AI Article Synopsis
- - The (142)Nd/(144)Nd ratio of the Earth is higher than that of solar ratios found in chondritic meteorites, which questions the belief that the silicate Earth has the same composition as chondrites.
- - A common theory to explain this discrepancy involves a hidden layer in the mantle rich in incompatible elements, but this idea doesn’t align with the heat flow observed in mantle plumes.
- - This leads to two possibilities: either the materials that formed the Earth weren't chondritic, or the Earth lost some of its matter due to collisions during its formation.
Article Abstract
The (142)Nd/(144)Nd ratio of the Earth is greater than the solar ratio as inferred from chondritic meteorites, which challenges a fundamental assumption of modern geochemistry--that the composition of the silicate Earth is 'chondritic', meaning that it has refractory element ratios identical to those found in chondrites. The popular explanation for this and other paradoxes of mantle geochemistry, a hidden layer deep in the mantle enriched in incompatible elements, is inconsistent with the heat flux carried by mantle plumes. Either the matter from which the Earth formed was not chondritic, or the Earth has lost matter by collisional erosion in the later stages of planet formation.
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