Magma

MAGMA

The Novarupta dome & the volcano Katmai (Alaska, @Laurent Arbaret)

What we do and who we are in brief

2 Magma Research Projects Funded by the French ANR

GASTON : PI, Fabrice Gaillard. This project tackles the fate of magmatic volatiles across planetary differentiation. Experimentation and modelling will be deployed to elucidate the magmatic conditions under-which volatiles can be lithophile, siderophile, chalcophile, magmatophile or atmophile. This should help answering the question of the role of magmatic processes in the definition of planetary habitability.

Follow this link to see more about GASTON.

 

VolcHalClim: PI, Tjarda Roberts (LPC2E), Co-I, Gaëlle Prouteau. This project tackles the fate of halogens during magma genesis and eruption. From the mantle to the atmosphere, the chain of processes controlling the behaviour of halogen elements will be investigated.

 

Giant Magmatic Processes within the Crust of the Himalayas

A group of Researchers led by ISTO provides a sound evidence that giant magmatic processes must be operating within the present-day crust of the Himalayan mountains. The team shows that the Pressure-Temperature conditions prevailing during the exhumation of Miocene rocks still operate today. This process can be decrypted from the enigmatic geophysical signal beneath the Tibetan Plateau. The team resolves here debate 20 year-old debate.

This is an article in Nature Communications, that is available here:

https://www.nature.com/articles/s41467-018-05934-7

contact: fabrice.gaillard@cnrs-orleans.fr


Understanding and modelling magmatism on Earth and elsewhere is required for a sustainable development of our society. We develop our research on magmatism addressing three time-scales:

(i)   The short time-scale expression of magmatism is volcanism: The immediate hazard associated to eruptions and the atmospheric impact associated to ashes and gases.

(ii) Most of the magmatism does not produce eruptions, but it involves stagnant magmas that cool down at depth during thousands of years. These are plutonic rocks. How this process affects the heat distribution, the strength of the crust and the distribution of fluids and metals with implications for ore processes, constitutes an important topic.

(iii)  At Geological time-scale, magmatic processes have played a central role in the processes of planetary differentiation by linking the deep geodynamics and the surface chemistry.

 

The group leitmotiv is simulating magmatic processes. By developing experimentation at pressure and temperature, our group has gained a know-how and an international reputation.

The Magma group is composed of 10 members and host numerous fellows joining the group for variable duration (internships, PhD, training, postdoc).

Lava Fountain at Stromboli volcano (Italia, @Giada Iacono-Marziano)

Here you find some links illustrating our approach : The experimental simulation of magmatic processes. These topics have contributed to the reputation of the Magma group.

The Mérapi volcano (Java Island, Indonesia, @Laurent Arbaret)

Magmatic Time-Scales

We deploy our methodologies to tackles three time-scales of magmatic processes. These are briefly outlined here more details can be found here.

The volcanic eruption and the pre-eruptive processes:

Mount Pelée, north of Martinique, produces andesitic magma and is famous for catastrophic eruptions.

We help in the evaluation of the volcanic risks by reconstructing the scenario leading to the eruption and simulating the syn-eruptive magmatic processes. We track the mineralogical footprints left within eruptions of the past to predict future activities.

The Geological Time-Scale of Magmatism

Fumaroles at Mt. Etna, on the ridge of the crater (Italy, @Giada Iacono-Marziano)

How the magmatic pipeline connecting the deep Earth to the surface has been operating over the fascinating geological time-scales? Here, we link the geodynamics of the mantle and the crust to the surface chemistry. Can we identify geodynamic secular changes affecting the Earth's surface? Can we link the planetary differentiation to the fate of volatile species and the abundances of carbon, water, sulfur, and nitrogen at the surface of a planet?

Non-volcanic magmatic transfers

Migmatite rocks with Garnet (red) and leucosome (white) supposed to be the source zone of crustal magma (France, @A Villaros).

Most of the magmatism does not produce eruption. This is the dark side of magmatism. During (tens of) thousands of years, magmas remain trapped at depth where they cool down, crystallize and degas. This can cause geochemical and geophysical anomalies including ore processes.

Four Focus groups

Group meetings occur on a monthly basis. We have four themes of group animations, ie. focus group. Some of these themes are shared with our colleagues from the CEMHTI and the LPC2E. The objective is to foster scientific debate, identify “hot topics”, and build sound projects.

  • Theme 1 : Magmatic volatiles. Any topics relating volatiles to melting, crystallization, degassing, and metals in magmatic systems.
  • Theme 2 : Mechanics of magmatic systems : The challenge is understanding the mecanics of magmatic systems at high degree of crystallization. Partial melting and magmatic crystal MUSHes at mantle crustal depth are discussed here. This theme is also intensively debated within the Granites initiative led by Laurent Arbaret and Fabrice Gaillard  at ISTO during autumn 2016.
  • Theme 3: Alkaline Magma. Anything related to the production and the differentiation of alkaline magma and their link with ore processes (REE, Nb, Ta, Zr, U) and their volatiles (halogens and carbon dioxide).
  • Theme 4: Physics & Chemistry of HT Materials. This is linked to the deployment of the PLANEX experimental plateform. This topic is co-deployed with our colleagues of the CEMHTI lab.

The group is composed of 4 Professor and assistant professor from the university of Orléans et 6 CNRS researchers. Five PhD students are currently working in the group. Four research engineers are frequently invited at the group meetings.

You can find here a brief description of our people (only in french).

There is a mind of MAGMA that is to say, a commonality in our approach, methods and way of addressing magmatism. This is simulating magmatic processes. Experimental simulations allow us to reconstruct the behaviour of magma and the fate chemical elements throughout igneous processes. This is an originality in the the geoscientific community deploying historically naturalistic methodologies.

You want to join the MAGMA group? Student or Researcher, you may just contact us (gaillard@cnrs-orleans.fr),

you can find here some links on what we can offer and what we are looking for.

GASTON is a project funded by the French ANR. It involves researchers from the laboratories of Orleans, Clermont-Ferrand, Paris and Nancy.

GASTON will tackle the fate of magmatic volatiles through the planetary differentiation processes marking the ages of Planet Earth.

Follow this link to see more about GASTON.