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Improving our understanding of the silicate weathering feedback mechanism by developing and applying novel isotope techniques
PhD project title:
Testing the interactions between chemical weathering and glacial cycles using novel isotope tracers.
Project description:
Throughout geological time, feedback processes have prevented runaway greenhouse and icehouse states, keeping Earth’s climate within habitable limits. The continental weathering of silicate rocks has been proposed to play an important role in such climate stability but is surprisingly poorly quantified. This PhD project seeks to provide new constraints on the operation of weathering as a climate feedback. Laboratory experiments will be used to investigate element release and lead isotope systematics during the chemical weathering of silicate rocks over a range of lithologies and grain sizes. These results will then be applied to examine variability in silicate weathering through Quaternary glacial-interglacial cycles.
Because the ocean is the ultimate repository for the particulate and dissolved products of continental denudation, ocean sediment cores represent unique archives of past weathering changes. A novel combination of isotope tracers extracted from different fractions of marine sediments will quantify weathering changes in response to past climate perturbations. Additionally, there is scope to explore Li isotope records in speleothems as proxies for terrestrial weathering linked to terrestrial ice sheet retreat.