Clustering of arc volcanoes caused by temperature perturbations in the back-arc mantle.
Nat Commun 2017;
8:15753. [PMID:
28660880 PMCID:
PMC5493751 DOI:
10.1038/ncomms15753]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 04/25/2017] [Indexed: 11/23/2022] Open
Abstract
Clustering of arc volcanoes in subduction zones indicates along-arc variation in the physical condition of the underlying mantle where majority of arc magmas are generated. The sub-arc mantle is brought in from the back-arc largely by slab-driven mantle wedge flow. Dynamic processes in the back-arc, such as small-scale mantle convection, are likely to cause lateral variations in the back-arc mantle temperature. Here we use a simple three-dimensional numerical model to quantify the effects of back-arc temperature perturbations on the mantle wedge flow pattern and sub-arc mantle temperature. Our model calculations show that relatively small temperature perturbations in the back-arc result in vigorous inflow of hotter mantle and subdued inflow of colder mantle beneath the arc due to the temperature dependence of the mantle viscosity. This causes a three-dimensional mantle flow pattern that amplifies the along-arc variations in the sub-arc mantle temperature, providing a simple mechanism for volcano clustering.
Volcanoes may cluster along volcanic arcs, but controls on cluster locations are still unclear. Here, using numerical models, the authors show that clustering along arcs is the result of inflow of hotter mantle material, and subdued inflow of colder material creating a 3D mantle flow pattern.
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