Overview

Project Highlights:

  • Working with new, undescribed assemblages of exceptionally preserved Cambrian microfossils
  • Geological fieldwork and sample-collection in Newfoundland, Canada
  • Using top-of-the-range microscope facilities and working with an international team of expert supervisors

Microfossils offer a rich record of early animal evolution and the attendant reconfiguring of ecosystems. This project will focus on exceptionally well-preserved acritarchs and small carbonaceous fossils (SCFs) to reach a new understanding of how animals dramatically changed the biosphere around half a billion years ago, in the Cambrian evolutionary ‘explosion’. The project aims to discriminate between animal- and non-animal microfossils, and constrain their biological affinities, modes of life, and distributions in space and time. The results will bring key insights into changes in diversity and ecology through a pivotal interval in Earth history.

Acritarchs are organic-walled microfossils of unknown affinity, extracted using standard palynological laboratory techniques. In contrast, more gentle procedures yield larger, more delicate SCFs that represent a range of organisms, including a diversity of animals. Despite this categorization, the two datasets overlap. Recently, we have begun to explore a combined approach, which promises to shed light on the affinities and significance of both acritarchs and SCFs, enhancing their application to key questions in palaeobiology, stratigraphy, and ancient ecosystems.

The project will focus initially on exceptionally well-preserved acritarchs and SCFs from the Forteau Formation of Newfoundland, Canada (Cambrian Stage 4, c. 510 million years ago). Hundreds of SCFs and thousands of acritarchs have already been prepared onto glass slides for analysis. In light of the SCFs, some palynomorphs are clearly derived from animals including arthropods, priapulid worms, and the slug-like Wiwaxia. Others remain enigmatic, such as the conical acritarchs known as Ceratophyton and Corollasphaeridium, which could represent animals or perhaps protists. At the same time, SCF-processing yields clumps, articulated arrays, and even faecal-pellets full of acritarchs, constraining their biological interpretation. Therefore, the Forteau material offers an unrivalled opportunity to resolve the affinities and ecologies of otherwise mysterious Cambrian microfossils. Any insights can then be applied more widely to help constrain the largest-scale patterns and processes of the Cambrian ‘explosion’. For example, do animal-derived microfossils extend back into the Ediacaran? Can acritarchs tell us about the structure of the plankton? And how did ecosystems respond to major events in evolution?

Microfossils from the lower Cambrian, variously interpreted as unicellular protists and animal body parts – but which are which?

Methodology

The first step is to document and identify the diverse acritarchs and SCFs from the Forteau Formation, using advanced light microscopy, scanning electron microscopy, measurements and shape analysis. Constraints on biological affinity will be provided by analysis of variability, identification of key characters, comparisons to articulated material, and patterns of distribution in space (reef edge vs. lagoonal vs. open shelf settings) and time (correlating via olenellid trilobites). Fieldwork is recommended for a detailed understanding of the stratigraphy and palaeoenvironment, and for additional sampling, as required. Insights will be tested using other assemblages from Laurentia and beyond, with visits to co-supervisors in Spain, and to museums elsewhere, to view comparative material. Further fieldwork is also encouraged, to prospect for new assemblages. Depending on the interests of the student, the project could be steered towards animals or non-animal acritarchs, palaeobiology or biostratigraphy, and lab-based, field-based, or literature-based/computational approaches.

Training and Skills

You will become proficient in a range of specialist skills in microscopy, imaging, laboratory processing, and field-work, and you will gain a detailed knowledge of various groups of Cambrian fossils. Leicester is equipped with state-of-the-art facilities for microfossil processing and imaging, including a range of scanning electron microscopes, and a palynological microscope with differential interference contrast, oil immersion lenses, and fluorescence capabilities. In the lab, you will be trained in processing, picking and mounting SCFs. In the field, you will be trained in sedimentary logging and sample collection. Furthermore, you will develop valuable transferrable skills in data analysis and problem-solving.

Timeline

Year 1: Training in microscopy techniques (transmitted light and scanning electron microscopy) and SCF laboratory preparation protocols. Familiarisation in the existing collections (in Leicester) of Forteau Formation palynomorphs and SCFs. Training in imaging and image analysis techniques. Acritarch and SCF identification and taxonomy. Fieldwork to study and resample the detailed stratigraphy of the Forteau Formation, Newfoundland, Canada.

Year 2: Analysis of biological and geological patterns: comparison of acritarchs to animal SCFs for an improved palaeobiological understanding; assessments of acritarch and SCF variability to test taxonomic and biostratigraphic schemes; comparisons to other successions and time intervals to gauge wider implications of pilot results. Visits to the University of Extremadura, Badajoz, Spain, and other museum collections for comparative material; additional field-sampling, as necessary. Conference presentations of preliminary results. Writing publications.

Year 3: Developing an integrated account of animal and non-animal diversity represented among Cambrian palynomorphs and SCFs: what the record tells us about the early evolution of animals, phytoplankton and benthic primary production; the potential applications in biostratigraphy and Cambrian ecosystem reconstruction. Conference presentations, writing papers for publication, and completion of thesis.

Partners and collaboration (including CASE)

The supervisory team includes a range of expertise to maximise the project’s impact. Tom Harvey pioneered the study of SCFs, and has helped build extensive collections of comparative material from the Cambrian of Laurentia, Baltica and China. Brian Pedder is an expert in Cambrian acritarchs and has worked as a biostratigrapher in industry. Sören Jensen and Teodoro Palacios have extensive knowledge of acritarchs and the Cambrian timescale. Mark Williams has broad experience of stratigraphy and palaeobiology through the Lower Palaeozoic and beyond. The supervisory team will open doors to a global network of expert collaborators.

 

Further Details

For further information please contact Dr Tom Harvey [thph2@le.ac.uk] and Prof Mark Williams [mri@le.ac.uk] at the University of Leicester.