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Department of Earth Sciences

 

Wed 05 Jun 17:30: TBC Building doors are card operated, so latecomers may not be able to access the venue.

Earth Sciences talks - Wed, 27/03/2024 - 12:36
TBC

Abstract not available

Building doors are card operated, so latecomers may not be able to access the venue.

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Wed 12 Jun 17:30: Palaeoecological Insights into the Causes and Consequences of Mid-Late Quaternary Megafauna Extinction in Asia and Australia Building doors are card operated, so latecomers may not be able to access the venue.

Earth Sciences talks - Wed, 27/03/2024 - 12:35
Palaeoecological Insights into the Causes and Consequences of Mid-Late Quaternary Megafauna Extinction in Asia and Australia

Mid-Late Quaternary megafauna extinctions have long intrigued researchers seeking to understand the causes and consequences of these significant ecological events. What role did fluctuations in climate, shifts in vegetation composition, alterations in habitat distribution, and the impact of human settlement play in megafauna extinction? One way to help us better understand the role of environmental change in the extinction process is to use palaeoecological techniques (pollen, spore and charcoal analysis) combined with well resolved geochronological estimates to reconstruct palaeoenvironmental conditions that occur before, during, and after past megafauna extinctions. Here I present two palaeoecological case studies that provide insights into megafauna extinction in Asia and Australia: (i) the largest ever primate and one of the largest of the southeast Asian megafauna, Gigantopithecus blacki, that persisted in China from about 2.0 million years until the late middle Pleistocene when it became extinct, well before the appearance of Homo sapiens on the landscape, and (ii) the multiple extinctions of megafauna that occurred across Australia around 50,000-40,000 years ago that coincide with a time when people were present across the Australian landscape. This presentation underscores the importance of interdisciplinary approaches integrating palaeoecological, geochronological, archaeological, and climatological perspectives to unravel the complexities of past megafauna extinctions and inform strategies for mitigating future biodiversity crises.

Building doors are card operated, so latecomers may not be able to access the venue.

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Wed 15 May 17:30: Radiocarbon dating and conspiracy theories Building doors are card operated, so latecomers may not be able to access the venue.

Earth Sciences talks - Wed, 27/03/2024 - 12:34
Radiocarbon dating and conspiracy theories

A range of conspiracy theories involving radiocarbon dating have become popular on the Internet over the past years. Examples include the radiocarbon dating of dinosaur fossils that supposedly reveal problems with a geologically old Earth, claims that entire centuries of European history have been made up, and archaeological sites that supposedly provide evidence for a long-lost Younger Dryas civilization that is being hidden or denied by “Big Archaeology”. We will look at what these conspiracy theories claim, followed by more down-to-Earth explanations. We then discuss the dangers of such conspiracy theories, and provide some pointers for dealing with them.

Building doors are card operated, so latecomers may not be able to access the venue.

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Wed 24 Apr 17:30: Title to be confirmed Building doors are card operated, so latecomers may not be able to access the venue.

Earth Sciences talks - Wed, 27/03/2024 - 12:33
Title to be confirmed

Abstract not available

Building doors are card operated, so latecomers may not be able to access the venue.

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Wed 15 May 17:30: Radiocarbon dating and conspiracy theories

Earth Sciences talks - Wed, 27/03/2024 - 11:23
Radiocarbon dating and conspiracy theories

A range of conspiracy theories involving radiocarbon dating have become popular on the Internet over the past years. Examples include the radiocarbon dating of dinosaur fossils that supposedly reveal problems with a geologically old Earth, claims that entire centuries of European history have been made up, and archaeological sites that supposedly provide evidence for a long-lost Younger Dryas civilization that is being hidden or denied by “Big Archaeology”. We will look at what these conspiracy theories claim, followed by more down-to-Earth explanations. We then discuss the dangers of such conspiracy theories, and provide some pointers for dealing with them.

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Department and Sedgwick Museum hold first Earth Sciences Fair

Earth Sciences news - Mon, 25/03/2024 - 11:12

On Saturday 23 rd March the Department of Earth Sciences and Sedgwick Museum hosted their first Earth Sciences Fair as part of the Cambridge Festival. Visitors had a chance to meet scientists and hear about their research to understand the planet we live on and tackle environmental challenges. Scientists and activities at...

Categories: Recent news and blogs

Ice on show at Royal Society Summer Science Exhibition

Earth Sciences news - Wed, 20/03/2024 - 10:40

Cambridge Earth Sciences and the British Antarctic Survey will be at the 2024 Royal Society Summer Science Exhibition , talking all about how we’re unlocking the past using ice cores from Antarctica. This annual event is a free, interactive experience for anyone curious about the latest advances in science and technology...

Categories: Recent news and blogs

UK Green Building Council Membership Renewed

The Cambridge Green Challenge News - Wed, 20/03/2024 - 09:36

The University of Cambridge is a member of the UK Green Building Council , an industry network dedicated to transforming the sustainability of the built environment. Any member of the University can access their guidance and sign up to hear about the latest news and learning opportunities in the sector (register at the...

Tue 23 Apr 11:00: Sedgwick Club Conference 2024

Earth Sciences talks - Wed, 13/03/2024 - 16:48
Sedgwick Club Conference 2024

Six 25 minute talks from a variety of areas of Earth Sciences; dynamic topography, mineral palaeomagnetism, science communication, rock deformation, seasonal climate events and palaeontology.

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Crystal defects yield improved estimates of earthquake energy balance

Earth Sciences news - Tue, 12/03/2024 - 15:01

Earthquakes happen when rocks deep underground break and slide past each other suddenly: releasing seismic waves that cause shaking. But shaking is just one way that earthquakes liberate their pent-up energy. Around 80% of an earthquake’s total energy actually stays within rocks close to the fault rupture. When a fault...

Categories: Recent news and blogs

Earth’s earliest forest revealed in Somerset fossils

Earth Sciences news - Fri, 08/03/2024 - 17:36

The oldest fossilised forest known on Earth – dating from 390 million years ago – has been found in the high sandstone cliffs along the Devon and Somerset coast of South West England. The fossils, discovered and identified by researchers from the Universities of Cambridge and Cardiff, are the oldest fossilised trees ever...

Categories: Recent news and blogs

Professor Sasha Turchyn receives Pilkington Prize for teaching excellence

Earth Sciences news - Thu, 07/03/2024 - 17:49

Professor Sasha Turchyn has been awarded the prestigious Pilkington Prize in recognition of her teaching excellence. Professor Sasha Turchyn is a lecturer in biogeochemistry and Director of Studies in Earth Sciences at Trinity Hall. The award acknowledged Sasha’s dedication to students, running fieldtrips and her work to...

Categories: Recent news and blogs

Wed 05 Jun 17:30: TBC

Earth Sciences talks - Thu, 07/03/2024 - 12:08
TBC

Abstract not available

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Thu 25 Apr 11:30: Specific Ion Effects in Colloidal Surface Forces

Earth Sciences talks - Thu, 07/03/2024 - 11:16
Specific Ion Effects in Colloidal Surface Forces

The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of the interactions of colloid particles has provided a useful framework for understanding general trends determining adsorption and aggregation of micro- and nanoparticles. The point-charge (Poisson-Boltzmann or Debye-Hückel) theory of electrolytes characterises the nature of the electrolyte solely by its pH and Debye length or ionic strength. So conventional theory is incapable of predicting the ion-specific distinction between, for instance, NaCl and KCl solutions, or between phosphate and citrate pH buffer solutions. But ion-specific phenomena (Hofmeister effects) are ubiquitous, and observed in protein aggregration, enzyme adsorption on nanoparticles, particle diffusion coefficients, charge reversal effects, bubble coalescence, lipid self-assembly, electrode capacitance.

Ion specificity essentially arises from the distinct electron structure of different ions. We identify two competing consequences. On the one hand, electronic polarisability drives ion dispersion forces [1], leading to adsorption of coions, or excess adsorption of counterions resulting in charge reversal [2]. On the other hand, the size of the electron cloud drives ionic steric forces, resulting in a limit to the concentration of adsorbed ions that results, for instance, in a diminution of electrode capacitance [3].

We account for these effects as additional nonelectrostatic contributions to the total chemical potential of ions, applied in a modified Poisson-Boltzmann model. For basic development of the ideas we use symmetry to simplify the geometry to 1D calculations. But implementing the solution using finite element methods, we obtain a framework that will be used to model the complex 3D geometries of porous electrodes and self-assembled lipid crystal phases. One long term aim is to predict the phase transitions between hexagonal, cubic and micellar phases relevant to, for instance, the physiology of RNA (COVID) vaccines.

References

[1] Importance of Accurate Dynamic Polarizabilities for the Ionic Dispersion Interactions of Alkali Halides. D.F. Parsons, B.W. Ninham. Langmuir 2010, 26(3), 1816–1823. https://dx.doi.org/10.1021/la902533x

[2] Buffer-specific effects arise from ionic dispersion forces. D.F. Parsons, C. Carucci, A. Salis. Phys. Chem. Chem. Phys., 2022, 24, 6544. https://dx.doi.org/10.1039/d2cp00223j

[3] Thermodynamics beyond dilute solution theory: Steric effects and electrowetting. D. Tadesse, D.F. Parsons. In: Encyclopedia of Solid-Liquid Interfaces (2024). https://dx.doi.org/10.1016/B978-0-323-85669-0.00137-9

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Earth’s earliest forest revealed in Somerset fossils

The oldest fossilised forest known on Earth – dating from 390 million years ago – has been found in the high sandstone cliffs along the Devon and Somerset coast of South West England.

Categories: News

Earth’s earliest forest revealed in Somerset fossils

Research News - Thu, 07/03/2024 - 10:27

The oldest fossilised forest known on Earth – dating from 390 million years ago – has been found in the high sandstone cliffs along the Devon and Somerset coast of South West England.

Thu 25 Apr 11:30: Specific Ion Effects in Colloidal Surface Forces

Earth Sciences talks - Thu, 07/03/2024 - 10:11
Specific Ion Effects in Colloidal Surface Forces

The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of the interactions of colloid particles has provided a useful framework for understanding general trends determining adsorption and aggregation of micro- and nanoparticles. The point-charge (Poisson-Boltzmann or Debye-Hückel) theory of electrolytes characterises the nature of the electrolyte solely by its pH and Debye length or ionic strength. So conventional theory is incapable of predicting the ion-specific distinction between, for instance, NaCl and KCl solutions, or between phosphate and citrate pH buffer solutions. But ion-specific phenomena (Hofmeister effects) are ubiquitous, and observed in protein aggregration, enzyme adsorption on nanoparticles, particle diffusion coefficients, charge reversal effects, bubble coalescence, lipid self-assembly, electrode capacitance.

Ion specificity essentially arises from the distinct electron structure of different ions. We identify two competing consequences. On the one hand, electronic polarisability drives ion dispersion forces [1], leading to adsorption of coions, or excess adsorption of counterions resulting in charge reversal [2]. On the other hand, the size of the electron cloud drives ionic steric forces, resulting in a limit to the concentration of adsorbed ions that results, for instance, in a diminution of electrode capacitance [3].

We account for these effects as additional nonelectrostatic contributions to the total chemical potential of ions, applied in a modified Poisson-Boltzmann model. For basic development of the ideas we use symmetry to simplify the geometry to 1D calculations. But implementing the solution using finite element methods, we obtain a framework that will be used to model the complex 3D geometries of porous electrodes and self-assembled lipid crystal phases. One long term aim is to predict the phase transitions between hexagonal, cubic and micellar phases relevant to, for instance, the physiology of RNA (COVID) vaccines.

References

[1] Importance of Accurate Dynamic Polarizabilities for the Ionic Dispersion Interactions of Alkali Halides. D.F. Parsons, B.W. Ninham. Langmuir 2010, 26(3), 1816–1823. https://dx.doi.org/10.1021/la902533x

[2] Buffer-specific effects arise from ionic dispersion forces. D.F. Parsons, C. Carucci, A. Salis. Phys. Chem. Chem. Phys., 2022, 24, 6544. https://dx.doi.org/10.1039/d2cp00223j

[3] Thermodynamics beyond dilute solution theory: Steric effects and electrowetting. D. Tadesse, D.F. Parsons. In: Encyclopedia of Solid-Liquid Interfaces (2024). https://dx.doi.org/10.1016/B978-0-323-85669-0.00137-9

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Thu 07 Mar 11:30: Novel processing and 3D correlative imaging of electrodes for batteries

Earth Sciences talks - Thu, 07/03/2024 - 08:59
Novel processing and 3D correlative imaging of electrodes for batteries

11.30 – 12.30

Dr Chun Ann Huang, Imperial College London

Rechargeable batteries can contribute to powering electric transportation and storing electrical energy generated from intermittent renewable sources. There are increasing demands for improving the rate capability and energy density of current Li ion batteries (LIBs) and solid-state Li metal batteries (SSLMBs), along with other types of batteries. Two novel processing technologies have been developed to optimise the battery electrode microstructure and improve ion diffusion kinetics: (i) directional ice templating (DIT) for fabricating thick (900 µm) cathodes with vertical pore arrays and porosity gradient for LIBs [1]; and (ii) directional freezing and polymerisation (DFP) for fabricating cathodes with vertical arrays of solid polymer electrolyte (SPE) directly incorporated in the cathode microstructure during processing for SSLM Bs [2]. Both techniques reduced tortuosity τ of ion diffusion pathways through electrode thickness to 1.5 from ~3.3 for commercial electrodes.

We then show a new correlative imaging technique of combining X-ray Compton scattering imaging (XCS-I) and computed tomography (XCT) that allows 3D pixel-by-pixel mapping of Li chemical stoichiometry variations in a LiNi0.8Mn0.1Co0.1O2 electrode within a coin cell battery (Fig. 1) [3,4]. Using this technique, we show how the anisotropic electrode microstructure improved Li+ ion diffusivity, homogenised Li+ ion concentration, and improved energy storage performance.

13.00 – 14.00

Eric Breard – University of Edinburgh

Enigma to Understanding: A Multidisciplinary Journey into the Mechanics of Concentrated Pyroclastic Density Currents

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Mon 11 Mar 18:00: Tracing horizons of habitability on Venus

Earth Sciences talks - Wed, 06/03/2024 - 19:57
Tracing horizons of habitability on Venus

Earth’s next-door neighbour, Venus, shines brilliantly in our night sky and has represented love and beauty since antiquity. Human exploration of Venus during the space age, however, revealed that its surface is boiling hot, its atmosphere is drier than the Atacama desert, and the whole planet is engulfed in thick clouds of acid. Now, almost 40 years since our last in-situ visitation of the planet Venus, humanity is sending a new fleet of probes to constrain its ancient climate history and to discover whether it may host life today. In this talk, I will trace the past and future of Venus exploration, and answer the questions: what does Venus’s ancient past mean for the habitability of exoplanets around distant stars? and how could Venus support extraterrestrial life today?

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Wed 06 Mar 16:00: Origin of carbonatites using the triple-isotope approach

Earth Sciences talks - Fri, 01/03/2024 - 16:28
Origin of carbonatites using the triple-isotope approach

Carbonatites are rare carbonate-rich igneous rocks derived from carbon and carbonate-rich regions of Earth’s mantle. Although a number of igneous processes are recognized to have controlled their compositions, the origin of the carbonate-rich nature of these magmas remains debated and has been linked to various mantle-related processes, including subduction and plume–lithosphere interaction. High-precision isotope measurements can provide insights into carbonatite petrogenesis, including the identification of subducted crustal material in their source region. In particular, combining mass-dependent and kinetically corrected Mg isotope data, also known as the triple-isotope approach, provides insights into mass fractionation processes driving mass dependent fractionation, which in turn allows to distinguish between equilibrium and kinetic processes. In this work, we report high-precision Mg stable isotope data for 59 carbonatites and associated silicate rocks from different localities and ages ranging from 3000 Ma to present-day. In addition, we also report Mg isotope data for 17 Phanerozoic carbonate rocks, with the aim of identifying the isotopic signature of carbonate-rich material potentially recycled to the carbonatite mantle source regions. We observe positive residual deviations after kinetic mass fractionation correction of the Mg isotope data for our carbonatites; an isotope signal that is also present in Phanerozoic carbonates. This observation establishes that a component of the Mg present in these samples experienced mass-dependent equilibrium isotopic fractionation processes, which are significantly larger at low temperatures. Given that the Mg results do not covary with C and O isotopic signals, the magnitude of the fractionation following the equilibrium law observed in carbonatites provides strong evidence for recycled material from the Earth’s surface in the mantle source of Ca- and Mg-rich carbonatites. Furthermore, associated silicate rocks present mantle-like Mg isotopic compositions in contrast with the genetically linked carbonatites – based on the Sr isotopes – for some complexes, which is best explained if the carbonatites and associated silicate rocks represent distinct generation of partial melts of a mantle source containing recycled carbonate.

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