Madsen Building F09, Room 405
School of Geosciences
The University of Sydney
Sydney, NSW 2006
Continental Large Igneous Provinces (LIPs) and the deep-time Carbon Cycle
Supervisors: Dr Sabin Zahirovic and Prof Dietmar Müller
The eruption of mantle plumes on Earth’s surface has fundamental consequences for the planet’s tectonics, topography, climate, biological diversity, and even sea level. The arrival of a plume head beneath the lithosphere can result in voluminous volcanic eruptions that build enormous volcanic plateaus, called Large Igneous Provinces (LIPs). One such example is the rapid eruption of the Siberian Traps ~250 million years ago, which injected enormous volumes of CO2 into the atmosphere (partly also from decarbonation of limestone bedrock and coal seams). The Siberian Traps eruption resulted in abrupt global climate change, and is thought to be responsible for the single biggest mass extinction in Earth’s geological past, occurring at the end of the Permian period.
Recent studies have begun looking into the role of weathering of such continental volcanic plateaus as a modulating effect on atmospheric CO2. Since these mantle plume products are composed of largely basaltic rock, the interaction with water in the atmosphere leads to rapid breakdown of the silica minerals, which triggers a chemical reaction that sequesters CO2 out of the atmosphere. This effect is amplified when the continental Large Igneous Provinces enter the tropics, where intense atmospheric weathering leads to accelerated carbon sequestration.
This summer project will combine mapped and dated Large Igneous Provinces with cutting-edge plate reconstructions in GPlates to study the interplay between plume eruptions, tectonics, the deep-time carbon cycle, and long-term climate since the Late Paleozoic. By calculating the total area of volcanic plateaus through time, and evaluating what portion of that area resides in the tropics, the project may shed clues on the link between volcanic plateau weathering and excursions observed in long-term climate proxy records. The project will be part of a broader collaboration with the international Deep Carbon Observatory, embedded in a long-term aim of modelling deep-time climate and the deep-Earth carbon cycle.