Hi everybody! Can anyone provide me with examples of very heavy delta-13C values in organic matter from modern environments (higher than -10 in TOC)? We have been studying Late Quaternary lake sediments from high- altitude lakes on various East African mountains. In our cores we have found delta-13C values as high as -7 per mille in TOC and -5 per mille in individual algal lipids. These occur at more than one site, and at two sites are associated with remains of green algae (Botryococcus and Pediastrum). We are in the process of setting up a modest stable-isotope lab here in association with the existing Radiocarbon Laboratory. More anon. Alayne F.A. Street-Perrott Research Professor of Physical Geography Tropical Palaeoenvironments Research Group Department of Geography University of Wales Swansea Singleton Park Swansea SA2 8PP Tel +44-1792-295910 Fax +44-1792-205556 e-mail [log in to unmask]