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Department of Earth Sciences

 

Mon 17 Feb 18:00: How to run a library: 20 years of employment

Earth Sciences talks - Tue, 11/02/2025 - 17:06
How to run a library: 20 years of employment

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Fri 21 Feb 16:00: Title to be confirmed

Earth Sciences talks - Mon, 10/02/2025 - 13:04
Title to be confirmed

Abstract not available

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Fri 21 Mar 16:00: Title to be confirmed

Earth Sciences talks - Mon, 10/02/2025 - 13:04
Title to be confirmed

Abstract not available

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Mon 10 Feb 18:00: Growing a Carboniferous Forest: Planning, Developing and Executing a Unique Palaeontological Excavation & Visitor Attraction

Earth Sciences talks - Fri, 07/02/2025 - 12:46
Growing a Carboniferous Forest: Planning, Developing and Executing a Unique Palaeontological Excavation & Visitor Attraction

Dr Tim Astrop is a palaeobiologist, evolutionary biologist, general nerd and the resident palaeontologist (fossil coordinator) for the Brymbo Fossil Forest project at Stori Brymbo, an exciting new natural, industrial and social heritage attraction coming to Wrexham in 2025-26. The Brymbo Fossil Forest is a globally unique palaeontological treasure; it represents a 314 million year old in-situ fossilised forest within the grounds of the old Georgian ironworks in Brymbo, North-Wales. In 2025 the site will see the completion of a purpose-built structure erected to excavate the fossils in a protected environment while being completely publicly accessible. The working team will consist exclusively of students and volunteers making it the endeavour the first of it’s kind. In this lecture Tim will talk about the history of the Brymbo site, the discovery of the fossil forest & it’s inferred paleoecology as well as the future of the site as a scientific endeavour and visitor attraction

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Wed 12 Feb 17:30: Climate-ice sheet interactions in the long-term past and their importance for the long-term future

Earth Sciences talks - Fri, 07/02/2025 - 11:57
Climate-ice sheet interactions in the long-term past and their importance for the long-term future

The simulation of the last deglaciation (about 20.000 years before present to present) represents a hitherto unsolved challenge for comprehensive state-of-the-art climate models. During my presentation, I will introduce our novel coupled atmosphere-ocean-vegetation-ice sheet-solid earth model that is used to simulate the transient climate. An ensemble of transient model simulations successfully captures the main features of the last deglaciation, as depicted by proxy estimates. In addition, our model simulates a series of abrupt climate changes, which can be attributed to different drivers that will be discussed throughout the presentation. I will furthermore show, how the model can be applied for simulations of the long-term future. The future simulations show, that parts of the Antarctic ice sheet become unstable even under low-emission scenarios, with significant implications for the modelled climate response. Sensitivity experiments additionally show that, the Greenland ice sheet may exhibit multiple steady-states under pre-industrial climate conditions. This has significant implications for a potential regrowth, once disintegrated entirely.

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Thu 13 Mar 11:30: TBC

Earth Sciences talks - Wed, 05/02/2025 - 09:17
TBC

Abstract not available

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Thu 20 Feb 11:30: TBC

Earth Sciences talks - Wed, 05/02/2025 - 08:52
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New exhibition takes visitors on a journey to the centre of Iceland’s volcanoes

Earth Sciences news - Tue, 04/02/2025 - 15:49

A new art-science exhibition at Downing College’s Heong Gallery brings Iceland’s incandescent volcanic eruptions and earth-shattering seismic tremors to Cambridge. Visitors will get a chance to get up close, and even embark on a journey inside, an Icelandic volcano—inspired by Jules Verne’s Journey to the Centre of the...

Categories: Recent news and blogs

Listening in on the pulse of a mantle plume: IMPULSE Expedition 2024  

https://blog.esc.cam.ac.uk/?feed=rss - Tue, 04/02/2025 - 15:05
Last summer, Cambridge PhD students Callum Pearman, Aisling Dunn and Philippa Slay joined an international scientific cruise to take the pulse of the Iceland mantle plume. Callum describes the science behind the expedition in the blog post below. What Did We Set Out To Find Out? The Iceland plume is a large column of especially …
Categories: Recent news and blogs

Listening in on the pulse of a mantle plume: IMPULSE Expedition 2024  

Earth Sciences blog - Tue, 04/02/2025 - 15:05
Last summer, Cambridge PhD students Callum Pearman, Aisling Dunn and Philippa Slay joined an international scientific cruise to take the pulse of the Iceland mantle plume. Callum describes the science behind the expedition in the blog post below. What Did We Set Out To Find Out? The Iceland plume is a large column of especially …
Categories: Recent news and blogs

Wed 12 Feb 14:00: H, He, and seismic evidence for a bilithologic plume-fed asthenosphere

Earth Sciences talks - Tue, 04/02/2025 - 14:10
H, He, and seismic evidence for a bilithologic plume-fed asthenosphere

Chemical diffusion in the mantle has typically been viewed to play a negligible role in geodynamic processes. However, diffusion rates for water (H) and helium (He) are large enough that they lead to observable differences between pyroxenite-rich melting associated with ocean island volcanism (OIB) and more peridotite-rich melting associated with mid-ocean ridge basalts (MORB). Laboratory measurements of diffusion rates of H and He at ambient mantle temperatures in olivine are of order 10 km/1.7Gyr for He and 250 km/1.7 Gyr for H. If the mantle is an interlayered mixture of recycled oceanic basalts and sediments surrounded by a much larger volume of residual peridotites, then chemical diffusion can shape the mantle in two important ways. Hydrogen will tend to migrate from peridotites into adjacent pyroxenites, because clinopyroxene (and its high-pressure metamorphs) has a much stronger affinity for water than the olivine and orthopyroxene that form the bulk of mantle peridotites. Therefore pyroxenite lithologies will typically have twice or more the water content of their surrounding damp peridotites. This will strongly favor the enhanced melting of pyroxenites that is now mostly agreed to be a common feature of the OIB source. Radiogenic 4He will have the opposite behaviour — it will tend to migrate from where it is produced in recycled incompatible-element-rich (e.g. U and Th-rich) pyroxenites into nearby, larger volume fraction, but U+Th-poorer peridotites, while the radioisotopes of Ar and Ne that are also produced by the decay of the incompatible elements K, U, and Th will diffuse much less, and thus remain within their original pyroxenite source. This effect leads to lower 4He/21Ne and 4He/40Ar ratios in OIB in comparison to the predicted values based on the mantle’s bulk geochemistry, and complementary higher 4He/21Ne and 4He/40Ar ratios in the MORB source that is formed by the plume-fed asthenospheric residues to OIB melt extraction at plumes.

The recent observation of a 150-km-deep positive shear velocity gradient (PVG) beneath non-cratonic lithosphere (Hua et al., 2023) is further evidence for the initiation of pyroxenitic melting at this depth within the asthenosphere. It also implies that lateral temperature variations at this depth are quite small, of order ±75°C. This near uniformity of temperatures near both mantle plumes and mid-ocean ridges is, in turn, strong evidence in favor of the hypothesis that the asthenosphere is fed by mantle plumes. We propose that two filtering effects occur as plumes feed the asthenosphere, removing both the hottest and coldest parts of upwelling plume material. First, the peridotite fraction in the hottest part of upwelling plume material melts enough for it to dehydrate, thereby transforming this fraction into a more viscous and buoyant hotspot swell root that moves with the overlying plate, not as asthenosphere. Second, since plume material is warmer than average mantle, it is more buoyant, creating a natural density filter that prevents any cooler underlying mantle from upwelling through it. Preferential melt-extraction from denser pyroxenites at mantle plumes also makes the asthenosphere compositionally buoyant with respect to its underlying, more pyroxene-rich mantle. These rheological and density filters will tend to make the asthenosphere sampled by melting at mid-ocean ridges have a more uniform temperature than its typical underlying mantle.

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Wed 12 Feb 14:00: Title to be confirmed

Earth Sciences talks - Tue, 04/02/2025 - 07:59
Title to be confirmed

Abstract not available

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Mon 03 Feb 18:00: Measuring landscape change in the polar regions with thermochronometry

Earth Sciences talks - Thu, 30/01/2025 - 12:29
Measuring landscape change in the polar regions with thermochronometry

Understanding how ice sheets change due to ongoing climate change is important and this requires numerical models. Times in Earth’s history that had a similar climate to predictions of the future can be used to test these model predictions. However, as ice sheets wax and wane they erode the landscape. This modifies how much ice the landscape can support. Therefore, it is crucial that we are able to accurately constrain landscape change. Thermochronometry, measures how rocks cool as they are brought to the surface by erosion and can be used to measure landscape change. I will present examples of using thermochronometry to understand landscape change in Greenland and Antarctica. 

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Ancient Antarctic ice offers insights into future climate scenarios

Earth Sciences news - Wed, 29/01/2025 - 16:15

Increasing greenhouse gas emissions are warming our planet at an unprecedented rate and scale. While anthropogenic warming has no direct historical parallel, warm episodes in Earth’s history can offer clues as to the future. A team of ice core scientists led by Cambridge University wanted to find out what happened to the...

Categories: Recent news and blogs

Tue 25 Feb 12:00: Evolution and effects of ecosystem engineers through the Phanerozoic

Earth Sciences talks - Mon, 27/01/2025 - 14:40
Evolution and effects of ecosystem engineers through the Phanerozoic

Ecosystem engineers are organisms whose behaviours change the physical characteristics of their habitats and modulate resource availability, thereby impacting the habitability of their environments for other biota. Given their profound impacts on ecological and evolutionary processes in the modern, palaeobiologists have long hypothesized that the rise of ecosystem engineers throughout Earth history has had increasingly positive impacts on the biosphere, contributing to the rise in marine biodiversity observed over the Phanerozoic. Here, I will highlight the role that animal ecosystem engineers have played in shaping ecological and environmental landscapes since the Ediacaran-Cambrian transition. Focusing on bioturbation, I will present how ecologically-informed biogeochemical modelling is used to show how evolutionary innovations and the environment work together to modulate an ecosystem engineer’s effects. Broadening timescales and ecological groups, I will also present new evidence using ecological meta-analyses that demonstrates that marine ecosystem engineers have had persistent strong positive effects on biodiversity over the entire Phanerozoic. Finally, I will propose a new framework for “Earth systems engineers” (ESE) – ecosystem engineer-type organisms whose activities play major roles in global resource cycles – and highlight major ESE innovations, transitions, and effects.

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