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LABORATOIRE G-TIME

GEOCHIMIE: TRAÇAGE ISOTOPIQUE, MINERAL, ET ÉLEMENTAIRE

GEOCHEMISTRY: ISOTOPIC, MINERAL AND ELEMENT TRACING



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1 December, 2017: Departmental seminar by Dr. Mike Cassidy (NERC fellow, University of Oxford)

"Explosive or effusive? Combining petrology with monitoring data to understand the magmatic system at Kelud volcano, Indonesia"

Abstract: "The parameters that govern the eruptive style at volcanoes are critical to understand, since the volcanic hazards posed to the nearby populations are directly related on whether an eruption is explosive or effusive. Eruptions from Kelud volcano located in East Java, Indonesia are difficult to forecast in that sense, because the eruptive style varies considerably, from effusive eruptions e.g. 1920 and 2007 to explosive eruptions in 1990 and 2014, despite near identical bulk rock compositions. Experiments were undertaken to constrain the magma storage conditions such as pressure, temperature and H2O-CO2 ratios prior to both explosive and effusive eruptions at Kelud and compared to monitoring data before the eruptions. The experiments suggest the last phase of magma storage for explosive eruptions is shallow (2-3 km), cold (~1000 C) and water-saturated, whereas CO2 fluxing during recharge prior to effusive eruptions, heats the magma, suppresses water contents, and lowers explosivity. No significant pre-eruptive deformation was recorded via InSAR prior to the 2014 explosive eruption, showing that explosive eruptions can occur without recent magma injections or inflation akin to the eruption of Calbuco volcano in 2015. Instead, the chemical degassing signature may be key to understanding the state of magma underneath the volcano."

Everyone is welcome! Join us at 12:00 in Building D, Room 5.236.


10 November, 2017: Departmental seminar by Prof. Isabel Ribeiro da Costa of Lisbon University

"Oceanic serpentinization: mineralogical and geochemical data from the Mid-Atlantic Ridge"

Abstract:It is nowadays recognized that serpentinization is an important process within the context of oceanic metasomatism, especially along slow-spreading mid-ocean ridges, where magmatic activity is at its lowest. In those environments, serpentinization affects ultramafic rocks of the lower crust and upper mantle and is itself the cause of further fracturing of the oceanic crust, which eventually enables exhumation of those deep-seated partially or totally serpentinized ultramafics.

Several samples from three sites on the Mid-Atlantic Ridge (Rainbow, Saldanha and Menez Hom) have yielded interesting insights into the textural, structural and chemical features that accompany the evolution of serpentine minerals.

Moreover, bulk geochemistry has also revealed that many of these serpentinites have gone through subsequent metasomatic processes, namely late seafloor oxidation and carbonatization and ore-forming hydrothermal alteration. Serpentinites showing evident signs of hydrothermal alteration are also quite a useful source of information concerning the hydrothermal fluids themselves.

Everyone is welcome! Join us at 12:00 in Building D, Room 5.236.


G-Time: A Day in the Life (a photographic study)

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*Photo credit to Ashlea Wainwright


20 October, 2017: Departmental seminar by Dr. Mario Fischer-Gödde of the University of Münster

"Constraints on Earth's late stage building blocks and the late veneer from nucleosynthetic Mo and Ru isotope heterogeneities"

Abstract: The presence of nucleosynthetic isotope heterogeneities in meteorites for elements with different geochemical affinities enables to deduce information on the nature of the planetary building blocks added at different stages of accretion. As a moderately siderophile element most of the Mo in the terrestrial mantle predominantly derives from building material accreted towards the final stages of the Earth's main growth phase. On the other hand the highly siderophile element Ru was almost entirely added with the late veneer, which represents the latest ~0.5% of mass accreted to the Earth after core formation had ceased.

High precision Mo and Ru isotopic data reveal that, compared to the Earth's mantle, primitive meteorites are characterized by increasing deficits in s-process Mo and Ru nuclides in the order of enstatite - ordinary - carbonaceous chondrites. Because the isotopic composition of the Earth's mantle for both elements is most similar to enstatite chondrites, this indicates that both Earth's late stage building blocks and the late veneer were dominated by materials of this type, i.e. reduced volatile-poor inner solar system materials. Hence, water and other volatile elements must have been brought to the Earth during earlier accretion stages.

Please join us at 12:00 in Building D, Room 5.236.


19 May, 2017: Departmental seminar by Dr. Katherine Joy of the University of Manchester

Abstract: The Moon is an archive of impact cratering in the Solar System throughout the past 4.5 billion years. The lunar impact record itself is controversial with several different models proposed to explain past impact flux. All of the Moon's large impact basins were formed between 4.5 Ga and ~3.8 Ga. However, the duration and magnitude of basin-formation is not well known. It may be that there was a sudden spike in bombardment between ~3.9 to 3.8 Ga when many basins formed (this is known as the lunar cataclysm hypothesis), or it could be that there was a period of late heavy bombardment lasting from ~4.2 to 3.8 Ga. Lunar meteorite samples provide a key record of impact cratering processes from regions outside of those sampled by the Apollo missions. We are currently studying the makeup and Ar-isotope age record of impact melts in several lunar meteorites to test global models of impact bombardment and investigate compositional heterogeneity of the lunar crust. In addition to further constraining the Moon's impact history, we have also investigated the record of asteroid and cometary material found on the Moon. We located and characterised small fragments of primitive asteroid fragments in Apollo 16 regolith samples of different ages.

Please join us at 13:00 in Building D, Room 5.236.


27-28 March, 2017: Seminar - "Medical applications of Cu, Zn and S isotope effects" by Francis Albarède of the Ecole Normale Supérieure de Lyon

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The seminar will be given (in French, but the slides will be written in English) in Forum E (on ULB's Plaine Campus) on Monday, March 27, at 16:00.

Prof. Albarède will be availble at ULB's Solbosch Campus (Building D, 5th floor) on March 28 for any questions/discussions.

Registration is free but mandatory via the following website: http://www.ulb.ac.be/facs/sciences/Albarede.html

Please put the dates in your agenda and distribute the announcement to your teams!


17 March, 2017: Departmental seminar - "Stable Thallium Isotope Variations in Magmatic Rocks" by Dr. Julie Prytulak of Imperial College London

Abstract: "Thallium is one of the heaviest naturally occurring elements and very little stable isotope fractionation between its two isotopes (203Tl and 205Tl) is predicted by classical theoretical calculations. However, due to its large nucleus, an analytically significant range of isotope compositions spanning over 35 epsilon units has been documented in natural samples. Low temperature environments have, by far, the largest isotope variations in nature. Here I will give an overview of this little explored element and its underlying isotope systematics. I will then explore the use of thallium elemental abundances and isotope compositions to investigate mantle heterogeneity and recycling processes in subduction zones. Hopefully, I will demonstrate that the unique chemical properties and low natural abundance of thallium, coupled with its extreme isotope fractionation, make it an ideal tracer of recycling processes in the solid Earth."

Please join us at 12:30 in Building D, Room 5.236.


10 March, 2017: Departmental seminar - "Planetary time scales, Moon, Mars, and meteorites" by Dr. Stephanie C. Werner of the University of Oslo

The talk will be held on Friday, 10 March at 12:00 in Building D, Room 5.236.


9 December, 2016: Departmental seminar - "Ureilites and their parent body, as a contrast to the 'Vesta paradigm' for differentiated asteroids" by Dr. Hilary Downes of Birkbeck University of London

The talk will be held on Friday, 9 December at 13:00 in Building D, Room 5.236.


7 December, 2016: Departmental seminar - "The Kimberlite 'Puzzle'" by Dr. Andrea Giuliani of Macquarie University

Abstract: "Kimberlites are uncommon volcanic rocks of volatile-rich ultramafic composition that only occur in continental areas. Despite their limited abundance, kimberlites have attracted considerable interest being the major host of diamonds and because kimberlites represent the deepest terrestrial melts preserved at surface. Kimberlites could therefore be exceptional probes of the deep Earth evolution. On the other hand, kimberlites are a real enigma in the Earth sciences. The highly reactive nature of kimberlite melts, the hybrid nature of kimberlite rocks, which include magmatic and abundant xenocrystic components, and their susceptibility to post-emplacement modification contribute to obscure the pristine features of kimberlite magmas. As a result, there is still significant controversy on most aspects of kimberlite geology and genesis despite nearly 50 years of dedicated studies. For instance, estimates of parental melt composition range from anhydrous, alkali-rich carbonate-chloride melts to hydrous, alkali-poor ultramafic compositions. In this seminar I will present an overview of the major features of kimberlite rocks and critically review the main issues concerning kimberlite research. These can be schematised as a 'kimberlite puzzle' whereby each piece of the puzzle cannot be resolved in isolation to obtain a valid conclusion. I will provide a range of petrographic and geochemical results for kimberlites from Kimberley (South Africa), which is the kimberlite type-locality, and discuss different aspects of kimberlite formation and evolution within the framework provided by the 'kimberlite puzzle'".

The talk will be held on Wednesday, 7 December at 11:00 in Building D, Room 5.236. We look forward to seeing you there!


26 October, 2016: Departmental seminar - "Micrometeorites: Understanding the fastest dust on the planet" by Dr. Matt Genge of Imperial College London

Abstract: "Micrometeorites are extraterrestrial dust particles that survive atmospheric entry to be recovered from the Earth's surface. These particles are the fastest dust on Earth, experiencing velocities of more than 11 km/s. Combining observations of real micrometeorites with numerical models of atmospheric entry helps us understand their formation."

The talk will be held on Wednesday, 26 October at 12:30 in Building D, Room 5.236. We look forward to seeing you there!


14 October, 2016: London meeting for the Activity Report of the International SEGH 2016 Conference

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This past July, Labo G-Time hosted the SEGH (Society for Environmental Geochemistry and Health) 2016 Conference. It was a great success!

110 delegates from 22 countries attended the meeting. Amongst them, 34 students actively participated, five of whom received an EAG grant (covering the registration fee). 114 abstracts were reviewed by the scientific committee and accepted after corrections. The scientific program was intense, including 59 talks and 55 posters! Four keynote speakers were invited: Prof. Reto Gieré from the University of Pennsylvania (USA), Prof. Montserrat Filella from the Université de Genève (Switzerland), Prof. Elijah Petersen from the NIST (USA), and Prof. Vincent Balter from Ecole Normale Supérieure de Lyon (France). The speakers covered a wide range of topics, such as: assessment of environmental and health impacts of airborne particulate matter; nanoparticle reference materials; criticity of trace elements in the current and future environments; and cancer-driven (Cu, Zn) isotopic fractionation.

A field-trip to the Liège area ended the conference. There, we visited the peat bogs from the Hautes-Fagnes --precious archives of the atmospheric deposits throughout the Holocene. This was followed by a visit to the slag heaps surrounding Liège, which record a strong fingerprint of the metallurgical industries but are also currently developing a natural new ecosystem with specific metal-tolerant plants.



Three awards were distributed at the end of the event to:

-Sebastiaan van de Velde (SEGH Best Oral Presentation)

-Alice Jarosikova (SEGH Best Poster)

-T. Gabriel Enge (Malcolm Brown Award for Outstanding Young Scientist)

See the SEGH website (http://www.segh.net/home/) for more details and articles on the work carried out by the SEGH 2016 young scientist medalists.



The city of Brussels was extremely welcoming with sunny weather (!) and the conference venue was a convivial open space where delegates could have lunch, discover Belgian beers, and initiate lively scientific discussion.

In summary, the SEGH 2016 conference in Brussels not only reached its initial objectives, but exceeded them; this annual conference provided a truly high-quality scientific platform for exchanges between complementary environment- and health-related disciplines: geochemistry, ecotoxicology, earth sciences, medicine...



The SEGH delegates and planners. Top left and bottom right: the group in the conference venue. Top right: delegates, including some G-Time members, enjoy a banquet among dinosaurs at the Royal Belgian Museum of Natural History. Bottom left: Prof. Nadine Matielli of G-Time gives the introduction talk to open the conference after the speech by the Science Faculty Dean, Muriel Moser.

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Belgian beer, SEGH-style!

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This would not have been possible without the organizational team from ULB and the precious contributions from all the participants. Thank you very much to all delegates!

Looking forward to seeing you in China in 2017!


3-4 October, 2016: Curation of Antarctic Meteorites: Concluding workshop of the BELAM (Belgian Antarctic Meteorites) project

Royal Belgian Institute of Natural Sciences - Rue Vautier 29 - 1000 Brussels

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In the frame of the BELAM project, funded by the Belgian Science Policy (Belspo), a new curation facility dedicated to Antarctic meteorite was installed at the Royal Belgian Institute of Natural Sciences in Brussels. As the project is now finishing, we would like to present those facilities to the scientific community, as well as the scientific results obtained so far on the Belgian Antarctic collection. In addition, we would like to take the opportunity of this meeting for gathering worldwide experts in curation, in order to share experience and best practices.



Invited speakers:

-Cari Corrigan (USA - Smithsonian Institute)

-Luigi Folco (Italy - University of Pisa)

-Jérome Gattacceca (France - CEREGE)

-Christian Koeberl (Austria - National History Museum, Wien)

-Kevin Righter (USA - NASA/JSC)

-Caroline Smith (UK - Natural History Museum of London)

-Akira Yamaguchi (Japan - National Institute of Polar Research)

-Brigitte Zanda (France - Musée d'Histoire Naturelles de Paris)



Final program



Registration is free and includes two lunches. The deadline is September 10, 2016. Registration is mandatory following this link.

If you wish to present your own curation facilities, or research dedicated to curation improvement, please contact Vinciane Debaille at vinciane.debaille@ulb.ac.be. Please use the same contact if you have any questions.

We* are looking forward to seeing you in Brussels!

*Sophie Decrée, Philippe Claeys, Vinciane Debaille, Lidia Pittarello, Steven Goderis and Marleen De Ceukelaire



Links:

Belspo

Royal Belgian Institute of Natural Sciences

VUB Earth System Science


30 September, 2016: Departmental seminar - "The story of the moons of Mars" by Dr. Pascal Rosenblatt

Dr. Pascal Rosenblatt from the Royal Observatory of Belgium will kick off the department's monthly seminar series with a talk on the history of the moons of Mars, Phobos and Deimos. The abstract is below:

"The two moons of Mars, Phobos and Deimos, were first thought to be asteroids captured by the red planet. The remote sensing of their surfaces argue in favor of this scenario but the present near-circular and near-equatorial orbit of the two moons could not fit expected orbits of capture objects. An alternative scenario has been proposed in which the two small moons of Mars were formed after a giant collision occurred more than 4 billions years ago, similarly to the formation of our Moon. But this scenario raises challenges as how to form small moons (and not a big one as for the Earth) and to maintain them in orbit around Mars over billions of years. A recent work has provided a solution to overcome these problems. It proposes that Mars had bigger moons in the past (now disappeared), which had favored the formation of smaller moons in a disc of debris extending at large distances from the planet. This new scenario will be explained in details after a brief review of previous ideas about the formation of the Martian moons. Eventually, the new missions scheduled by the Japanese (JAXA) and European (ESA) space agencies will be presented. Those missions aim to bring back to Earth sample of the surface of Phobos and are foreseen for launch at around 2024."

The talk will be held on Friday, 30 September, at 13:00, in Building D, Room 5.236. We look forward to seeing you there!


Autumn, 2016: G-Time welcomes three new young scientists thanks to the F.R.S.-FNRS fellowship

The FNRS has awarded Hughes Beunon four-year funding to support his PhD thesis studying refractory ultrabasic xenoliths from the Kerguelen Archipelago as tools to better understand the buoyancy of the Kerguelen oceanic plateau.

Corentin Caudron is one of the scientists to win the FNRS post-doctoral fellowship. His research focuses on

Baptiste Debret was awarded a three-year postdoctoral fellowship by the FNRS. The main subject of his study is dedicated to the role of serpentinites in global redox cycles on Earth through time.

Welcome!


Autumn, 2016: Laboratoire G-Time Fall Seminar Series

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July-August, 2016: G-Time in the Philippines

In collaboration with PHIVOLCS (Philippine Institute of Volcanology and Seismology), Professor Alain Bernard, Ph.D. student/teaching assistant Katharine Maussen, Ph.D student Raymond Maximo (jointly affiliated with PHIVOLCS), and two master's students (Djenan Ratkovic and Julien Robic), will travel to the Philippines for field work. They will make a geochemical study of the crater lake of Taal Volcano and the hot springs of the Cagua Volcano in order to better understand the hydrothermal system of the two volcanoes and the consequences of volcanic activity changes. A floating platform that continuously measures the concentration of CO2 in the water will be installed this summer.

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