Links
The Geological Society of America (GSA)
http://www.geosociety.org/
American Geophysical Union (AGU)
http://www.agu.org/
American Association of Petroleum Geologists (AAPG)
http://www.aapg.org/
Astrobiology at NASA Ames
http://astrobiology.arc.nasa.gov/
Society of Sedimentary Geologists (SEPM)
http://www.sepm.org/
International Association of Sedimentologists (IAS)
http://www.iasnet.org/