Dr Abi Plimmer

Postdoctoral Research Fellow in Geodynamics

I am a postdoctoral research associate at Universitetet i Bergen (UiB), where I explore the evolution of the North Atlantic volcanic rifted margins through numerical modelling. This research seeks to better understand the spatial and temporal variations in magmatism during rifting. I am particularly interested in lithosphere-mantle interactions and the feedback between the two domains to drive tectonic systems.

This builds on my previous research at Cardiff University, focussing on the interactions between mantle geodynamics and tectonic processes throughout the supercontinent cycle. Much of this work involved developing and using the 3D mantle convection code TERRA to simulate Earth's long-term evolution. My current research integrates these interests with the skills gained during my Masters studies at the University of Leeds, where my dissertation combined 2D models (using the ASPECT code) with seismic data to investigate the effect of extension rate on magmatism at rifted margins. I am always keen to collaborate and share ideas—please feel free to get in touch!

Email me at: abigail.plimmer@uib.no

Abigail Plimmer
Research
Research Interests
  • Geodynamic modelling
  • Plate tectonics
  • Rifted margin evolution
  • Plume dynamics
  • Lithosphere and mantle coupling
  • Earth's tectonic evolution

My current research investigates the spatial and temporal controls on magmatism across the North Atlantic rifted margins using 2D and 3D numerical models. This work will build on my previous studies and contribute to a more comprehensive picture of mantle–lithosphere coupling in tectonically active regions.

Previously, I have approached this at a global scale, exploring how mantle dynamics are coupled with the lithosphere throughout the supercontinent cycle. Using 3D global mantle circulation model, I investigated the dynamics of mantle downwellings and the influence of plate motions on slab sinking in the deep mantle; the coupling between deep mantle structures and surface tectonics; and the ways in which lithospheric structure impacts mantle flow from supercontinent assembly to breakup.

Experience

Geodynamics and Basin Studies Reseach Group, Institutt for Geovitenskap, UiB, Bergen
Project: Paleogene Basin Development on the Vøring and Møre Margins | PALMAR.
PI: Prof. Ritske Huismans

Tectonics & Geophysics Research Group, School of Earth & Environmental Sciences, Cardiff University, Cardiff, UK
Project: Mantle Circulation Constrained (MC2): A multidisciplinary 4D Earth framework for understanding mantle upwellings.
PI: Prof. J. Huw Davies

Tectonics & Geophysics Research Group, School of Earth & Environmental Sciences, Cardiff University, Cardiff, UK
PhD Thesis: Constraining the relationship between mantle circulation and supercontinent cycles.
Supervisors: Prof. J. Huw Davies, Prof. James Wookey, Dr James Panton

School of Earth & Environment, University of Leeds, Leeds, UK
MSc Dissertation: Assessing the role of extension velocity and magmatic additions as controls on magmatic budget during rifting and rifted margin formation.
Supervisors: Dr Mohamed Gouiza, Dr Tim Craig
Awarded: Distinction

Department of Earth, Ocean, and Environmental Sciences, University of Liverpool, Liverpool, UK
BSc Dissertation: The Geological History of the Camaret-Sur-Mer Region of the Crozon Peninsula.
Supervisors: Dr Paul Wallace, Prof Peter Burgess
Awarded: 1st Class

Awards & Grants
  • EGU Poster Award Winner – 2024
    Awarded for poster presentation at EGU Geodynamics Division: Ada Lovelace Workshop on Modelling Mantle & Lithosphere Processes
  • BGA PGRiP Poster Prize Winner – 2023
    Awarded for poster presentation at BGA Postgraduate Research in Progress (PGRiP) conference
  • NERC GW4+ Doctoral Training Partnership PhD Studentship – 2021-2025
    Fully funded PhD studentship at Cardiff University
  • Schlumberger Oilfield UK Plc Prize for best taught performance – 2021
    Awarded to the student in the final year of a programme of study leading to the degree of MSc Structural Geology with Geophysics who achieves the highest overall grade point average
  • £9000 Marsden Alumnus Award – 2020
    Scholarship to facilitate Masters studies at University of Leeds
  • £7000 Leeds Masters Scholarship – 2020
    Scholarship to facilitate Masters studies at University of Leeds
  • LGS Overall Excellence Prize for BSc Geology and Physical Geography – 2020
    Awarded to the student in the third year who attains the highest grade point average for the programme Geology and Physical Geography
  • Mineralogical Society of Great Britain & Ireland Student Award – 2019
    Awarded to second-year student with the highest ranking marks in mineralogy and petrology
Publications

Articles

Abstract: The relationship between the lithosphere and the mantle during the supercontinent cycle is complex and poorly constrained. The processes which drive dispersal are often simplified to two end members: slab pull and plume push. We aim to explore how lithosphere thickness and viscosity during supercontinent assembly may affect the interaction of deep mantle structures throughout the supercontinent cycle. We consider supercontinental lithosphere structure as one of many potential processes which may affect the evolution of upwellings and downwellings and therefore systematically vary the properties of continental and cratonic lithosphere, respectively within our 3D spherical simulations. The viscosity and thickness of the lithosphere alters the dip and trajectory of downwelling material beneath the supercontinent as it assembles. Focusing on Pangea, we observe that plumes evolve and are swept beneath the center of the supercontinent by circum-continental subduction. The proximity of these upwelling and downwelling structures beneath the supercontinent interior varies with lithosphere thickness and viscosity. Where slabs impinge on the top of an evolving plume head (when continental and cratonic lithosphere are thick and viscous in our simulations), the cold slabs can reduce the magnitude of an evolving plume. Conversely, when the continental lithosphere is thin and weak in our simulations, slab dips shallow in the upper mantle and descend adjacent to the evolving plume, sweeping it laterally near the core-mantle boundary. These contrasting evolutions alter the magnitude of the thermal anomaly and the degree to which the plume can thin the lithosphere prior to breakup.

Abstract: Mantle circulation in the Earth acts to remove heat from its interior and is thus a critical driver of our planet’s internal and surface evolution. Numerical mantle circulation models (MCMs) driven by plate motion history allow us to model relevant physical and chemical processes and help answer questions related to mantle properties and circulation. Predictions from MCMs can be tested using a variety of observations. Here, we illustrate how the combination of many disparate observations leads to constraints on mantle circulation across space and time. We present this approach by first describing the set-up of the example test MCM, including the parameterization of melting, and the methodology used to obtain elastic Earth models. We subsequently describe different constraints, that either provide information about present-day mantle (e.g. seismic velocity structure and surface deflection) or its temporal evolution (e.g. geomagnetic reversal frequency, geochemical isotope ratios and temperature of upper mantle sampled by lavas). We illustrate the information that each observation provides by applying it to a single MCM. In future work, we shall apply these observational constraints to a large number of MCMs, which will allow us to address questions related to Earth-like mantle circulation.

Abstract: We use a multidisciplinary approach to investigate how the parameter space of mantle convection affects present-day mantle composition. We compare 22 forward geodynamical mantle circulation model simulations against 24 variants of a geochemical inversion model of the global radiogenic isotope data set of mantle-derived lavas. Both models are fully independent but able to output compositional parameters for the lower mantle sampled by upwelling mantle plumes and for the upper mantle sampled by mid-oceanic ridges. Geodynamical model results suggest an excess degree of peridotite melt-depletion ΔFd = +0.4% ± 0.4% and an excess amount of recycled crust ΔfRC = +2.7% ± 3.1% in plumes compared to ridges, while the geochemical inversion returns ΔFd = +0.4% ± 1.2% and ΔfRC = +1.5% ± 0.6%. Models are thus in quantitative agreement but with opposite sensitivities, allowing to restrict their respective parameter space. Geodynamical runs show best fits with the narrow geochemical ΔfRC for core-mantle boundary (CMB) temperatures of 3,400–3,800 K and a recycled crust buoyancy number of 0.44–0.66. A dense primordial layer at the CMB also leads to a better fit. Variants of our geochemical model show a best fit with the narrow geodynamical ΔFd value when early mantle differentiation occurs in the garnet stability field. We also find that the formation of early compositional heterogeneities is needed to fully explain the isotope range of mantle melts. Our work emphasizes the need to correct isotopic data for the effects of non-magmatic processes in a quantitative geochemical model before extracting the parameters relevant to a comparison with geodynamical model results.

Submitted

Plimmer, A., Davies, J.H. The Superpile Cycle: the mobility of LLSVPs in response to plate tectonics. Submitted to Nature Geoscience.

Presentations & Workshops
Conferences & Presentations
  • Cardiff Tectonics & Geophysics Research Group Seminar - 2025
    The Superpile Cycle: the stability of LLSVPs in response to plate tectonics [talk].
  • AGU Fall Meeting - 2024
    Investigating the role of plate tectonics on the stability & plume generating capacity of deep mantle structures [poster].
  • Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics - 2024
    The effect of lithosphere structure on mantle dynamics through the supercontinent cycle [poster].
  • NERC GW4+: Earth Science & Hazards - 2024
    Mantle structures beneath an evolving supercontinent [poster & talk].
  • EGU General Assembly - 2024
    Slab dynamics in the mantle: a back-to-basics approach [poster].
  • UK-SEDI - 2024
    Mantle upwellings and supercontinent breakup in response to lithosphere heterogeneity [talk].
  • Cardiff EARTH Seminar - 2023
    Assessing the role of lithosphere heterogeneity on mantle circulation models [talk].
  • BGA PGRiP (Postgraduate Research in Progress) - 2023
    The role of oceanic, continental, and cratonic lithosphere on mantle circulation [poster].
  • BGA PGRiP - 2022
    Sensitivity of slab sinking times to mantle viscosity and slab buoyancy. [poster].
  • Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics - 2022
    Sensitivity of slab sinking times to mantle viscosity and slab buoyancy. [poster].
Training & Workshops
  • ASPECT workshop - 2024
    Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics
  • Cardiff University Education Associate Fellow Progamme - 2023/24
    Cardiff Learning & Teaching Academy
  • Project Management for Researchers - 2023
    Cardiff Doctoral Academy
  • Advanced Infographics Training - 2023
    NERC GW4+ DTP, Infohackit
  • Academic Immersive Writing Course - 2022
    NERC GW4+ DTP
Teaching

Throughout my time at Cardiff University I have facilitated teaching on a range of undergraduate modules. I am committed to creating an inclusive and supportive learning environment which encourages students to become independent learners, and have explored this through my participation in the AdvanceHE-accredited Cardiff University Education Associate Fellow Programme.

1st Year Undergraduate

Responsibilities:

  • Teaching and Technical Support: Instruct students on using GIS software to identify geological structures and analyze data in a virtual environment, supplementing fieldwork skills.
  • Geological Mapping and Analysis: Guide students in reading, interpreting, and creating geological maps, fostering their understanding of geological structures through digital tools.
  • Assessment and Feedback: Grade student assessments and provide detailed, constructive feedback to support their academic development and understanding of geological mapping and GIS applications.

Responsibilities:

  • Teaching and Pastoral Support: Deliver undergraduate field courses in structural geology and geological field skills (e.g., cross sections, mapping). Provide academic guidance and pastoral support to students during fieldwork.
  • First Aid: Serve as a certified First Aider, ensuring student safety and managing health-related emergencies during field courses.
  • Logistics Support: Assist in organizing field trips, including logistical planning and coordination of necessary resources and equipment.

2nd Year Undergraduate

Responsibilities:

  • Advanced Structural Geology and Geophysics Instruction: Teach second-year undergraduates to solve complex structural geology problems and introduce geophysical datasets, fostering their ability to integrate geological and geophysical methods.
  • Integration of Geophysical and Geological Skills: Help students apply both geophysical datasets and geological principles to interpret and reconstruct the geological evolution of remote regions, enhancing their multidisciplinary analytical skills.
  • Formative Feedback and Academic Support: Provide formative feedback to ensure students’ understanding of complex Earth science concepts, offering guidance to help them tackle advanced geological problems.

Responsibilities:

  • Field-Based Structural Geology Support: Guide students in solving structural geology problems in the field, helping them analyze outcrops and scale small-scale observations into a regional deformation history.
  • Geodynamic Context and Field Analysis: Assist students in understanding the geodynamic context of field sites, particularly in Snowdonia and North Spain, encouraging them to connect local observations to broader geological processes.
  • Student Liaison and Formative Feedback: Act as an intermediary between students and professors, providing feedback on field skills, observations, teamwork, and preparation for independent mapping projects, ensuring readiness for dissertation work.

Outreach & Extra-curriculars
  • A-Level Geodynamics Masterclass at local 6th Form College through the Brilliant Club (2022)
  • Member of Athena SWAN EDI subgroup (2021–present)
  • Member of URGE podlet (Unlearning Racism in Geosciences; 2021–present)
  • Postgraduate EDI Representative (2021–present)
  • Delivered Scholars Programme Environmental Science course to local secondary school through the Brilliant Club (2021–2022)
  • MSc Course Representative (2020–2021)
  • Liverpool Women in Geoscience Earth Day Event (2020; cancelled due to COVID pandemic)
  • Liverpool Women in Geoscience International Women's Day Seminar (2020)
  • Created & led Liverpool Women in Geoscience (2019–2020)
  • Herdman Geological Society Vice President (2019–2020)
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