logo News Research themes People Courses Facilities Analytical services Contact

LABORATOIRE G-TIME

GEOCHIMIE: TRAÇAGE ISOTOPIQUE, MINERAL, ET ÉLEMENTAIRE

GEOCHEMISTRY: ISOTOPIC, MINERAL AND ELEMENT TRACING



12


NEWS

26 October, 2018: Departmental seminar by Dr. Rosario Brunetto (Université Paris-Sud)

"Asteroid surfaces: irradiation and spectroscopy, in laboratory and in space"

Abstract: "Primitive extraterrestrial materials are characterized by a large heterogeneity of composition at small scales. This heterogeneity is observed in the laboratory on some meteorites and interplanetary dust with different techniques. Among these, infrared micro-spectroscopy has the advantage of being totally non-destructive and allowing a direct comparison with the astronomical observations of the minor bodies of the Solar System. Thanks to recent developments of "Focal Plan Array" matrix detectors, high spatial resolution and short acquisition IR mapping and IR tomography are now possible. In this presentation I will show some recent measurements of FTIR spectral imaging on different extraterrestrial materials, obtained in collaboration with the SMIS beamline of the SOLEIL synchrotron (France).

In the second part I will present new spectral imaging data of meteorites irradiated in the laboratory with 40 keV ions, as a simulation of solar wind irradiation of the asteroid surfaces. Together with the irradiation effects measured in the particles of the asteroid Itokawa (collected by the Hayabusa mission), these experiments support the spectral interpretation of the observations of asteroids, to establish a link between asteroids and meteorites and to understand the energetic processes that modify the surfaces of the small bodies. In samples irradiated in the laboratory we observe spectral variations of organic and mineral components, as well as variations in albedo. These irradiation effects as a function of the dose are then compared on a micron-scale with the compositional heterogeneity of the original materials, to determine which spectral bands are more sensitive to the effects of space weathering.

The results will be discussed in the context of the asteroid sample return missions Hayabusa2 (JAXA) and OSIRIS-REx (NASA)."

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


17 October, 2018: Departmental seminar by Dr. Volker Dietze (German Meteorlogical Service)

‚ÄúParticulate matter (PM) passive sampling with subsequent single-particle analysis as an economical and effective approach for possible ecosystems impact assessments‚ÄĚ

Dr. Dietze is the head of the Particle Laboratory and he is currently involved in several monitoring and research programs in Germany and in the CHASE project (Unravelling Particle Chemistry in Dronning Maud Land: from atmosphere to surface snow).

Please join us at 12:15pm in Building D, Room 5.236.


Starting September, 2018: G-Time plays host to the CRUMBEL team

The CRUMBEL project studies the collections of cremated bone found in Belgium dating from the Neolithic to the Early-Medieval period using state of the art analytical and geochemical analyses.

To carry out the various structural, elemental and isotopic analyses, two geochemical laboratories open their doors to the CRUMBEL team: G-Time at ULB and the Analytical, Environmental and Geo-Chemistry (AMGC) research unit at VUB.

Welcome, CRUMBEL team!

www.crumbel.org


14 September, 2018: PhD defense of Maria Valdes

logo

13 June, 2018: PhD defense of Katharine Maussen

logo

30 May, 2018: G-Time family portrait

logo

Back left, left to right: Aubry, Hugues, Jeroen; Middle row, left to right: Raymond, Nina, Stefania, Christophe, Ashlea, Giacomo, Julien, Sabrina, Wendy, Cedric; Front row, left to right: Baptiste, Nadine, Maria, Vinciane, Hamed; Downstage left: banana, cup, keys, sandwich, Fanta


24 May, 2018: Departmental seminar by Dr. Christophe Snoeck (Vrije Universiteit Brussel)

"Trials by Fire - An Archaeological tale of Cremated People"

Abstract: "Over the last 50 years, archaeological research has vastly expanded combining a wide range of new methods developed in different scientific fields. More specifically, different analytical and geochemical methods have been applied to the study of human remains to learn more about their diet, mobility, landscape use and environmental conditions. The focus, however, remained on inhumed individuals, as it was believed that the high temperature reached during cremation (up to 1000°C) destroyed the information contained in bone. Consequently, the lives of our ancestors that were cremated remains particularly enigmatic which crucially limits our understanding of our past.

Indeed, cremation was one of the main funeral practices if not the major one in Belgium (and many other parts of Europe) during the Late Neolithic through to the Roman Period. It remained also important during the following 'Early-Medieval Period' (up to 700 AD). This represents more than 3000 years of Belgian history. Recent advances in the bioarchaeological study of cremated bone, however, open new possibilities to understand the lives of cremated people using state of the art analytical and geochemical methods.

This talk presents the analytical and geochemical developments for the study of cremated bone carried out over the last 8 years jointly between the University of Oxford, the ULB and the VUB. These results were successfully applied to several archaeological sites, including the iconic British site of Stonehenge. Bringing together researchers from the VUB, ULB, UGent and KIK-IRPA, the new EOS-CRUMBEL project (Cremation, Urns and Mobility - Population Dynamics in Belgium), is taking a new step forward in the study of cremated people with a special focus on Belgian human cremations."

The seminar will be followed by a drinks reception to introduce the EOS CRUMBEL Team (of which Dr. Snoeck is the Scientific Coordinator) to the ULB and VUB Academic Communities.

Please join us at 1:00pm in Building D, Room 5.236.


20 April, 2018: Departmental seminar by Prof. Maria Schönbächler (ETH, Zürich)

"Recent advances in Nb-Zr chronometry and early silicate differentiation of asteroids and planets"

Abstract: "The short-lived 92Nb-92Zr decay system is a powerful chronometer to date processes in the early solar system. The p-process isotope 92Nb decays to 92Zr with a half-life of ~37 Myr. Niobium and Zr are fractionated from each other during early silicate differentiation. For this reason, the Nb-Zr chronometer can be applied to date early silicate differentiation on planets (i.e. Earth and Mars), but also on smaller bodies as sampled by meteorites (e.g. basaltic achondrites). In this talk, I will present new results obtained with the Nb-Zr chronometer.

Join us at noon in Building D, Room 5.236.


16 March, 2018: Departmental seminar by Michael Zavadski

"All about the new Mineral Museum website"

Join us at 12:15pm in Building D, Room 5.236. The presentation will will be given in French. À plus!


March 2018: Dr. Matthias van Ginneken returns from Antarctica

Accompanied by Dr. Steven Goderis of the VUB, Matthias van Ginneken set out on a meteorite harvesting expedition in the Sør Rondane Mountains, located near Princess Elisabeth Station in Antarctica. The main purpose of the BELAM (Belgian Antarctic Meteorites) expedition was to search for micrometeorites on mountain tops and in glacial moraines.

Matthias made a video of the expedition!

See the full article about the expedition here

and Matthias' personal page, micro-meteorite.com.


15 January, 2018: Departmental seminar by Prof. Ryan Mathur (Juniata College, USA)

"Transition metal isotopes used to understand sources of metal and the evolution of hydrothermal systems in ore deposits"

The presentation will focus on what type of information transition metal isotope values from ores and related materials can tell us about the hydrothermal systems from which they were derived. The focus of the talk will show how copper, silver and tin isotope compositions of ores and other geologic materials can be used to understand the physiochemical evolution of ore forming fluids. Specifically, the talk will examine Cu isotopic data from Pebble and Dexing, Mo isotope data from Dahutang and Iranian PCDs, Ag isotope data from a variety of settings and Sn isotope data from Cornwall and Bolivian porphyry deposits.

Everyone is welcome! Join us at 4pm in Building D, Room 5.236.


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)

logo

*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

logo

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

logo

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.

logo logo logo logo

Belgian beer, SEGH-style!

logo

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

logo

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