The Chandler annual resonance and its possible geophysical significance

The secular decrease of the earth's rotation rate has caused the Chandler and annual modes of the earth's wobble to resonate in the past. The physics of the resonance is discussed as well as its thermal impact on the mantle. Energy of the order of 10²⁶ erg/year were dissipated in the upper mantle during the resonance. Estimates of the epoch and duration of the resonance place them at about 185 m.y. ago and about 10 m.y., respectively. The possibility of a causal connection between the resonance and the onset of continental drift is suggested.