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On My Scanner

A polished surface of small finger-like stromatolites, mounds made by Cyanobacteria (blue-green algae) and other microorganisms. This specimen is 1.9 billion years old, from the famous Gunflint Formation, Lybster Township, northwest Ontario (The Manitoba Museum, B-129).

A polished surface of small finger-like stromatolites, mounds made by Cyanobacteria (blue-green algae) and other microorganisms. This specimen is 1.9 billion years old, from the Gunflint Formation, Lybster Township, northwest Ontario (The Manitoba Museum, B-129; all scales are in millimetres).

This week I have been working on an exhibit about the early history of life on Earth. We have selected several specimens for this exhibit, including examples of stromatolites, mat-like structures formed by bacteria and Cyanobacteria (blue-green algae). Some of the Precambrian specimens in our collection had been cut and polished, so I have been putting them on my flatbed scanner to produce images.

A detail of part of the specimen shown above. The layers were produced as the microbes bound limey sediment on the seafloor (TMM B-129).

A detail of part of the specimen shown above. The layers were produced as the microbes bound limey sediment on the seafloor (TMM B-129).

Modern scanners are very sophisticated digital imaging devices. Most people don’t seem to consider using them for anything other than photos and documents, but I know many paleontologists who scan flat fossils and microscope slides.

I have been doing this for years; I used to put a sheet of mylar on the glass to protect it from scratching, but I found that produced weird light effects (or “artifacts”). So nowadays I am just very careful, and place the fossil on the end of the scanner bed opposite the part usually used for photos.

Clotted and layered microbial textures in a specimen from the Gunflint Formation at Schreiber Channel, northwest Ontario. This is the site from which Barghoorn described microscopic examples of early bacteria.

Clotted and layered microbial textures in a specimen from the Gunflint Formation at Schreiber Channel, northwest Ontario (TMM B-130). This is the same site from which Tyler and Barghoorn described microscopic examples of early bacteria.

Scanners are generally better than cameras when you want to photograph items that are flat or nearly flat; any imperfections in these images come from the way in which the rocks were polished.

Thin section (microscope slide) of a layered structure from Schreiber Channel

Thin section (microscope slide) of a layered structure from Schreiber Channel

The Gunflint Formation (or “Gunflint chert”) is a succession of iron-rich sedimentary rocks exposed in northwest Ontario and northern Minnesota. This unit, dating from about 1.9 billion years ago in the Proterozoic Eon of the Precambrian, yielded some of the first-known well-preserved Precambrian microfossils.

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Graham Young

Curator of Geology & Paleontology

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Graham Young grew up in Fredericton, New Brunswick. After doing a B.Sc. in biology at the University of New Brunswick, he switched to geology and did an M.Sc. in paleontology at the University of Toronto. After completing a Ph.D. at the University of New Brunswick in 1988, Graham spent two years in Newcastle, England, studying fossils from the Island of Gotland, Sweden. He moved to Winnipeg in 1990 to do research at the University of Manitoba, and has worked at the Manitoba Museum since 1993.

At the Museum, Graham’s curatorial work involves all aspects of geology and paleontology. He is responsible for building the collections, dealing with public inquiries, and preparing exhibits. Over the years, Graham’s research has become broader in scope, moving from specialist studies of fossil corals, towards research on ancient environments, ecosystems, and unusual fossils such as jellyfish and horseshoe crabs. Most of his current field research is on sites in the Grand Rapids Uplands and elsewhere in northern Manitoba.