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Geolunchs are informal seminars that takes place on friday (12h30-13h30) in room 203 of the La Doua lab.
We talk about planetology, seismology, tectonics, and so on !

Here is the list of coming geolunchs. Join the mailing list this way

Program 2020

Wednesday 19th February / salle Fontanne 13h30 : Isabelle Daniel (LGL-TPE). CAYMAN 2020.

Thursday 20th February / salle master 12h30 : Romain Lafay (Géoscience Montpellier)

The hydrothermal carbonatization of mantle rocks in orogenic belt impacts Earth carbon cycling and constitutes a socio-economic potential for atmospheric CO2 mitigation. Listvenite (carbonatized and silicified peridotite) constitutes the endmember after peridotite carbonatization. Occurrences of listvenites are found in the Samail ophiolite (Sultanat of Oman) basal section atop the Basal Thrust but questions remains concerning their origin.

This study provides results to 1) understand the carbonatization reaction sequence and the way it develops, 2) define the linkage between serpentinization and carbonatization reaction, 3) evaluate the potential source of fluid generating these reactions in the mantle section and 4) calculate mass balance between geological reservoirs during Samail ophiolite obduction.

Our interpretations are based on the petrographic study of the ophiolite section of Hole BT1B drilled at Wadi Mansah (International Continental Scientific Drilling Program (ICDP) Oman drilling project (OmanDP)). Hole BT1B recovered 100% continuous drill core crossing 200 meters of altered mantle rocks (serpentinite, ophicarbonates and listvenite), and 100 meters of the underlying metamorphic sole (shists and greenstones).

Petrographic and thermodynamic investigations reveal that serpentinization precede listvenitization and allow to propose the following carbonatization sequence marked by 1) the crystallization of ferroan-magnesite then 2) magnesite and finally 3) dolomite accompanying quartz precipitation. This suite of reactions is accompanied by the transition from magnetite to hematite stability field. Overlapping relationships and specific chemical zoning in carbonates reflect the development of heterogeneities during alteration in response to 1) alteration regime changes (i.e. fluid-rock ratio or reaction kinetic), 2) local redox condition and 3) evolution of dissolved carbon concentration in the reactive fluid.

While high concentration in dissolved carbon are not a prerequist to explain peridotite carbonatization, ophicarbonates and listvenite represent a sink for gigatons of carbon which required the transfer of huge amount of fluids whose composition and origin can be apprehended by this petrographic study.

Friday 21th February / salle 203 12h30 : Pierre Borgnat (ENS Lyon) Datalunch

Monday 24th February / salle Fontanne 14h00 : Magali Riesner (LEGA, CEA)

Tuesday 25th February / salle 203 12h30 : Ludovic Huguet (IRPHE).

Wednesday 26th February / salle 203 12h30 : Anne Barnoud (LMV, Clermond Ferrand).

Thursday 27th February / salle 203 12h30 : Aurélie Pace (U. Angers).

Friday 28th February / salle 203 12h30 : Martina Ulvrova (ETH).

Monday 2nd March / salle Fontanne 14h00 : Jean-Alexis Hernandez (CEED, U. Oslo)

Wednesday 4th March / salle 203 12h30 : Blandine Gardonio (ENS Paris).

Tuesday 3rd March / salle 203 12h30 : Thomas François (Géosciences Paris Sud).

Thursday 5th March / salle 203 12h30 : Maëlis Arnould (CEED, U. Oslo)

Friday 6th March / salle 203 12h30 : Navid Hedjazian (LGL-TPE). Downscaling of seismic tomography.

Tuesday 10th March / salle 203 12h30 : Cédric Twardzik (EOST).

Wednesday 11th March / salle master 12h30 : Marie-Laure Pons (CEREGE).

Monday 16th March / salle Fontanne 14h00 : Romain Jattiot (U. Brême)

Tuesday 17th March / salle 203 12h30 : Pierre Strzerzynski (U. Le Mans) 

Wednesday 18th March / salle 203 12h30 : Marie Bocher (ETH).

Thursday 19th March / salle 203 12h30 : Loïc Fourel (NGU).

Friday 20th March / salle 203 12h30 : Paul Angrand (GET-OMP).

Monday 23th March / salle Fontanne 14h00 : Ricardo Asti (Géosciences Rennes).

Tuesday 24th March / salle 203 12h30 : Benjamin Bultel (CEED, U. Oslo). Heritage of water-rock interactions on Mars.

Wednesday 25th March / salle 203 12h30 : Loraine Gourbet (ISTerre).

Thursday 26th March / salle 203 12h30 : Antoine Triantafyllou (U. Liège)

Friday 17th April : Vincent Perrier (LGL-TPE). Vincent will speak about Ct Scan and 3D reconstructions of fossils with exceptional preservation.


Program 2019

Program 2018

Program 2017