Periodic Reporting for period 3 - V-ECHO (Revealing hidden volcanic triggers for global environmental change events in Earth’s geological past using mercury (Hg))
Periodo di rendicontazione: 2022-06-01 al 2023-11-30
Rapid global change events such as mass extinctions punctuate Earth’s geological history. These have driven life’s evolution, shaping the world today. However, the exact processes that trigger or modulate them remain enigmatic. Episodes of large-scale volcanism, namely large igneous provinces (LIPs), are a prime contender. A major obstacle to unravelling the role of LIPs in rapid global change has been lack of a direct/unique proxy for volcanism in the sediments that record events. Without one, determining LIP occurrence and exact temporal relations is challenging, especially where the rock record of LIPs is incomplete. Recent studies have revealed the huge promise of mercury (Hg) as a marker of large-scale volcanism. However, while Hg-record acquisition is gaining pace, we still lack the vital process understanding of the proxy needed to realize its full potential. V-ECHO will test the overarching hypothesis: widespread mercury ‘spikes’ in the geological record are definitive evidence of LIP volcanism even in the absence of coeval lavas.
V-ECHO takes an integrated and interdisciplinary approach to develop a process understanding of LIP perturbations to the global Hg cycle and how these translate into sedimentary records. It addresses key questions on Hg sources (emission from magmas or thermal metamorphism of intruded rocks) and sinks (deposition pathways and sedimentary preservation). It combines new measurements with novel experimental techniques and explores key differences in the global Hg cycle deep in Earth’s past. Ultimately V-ECHO will test whether we can ‘sniff out’ the sedimentary echoes of lost LIPs, especially in the Palaeozoic and Neoproterozoic where the LIP record becomes ever sparser. It will explore proposed volcanic triggers for major Earth change events (e.g. oceanic anoxic events, ‘snowball Earths’) in unprecedented ways. V-ECHO promises a step-change in understanding of environmental impacts of LIP volcanism throughout Earth history.
V-ECHO takes an integrated and interdisciplinary approach to develop a process understanding of LIP perturbations to the global Hg cycle and how these translate into sedimentary records. It addresses key questions on Hg sources (emission from magmas or thermal metamorphism of intruded rocks) and sinks (deposition pathways and sedimentary preservation). It combines new measurements with novel experimental techniques and explores key differences in the global Hg cycle deep in Earth’s past. Ultimately V-ECHO will test whether we can ‘sniff out’ the sedimentary echoes of lost LIPs, especially in the Palaeozoic and Neoproterozoic where the LIP record becomes ever sparser. It will explore proposed volcanic triggers for major Earth change events (e.g. oceanic anoxic events, ‘snowball Earths’) in unprecedented ways. V-ECHO promises a step-change in understanding of environmental impacts of LIP volcanism throughout Earth history.
The main results achieved so far:
• Demonstration of mercury as an indicator for ancient terrestrial biomass fluxes in the geological past, a key parameter to understand past carbon cycle, climate and ecology (Dal Corso et al., 2020).
• New insights into what caused (volcanism pushing the Earth-system over a tipping point) the Paleocene-Eocene Thermal Maximum (PETM), one of the most rapid and dramatic instances of climate change in the history of the Earth (Kender et al., 2021).
• New evidence of a link between the Late Triassic Carnian Pluvial Episode (CPE), a time of biological turnover and environmental perturbations, and the Wrangellia large igneous province volcanism (Mazaheri-Johari et al., 2021).
• Contribution to a major review the underlying magmatic origins, igneous life cycle, volatile release and environmental impacts of large igneous province (LIP) volcanism (Black et al., 2021)
• Contribution to new drill cores via the International Continental Scientific Drilling Program project JET (Jurassic stratigraphy, carbon cycling and paleoclimate) and International Ocean Discovery Program expedition 396 to the Norwegian Margin.
• Demonstration of mercury as an indicator for ancient terrestrial biomass fluxes in the geological past, a key parameter to understand past carbon cycle, climate and ecology (Dal Corso et al., 2020).
• New insights into what caused (volcanism pushing the Earth-system over a tipping point) the Paleocene-Eocene Thermal Maximum (PETM), one of the most rapid and dramatic instances of climate change in the history of the Earth (Kender et al., 2021).
• New evidence of a link between the Late Triassic Carnian Pluvial Episode (CPE), a time of biological turnover and environmental perturbations, and the Wrangellia large igneous province volcanism (Mazaheri-Johari et al., 2021).
• Contribution to a major review the underlying magmatic origins, igneous life cycle, volatile release and environmental impacts of large igneous province (LIP) volcanism (Black et al., 2021)
• Contribution to new drill cores via the International Continental Scientific Drilling Program project JET (Jurassic stratigraphy, carbon cycling and paleoclimate) and International Ocean Discovery Program expedition 396 to the Norwegian Margin.
The use of Hg as a proxy for ancient terrestrial biomass fluxes in the geological record has the potential to significantly advance the research field beyond the state of the art and was not among the expected results of the project. This idea is presented with data and modelling in Dal Corso et al. (2020) and there is plenty to explore in terms of how this proxy might behave. This was an unplanned development that arose from Mather’s visit to give a seminar in Leeds and a brainstorming session with colleagues there.