Using electromagnetic waves originating in the ionosphere and magnetosphere, conductivity profiles reaching the deep upper mantle show surprising variability in water content.
S. D. Jacobsen
Editor, Geophysical Research Letters
Extremely High Carbon Return in Certain Volcanic Arcs
By comparing measured volcanic output with subducted carbon fluxes from drill cores, the Lesser Antilles subduction zone shows nearly complete slab carbon release at sub-arc depths.
Tracking Reverse Weathering
Using beryllium isotopes to track in situ formation of clays in the ocean, known as reverse weathering, will improve global models of atmospheric carbon dioxide and ocean alkalinity.
What Controls How Quickly Faults Heal?
The rates at which fault zones “heal” through secondary mineralization have been elusive, but uranium-thorium dating of calcite growth in fault-zone fractures may provide the answer.
Thermal Convection Can Power the Geodynamo
New high-pressure experiments on fluid iron suggest thermal convection without compositional buoyancy is sufficient to drive the dynamo generating Earth’s magnetic field.
Hiding Deep Hydrous Melts at the Core-Mantle Boundary
Silicate melts containing H2O in the lowermost mantle are surprisingly dense and may stagnate there, trapping primordial volatiles and potentially causing some of the ultra-low velocity zones.
Crystals Connect Bubbles in Explosive Magmas
Hydrous silica-rich magmas can degas through connected bubble pathways when as little as 20% crystals are present, influencing transitions from explosive, Vulcanian-style eruptions to lava effusion.
Carbonate Melting Enhances Mantle CO2 Fluxes in Old Ocean Basins
The amount of CO2 segregated from the mantle by carbonate melting beneath old oceanic crust may equal that emitted along the mid-ocean ridge system, thereby contributing to the global carbon cycle.