A University of Oklahoma-led study links vast amounts of iron-rich dust deposits from the late Paleozoic period of 300 million years ago with implications for major ecosystem fertilization and a massive drawdown of atmospheric carbon.

Understanding iron fertilization and other deep-time events may explain present and future climate change and aid scientists and policymakers when making decisions related to geoengineering the Earth.

"Humans are now a geologic force on the planet, meaning our activities have a global environmental impact and will be recorded in the future geologic record," said Gerilyn Soreghan, professor in the OU School of Geology and Geophysics, Mewbourne College of Earth and Energy.

"For example, emissions of greenhouse gases caused by human activity are occurring at a rate that, as far as we can detect, is unprecedented in Earth history."

In this study, Soreghan and colleagues from the University of California Riverside, Florida State University, University of Leeds, Hampton University and Cornell University explore iron fertilization by atmospheric dust 300 million years ago and what would have followed.

Earth's atmosphere 300 million years ago was perhaps the dustiest of all time. Dust links to carbon because of the iron--a key nutrient for nearly all life, so atmospheric dust acts as a fertilizer.

Iron fertilization has been proposed as a serious geoengineering scheme to control future atmospheric carbon and climate change even though the consequences of potentially analogous events recorded in deep time remain incompletely investigated.

Soreghan and her colleagues argue that more research on deep-time events is needed. Research on Earth's deep-time record offers insights on the potential impacts of such schemes.

The Geological Society of America has published an article on this study, "Extreme eolian delivery of reactive iron to late Paleozoic icehouse seas," in the scientific journal Geology.