Increasing complexity in magmatic architecture of volcanoes along a waning hotspot
In: Nature Geoscience. Nature Publishing Group: London. ISSN 1752-0894; e-ISSN 1752-0908, more
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| Authors | | Top |
- Tapu, A.T.
- Ubide, T.
- Vasconcelos, P.M.
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| Abstract |
Mantle plumes are key drivers of volcanism within tectonic plates. Variations in plume flux and the resulting magma flux are expected within a plume’s lifetime, but their impact on volcanic architecture and eruption products and styles remains poorly constrained. Here we combine mineralogy, petrology and geochronology of Earth’s longest continental hotspot chain to assess the effects of waning plume strength on magma flux and pre-eruptive magma transport and storage. We focus on Cenozoic age-progressive volcanoes across eastern Australia, divided by a change in plate motion and voluminous volcanism. Northern volcanoes are older and ‘long-lived’ (3.5–7 million years (Ma)) and erupted high volumes (>800 km³) of bimodal magmas (basalts and rhyolites), producing homogeneous, crystal-poor basalts (~3 vol% phenocrysts). Southern volcanoes are smaller (<300 km³), ‘short-lived’ (≤1.5 Ma) and split into two parallel tracks that erupted more evolved and texturally complex magmas (~12 vol% phenocrysts, internally zoned). These findings imply waning magma flux leads to increasingly complex feeder systems that enhance magma storage and differentiation. Similar trends in hotspot tracks globally suggest that plume and magma flux play a crucial role in the evolution of intraplate volcanoes. |
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