TY - JOUR
T1 - A basal magma ocean dynamo to explain the early lunar magnetic field
AU - Scheinberg, Aaron L.
AU - Soderlund, Krista M.
AU - Elkins-Tanton, Linda
N1 - Funding Information:
This work was funded with NSF Grant No. 0909206. We thank J. Wisdom for use of computational resources as well as J. Tyburczy, J.-F. Lin, and N. Dygert for fruitful discussions on the electrical conductivity of mantle rocks.
Funding Information:
This work was funded with NSF Grant No. 0909206 . We thank J. Wisdom for use of computational resources as well as J. Tyburczy, J.-F. Lin, and N. Dygert for fruitful discussions on the electrical conductivity of mantle rocks.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/6/15
Y1 - 2018/6/15
N2 - The source of the ancient lunar magnetic field is an unsolved problem in the Moon's evolution. Theoretical work invoking a core dynamo has been unable to explain the magnitude of the observed field, falling instead one to two orders of magnitude below it. Since surface magnetic field strength is highly sensitive to the depth and size of the dynamo region, we instead hypothesize that the early lunar dynamo was driven by convection in a basal magma ocean formed from the final stages of an early lunar magma ocean; this material is expected to be dense, radioactive, and metalliferous. Here we use numerical convection models to predict the longevity and heat flow of such a basal magma ocean and use scaling laws to estimate the resulting magnetic field strength. We show that, if sufficiently electrically conducting, a magma ocean could have produced an early dynamo with surface fields consistent with the paleomagnetic observations.
AB - The source of the ancient lunar magnetic field is an unsolved problem in the Moon's evolution. Theoretical work invoking a core dynamo has been unable to explain the magnitude of the observed field, falling instead one to two orders of magnitude below it. Since surface magnetic field strength is highly sensitive to the depth and size of the dynamo region, we instead hypothesize that the early lunar dynamo was driven by convection in a basal magma ocean formed from the final stages of an early lunar magma ocean; this material is expected to be dense, radioactive, and metalliferous. Here we use numerical convection models to predict the longevity and heat flow of such a basal magma ocean and use scaling laws to estimate the resulting magnetic field strength. We show that, if sufficiently electrically conducting, a magma ocean could have produced an early dynamo with surface fields consistent with the paleomagnetic observations.
KW - geodynamics
KW - geodynamo
KW - lunar magnetism
KW - magma ocean
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U2 - 10.1016/j.epsl.2018.04.015
DO - 10.1016/j.epsl.2018.04.015
M3 - Article
AN - SCOPUS:85045585362
SN - 0012-821X
VL - 492
SP - 144
EP - 151
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -