- Of or relating to the history of the earth.
- Resulting from geological processes.
2005, Kuykenda, William, Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations, DIANE Publishing, ISBN 9781428904491, page 61:
- Geogenic emissions are primarily the result of oil or natural gas seeps and soil wind erosion. In addition, lightning may also be a significant contributor to natural NO2 emissions in an inventory area. Volcanoes and fumaroles (i.e., vapor or gas vents in a volcanic region) can be additional sources of geogenic emissions.