood cellulose ¹⁸O as an indicator of paleoclimate on > millenial time scales.

Richter, Suzanna^*,1, Johnson, Arthur¹, ¹ Department of Earth and Environmental Science, Philadelphia, PA, U.S.A.

ABSTRACT- Using conifer and angiosperm wood cellulose from 35 forested landscapes across North America and the Caribbean, we created regression models to estimate site mean annual temperature (MAT) and precipitation ¹⁸O from cellulose ¹⁸O. At a given site, cellulose ¹⁸O is about 2 per mil more enriched in conifers than in angiosperms and both are very strongly correlated with MAT (R²=.96), and with precipitation ¹⁸O (R²=.93). We used cellulose from wood buried in sediments for 200 to 45 million years to estimate MAT at various locations in North America, Siberia and coastal Chile for the Holocene, Pleistocene, Pliocene, Miocene, Oligocene and Eocene. We found MAT values that coincided with MAT estimates from other biological proxies up to about 40 ka. However, the MAT estimates from 3 million-year-old through 45 million-year-old preserved Arctic and Siberian wood-cellulose are much lower (at least 7 C) than the MAT estimates derived from other biological proxies. Different geographic patterns of ¹⁸O in precipitation in the Tertiary compared to today is the most reasonable explanation for the discrepancies.

Key words: cellulose ¹⁸O, paleoclimate, Tertiary wood