The planet’s oceanic crust has been shaped over hundreds of millions of years by volcanic activity – but much of this volcanic system is hidden below the seafloor.
Magma moves and solidifies to add two million kilograms of new material to the Earth’s crust every second during a process called seafloor spreading. However, how this magma migrates and what controls this remain puzzling.
New research led by the University of Plymouth aims to unlock some of these mysteries and provide greater understanding of the dynamic processes occurring at depth beneath the seafloor.
Along the East Pacific Rise, home to the most magmatically active seafloor spreading axis on Earth, geophysicists have imaged thin, lens-shaped magma chambers known as axial melt lenses.
They are thought to sit on top of hot mushes made up of crystals surrounded by small amounts of magma, and this system in the lower crust feeds magma upwards through conduits known as dykes which, in turn, leads to the eruption of lava onto the seafloor.
How this process occurs is currently poorly understood because the deep crust is largely inaccessible in the oceans. So instead, researchers will study an ancient section of seafloor now exposed on land in the Oman mountains, and use a combination of analytical methods to determine the pathways followed by magma during the construction of oceanic crust by seafloor spreading.
The project is being supported by a grant of more than £650,000 from the Natural Environment Research Council, part of UK Research and Innovation. It will be led in Plymouth by Professor of Geophysics and Geodynamics Antony Morris and Dr Michelle Harris, Lecturer in Earth Sciences, and involves a partnership with Professor Chris MacLeod (Cardiff University) and Dr Benoit Ildefonse (University of Montpellier).
Professor Morris, the project’s principal investigator, led a study demonstrating how geophysical magnetic methods may be used to discover magma pathways in Oman, published in Geology in March 2019.