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B306: Tracking the aftermath of the Cambrian Explosion with Small Carbonaceous Fossils (SCFs) (Lead Supervisor: Nick Butterfield, Earth Sciences)

Supervisor: Nick Butterfield (Earth Sciences)

Importance of the area of research:

The Cambrian “explosion” of large animals marks the onset of the modern marine biosphere, but the system remained conspicuously archaic until the mid-Ordovician.  Although this interval is relatively well documented in terms of shelly fossils, the record of non-biomineralizing diversity is limited to rare, exceptionally preserved biotas, typically associated with unusual or extreme environments.  Our recent identification of a common, but largely overlooked category of organic-walled fossils – those too small to be seen on bedding surfaces, but too large or delicate to be recovered by conventional palynological processing – offers a novel means of tracking real evolutionary patterns through the early Palaeozoic (Butterfield & Harvey 2012).

Project summary:

Small Carbonaceous Fossils (SCFs) include a rich diversity of (mostly disarticulated) metazoan remains, some of which derive from taxa known only from Burgess Shale-type biotas, but others that are surprisingly modern.  Most importantly, SCFs are widely distributed in normal marine mudstones through the Cambrian-Ordovician interval.  Middle to late Cambrian strata extend over much of North America, but are particularly well preserved in subsurface drillcore of the Deadwood Formation in North Dakota and Montana.  This project will pursue a study of SCFs in these drillcores, with follow-up work on contiguous outcrops in South Dakota, Montana and Wyoming. 

What the student will do:

The student will conduct at least one field season investigating Cambrian strata in the NW United States.  SCFs will be isolated from unoxidized mudstone samples using a gentle HF acid extraction technique, and individually picked for microscopic analysis.  Systematic work will be aimed at resolving/reconstructing biologically meaningful taxa based on large fossil populations – and recognition that most SCFs are the fragmentary remains of larger organisms.  Assembly of a global database of SCFs will allow broader evolutionary, ecological and environmental patterns to be resolved, and integrated with contemporaneous palaeontological signatures.  This is a very open-ended project that might head in any number of directions, depending on what fossils emerge and the particular interests of the student.  Initial work will be based on pre-collected (fossiliferous) samples.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.


Butterfield NJ, Harvey THP. 2012. Small carbonaceous fossils (SCFs): a new measure of Paleozoic palaeobiology. Geology 40:71–74.

Harvey THP, Vélez MI, Butterfield NJ. 2012. Exceptionally preserved crustaceans from western Canada reveal a cryptic Cambrian radiation. Proceedings of the National Academy of Sciences, U.S.A 109:1589–1594.

Smith MR, Harvey THP, Butterfield NJ. 2015. The macro- and microfossil record of the Cambrian priapulid Ottoia. Palaeontology 58:705–721.  doi: 10.1111/pala.12168.

Follow this link to find out about applying for this project.

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