Knowledge of the amount and distribution of radiogenic heating in the mantle
is crucial for understanding the dynamics of the Earth, including its thermal
evolution, the style and planform of mantle convection, and the energetics of
the core. Although the flux of heat from the surface of the planet is robustly
estimated, the contributions of radiogenic heating and secular cooling remain
poorly defined. Constraining the amount of heat-producing elements in the Earth
will provide clues to understanding nebula condensation and planetary formation
processes in early Solar System. Mantle radioactivity supplies power for mantle
convection and plate tectonics, but estimates of mantle radiogenic heat
production vary by a factor of more than 20. Recent experimental results
demonstrate the potential for direct assessment of mantle radioactivity through
observations of geoneutrinos, which are emitted by naturally occurring
radionuclides. Predictions of the geoneutrino signal from the mantle exist for
several established estimates of mantle composition. Here we present novel
analyses, illustrating surface variations of the mantle geoneutrino signal for
models of the deep mantle structure, including those based on seismic
tomography. These variations have measurable differences for some models,
allowing new and meaningful constraints on the dynamics of the planet. An ocean
based geoneutrino detector deployed at several strategic locations will be able
to discriminate between competing compositional models of the bulk silicate
Earth.Comment: 34 pages, 6 tables, 5 figures, 2 supplementary figures; revised
version submitted to Earth Planet. Sci. Let
