Mantle plume-subduction zone interactions over the past 60 Ma

A variety of mantle plume types have been proposed and there is a wide range of ways that these plumes might interact with subduction zone arcs. This study looks at the frequency of interaction between previously catalogued plumes and subduction zones while also assessing the potential role of slab windows to either generate false plume signals or contribute to genuine examples of mantle plume-subduction zone interactions. Of the plumes included in several widely cited catalogues, 29% have moved within 1000 km of a subduction zone and 17% have moved within 500 km of a subduction zone over the past 60 Ma, assuming that the plume life span extended over this period. Of the plumes that moved within 1000 km of a subduction zone, 56% are rated as either a deep or mid-mantle plume by an author of at least one of the catalogues. The 44% of interacting plumes that are not rated as mid-mantle or deep by at least one author are the most likely to be related to "top-down" plate tectonic processes. This study shows that they were never coincident with a slab window, although they have often interacted within distances of 1000 km. The manner of interaction between plumes and slab windows depends on the relative positions of the plume, ridge, and slab window. Of the plumes that interact over a 1000 km circular "Zone of Potential Interaction" (ZPI), 28% are no longer interacting today, but have survived that process. While most plumes interact in the form of a ZPI moving over a trench from either behind or in front of the trench, several plumes do cross the trench, demonstrating that plumes can survive even that interaction. Plume-trench interaction occurs in clusters in the northeast and southwest Pacific with limited events in the northwest and southeast Pacific. The presence of dusters in the northeast and southwest Pacific may be caused by the closer proximity of mid-mantle and deep plumes to a subduction zone in these areas. Whereas some deeper plumes may be modified by slab related mantle flow, the coincidence of shallow plumes with changes in plate boundaries suggests an origin related to sites of weakness or extension in the oceanic crust. (C) 2015 Elsevier B.V. All rights reserved.