Scientists to investigate how volcanic activity is affected by obstacles inside the Earth
Dr Lara Kalnins leads a interdisciplinary study investigating how warm materials, rising from deep in the Earth's mantle, negotiate subducted tectonic plates and how this affects the volcanic events we see on the surface.
An interdisciplinary team led by Royal Society of Edinburgh Research Fellow Dr Lara Kalnins has received funding from the Natural Environment Research Council (NERC) to investigate how warm, upwelling material from deep in the Earth’s mantle negotiates obstacles such as the edges of tectonic plates and how these obstacles affect the volcanism we see at the surface.
The study will focus on three chains of extinct volcanoes, one along the east coast of Australia and two underwater in the Tasman and Coral Seas.
These long, parallel, lines of volcanoes could represent rare examples of material from very deep inside the Earth reaching the surface, having come from potentially as deep as the core-mantle boundary - approximately 3000 kilometres beneath the Earth's surface.
The team at Edinburgh and the Scottish Universities Environmental Research Centre (SUERC) will use new samples and geophysical data from an upcoming expedition on the Australian oceanic research vessel "Investigator" to the two marine chains.
The scientists will use chronology to determine the age of each volcano, chemistry to determine what type of mantle melted, and geodynamic modelling to determine what processes could create this unique pattern.
Journey through the Earth
In particular, they will look at what happens to the rising material as it has to navigate the complex structures of the upper mantle. To reach the surface, it has to pass through two phase changes, where minerals change form due to changing pressure and temperature, one of which makes it harder for material to continue rising.
In areas like Australia, it may also need to go around pieces of subducted slab - the edges of tectonic plates. Finally, it will interact with the topography on the underside of the plates, which can create turbulence and eddies in the mantle flow because of the steep edges between the deep ‘keels’ of the continents and the much thinner oceanic plates.
"These chains of volcanoes offer us a unique opportunity to learn not only about material coming from the deep mantle, but also about what happens to it as it rises up to 3000 km from the lower mantle before reaching the surface."