Madison East

Summer Scholarship Student

meas7937@uni.sydney.edu.au

Phone: –

Research Project

Subduction Volume Flux and deep-time climate and sea level

Supervisors: Prof Dietmar Müller, Dr Simon Williams and Dr Sabin Zahirovic

Plate tectonics dominates long-term climate and sea level changes by rearranging continents, modifying the planet’s topography and bathymetry, and changing the flux of greenhouse gases in the atmosphere. As tectonic plates evolve, the nature and length of plate boundaries changes through time. A notable example is the mid-Cretaceous sea level highstand, which is linked to fast seafloor spreading rates and higher rates of subduction. This pulse in seafloor generation led to larger areas of younger and more buoyant oceanic crust, which displaced more water onto the continents, resulting in record-high sea levels. As more oceanic crust is generated, older crust has to be destroyed elsewhere through the process of subduction, which itself releases enormous amounts of CO₂ into the atmosphere and can result in greenhouse climate conditions on the planet.

Previous studies have estimated the volume of subducted plates using simplistic and schematic models of past plate boundaries, but have made important contributions linking slab flux to atmospheric CO₂ trends. By using the latest plate reconstructions in GPlates, we can model the evolution of plate boundaries through time, and compute their lengths, as well as extract the convergence rate at subduction zones. This summer project will use the plate reconstructions in GPlates, along with Python scripting workflows, to compute slab flux since the Late Paleozoic (~400 million years ago to present), and analyse the trends in the context of atmospheric CO₂ proxies and published sea level curves. This project will form part of an ongoing collaboration with the international Deep Carbon Observatory, which is composed of a dynamic community of inter-disciplinary researchers that study the planet’s deep-time and deep-Earth carbon cycle, and the consequences for climate, sea level and the evolution of life.

Short Bibliography

Madison is currently completing her third year of a BSc (Advanced) majoring in ‘Geology and Geophysics’ and ‘Marine Science’. Following her first involvement with the EarthByte group during the summer of 2016/17 she is now working as a research assistant, and continuing work on a project looking at subduction volume flux through time.

See below for EarthByte content related to Madison.