Chemical weathering in central iceland: an analog of pre-silurian weathering.

The rate of chemical weathering in central Iceland is two to three times more rapid in areas with plant cover than in barren areas. This relatively small difference in chemical weathering rates suggests that atmospheric CO(2), pressures no greater than five times the present value were needed to sustain present-day rates of chemical weathering before the development of higher land plants in the Silurian.