Which mechanism causes mantle heterogeneity near subduction zones as the subducting slab descends?

💡 Explanation

When a subducting slab descends, slab dehydration occurs because increased pressures and temperatures force water and other volatiles out of the slab's minerals, metasomatizing the overlying mantle wedge. Therefore slab dehydration results in mantle heterogeneity, rather than decompression melting, radiogenic heating, or crustal rebound which happen through different geologic processes.

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