VOL. 15, No. 11 A PUBLICATION OF THE GEOLOGICAL SOCIETY OF AMERICa NOVEMBER 2005 Inside: Emergence of the aerobic biosphere during the Archean-Proterozoic transition: Challenges of future research, by Victor A. Melezhik et Al., p. 4 Section Meetings: Cordilleran, p. 12 Rocky Mountain, p. 15 VoluMe 15, NuMbeR 11 NOveMbeR 2005 Cover: Paleoproterozoic (2200 Ma) lacustrine dolostone from the Pechenga Greenstone belt, northeast Fennoscandian Shield. Width of field is 15 cm. The laminated red (oxidized) dolostone is anomalously enriched in 13C (δ13C = +8‰), while the overlying material, representing the oldest known traver- GSA TODAY publishes news and information for more than tines in the world, are 13C-depleted (δ13C = −7‰). Note that 18,000 GSA members and subscribing libraries. GSA Today these rocks have experienced greenschist-facies metamor- lead science articles should present the results of exciting new phism. The 13C-rich dolostones from the Fennoscandian Shield research or summarize and synthesize important problems exemplify the evidence for an extreme global perturbation to or issues, and they must be understandable to all in the earth the carbon cycle at this time, although interpretation of these science community. Submit manuscripts to science editors 13 Keith A. Howard,
[email protected], or Gerald M. Ross, lacustrine rocks in terms of a global marine δ C excursion is
[email protected]. not straightforward. See “emergence of the aerobic biosphere during the Archean-Proterozoic transition: Challenges of future GSA TODAY (ISSN 1052-5173 USPS 0456-530) is published 11 research,” by Victor A. Melezhik et al., p. 4–11. times per year, monthly, with a combined April/May issue, by The Geological Society of America, Inc., with offices at 3300 Penrose Place, Boulder, Colorado.