Sandstones in Brittany

Anthony Pochon Post-doc


Post-doc ISTO - March 2020 / February 2021


Mobilisation processes of antimony (and related metals such as, W and Hg) associated to the mafic magma emplacement, an experimental study coupled with natural observations.

Tracing metal sources in hydrothermal systems is fundamental to understand the global processes, which led to formation of ore deposits. Thus, the aim of this study is to assess whether the metal enrichment of the fluids producing the Sb-Hg±W deposits can be ascribed to (i) a metal enrichment of the primary mafic magma, and/or (ii) an efficient extraction of metals from the parent magma during its high temperature degassing, and/or (iii) an efficient hydrothermal leaching of igneous and sedimentary rocks through the fluid ascent path. To do this, this work will be divided in three parts:

(i) First, A review of existing literature about Sb-W-Hg ore systems (e.g. targeting some key areas) and melt inclusions in mafic/ultramafic magmas of different geodynamic settings, will be performed in order to constrain possible metal contents of parent magmas frequently associated with Sb-W-Hg ore deposits.

(ii) Secondly, the main mineralogical carriers of the Sb, W, and Hg and the chemical reactions that took place during magmatic and/or hydrothermal processes leading to metal enrichment will be identified. Mass balance calculations will be performed in order to evaluate the amount of mobilised metals (Sb, W and Hg) by hydrothermal processes, in agreement with observed metasomatic geochemical variations between altered host rocks and unaltered host rocks.

(iii) Finally, experimental studies will investigate the respective roles of fluid-rock interactions and magmatic degassing in determining the metal budget of hydrothermal fluids.


Anthony Pochon - PhD

Research interests

I am currently a postdoctoral research fellow at the Earth Sciences Institute of Orleans (ISTO, University of Orleans, France), mainly motivated by the history and the understanding about the mobilization processes of precious and rare metals (Sb, W, Au…) from the subduction to the post-collisional context. To address major key questions about the mobilization processes leading to ore deposits, my scientific approach consists of coupling field observations, elemental and isotopic analytical techniques.

My scientific skills fall in the fields of structural geology, petrology and geochemistry. More specifically, I use in-situ tools such as LA-ICP-MS or LIBS to investigate the mobility and the redistribution of trace elements during strain localization, metamorphic reactions and hydrothermal alteration. The dating of hydrothermal event is also a part of my expertise, especially with the U-Pb geochronometer coupled to a detailed study of mineral assemblages and the associated behavior of trace elements.


Mar. 2020 - present

Post-Doctoral Research Fellow

Earth Sciences Institute of Orleans, ISTO-CNRS, Orléans, France

Mobilisation processes of antimony (and related metals such as, W and Hg) associated to the mafic magma emplacement, an experimental study coupled with natural observations.


Jun. 2018 - Dec. 2019

Post-Doctoral Research Fellow

French Geological Survey, BRGM, Orléans, France

Physicochemical tracing of natural gold from French Guiana


Oct. 2014 - Dec. 2017

PhD in Earth Sciences

Géosciences Rennes, Université de Rennes 1, France

Mafic magmatism and Sb-Au mineralisation in Central Brittany (France):  spatiotemporal control and metallogenic implications.


Sep. 2012 - Jun. 2014

Master of Science (MSc) in Earth Sciences

Observatoire des Sciences de la Terre et de l’Univers d’Orléans (OSUC), Université d’Orléans, France & Université du Québec à Montréal (UQAM), Montréal, Canada

Fev. 2014-Jun. 2014: Geological controls of Au-Sb mineralisation in Central Brittany

Apr. 2013-Jun. 2013: Olivine fabric and strain localization in the upper mantle: evidence from fluid circulation induced by granular flow


Sep. 2008 - Jun. 2012

Bachelor of Science (BSc) in Earth Sciences

Université de Franche-Comté, Besançon, France


7) Pochon A, Desaulty AM, Bailly L (2020) Handheld Laser-Induced Breakdown Spectroscopy (LIBS), a fast and easy way for tracing gold?. Journal of Analytical Atomic Spectrometry 35, 254-264.

6) Pochon A, Branquet Y, Gloaguen E, Ruffet G, Poujol M, Boulvais P, Gumiaux C, Cagnard F, Baele JM, Kéré I, Gapais D (2019) A Sb ± Au mineralizing peak at 360 Ma in the Variscan Belt. BSGF – Earth Sciences Bulletin Vol: 180016. doi: 10.1051/bsgf/2019004.

5) Pochon A, Gloaguen E, Branquet Y, Poujol M, Ruffet G, Boiron MC, Boulvais P, Gumiaux C, Cagnard F, Gouazou F, Gapais D (2018) Variscan Sb-Au mineralization in Central Brittany (France): a new metallogenic model derived from the Le Semnon district. Ore Geology Reviews 97, 109-142.

4) Pochon A, Beaudoin G, Branquet Y, Boulvais P, Gloaguen E, Gapais D (2017) Metal mobility during hydrothermal breakdown of Fe-Ti oxides: insights from Sb-Au mineralizing event (Variscan Armorican Massif, France). Ore Geology Reviews 91, 66-99.

3) Précigout J, Prigent C, Palasse L, Pochon A (2017) Water pumping in mantle shear zones. Nature Communications 8. doi: 10.1038/ncomms15736.

2) Pochon A, Poujol M, Gloaguen E, Branquet Y, Cagnard F, Gumiaux C, Gapais D (2016) U-Pb LA-ICP-MS dating of apatite in mafic rocks: Evidence for a major magmatic event at the Devonian-Carboniferous boundary in the Armorican Massif (France). American Mineralogist 101, 2430-2442.

1) Pochon A, Gapais D, Gloaguen E, Gumiaux C, Branquet Y, Cagnard F, Martelet G (2016) Antimony deposits in the Variscan Armorican belt, a link with mafic intrusives? Terra Nova 28, 138-145.