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Updated: Jun 30, 2026

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
Published on: March 29, 2016
Compositional stratification in the deep mantle
Kellogg1, Hager, van der Hilst RD
1Department of Geology, University of California, Davis, CA 95616, USA. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 01239, USA.
Abstract:
A boundary between compositionally distinct regions at a depth of about 1600 kilometers may explain the seismological observations pertaining to Earth's lower mantle, produce the isotopic signatures of mid-ocean ridge basalts and oceanic island basalts, and reconcile the discrepancy between the observed heat flux and the heat production of the mid-ocean ridge basalt source region. Numerical models of thermochemical convection imply that a layer of material that is intrinsically about 4 percent more dense than the overlying mantle is dynamically stable. Because the deep layer is hot, its net density is only slightly greater than adiabatic and its surface develops substantial topography.
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