Novel application of confocal laser scanning microscopy and 3D volume rendering toward improving the resolution of the fossil record of charcoal

PLoS One. 2013 Aug 15;8(8):e72265. doi: 10.1371/journal.pone.0072265. eCollection 2013.


Variations in the abundance of fossil charcoals between rocks and sediments are assumed to reflect changes in fire activity in Earth's past. These variations in fire activity are often considered to be in response to environmental, ecological or climatic changes. The role that fire plays in feedbacks to such changes is becoming increasingly important to understand and highlights the need to create robust estimates of variations in fossil charcoal abundance. The majority of charcoal based fire reconstructions quantify the abundance of charcoal particles and do not consider the changes in the morphology of the individual particles that may have occurred due to fragmentation as part of their transport history. We have developed a novel application of confocal laser scanning microscopy coupled to image processing that enables the 3-dimensional reconstruction of individual charcoal particles. This method is able to measure the volume of both microfossil and mesofossil charcoal particles and allows the abundance of charcoal in a sample to be expressed as total volume of charcoal. The method further measures particle surface area and shape allowing both relationships between different size and shape metrics to be analysed and full consideration of variations in particle size and size sorting between different samples to be studied. We believe application of this new imaging approach could allow significant improvement in our ability to estimate variations in past fire activity using fossil charcoals.

Publication types

  • Historical Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Charcoal / chemistry*
  • Ecosystem
  • Fires / history*
  • Fossils*
  • Geologic Sediments / analysis*
  • History, Ancient
  • Imaging, Three-Dimensional / instrumentation
  • Imaging, Three-Dimensional / methods*
  • Microscopy, Confocal / instrumentation
  • Microscopy, Confocal / methods*
  • Particle Size
  • Time Factors


  • Charcoal

Grant support

This research was supported by funding from a European Union Marie Curie Intra-European Fellowship (FILE-PIEF-GA-2009-25378 to CMB), a Marie Curie Career Integration Grant (PyroMap PCIG10-GA-2011-303610 to CMB), a University of Exeter Outward Mobility Academic Fellowship (to CMB) and the US National Science Foundation (DBI-1052997 to SWP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.