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Project

Hot or Cold? Did changes in volcanic activity influence global temperature evolution throughout geological climate-change events (FWOTM1048)

Earth’s history has been marked by frequent episodes of global-scale
marine anoxia and organic-matter burial, particularly in the
Cretaceous, Devonian, and Silurian. CO2 emissions associated with
large igneous provinces are thought to have caused rapid climate
warming during the Cretaceous events (e.g., Early Aptian oceanic
anoxic event; OAE 1a: ~120 Ma). However, OAE 1a also featured
transient cold pulses during the overarching warming, whilst the
Devonian and Silurian events (e.g., Frasnian–Famennian crisis: ~372
Ma) were typically characterized by global cooling. It is unclear
whether the OAE 1a cooling pulses reflect a volcanic hiatus or
enhanced CO2 drawdown via silicate weathering/organic-matter
burial. A further question is whether the Devonian and Silurian crises
were initiated by volcanism, but with any warming effect totally offset
by carbon burial, or had a different trigger to the Cretaceous anoxic
events. This proposal employs two widely-used proxies of volcanism
(mercury contents and osmium isotopes) to study records of the
Cretaceous, Devonian, and Silurian events, focusing on sites that
document palaeoclimate trends, enabling direct comparison between
changes in volcanic activity and global temperatures. These results
will highlight the extent to which volcanism operated during each
cooling episode, and thus the importance of volcanic activity in
controlling global temperatures at those times.
Date:1 Oct 2021 →  1 Oct 2023
Keywords:Palaeoclimate, Large igneous province volcanism, Trace-metal geochemistry
Disciplines:Volcanology, Stratigraphy, Geochemistry not elsewhere classified, Sedimentology, Inorganic geochemistry