Recurrent evacuation of mantle mush in ocean islands revealed by clinopyroxene from La Palma.

Recurrent evacuation of an evolved mantle crystal mush at La Palma occurs within a week before eruptions, involving at least one instance of basanitic recharge.

• Why it matters: Understanding magma plumbing and its variations is crucial for interpreting volcanic unrest signals and eruption forecasting, especially in low-flux ocean island volcanoes where data are limited.
• What they did: Clinopyroxene zoning from eruptions in 1712, 1971, and 2021 was analyzed using trace element mapping, thermobarometry, and cluster analysis to track mantle processes over time.
• The result: Findings reveal that a cool, evolved phonolitic mush resides in the upper mantle and is recycled by mafic recharge, which facilitates magma ascent and influences eruption timing, highlighting common mantle processes in ocean island basalts.