Change in the Moment of Inertia of the Earth as a Result of a Growing Core
The possibility that the growth of the Earth’s core has been gradual seems to have been proposed first by Urey (1952). He arrived at this hypothesis by geochemical reasoning. He argued that the abundance of volatile elements in the Earth’s crust was greater than would be expected if the Earth had ever been molten. Because it is then inferred that the Earth was formed cold by a process of accretion, the formation of the core, presumed to be chemically distinct from the mantle, presents a problem not before recognized as one. Urey’s solution was that the separation of iron toward the geocenter could only have taken place gradually. He raised the important question as to whether the growth was yet entirely complete. This idea was later adopted by Runcorn (1962) as a possible cause of changes in the convection pattern in the Earth’s mantle. These changes were necessary ways of explaining continental drift, recent evidence for which is the systematic differences in the paleomagnetic polar wandering paths determined from different continents.
KeywordsOrbital Angular Momentum Middle Devonian Convection Pattern Continental Drift Spin Angular Momentum
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