Dr. Sebastian Fuchs

Marine Mineral Resources
Magmatic und Hydrothermal Systems
Dynamics of the Oceanfloor

GEOMAR | Helmholtz-Centre of Ocean Research Kiel

Office:

Tel.: +49-431-600-1423
E-Mail: sfuchs(at)geomar.de

Address:

Building 8A-112, east shore
Wischhofstrasse 1-3
24148 Kiel
Germany

Scientific interests

I am combining hydrothermal geochemistry, geochemical modelling, geometallurgy, microanalyticsto investigate the behaviour and concentration mechanisms of precious and rare metals in seafloor hydrothermal systems, including the research on the:

  • Physico-chemical processes on the transport and flocculation of metals in magmatic-hydrothermal fluids of Black and White Smokers,
  • Thermodynamic / geochemical reaction path modelling of seafloor hydrothermal systems,
  • Nature and properties of micro- and nanoparticles (esp. "invisible gold" ) in seafloor massive sulfide deposits,
  • Microbial-induced precipitation of metals from hydrothermal fluids,
  • Geometallurgy & ore petrology of marine, hydrothermal mineralizations (esp. electron microscope-based data aquisition and processing),
  • New approaches in the application of electron microscopic methods (SEM / (S)TEM) in the research of ore deposits.

Education and scientific background

since 02/2016

Research scientist at GEOMAR - Helmholtz-Centre for Ocean Research Kiel
(supported by the Helmholtz Postdoctoral Fellowship)

09/2010 - 01/2016

PhD at McGill University, Montréal (Canada) in hydrothermal geochemistry, nanogeoscience & mineral resources. Supervision by Prof. Anthony "Willy" Williams-Jones

2012-2014

Exploration- and mining geologist at TATA Steel Minerals Canada (temporary during PhD studies)

05/2008 - 09/2009    

Research assistant at the Institute of Mineralogy, Crystallography und Materials Science at the University of Leipzig

  • Supervision of the electron microprobe laboratory
  • Scientific coordination of the bilateral BMBF-NRF (Germany / South Africa) funded research project: "Geochemical Fingerprinting of Southafrican Gold as a Tool for Provenance Analyses" 

01/2008 - 09/2009

Master of Science in Geology at the University of the Free State (South Africa)
MSc. degree awarded with distinction (grade A+)

09/2002 - 05/2008

Diplom (German MSc. equivalent) in Mineralogy and Geology at the Universität Leipzig und Martin-Luther Universität Halle-Wittenberg (University partnership).
Diplom awarded with overall grade of 1.4

 

Research projects

Two research projects are present below to give some insights into my reseach!

1) Micro- und nanosized mineralisations in seafloor massive sulfide deposits

(C) Project in collaboration with FIBICS Inc. (Ottawa, Kanada) and ZEISS.


This following video shows a cross-section through a micro-sized Black Smoker conduit. This micro smoker contains elevated concentrations of Cu, Zn, Pb, Fe, Au und Ag. The sulfides chalcopyrite, bornite, atacamite, digenite and covellite are the principal ore minerals. This sample is one of those with the highest quantities of micro- to nano-sized native gold grains found to date on the modern seafloor. High-resolution electron microscopy (SEM in this video) provides information on the distribution, textures, volume and precipation mechanisms of gold in the massive sulfides.

Video:

Video: Please wait until video is loaded!

2) Oil-induced Au and U precipiation in the Witwatersand gold and uranium deposits, South Africa

(C) Project in collaboration with FIBICS Inc. (Ottawa, Kanada) und ZEISS.

The formation of gold and uranium ore in deposits in the Witwatersrand basin is matter of debate over several decades. For this project we use SEM- and (S)TEM-based methods to show that oil-in-water micro-emulsions play an essential role to cause the flocculation of metal. Native gold precipitates due to chemical reduction processes and by enclosing droplets of fossil crude oil. On contrary, uranium was transported by the liquid oil and fluccolated as uraninite nanoparticles due to thermal hydrocarbon maturation.

More information in the press release:
https://www.geomar.de/en/news/article/entstehung-von-goldlagerstaetten-in-suedafrika/

Images & Videos:


Reconstructed 3D-model of a gold-bearing uraninite nanocrystal aggregate (nanotomography)
Gold nanoparticles (captured with (S)TEM)
Residue of fossil oil that contain uraninite nanocrystals (captured with (S)TEM)

Video: Please wait until video is loaded!

Teaching

Experience in the teaching of seminars and teaching assistance of lectures at McGill Univerity and University of Leipzig, including the courses "introduction to mineralogy", "properties of minerals", "hydrogeology", "ore microscopy" and "applied mineralogy".

Grants

Several major and minor grants, including the Helmholtz Postdoctoral Fellowship, McGill entrance fellowship, McGill international student grant, Howard Fellowship, GEOTOP PhD student grant, SEG student research grant, several SEG, Goldschmidt and DAAD Travel grants.

Publications

Peer-reviewed journal publications (as of 2017)

Gartman, A., Hannington. M, Jamieson, J., Peterkin, B., Garbe Schönberg, D., Findlay, A., Fuchs, S., & Kwasnitschka, T. (2017). Boiling-induced formation of colloidal gold in black smoker hydrothermal fluids. Geology, 46(1), 39–42. 

Migdisov, A. A., Guo, A., Williams-Jones, A.E., Sun, C.J.,Vasyukova, O., Sugiyama, I., Fuchs, S., Pearce, K., & Roback, R. (2017). Hydrocarbons as ore fluids. Geochemical Perspectives Letters, 5, 47–52.

Fuchs, S., Schumann, D., Williams-Jones, A.E.,  Murray, A., Couillard, M., Lagarec, K., Phaneuf, M., & Vali, H. (2017). Gold and uranium concentration by interaction of immiscible fluids (hydrothermal and hydrocarbon) in the Carbon Leader Reef, Witwatersrand Supergroup, South Africa. Precambrian Research, 293, 39–55. 

Fuchs, S., Williams-Jones, A., Jackson, S. E., & Przyblowicz, W. (2016). Metal distribution in pyrobitumen of the Carbon Leader Reef, Witwatersrand Supergroup, South Africa: Evidence for liquid hydrocarbon ore fluids. Chemical Geology, 426, 45–59.

Fuchs, S., Williams-Jones, A. E., & Przybylowicz, W. J. (2016). The origin of the gold and uranium ores of the Black Reef Formation, Transvaal Supergroup, South Africa. Ore Geology Reviews, 72(1), 149–164.

Fuchs, S., Schumann, D., Williams-Jones, A. E., & Vali, H. (2015). The growth and concentration of uranium and titanium minerals in hydrocarbons of the Carbon Leader Reef, Witwatersrand Supergroup, South Africa. Chemical Geology, 393–394(0), 55–66.Schumann, D., Fuchs, S., Stromberg, J. M. & Banerjee, N. P. (2014). Combining Terapixel-Scale SEM Imaging and High-Resolution TEM Studies for Mineral Exploration. Microscopy and Microanalysis 20, S3-4.

Fuchs, S., Przybylowicz, W. J., & Williams-Jones, A. E. (2014). Elemental imaging of organic matter and associated metals in ore deposits using micro-PIXE and micro-EBS. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 318, Part A(0), 157–162.

Selected conference contributions:

Fuchs, S., Schumann, D., Williams-Jones, A. E., Schreiber, A., Lagarec, K., Murray, D. W., & Vali, H. (2015). Oil-triggered gold deposition in the Witwatersrand, South Africa (Vol. 2015). Presented at the AGU-GAC-MAC-CGU Joint Assembly 2015, Montreal, Canada.

Fuchs, S., Schumann, D., Williams-Jones, A., & Vali, H. (2013). Hydrocarbons: A Source of Uranium and Titanium in the lower Witwatersrand, South Africa (Vol. 2013). Presented at the GAC-MAC Annual Meeting, Winnipeg, Canada.

Fuchs, S., Williams-Jones, A., & Przyblowicz, W. (2012). Electrochemical precipitation of gold from a hydrothermal uid in the Black and Kimberley Reefs, South Africa. Mineralogical Magazine, 76(6), 1724.

Fuchs, S., Kloess, G. & Williams-Jones, A.E., (2011). Petroleum as a potential agent for gold transport and deposition in the Black Reef Formation. South Africa. in: Barra, F. (ed.), Let’s Talk Ore Deposits, Vols I and II, Antofagasta: Ediciones Univ Catolica Norte, 584-586.11.

Gauert, C. D. K., Fuchs, S., Batchelor, D. and Kloess, G., (2011). Black Reef and Witwatersrand Gold Fingerprint, South Africa. Mineralogical Magazine, 75(3), 897.

Fuchs, S., Migdisov, A. A., & Williams-Jones, A. E. (2011). The transport of gold in petroleum: an experimental study. Mineralogical Magazine, 75(3), 871.