Rosalie Tostevin

Rosalie has a PhD in Precambrian sedimentary geochemistry from UCL, and a Master’s degree in geology from the University of Cambridge. She worked as a postdoc at the University of Otago for six months and the University of Oxford for three years. She joined the University of Cape Town as a lecturer in 2019.


Joseph Madondo

Joseph’s research interests include the geology and geochemistry of fossil manganese deposits. He is currently working on the hydrothermal upgrading of the Wessels-type manganese ore in the Kalahari Manganese Field (KMF) using geochemical and mineralogical analyses.

PhD Students

Ansahmbom Nke

Co-supervisors: Harilaos Tsikos and Lorena Tafur

Ansa is using multiple geochemical proxies to reconstruct the distribution of redox zones in South African marine basins during the Great Oxidation Event. He is interested in the relationship between oxygen availability and the primary mineralogy of iron-bearing minerals in BIF horizons.

Bontle Mataboge

Co-supervisor: Rachel Wood

Bontle is a palaeontologist working on the Late Ediacaran fossil record from the Nama Group. She is integrating palaeo-ecological work with geochemical proxies to understand the role of oxygen in early animal communities.

Jessica Von Der Meden

Main supervisor: Chris Harris. Co-supervisor: Jayne Wilkins

Jess is investigating the palaeoclimate associated with human occupation of the Kuruman Hills, Northern Cape, during the Late Pleistocene. She uses U-Th dating, trace element and stable isotope techniques on secondary carbonate deposits (tufas) to reconstruct the timing of their formation and the environment during their deposition.

Master’s Students

Aidan Wilton

Aidan is mapping microbial ecosystems in the Nama Group, South Africa, and using high resolution geochemical analysis to decipher their formation mechanism and local redox environment.


McDonald Mtonda

Mcdonald analysed carbon, oxygen and strontium stable isotopes in carbonate rocks from the Neoproterozoic Nama Group to constrain changes in weathering during the emergence of skeletal life.

Neo Seloi

Neo’s honours project explored multi-annual oxygen isotope signals preserved in marine shells. His work will contribute to the development of a new environmental and ecological proxy that can be applied in deep time.

Brooke Johnson

Main supervisor: Nick Tosca. Co-supervisor: Stuart Robinson

Brooke’s PhD was based at the University of Oxford, researching redox conditions and phosphorous cycling in the Mesoproterozoic Roper Group, Australia, using traditional petrography and modern micro-analytical techniques.

Mapaseka Mashego

For her Honours project, Mapaseka investigated trace elements in carbonates from the Upper Nama Group to constrain local oxygen levels in the final stages of the Ediacaran.

Matthew Brady

Matt was a Master’s student at the University of Oxford, and used experiments to constrain sedimentary phosphate cycling under ferruginous conditions.

Alice Ashpitel

Alice was a Master’s student at the University of Oxford. She used experiments to understand iron and carbon cycling on early Mars.

Honorary Members

Dora Tostevin

Sometimes assists in the field. Loves the outdoors. Expert on sticks and squirrels.

%d bloggers like this: