Numerical modeling the process of deep slab dehydration and magmatism

Area of Science:

• Geophysics
• Geochemistry
• Tectonics

Background:

• Ocean-continent subduction zones are critical geological settings for understanding plate dynamics and magmatism.
• Deep plate hydration and dehydration processes significantly influence mantle geochemistry and melting.
• Previous models have not fully captured the temporal evolution of water transport and its impact on deep mantle melting.

Purpose of the Study:

• To investigate the dynamic processes of deep plate hydration and dehydration in subduction zones using a high-resolution thermo-mechanical model.
• To reveal the pathways and temporal evolution of water transport to the deep mantle.
• To understand the role of plate dehydration in triggering partial melting and magmatic activity.

Main Methods:

• A 2D high-resolution thermo-mechanical coupled numerical model was employed.
• The model simulates the complex interactions between plate tectonics, fluid transport, and thermal processes.
• Analysis focused on water pathways, dehydration reactions, and melt generation at various depths.

Main Results:

• Plate dehydration is a key trigger for partial melting in the deep mantle and subsequent magmatic activity.
• Melt volumes produced differ significantly with depth, with weaker dehydration reactions in deeper regions.
• Reaching suitable pressure-temperature (P-T) conditions for hydrous melting takes longer in the deep mantle.

Conclusions:

• Water transport to the deep mantle is geophysically significant, influencing magmatic processes.
• Deep dehydration reactions play a crucial role in the formation of magma chambers beneath continental plates.
• The study provides insights into the long-term evolution of water cycling and magmatism in subduction zones.