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Earth and Environmental Sciences

Photo of Dr Clemens Vinzenz Ullmann

Dr Clemens Vinzenz Ullmann

Proleptic Lecturer


I am a geochemist with particular interest in the geochemistry of modern and ancient marine shells and am part of the Deep Time Global Change Group. My current role is Lecturer in Palaeontology, Palaeobiology, Biogeochemistry at the Camborne School of Mines.

The three main topics I am working on are carbonate diagenesis, vital effects related to the process of bio-mineralization and reconstruction of past environments using isotopic and element tracers. I have been involved in work from the Mesoproterozoic up to modern times, but my main focus has been the Jurassic.

Marine animals form carbonate shells which vary greatly in composition, but follow predictable trends, an observation that may help to eventually reconstruct the past composition of seawater with improved certainty. In order to increase the quality of these reconstructions I am actively working on characterising the geochemical patterns of biomineralisation in modern calcite secreting organisms, e.g., bivalves, brachiopods, and barnacles, and fossils of extinct organisms such as the rostra of belemnites.

In order to help understanding past environmental conditions using proxy data, post-depositional effects modifying or erasing the original environmental signatures in sedimentary strata have to be controlled. Through detailed work on fossil materials, and covering novel proxies, as well as studying diagenetic signatures down to species-specific effects, much improved environmental reconstructions become feasible.

The isotopic signatures of large, marine fossil shells have traditionally been used to reconstruct carbon cycle and seawater temperatures. However, the geochemistry of fossils can also help to guide interpretations of palaeoecology which otherwise is limited to the assessment of fossil morphology and comparison to modern relatives. Using innovative methodology for example on belemnite rostra and brachiopod shells, the understanding of their ecology can be improved.

In addition to my research activity I act as an associated editor of Palaeo3 and am a mentor in the Publons Peer Reviewing Academy having received peer review awards in 2019 and 2017.


2021-                               Lecturer in Palaeontology, Palaeobiology, Biogeochemistry

2016-2021                        Researcher Co-I; University of Exeter, UK. Early Jurassic Earth System and Timescale (JET)

2014-2016                        Leopoldina Fellow; University of Exeter, UK. Research on biomineralization of brachiopods, barnacles and belemnites. 

2013-2014                        Post Doc; University of Copenhagen, Denmark. Research on geochemical proxies in biogenic carbonates. 

2012-2012                        Academic visitor; University of Oxford, UK. Lithium isotopes in belemnite calcite and Jurassic chemostratigraphy. 

2010-2013                        PhD; University of Copenhagen, Denmark.

2008-2010                        MSc; Freie Universität Berlin, Germany.

2005-2008                        BSc; Freie Universität Berlin, Germany.




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  • Ullmann CV, Wiechert U, Korte C. (2009) Stable isotope variations in a modern North Sea oyster shell reflect annual environmental changes, GEOCHIMICA ET COSMOCHIMICA ACTA, volume 73, no. 13, pages A1360-A1360. [PDF]

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Further information


My research focuses on the use of geochemical techniques to extract information about past environments from fossil shells. This palaeoenvironmental research is intimately connected with studies on biomineralization and diagenesis as well the development of new techniques and proxies to tell about past environmental conditions and the ecology of extinct organisms.

Geochemistry of biomineralization

Shell material bears the structural and geochemical imprints of the animal that secreted it, and it is often characterised by multiple shell structures (such as the different shell structures of modern oysters shown below) and correspondingly complex shell geochemistry. Understanding, and making use of such compositional and structural variability permits extracting much more detailed and reliable information about past environmental conditions. 

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Fossil diagenesis

Much of the general processes and geochemical changes to fossils associated with diagenesis have been established in the 1970s and 1980s, but technological progress has enabled much more rapid analysis of ever smaller sample quantities as well as novel proxies helping to understand diagenetic processes specific to each sedimentary succession and type of fossil, such as the slightly crushed, cemented Late Triassic brachiopod from New Caledonia shown below. Investigating species-specific diagenesis at each studied locality improves the robustness of environmental reconstructions substantially.

Reconstructing palaeoenvironment and ecology

The modes of life of extinct organisms can be very tricky to reconstruct, especially when no similar modern species are still alive. Ecology can have a strong influence on how geochemical proxies are recorded in their shells and this in turn complicates making inferences about palaeoenvironmental conditions. For example, the two fossil brachiopod species from the Toarcian (Early Jurassic) of Spain shown below are interpreted to have differing ecologies based on their different shell structure and geochemistry, with Soaresirhynchia likely having had a slower metabolism and slower shell growth. Adding geochemical and shell structure information to the tool box of palaeontologists to better constrain palaeoecology is a new and exciting field of research.

External Engagement

Media coverage

External visitors

  • Iben Winter Hougård (University of Copenhagen, Denmark; 2018)
  • Dr Madeleine Vickers (University of Copenhagen, Denmark; 2018, 2019)
  • Johannes Monkenbusch (University of Copenhagen, Denmark; 2018, 2019)
  • Dr Georgi Granchovski (Bulgarian Academy of Sciences; 2019)


I am contributing to a number of modules for which my ongoing research is relevant:

Year 1

  • CSM1031 Earth and Environmental Chemistry (Module Convenor)
  • CSM1036 Field Geology and Geological Maps (contribution)
  • CSM1044 Earth History and Palaeontology (contribution)

Year 2

  • CSM2183 Sedimentology and Stratigraphy (contribution)

Year 3

  • CSM3071 Geological History of Life on Earth (contribution) 
  • CSM3379 Summer Vacation Project (project supervision)


PhD students

MSc students

Administrative Roles

I fulfil the following administrative roles:

Cornwall ECR representative to the the Research and Impact Executive Committee (RIEC)

I am representing Early Career Researchers (ECRs) at RIEC, assisting in making the ECR voice heard at the highest institutional level. As RIEC rep I also attend and sometimes chair ECR liaison fora and interact closely with Early Career Researcher Network leads.

Department of Earth and Environmental Sciences Academic lead for ECRs

At departmental level I work closely with Early Career Researcher Network leads to create a positive working atmosphere and increase involvement of ECRs in university business, as well as assisting with their career development, as well as the awareness and implementation of the Researcher Concordat.

Department of Earth and Environmental Sciences Academic deputy Academic lab liaison

I am working with academics, students, professional and technical services, to create a vibrant lab community and to maintain and improve processes for quality control and quality assurance for analytical geochemistry.

Camborne School of Mines Academic Conduct Officer

In cases of suspected poor academic practise or academic misconduct of students I am the go-to person at discipline level at Camborne School of Mines.

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