Lithium and Lithium Isotopes in Earth’s Surface Cycles

Abstract

Lithium and its isotopes can provide information on continental silicate weathering, which is the primary natural drawdown process of atmospheric CO2 and a major control on climate. Lithium isotopes themselves can help our understanding of weathering, via globally important processes such as clay formation and cation retention. Both these processes occur as part of weathering in modern surface environments, such as rivers, soil pore waters, and groundwaters, but Li isotopes can also be used to track weathering changes across major climate-change events. Lithium isotope evidence from several past climatic warming and cooling episodes shows that weathering processes respond rapidly to changes in temperature, meaning that weathering is capable of bringing climate back under control within a few tens of thousands of years.