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Department of Earth Sciences

 
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A collection of all the seminars going on at the Department, either on the downtown site, or out at the Bullard Laboratories
Updated: 22 min 52 sec ago

Wed 03 Nov 16:00: Creeping gabbro: Mafic rock deformation from nature and experiments

8 hours 13 sec ago
Creeping gabbro: Mafic rock deformation from nature and experiments

Unaltered mafic rocks consist of mechanically strong minerals (e.g. pyroxene, plagioclase and garnet) that can be deformed by crystal plastic mechanisms only at high temperatures (>800°C). Yet, many mafic rocks do show extensive deformation by non-brittle mechanisms when they have been subjected to lower temperature conditions. In such cases, the deformation typically is assisted by mineral reactions. In this seminar, I will show results of microstructural and chemical analysis that indicate dissolution-precipitation creep (as a type of diffusion creep) plays a major role in deformation of gabbro lenses at upper amphibolite facies conditions. Synchronous deformation and mineral reactions of clinopyroxene suggest that mafic rocks can become mechanically weak during a general transformation weakening process, i.e. the interaction of mineral reaction and deformation by diffusion creep. The weakening is directly connected to a fluid-assisted transformation process that facilitates diffusion creep deformation of strong minerals at far lower stresses and temperatures than dislocation creep. Initially strong lithologies can become weak, provided that reactions can proceed during deformation; the transformation process itself is an important weakening mechanism in mafic (and other) rocks, facilitating deformation at low differential stresses and low stress exponents.

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Fri 22 Oct 15:00: Marine sedimentary carbon cycling This is a hybrid event. It will be live in the Tilley Lecture Theatre and broadcast on Zoom (https://zoom.us/j/99984123581)

Thu, 21/10/2021 - 15:26
Marine sedimentary carbon cycling

The removal of carbon from the surface of the planet is a critical component of the long-term carbon cycle; this removal is through the deposition and subsequent burial of organic carbon and carbonate minerals in the ocean. Sedimentary, post-depositional, processes play a key role in the global carbon cycle as much of the organic carbon deposited in marine sediments is broken down through a series of microbial reactions, releasing the organic carbon and directly impacting the saturation state of carbonate minerals. In this talk I will discuss my research into the drivers of modern sedimentary carbon cycling using approaches ranging from multiple isotope system measurements, machine learning and reactive transport modelling. I will then show how this improved understanding can be used to determine how changing oceanic conditions would have impacted carbon cycling in marine sediments over the Phanerozoic.

This is a hybrid event. It will be live in the Tilley Lecture Theatre and broadcast on Zoom (https://zoom.us/j/99984123581)

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Thu 28 Oct 15:00: Just how weird is the solar system? This is a hybrid event. The talk will be given via Zoom (https://zoom.us/j/99984123581), and screened live in the Tilley Lecture Theatre.

Thu, 21/10/2021 - 09:51
Just how weird is the solar system?

In addition to the perhaps unusual presence of life, our solar system has two highly peculiar characteristics in its inorganic isotopic signature. The first is a marked abundance of the extremely neutron rich nuclide 48Ca relative to its slightly less neutron rich sibling 46Ca. Such relative isotopic abundances require a substantial input of eluvia from a rare type of super-nova, unexpected in a stellar nursery environment. Secondly, there is evidence that the solar system started life with sufficient abundance of short-lived 26Al (half life ~0.75Ma) to drive early planetary melting, but this requires alarmingly short transit times of material from the stellar source of 26Al to the proto-solar disk. Given these significant implications of these isotopic observations, it is critical to check that they are robust. Indeed, there are plausible alternative rationalisations of the data. In this talk I will recount attempts to place novel constraints on the validity of these striking isotopic signatures to investigate if we are truly odd or just mis-understood.

This is a hybrid event. The talk will be given via Zoom (https://zoom.us/j/99984123581), and screened live in the Tilley Lecture Theatre.

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Mon 01 Nov 18:00: Title to be confirmed

Wed, 20/10/2021 - 18:51
Title to be confirmed

Abstract not available

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Mon 01 Nov 18:00: Title to be confirmed

Wed, 20/10/2021 - 12:08
Title to be confirmed

Abstract not available

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Mon 15 Nov 18:00: Winchcombe: The First UK Meteorite in 30 Years

Wed, 20/10/2021 - 12:07
Winchcombe: The First UK Meteorite in 30 Years

On the 28th February 2021 a fireball was seen/heard across the UK, an event which was recorded by both dedicated fireball cameras and ordinary dash cams. Several pieces of the new meteorite were quickly recovered, which was calculated to have dropped in Gloucestershire. As part of the initial recovery team, Natasha was one of the first scientists on the scene to see & hold the meteorite. She is now leading an analysis team at the University of Plymouth who have a small fragment of the newly named Winchcombe meteorite, and is beginning to unravel its mysteries. Join us as we explore the science behind the observation, recovery, and classification of the UK’s first new meteorite in 30 years.

Dr Natasha Stephen is a geologist by training, focusing on extra-terrestrial materials & planetary science. Natasha is Director of Plymouth Electron Microscopy Centre at the University of Plymouth, where she is also a lecturer in the Faculty of Science & Engineering. Natasha has been working with extra-terrestrial materials including the Moon, Mars, and asteroids, for 12 years since starting her PhD at Imperial College London jointly with the Natural History Museum, London. Natasha has searched for meteorites in both the Northern and Southern hemispheres, and classifies them using the non-destructive techniques available in her own analytical microscopy facility in the SW of England.

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Wed 27 Oct 16:00: Earthquake ground-motion assessment and rupture behaviours of induced seismicity from deep geothermal production

Tue, 19/10/2021 - 14:30
Earthquake ground-motion assessment and rupture behaviours of induced seismicity from deep geothermal production

With UK’s net-zero carbon emissions goal for 2050, geothermal energy has become a promising renewable energy source with its low carbon footprint. In 2020, it stood for 4.5% of UK’s renewable energy, and there are several geothermal projects planned for the near future. However, one of the risks associated with geothermal production is induced seismicity. Although small microseismic events are natural at geothermal sites, a few recent cases of larger earthquakes overseas have alarmed the public, caused damage, and paused or halted the energy development. Thus, as UK is developing its geothermal sites, it is important to analyse the first earthquakes available from each location to better understand how the regions respond to ground motions and how the earthquakes behave.

Using a local Raspberry Shakes seismic network, we examined the induced earthquakes from the United Downs geothermal site in Cornwall, UK, and found that the region experiences more high-frequency content than expected based on relevant models. We also concluded that low-cost Raspberry Shakes are a suitable alternative for preliminary seismic hazard analysis in regions lacking seismic networks. Additionally, we investigated the first induced earthquakes from the Helsinki, Finland, deep geothermal site to get a closer look at the rupture behaviour of the earthquakes, identifying clear rupture directivity and complex behaviour similar to larger, natural earthquakes.

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Mon 15 Nov 18:00: Title to be confirmed

Tue, 19/10/2021 - 13:08
Title to be confirmed

Abstract not available

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Mon 29 Nov 18:00: How Do Rocks React to Outbursts from the Sun?

Tue, 19/10/2021 - 13:07
How Do Rocks React to Outbursts from the Sun?

Have you ever seen the northern lights flickering above? Did you know that their source (the solar wind) is interacting with Earth’s magnetic field and can produce strong electrical currents in the ground? These so-called geomagnetically induced currents (GICs) have detrimental effects on many ground-based structures like the high voltage power transmission grid. The amplitude of GICs does depend on the ground electrical conductivity – the rocks beneath our feet! Our modern reliance on technology has made us vulnerable to this natural phenomenon. A day without electricity in the UK would certainly not only be inconvenient but also have huge economic consequences. In this talk I will introduce the geohazard space weather, its interaction with the geomagnetic field and how models of conductivity help to quantify and even forecast the impacts on the power grid, pipelines and the railway in the UK.

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Mon 08 Nov 18:00: Tracking the Earth's Mantle Through Space and Time

Tue, 19/10/2021 - 13:06
Tracking the Earth's Mantle Through Space and Time

Viscosity measurements for the upper mantle imply that on a large-scale, over geological periods of time, the upper mantle should be a relatively well-mixed reservoir within the Earth. However, ocean-scaled geochemical differences across the upper mantle have been known since the 1980’s, with the identification of isotopic anomalies such as the DUPAL anomaly and SOPAL . Furthermore, isotopic characteristics of depleted, Indian Ocean mid-ocean-ridge-basalts (MORB), which is often synonymous with the DUPAL anomaly, have been documented in Neo-Tethys and Paleo-Tethys MORB prior even to the formation of the Indian Ocean, suggesting that perhaps the upper mantle is not so well mixed as we might anticipate. However, it is not clear how isotopic anomalies could persist in the upper mantle through successive plate re-organisations given the 100-1000’s millions of years of radiogenic ingrowth necessary to generate differences in depleted mantle composition. I will explore this question using 3D spherical numerical mantle circulation models embedded with geological paleo-tectonic reconstructions.

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Mon 01 Nov 18:00: Winchcombe: The First UK Meteorite in 30 Years

Tue, 19/10/2021 - 13:06
Winchcombe: The First UK Meteorite in 30 Years

On the 28th February 2021 a fireball was seen/heard across the UK, an event which was recorded by both dedicated fireball cameras and ordinary dash cams. Several pieces of the new meteorite were quickly recovered, which was calculated to have dropped in Gloucestershire. As part of the initial recovery team, Natasha was one of the first scientists on the scene to see & hold the meteorite. She is now leading an analysis team at the University of Plymouth who have a small fragment of the newly named Winchcombe meteorite, and is beginning to unravel its mysteries. Join us as we explore the science behind the observation, recovery, and classification of the UK’s first new meteorite in 30 years.

Dr Natasha Stephen is a geologist by training, focusing on extra-terrestrial materials & planetary science. Natasha is Director of Plymouth Electron Microscopy Centre at the University of Plymouth, where she is also a lecturer in the Faculty of Science & Engineering. Natasha has been working with extra-terrestrial materials including the Moon, Mars, and asteroids, for 12 years since starting her PhD at Imperial College London jointly with the Natural History Museum, London. Natasha has searched for meteorites in both the Northern and Southern hemispheres, and classifies them using the non-destructive techniques available in her own analytical microscopy facility in the SW of England.

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Mon 25 Oct 18:00: Geophysics in Antarctica

Tue, 19/10/2021 - 13:05
Geophysics in Antarctica

Projections of likely sea level rise by 2100 range from 28 to 101 cm. This wide range depends a great deal on the amount of fossil fuel we burn over the next decades. However, due to poorly understood processes occurring in the ice sheets, and how they will respond to the warming climate and ocean, bigger numbers than this are not out of the question. One way to improve our understanding is with geophysical observations made on the ice sheet itself. In this talk I’ll explain how and why we do things like seismic experiments on ice shelves, record tiny icequakes from beneath ice streams and even measure the orientation of ice crystals using radar.

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Thu 21 Oct 11:30: Particle Plumes in Cross Winds - Going to Extremes

Tue, 19/10/2021 - 09:19
Particle Plumes in Cross Winds - Going to Extremes

To book an in-person seat at the seminar this Thursday please use the link below – please note that once the number is reached you will not be able to register but will be able to watch via the Zoom link at the bottom of this email. There will also be a selection of individually wrapped sandwich lunches for everyone who is attending in-person.

https://stokes.cceif.group.cam.ac.uk:1763/seminarreg/164302

Face coverings are expected to be worn on arrival at the BPI Institute AND during the seminar and in all communal areas. Face coverings should only be removed once you have collected lunch and are back at your seat. Please also note that for ventilation windows in the Open Plan Area must remain open at all times.

BPI Seminar – Thursday 21 October 2021

11.30

Andy Woods, BPI , University of Cambridge Particle Plumes in Cross Winds

Stuart Clarke, BPI , University of Cambridge Surface Science – Going to Extremes Time: Oct 21, 2021 11:15 AM London

To attend via Zoom:

https://zoom.us/j/94345857670

Meeting ID: 943 4585 7670

To attend the meeting, just open the meeting link in e.g., a web browser, which, if you have not already installed Zoom, will start a download and the quick installation of a small client will be necessary. If you already have Zoom, you already know what to do – and the link can be entered as the message ID.

The link will be live from 11.15am. By default you will be muted and not emitting video, so remember to unmute yourself before asking questions.

This talk is part of the Seminars for the Centre for Environmental and Industrial Flows series.

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Thu 28 Oct 11:30: Conformation of Organic Friction Modifiers under shear - Alex Routh

Mon, 18/10/2021 - 14:00
Conformation of Organic Friction Modifiers under shear - Alex Routh

Conformation of Organic Friction Modifiers under shear – Alex Routh

Organic Friction Modifiers (OFMs) are small amphiphilic molecules commonly added to engine oil formulations. They are known to reduce friction between moving metal parts. The conventional view is that these molecules operate with the polar headgroup attaching to the metal surface and the alkyl chain extending into solution. This conformation remains unproven and there is no knowledge of the effect of shear on the OFM

To investigate the conformation of OFMs we have built a tribometer which fits onto neutron reflectivity beamlines. This allows the structure of OFMs to be probed whilst simultaneously applying a well defined shear.

Evidence is found for the OFM conformation to be reverse micelles adsorbing onto iron oxide surfaces.

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Thu 25 Nov 15:00: Using ecology to unlock the secrets of early animal evolution

Mon, 18/10/2021 - 12:17
Using ecology to unlock the secrets of early animal evolution

The sudden appearance of animals in the fossil record, after billions of years of microbial life, is one of the most dramatic events in the history of life on Earth. These oldest known animals are found in the Ediacaran time period (630–541 Ma), just before the Cambrian radiation. Studying Ediacaran evolution is fraught with difficulties due to the unique anatomies of Ediacaran organisms. But we have one potential avenue of attack – the preservation of Ediacaran fossils is exceptional, with thousands of organisms preserved where they lived. To exploit that information we can use a suite of ecological methodologies, normally only used on extant communities.

During this talk I will highlight how this rich data source, combined with cutting edge technological and ecological advances, has transformed our understanding of Ediacaran life. The talk will explain how laser-scanning has transformed our ability to digitally capture hundreds of square meters of Ediacaran bedding planes across the wind-swept coasts of Newfoundland. Over the last four years my team and I have used a micron-resolution laser scanner to capture almost 20,000 fossils in-situ across from Newfoundland, Canada and Charnwood Forest, UK. I will go on to explain how this unprecedented dataset has been used with careful spatial and Bayesian approaches to enable the teasing-apart of Ediacaran eco-evolutionary dynamics, and finally how these Ediacaran organisms paved the way for the rapid Cambrian radiation of animals. This lecture will explain how we were able to discover secrets such as the how some Ediacaran species were dominantly clonal, how Ediacaran communities are highly unusual, rarely competing with each other for food and final how variations in the local habitat may be driving Ediacaran diversification and paving the way for the Cambrian radiation.

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Thu 21 Oct 15:00: Marine sedimentary carbon cycling This is a hybrid event. It will be live in the Tilley Lecture Theatre and broadcast on Zoom (https://zoom.us/j/99984123581)

Mon, 18/10/2021 - 12:16
Marine sedimentary carbon cycling

The removal of carbon from the surface of the planet is a critical component of the long-term carbon cycle; this removal is through the deposition and subsequent burial of organic carbon and carbonate minerals in the ocean. Sedimentary, post-depositional, processes play a key role in the global carbon cycle as much of the organic carbon deposited in marine sediments is broken down through a series of microbial reactions, releasing the organic carbon and directly impacting the saturation state of carbonate minerals. In this talk I will discuss my research into the drivers of modern sedimentary carbon cycling using approaches ranging from multiple isotope system measurements, machine learning and reactive transport modelling. I will then show how this improved understanding can be used to determine how changing oceanic conditions would have impacted carbon cycling in marine sediments over the Phanerozoic.

This is a hybrid event. It will be live in the Tilley Lecture Theatre and broadcast on Zoom (https://zoom.us/j/99984123581)

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Thu 04 Nov 15:00: Productivity and dissolved oxygen controls on the Southern Ocean deep-sea benthos during the Antarctic Cold Reversal This is a hybrid event. The talk will be given via Zoom (https://zoom.us/j/99984123581), and screened live in the...

Mon, 18/10/2021 - 12:14
Productivity and dissolved oxygen controls on the Southern Ocean deep-sea benthos during the Antarctic Cold Reversal

The Antarctic Cold Reversal (ACR; 14.7 to 13 thousand years ago; ka) phase of the last deglaciation saw a pause in the rise of atmospheric CO2 and Antarctic temperature, that contrasted with warming in the North. A re-expansion of sea ice and a northward shift in the position of the westerly winds in the Southern Ocean are well-documented, but the response of deep-sea biota and the primary drivers of habitat viability remain unclear. Here we present a new perspective on ecological changes in the deglacial Southern Ocean, including multi-faunal benthic assemblage (foraminifera and cold-water corals) and coral geochemical data (Ba/Ca and δ11B) from the Drake Passage. Our records show that, during the ACR , peak abundances of thick-walled benthic foraminifera Uvigerina bifurcata and corals are observed at shallow depths in the sub-Antarctic (~300 m), while coral populations at greater depths and further south diminished. Our ecological and geochemical data indicate that habitat shifts were dictated by (i) a northward migration of food supply (primary production) into the Subantarctic Zone and (ii) poorly oxygenated seawater at depth during this Antarctic cooling interval.

This is a hybrid event. The talk will be given via Zoom (https://zoom.us/j/99984123581), and screened live in the Tilley Lecture Theatre.

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Thu 21 Oct 11:30: Some Thoughts on Decarbonising Heating Systems and Surface Science - Going to Extremes

Mon, 18/10/2021 - 10:38
Some Thoughts on Decarbonising Heating Systems and Surface Science - Going to Extremes

To book an in-person seat at the seminar this Thursday please use the link below – please note that once the number is reached you will not be able to register but will be able to watch via the Zoom link at the bottom of this email. There will also be a selection of individually wrapped sandwich lunches for everyone who is attending in-person.

https://stokes.cceif.group.cam.ac.uk:1763/seminarreg/164302

Face coverings are expected to be worn on arrival at the BPI Institute AND during the seminar and in all communal areas. Face coverings should only be removed once you have collected lunch and are back at your seat. Please also note that for ventilation windows in the Open Plan Area must remain open at all times.

BPI Seminar – Thursday 21 October 2021

11.30

Andy Woods, BPI , University of Cambridge Some Thoughts on Decarbonising Heating Systems

Stuart Clarke, BPI , University of Cambridge Surface Science – Going to Extremes Time: Oct 21, 2021 11:15 AM London

To attend via Zoom:

https://zoom.us/j/94345857670

Meeting ID: 943 4585 7670

To attend the meeting, just open the meeting link in e.g., a web browser, which, if you have not already installed Zoom, will start a download and the quick installation of a small client will be necessary. If you already have Zoom, you already know what to do – and the link can be entered as the message ID.

The link will be live from 11.15am. By default you will be muted and not emitting video, so remember to unmute yourself before asking questions.

This talk is part of the Seminars for the Centre for Environmental and Industrial Flows series.

Add to your calendar or Include in your list

Thu 21 Oct 11:30: Some Thoughts on Decarbonising Heating Systems and Surface Science - Going to Extremes

Mon, 18/10/2021 - 08:54
Some Thoughts on Decarbonising Heating Systems and Surface Science - Going to Extremes

Some Thoughts on Decarbonising Heating Systems – Andy Woods Surface Science – Going to Extremes – Stuart Clarke

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