Zooming in on Microscopic Analysis at SA

Sustainable Archaeology has a new piece of analytical equipment - a Nikon SMZ-25 stereoscopic microscope. We are excited by the versatility of this new instrument, which will allow us to view objects within a range of 6.3 to 315x magnification with both direct and transmitted light sources.

Chad Steele, from Nikon Canada, puts the SMZ-25 together.

No single piece of equipment has arrived at our facility intact - everything from our humidity readers to our microCT scanner, even our building, have arrived in multitudes of pre-assembled pieces. This single microscope was no exception - above is an image of just a fraction of the packaging that this piece of equipment came in.

The SMZ-25 is a fully automated microscope; magnification, zoom and even lighting are mechanically adjusted either on the computer or the separate control unit/monitor. Besides magnification, there are a number of lighting options that increase the versatility of the system. It has a transmitted light source in the base that forces light up through an object, allowing us to view things like thin-sections of ceramic or soil on prepared slides. There is a ring light that sits on the lens, providing even illumination of an object, such as a trade bead, from the top-down. And there are goose-neck fibre-optic lights that allow us to move and adjust the angle of the light source to capture and highlight surface details on an object, such as use-wear on the edge of a projectile point. Oblique coherent contrast (OCC) illumination provides contrast and colour to otherwise clear and colourless objects such as diatoms (microscopic algae) or starch. The unit is also equipped with a 5 megapixel camera for capturing publication-quality images, and the Nikon NIS-Elements software comes with the ability to focus-stack (z-stack) multiple images upon one-another in order to capture a clear image with a greater depth-of-field.

Nikon SMZ-25 stereomicroscope with camera and remote control unit.

We look forward to using the microscope to examine floral remains such as seeds and even pollen, phytoliths or diatoms from archaeological sediments. It will also be used to examine the temper inclusions in ceramics, cut marks on faunal remains, usewear on tools, to identify the species of wood/charcoal samples and even examine fingerprints in clay objects. With analytical software capable of defining regions of interest and morphology, counting, measuring, and filtering, this stereomicroscope makes a valuable contribution to the Imaging capabilities of Sustainable Archaeology: Western.

Flotation Machine in Action

Featured in a previous post, Sustainable Archaeology's soil flotation machine from R. J. Dausman Technical Services, Inc. was put through its paces today. A team from New Directions Archaeology Ltd. was on site to un-crate and set up the machine, running the first tests out in the Lawson village at the Museum of Ontario Archaeology, next door. They will be floating dry sediment samples over the next few days that they have collected from some recent excavations the company has been working on.

The machine requires access to running water for its initial fill, as well as access to a source of electricity for circulating the water in the tank. After its initial fill, the machine recycles water within itself to allow for light-fraction flotation, and heavy-fraction rinsing with an attached spray-hose. The material captured in the screens is then allowed to dry on newspaper before it is packaged, and later analyzed. The fine mesh, as seen in the images below, allows for the capture of tiny floating artifacts, such as tobacco seeds. A courser mesh filters the heavier fraction of sediment, which can include artifacts such as shell, bone and pieces of flaked stone tool.

Ark of the Covenant, or....?

While the large crate and black wrapping material may give off an exciting aura of mystery, we have to  disappoint our fellow archaeologists with the news that the latest arrival at the facility is not the Ark of the Covenant, but in fact a soil flotation machine from R. J. Dausman Technical Services, Inc.

A microCT and Archaeobotanical Analysis of Charcoal

The microCT scanner at Sustainable Archaeology was used to non-destructively study charcoal remains from the Arkona site, a ca. AD 1200 Younge Phase village site in Ontario. The scanned charcoal was analyzed and identified by Ontario archaeobotanist Rudy Fecteau. Using the microCT allowed for the charred remains to be digitally "split" in order to examine internal structures while preserving the original specimen for future analysis.

As noted in the video, the species of the second charcoal sample was not determined, and we invite our blog readers to assist us with the identification. Below are two closeup images giving a closer look at the internal structures of the second sample. If you have an idea of what the species might be, let us know by commenting on the blog, by tweeting the answer to us (@SustArchaeology), or by posting on our Facebook page.

 Special thank you to Rudy Fecteau for providing feedback and analysis on our scans, and for the delicious strawberry loaf!