Fri 08 Mar 16:00: Extent and Implications of Dynamic Support Beneath Antartica and its Fringing Oceanic Basins
Abstract not available
- Speaker: Aisling Dunn
- Friday 08 March 2024, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Tue 20 Feb 12:00: Rapid temperature fluctuations in the early Iceland plume revealed by olivine-spinel and melt thermometry
The generation of Large Igneous Provinces (LIPs) – huge outpourings of lavas associated with tectonic rifting – is a hotly debated topic with competing models variously invoking hot mantle plumes, insulative heating by supercontinents or edge driven convective instabilities. Mantle temperature and its temporal variation during LIP magmatism is key to distinguishing between these different models. Despite this, there are as yet no detailed stratigraphically constrained studies of mantle temperature through a LIP succession.
To address this, we have applied olivine-spinel and melt-only thermometry to constrain mantle potential temperature through a sequence of lavas from Co. Antrim, Northern Ireland, formed during the earliest expression of the North Atlantic Igneous Province. Mantle potential temperature derived from olivine-spinel and melt-only methods give consistent temperature ranges of 1374–1472°C and 1403–1521°C, respectively. Notable both temperature records indicate significant (100-120°C) variation in melting temperature over a relatively short stratigraphic during earlier forming magmas and much less variation in later formed magmas, suggesting initial instability or pulsing which stabilised with time.
Variability in melting temperature is mirrored by proxies for crustal and volcanic processes; Ni contents of olivine are elevated (
- Speaker: Elliot Carter, Trinity College Dublin
- Tuesday 20 February 2024, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.
Tue 13 Feb 12:00: Data-driven slow earthquake dynamics
Earthquakes are a destructive natural phenomenon with high societal costs and impact. A better understanding and characterisation of their underlying governing equations can help to better estimate the hazard associated with them. Slow slip events (SSEs) show many similarities with regular earthquakes but are characterised by a much shorter recurrence time (months/years instead of decades/millennia), offering us the possibility to study multiple cycles. Being able to model their dynamics can answer questions concerning the complexity of the frictional failure phenomenon at natural scale and its predictability. Studying slow earthquakes in nature and in the lab, I will show how a system of Stochastic Differential Equations can help us better characterise the seismic cycle, offering an alternative way to the classical two end members (purely deterministic or purely stochastic) used to describe seismicity. Blending the deterministic and stochastic approaches shows that friction is highly sensitive to small perturbations, suggesting that the macroscopic dynamics is influenced by small scale interactions. The so-called fast degrees of freedom active at the small spatio-temporal scales can be taken into account via a stochastic framework, while the underlying low-dimensional deterministic dynamics is used as a support to describe the evolution of the system.
- Speaker: Adriano Gualandi, Department of Earth Sciences
- Tuesday 13 February 2024, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.
Tue 05 Mar 12:00: Paallavvik Island and the search for Earth's primitive water
For over a decade I have been working to answer the question ‘where did Earth source its water from?’ The answer may lie within igneous mantle plume rocks. This talk will focus on my 2021 expedition to Paallavvik Island, in search of geochemically anomalous picrite samples from the cliff sections of this uninhabited, polar-bear infested island, which sits off the east coast of Baffin Island.
- Speaker: Lydia Hallis, University of Glasgow
- Tuesday 05 March 2024, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.