Coordination and competition between soil magnetic particles driven by
contrary climate development
The ferrimagnetic (FM) and antiferromagnetic (AFM) particles of iron
oxides are considered pedogenic and climatic indicators due to their
enrichment with comparable increasing in rainfall and temperature.
However, the opposite changes in rainfall and temperature result in
rapid change of relative humidity (RH), which could lead to their
competition and transformation. We examined two soil sequences undergone
contrary climate development on the eastern edge of the Tibetan Plateau.
The dry and warm climate with low RH favors the coordinative enrichment
of AFM hematite and FM particles, while the wet and cool climate with
high RH mainly produces goethite but leads to competition between low
content AFM hematite and FM particles. The outcome well interprets the
changing relationship between color and magnetism in soils and
sediments, and suggests that temperature is as important as
precipitation in paleoclimate reconstruction based on iron oxides,
especially during strong dry-wet cycles and climate pattern shifts.