Abstract
Recent advances in Earth System Models, high-performance computing, and im-provements in understanding deep-time boundary conditions such as paleogeogra-
phy and atmospheric CO2 have enabled paleoclimate simulations across the entire
Phanerozoic (540 million years). These developments have moved paleoclimate re-
search in a more quantitative and dynamic direction. A key component of the Earth
system, the dust cycle, can now be better constrained by building on these devel-
opments in deep time. However, simulating the dust cycle with fully coupled Earth
System Models over geological timescales remains highly computationally expensive.
To address this challenge, this thesis develops offine dust models, DUSTY 1.0 and
DUSTY-dep, which work together with the Earth System Model HadCM3L as a
modelling framework of an alternative approach to offer first-order constraints on
the dust cycle in deep time.
The model framework developed in this study produces quantified estimates
of desert dust emission fields and marine dust deposition fields for approximately
every five million years throughout the Phanerozoic. Where possible, the simulated
outputs are compared with geological records to provide a broad estimation of
uncertainties. The variation of dust emissions and depositions through time is
analysed and identified to be primarily driven by changes in paleogeography.
Moreover, motivated by the fertilising effect of dust-borne iron, the simulated
marine dust deposition fields are implemented with the cGENIE model to investigate
the marine biogeochemistry response to dust input in typical periods. This study
examines the pre-industrial and late Permian periods to explore the impacts of
dust under contrasting climate states and continental configurations.
This study develops an effcient modelling framework for simulating the global
dust cycle and its biogeochemical impacts in the deep-time past. It provides the
first quantitative estimations for unexamined intervals. Both the model framework
and the resulting simulations serve as a foundational reference for future studies
aiming to deepen our understanding of the role of dust in Earth system evolution.
| Date of Award | 30 Sept 2025 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Dan Lunt (Supervisor) & Fanny M Monteiro (Supervisor) |
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