Associate professor in Earth Science. My expertise includes paleoclimate change during periods of elevated volcanism, global element cycles, and inorganic geochemistry.
The main focus of my current research is how large igneous provinces (LIPs) can affect surface global element cycles. The emplacement of LIPs throughout geological history is often coincident with rapid and sustained climate variations, affecting both marine and terrestrial ecosystems. Four of the ‘big five’ mass extinction events through the Phanerozoic occur at the same time as a LIP emplacement, suggesting a possible causal relationship. However, there are numerous factors associated with a LIP emplacement that make each event unique. Factors such as the size of the province, the duration of magmatic and volcanic activity, and whether it is emplaced into continental or oceanic crust have a large impact on subsequent environmental effects. Understanding how these processes affect sources and sinks of elements such as carbon is key to unravelling the relationship between LIPs and environmental change in the rock record. Moreover, a strong comprehension of these natural events provides a proxy for current and future climate change. The International Panel on Climate Change (IPCC) 6th Assessment Reports note that paleoclimate proxy records “extend beyond the variability of recent decadal climate oscillations and thus provide an independent perspective on feedbacks between climate and carbon cycle dynamics.” Therefore, multidisciplinary geoscience research can inform between past and current environmental changes and vice versa.
Large igneous provinces are characterized by the rapid eruptions of huge continental flood basalt provinces. The gases released during these eruptions include large volumes of carbon, which can impact global temperatures if fluxes are of sufficient magnitude. In addition, contact metamorphism of sedimentary rocks affected by the magmatic plumbing system can lead to volatilization and explosive ejection of greenhouse gases to the surface. In addition, LIPs can also alter climate through a variety of indirect processes. The eruption of large flood basalts significantly enhances global silicate weathering, as the reactive magmatic crystal break down to form clays, free cations (e.g., Ca), and bicarbonate, consuming atmospheric CO2 in the process. The clays tend to form soils, while the other components are highly soluble and are transported to the oceans where they eventually form carbonate through biotic and abiotic processes. The erosion of basalt also releases all bio-limiting nutrients except nitrogen, so the increased nutrient fluxes can also elevate the biological carbon pump. These processes are temperature-dependent, and form a key negative feedback to global warming through elevated CO2 concentrations. LIPs are often accompanied by thermal uplift events that cause plateaus several km high, which are often followed by the onset of rifting and continental break up. These two factors can have a marked effect on atmospheric and oceanic circulation, depending on the factors such as the location and latitude of volcanic activity. My research and collaborations seek to improve our understanding of the climatic and environmental impacts of LIP emplacements so that these perturbations can be used as a natural analogue for environmental issues facing us today.