Subduction Zone Magnetism: The Influence of Metamorphism and Serpentinization in the Mantle Wedge

Journal article

Plain Language Summary: The mantle wedge is a triangular prism of rock that lies between an overlying tectonic plate and underlying subducting slab in a subduction zone. Rocks from the mantle wedge have been brought up from great depth and exposed on the surface of Santa Catalina Island/Pimu'nga, USA. Samples collected from the island provide a rare opportunity to directly study an ancient hydrated mantle wedge. We are particularly interested in the magnetic properties of these samples, which affect surface magnetic measurements. We find at least two compositionally distinct groups of magnetic minerals formed through different processes: (a) metamorphic change and (b) hydration reactions. The two magnetic types of magnetic mineral possess different magnetic properties, and so affect surface magnetic measurements in different ways. Surface magnetic measurements can be used to infer subduction zone thermal structure, which is greatly important for assessing their potential as seismic and volcanic hazards. As such, a better understanding of the magnetic properties of mantle rock can facilitate improvements in understanding the natural hazards associated with subduction zones.

Authors: Li, Y; Lindquist, PC; Han, D; Fish, B; Harrison, RJ

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Geochemistry, Geophysics, Geosystems
• Volume: 27
• Issue: 3
• Article number: e2025GC012354
• Publication date: 2026-03-05
• Acceptance date: 2026-02-19
• DOI: 10.1029/2025gc012354
• EISSN: 1525-2027
• ISSN: 1525-2027
• Language: English