Welcome to the Chemical Sedimentology Group!

We are a diverse group of researchers working on a range of topics spanning the fields of geochemistry, sedimentary geology, Earth history, and geobiology. Each of us brings a different background and perspective to bear on these problems, and we all learn from each other. We all share the same interest in the co-evolution of environment and life, and adopt a similar approach to the research problems described below.

What is chemical sedimentology? In his seminal 1971 book, Bob Berner described chemical sedimentology as a “chemical approach to the study of sediments, regardless of how they are classified”. Aqueous geochemistry provides an important framework in which to understand the connections between sedimentary rocks, their precursor sediments, and the physical and chemical conditions that produced them. We use the “chemical approach” as a vehicle to re-animate and explore ancient chemical systems on Earth and Mars, and then look to apply what we learn from the laboratory to the field and under the microscope. This gives us what we think is a unique perspective in disentangling how our planet has changed through time, and how this influenced the evolutionary trajectory of life.

 (Group photo)

Who we are

Nick Tosca (Principal investigator)

Imad Ahmed (Post-doctoral research fellow)

Rebecca Tosca (Post-doctoral research fellow; University of Cambridge)

Rosalie Tostevin (Post-doctoral research fellow)

Ben Tutolo (Post-doctoral research fellow)

Clancy (Zhijian) Jiang (DPhil student)

Shahab Varkouhi (DPhil student; Co-supervised by Joe Cartwright)

Alice Ashpitel (MSc student)

Alice Barroll (Laboratory & X-ray diffraction technician)

What we do

The Fe-chemistry of early Mars

Iron formation and the chemistry of Precambrian seawater

Bioinorganic chemistry and nutrient crises in Precambrian basins

Carbonate / Mg-silicate geochemistry, sedimentation, and diagenesis

Chemical weathering, clay formation, and isotopic fractionation

How we do it

Experimental aqueous geochemistry laboratory:

     – Anaerobic chambers
     – Metrohm VA voltammeter
     – HACH benchtop spectrophotometer
     – Reaction systems / auto titration
     – Other equipment
Perkin-Elmer Frontier FT-IR spectrometer
     – HATR flow-through experimentation setup
Panalytical Empyrean powder X-ray diffractometer (you can call him Ray)


The research we pursue would be impossible were it not for the generous support from government, industrial, and private sponsors. We gratefully acknowledge support from:

STFC & UK Space Agency


Petrobras S.A.

BG Group

The Leverhulme Trust

The Department of Earth Sciences and the University of Oxford

St Peter’s College

Collaborators, friends, and group alumni