Physics and Astronomy Calendar

Antineutrino studies are providing fundamental data for both particle physics and geology. Recent results from antineutrino (geoneutrino) studies at KamLAND are coincident with geochemical models of Th and U in the Earth. KamLAND and Borexino antineutrino detectors are on line, thus uncertainties in counting statistics will be reduced as data are accumulated. The SNO+ antineutrino detector, situated in Sudbury Ontario, the middle of the North American plate, will come on line in 3+ years and will be best suited to yield a precise estimate of
the continental contribution to the Earth's Th & U budget. The proposed Hanohano antineutrino detector is oceanic based, designed to be towed to its location and position on the seafloor and is capable of multi-deployment. This detector would provide a precise estimate of the mantle contribution to the Earth's Th & U budget (~15% uncertainty) following a 1-yr deployment. Much needed constraints from potassium-derived antineutrinos remain elusive, but efforts to overcome technical challenges are being studied.
The distribution of heat producing elements in the Earth drives convection and plate tectonics. Geochemical models posit that of the heat producing elements, ~40% are in the continental crust and the remainder in the mantle. Although models of core formation allow for the incorporation of heat producing elements (including a geo-reactor in the core), the core contribution of radiogenic heating is considered to be negligible. Most parameterized convection models for the Earth require significant amounts of radiogenic heating of the Earth, a factor of two greater than geochemical models predict. The initial KamLAND results challenge these geophysical models and support geochemical models calling for a significant contribution from secular cooling of the mantle.