Doctoral position in isotope geochemistry for marine authigenic clay formation and the silicon cycle 100%, Zurich, fixed-term
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Doctoral position in isotope geochemistry for marine authigenic clay formation and the silicon cycle
100%, Zurich, fixed-term
print Drucken
Marine authigenic clay formation, sometimes called "reverse weathering," is being increasingly recognised as an
important facet of the series of Earth surface processes that interact to regulate ocean chemistry, elemental cycles,
and the exogenic carbon cycle.
We are seeking a curious and motivated doctoral student to join the Earth Surface Geochemistry group at ETH Zurich in
order to study the formation of authigenic clay minerals in the laboratory and natural environment and explore their
impact on the global cycle of silicon and its isotopes.
Project background
In modern marine sediment, small-scale and poorly ordered authigenic clays form during early diagenesis when two key
ingredients are present: reactive silica, usually the hard parts of siliceous organisms like diatoms; and reactive
metal phases like iron (oxyhydr)oxides and aluminium oxides sourced from the continents. As a consequence, the marine
biogeochemical cycle of silicon is a key control on marine authigenic clay formation in the modern ocean, and how this
process may have changed in Earth's past.
At the same time, numerous lines of evidence suggest that authigenic clay formation strongly fractionates the stable
isotopes of silicon, such that silicon isotopes may prove to be a sensitive tracer of the processes involved in early
silica diagenesis -- but also that authigenic clay formation, and how it has changed in the past, may exert an
important influence on the marine isotope mass balance of silicon.
With this background, this research project aims to resolve key existing uncertainties regarding the influence of
authigenic clay formation on silicon and its isotopes, thus allowing a better understanding of its systematics in the
modern system, and of how micro-scale clays can influence global elemental cycles through Earth's history.
Job description
Your research will be situated at the interface between isotope geochemistry and the characterisation of small-scale
authigenic minerals using advanced imaging techniques. You will work on a diversity of samples ranging from
experimentally precipitated phyllosilicates to natural marine sediment. Your tasks will centre around:
- using isotope geochemical methods to process synthesised and natural samples for analysis of Si stable isotope
composition by MC-ICP-MS
- characterising the nature and structure of experimental and naturally-occurring authigenic clay minerals using
advanced microscopic analyses (FTIR, SEM-EDX, TEM-SAED)
- analysing the chemical composition of reactive silica pools in natural marine sediment by ICP-MS, and using
statistical techniques to infer their nature
- interpreting your results in the context of the broader literature, and understanding their implications for the
global silicon cycle
- presenting your results at international conferences and in peer-reviewed journals
While most samples have already been sourced, there are opportunities to participate in oceanographic sampling
campaigns with project partners.
Profile
We are looking for a motivated candidate with:
- an MSc degree in earth or environmental sciences or a related field
- a strong interest in isotope geochemistry and advanced imaging methods
- curiosity about the diversity and complexity of marine authigenic minerals
- committment to accurate and precise lab analyses
- good command of English (spoken and written)
- the ability to work independently as well as in a collaborative environment
Prior experience in clay mineralogy, isotope geochemical techniques (clean laboratory work, column chromatography,
MC-ICP-mass spectrometry), or electron microscopic imaging are an advantage but not a prerequisite.
Workplace
Workplace
We offer
- A collegial and collaborative research group studying the geochemistry of the surface Earth system
- Continued education and opportunities for networking through international conferences
- State-of-the-art mass-spectrometric facilities
- A large instrument park of electron microscopic facilities via ETH Zurich's ScopeM centre
- Secured funding for a 4-year doctoral position
chevron_right Working, teaching and research at ETH Zurich
We value diversity and sustainability
In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value
diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students
are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open
environment that allows everyone to grow and flourish. Sustainability is a core value for us – we are consistently
working towards a climate-neutral future.
Curious? So are we.
We look forward to receiving your online application with the following documents:
- a CV
- a brief motivation letter
- the names of three referees
Further information about the Earth Surface Geochemistry group can be found on our website. If you have any questions
regarding the position, you are welcome to contact Dr. Gregory de Souza (gregory.desouza@eaps.ethz.ch).
Evaluation of applicants will begin on 15 January 2026 and will continue until the position is filled. Early
applications are encouraged.
About ETH Zürich
ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our
excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000
people from more than 120 countries find our university to be a place that promotes independent thinking and an
environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we
work together to develop solutions for the global challenges of today and tomorrow.
About ETH Zürich
ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our
excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000
people from more than 120 countries find our university to be a place that promotes independent thinking and an
environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we
work together to develop solutions for the global challenges of today and tomorrow.
100%, Zurich, fixed-term
print Drucken
Marine authigenic clay formation, sometimes called "reverse weathering," is being increasingly recognised as an
important facet of the series of Earth surface processes that interact to regulate ocean chemistry, elemental cycles,
and the exogenic carbon cycle.
We are seeking a curious and motivated doctoral student to join the Earth Surface Geochemistry group at ETH Zurich in
order to study the formation of authigenic clay minerals in the laboratory and natural environment and explore their
impact on the global cycle of silicon and its isotopes.
Project background
In modern marine sediment, small-scale and poorly ordered authigenic clays form during early diagenesis when two key
ingredients are present: reactive silica, usually the hard parts of siliceous organisms like diatoms; and reactive
metal phases like iron (oxyhydr)oxides and aluminium oxides sourced from the continents. As a consequence, the marine
biogeochemical cycle of silicon is a key control on marine authigenic clay formation in the modern ocean, and how this
process may have changed in Earth's past.
At the same time, numerous lines of evidence suggest that authigenic clay formation strongly fractionates the stable
isotopes of silicon, such that silicon isotopes may prove to be a sensitive tracer of the processes involved in early
silica diagenesis -- but also that authigenic clay formation, and how it has changed in the past, may exert an
important influence on the marine isotope mass balance of silicon.
With this background, this research project aims to resolve key existing uncertainties regarding the influence of
authigenic clay formation on silicon and its isotopes, thus allowing a better understanding of its systematics in the
modern system, and of how micro-scale clays can influence global elemental cycles through Earth's history.
Job description
Your research will be situated at the interface between isotope geochemistry and the characterisation of small-scale
authigenic minerals using advanced imaging techniques. You will work on a diversity of samples ranging from
experimentally precipitated phyllosilicates to natural marine sediment. Your tasks will centre around:
- using isotope geochemical methods to process synthesised and natural samples for analysis of Si stable isotope
composition by MC-ICP-MS
- characterising the nature and structure of experimental and naturally-occurring authigenic clay minerals using
advanced microscopic analyses (FTIR, SEM-EDX, TEM-SAED)
- analysing the chemical composition of reactive silica pools in natural marine sediment by ICP-MS, and using
statistical techniques to infer their nature
- interpreting your results in the context of the broader literature, and understanding their implications for the
global silicon cycle
- presenting your results at international conferences and in peer-reviewed journals
While most samples have already been sourced, there are opportunities to participate in oceanographic sampling
campaigns with project partners.
Profile
We are looking for a motivated candidate with:
- an MSc degree in earth or environmental sciences or a related field
- a strong interest in isotope geochemistry and advanced imaging methods
- curiosity about the diversity and complexity of marine authigenic minerals
- committment to accurate and precise lab analyses
- good command of English (spoken and written)
- the ability to work independently as well as in a collaborative environment
Prior experience in clay mineralogy, isotope geochemical techniques (clean laboratory work, column chromatography,
MC-ICP-mass spectrometry), or electron microscopic imaging are an advantage but not a prerequisite.
Workplace
Workplace
We offer
- A collegial and collaborative research group studying the geochemistry of the surface Earth system
- Continued education and opportunities for networking through international conferences
- State-of-the-art mass-spectrometric facilities
- A large instrument park of electron microscopic facilities via ETH Zurich's ScopeM centre
- Secured funding for a 4-year doctoral position
chevron_right Working, teaching and research at ETH Zurich
We value diversity and sustainability
In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value
diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students
are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open
environment that allows everyone to grow and flourish. Sustainability is a core value for us – we are consistently
working towards a climate-neutral future.
Curious? So are we.
We look forward to receiving your online application with the following documents:
- a CV
- a brief motivation letter
- the names of three referees
Further information about the Earth Surface Geochemistry group can be found on our website. If you have any questions
regarding the position, you are welcome to contact Dr. Gregory de Souza (gregory.desouza@eaps.ethz.ch).
Evaluation of applicants will begin on 15 January 2026 and will continue until the position is filled. Early
applications are encouraged.
About ETH Zürich
ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our
excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000
people from more than 120 countries find our university to be a place that promotes independent thinking and an
environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we
work together to develop solutions for the global challenges of today and tomorrow.
About ETH Zürich
ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our
excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000
people from more than 120 countries find our university to be a place that promotes independent thinking and an
environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we
work together to develop solutions for the global challenges of today and tomorrow.