Thomas Wong Hearing, Postgraduate Researcher

Constraining the marine environment of the Cambrian metazoan adaptive radiationTom Wong Hearing

Supervisors: Dr Tom Harvey (University of Leicester), Professor Mark Williams (University of Leicester), Professor Sarah Gabbott (University of Leicester), Dr Phil Wilby (BGS), Professor Melanie Leng (NIGL)

Research Group: Palaeobiology, Palaeoenvironments and Palaeoclimates

Rocks and fossils of Cambrian age (541–485 million years ago) record the emergence and establishment of animal-dominated marine ecosystems – the first time metazoan life sculpted Earth’s surface, albeit with some bizarre inhabitants. However, the environments in which these early animals evolved remain remarkably unconstrained. My research aims to quantify these ancient environments using biogeochemical data from some of the earliest animal remains known as ‘small shelly fossils’ (SSFs).

Brief Biography

  • 2014 – present: Geology PhD student, University of Leicester.

P.C. Sylvester-Bradley Award (2017).

  • 2010 – 2014: MEarthSci Earth Science, University of Oxford.

Palaeontological Association Prize (2014).

Masters Thesis: Depositional environment and taphonomy of the Llanfallteg Lagerstätte. Supervised by Prof Martin Brasier, Dr David Legg.

  • 2010: UK Young Scientist of the Year (National Science and Engineering Competition).

Project Overview

The emergence of animals and the subsequent radiation of the major metazoan body plans in the fossil record is documented in rocks of the late Neoproterozoic–early Cambrian transition. Discoveries of exceptional fossil preservation (Konservat-Lagerstätten, such as the world renowned Burgess Shale of Canada) help to illuminate the biological aspects of this major ecological revolution. However, there are few quantitative constraints on marine environments of this time. In particular, there are a lack of data constraining temperatures, temperature gradients and oxygen concentrations of Cambrian oceans. These are all factors that have been invoked to explain radiation and extinction events throughout the Cambrian Period.

Over the course of this PhD project, I aim to derive the first numerical values for ocean temperatures in the early Cambrian (Terreneuvian Series and Series 2) from oxygen isotope (δ18O) signatures preserved in phosphatic microfossils. Specifically, I will test the hypotheses that

  • SSFs from the Lower Comley Limestone Formation, Cambrian Series 2 of Shropshire, preserve original skeletal bioapatite, and
  • this bioapatite δ18O provides reliable proxy data for the marine environment of the Cambrian radiation on the high-latitude (60°S) palaeocontinent Avalonia.

δ18O data have been used to reconstruct global temperatures throughout the Phanerozoic and conodont bioapatite is routinely used in the post-Cambrian Palaeozoic. This study will address a 50 million year gap in palaeoenvironmental understanding at the beginning of the Phanerozoic Eon.

Reconstructing ancient environments, their variability and limits, is important to understanding how modern environments may be expected to respond to modern climate changes. This work is also immensely intellectually satisfying, which is perhaps the main reason that I pursue it.

Publications

  • Hearing, T.W., Harvey, T. H. P., Williams, M., Leng, M.J., Lamb, A.L., Wilby, P.R., Gabbott, S.E., Pohl, A., Donnadieu, Y., An early Cambrian greenhouse climate. Science Advances, Vol. 4, No. 5, Article eaar5690, May, 2018.
  • Williams, M., Perrier, V., Bennett, C., Hearing, T., Stocker, C. and Harvey, T., 2015. Ostracods: The ultimate survivors. Geology Today, v 31, p 193–200. doi: 10.1111/gto.12108

Academic awards

  • P.C. Sylvester-Bradley Award – Geology Department, University of Leicester, 2017.
  • Palaeontological Association Prize – Department of Earth Science, University of Oxford, 2014.
  • UK Young Scientist of the Year – National Science and Engineering Competition, 2010.

Selected conference presentations

  • Hearing, T.W., Pohl, A., Williams, M., Harvey, T.H.P., and Donnadieu, Y., 2017. Coupling palaeoclimate data and numerical climate models to constrain Cambrian palaeogeography. Palaeontological Association 61st Annual Meeting. [Talk]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S.E., Wilby, P., Leng, M.J., and Lamb, A.L., 2017. Can the phosphate oxygen palaeothermometer constrain Cambrian climates?  ISECT 2017. [Talk]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S.E., Wilby, P., and Leng, M.J. 2016. Can phosphatic microfossils constrain Cambrian climates? Palaeontological Association 60th Annual Meeting. [Talk]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S., Wilby, P., and Leng, M.J., 2016. Cambrian microfossils to Cambrian climates: can ‘small shelly fossils’ be used to quantify ancient ocean conditions? Progressive Palaeontology, Oxford. [Talk, Highly Commended]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S., Wilby, P., and Leng, M.J., 2015. Resolving biology and taphonomy in Cambrian 'small shelly fossils'. Palaeontological Association 59th Annual General Meeting , Cardiff. [Poster]
  • Hearing, T.W., Legg, D.A., Botting, J.P., Muir, L.A., McDermott, P.M. and Gabbott, S., 2015. Burgess Shale-type preservation beyond the Cambrian: an example from the Middle Ordovician Llanfallteg Biota, South Wales. Rise of Animal Life (RALI) 2015. [Talk]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S., Wilby, P., and Leng, M.J., 2015. A new proxy to constrain Cambrian sea temperatures. Past Earth Network Opening Conference, Crewe Hall. [Poster, Prize Runner-up]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S., Wilby, P., and Leng, M.J., 2015. Small Shelly Fossils: a new approach to calculating Cambrian ocean temperatures. BUFI Science Festival 2015. [Poster, Winner 6th Form Prize]
  • Hearing, T.W., Harvey, T.H.P., Williams, M., Gabbott, S., Wilby, P., and Leng, M.J., 2015. Quantifying the context of the Cambrian metazoan radiation: a geochemical approach. Progressive Palaeontology Programme with Abstracts. [Lightning Talk]
  • Hearing, T.W., Legg, D.A., Botting, J.P., Muir, L.A., McDermott, P.M., and Brasier, M.D., 2014. The Llanfallteg biota – exceptional preservation of a Burgess Shale-type arthropod from the Middle Ordovician of South Wales. Palaeontological Association 58th Annual Meeting, Programme with Abstracts. [Poster, Highly Commended]

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