Dendrites in rock: Getting a microscopic view

Last summer, I had my first research job: a geology summer student at the Canadian Museum of Nature as part of its Scientific Training Program. It was an incredible experience. At first, though, I was very nervous. Thankfully, the work environment was very student friendly which took away my fear of messing up.

Throughout the summer I was given lots of opportunities for hands-on tasks. My favourite was learning how to operate the museum’s Scanning Electron Microscope (SEM). With this technology, I looked at minerals 20-times smaller than the width of a human hair. It was fascinating to see how crystal structures stay the same, whether it’s a mineral 0.002mm small or one 20m tall.

Dendrite-SEM_noedit

A magnesium oxide dendrite in a specimen from the Pilbara Region of Western Australia. Field of view 0.44mm. Image: Ann Presley © Canadian Museum of Nature.

During my SEM work with museum researcher Aaron Lussier I had the opportunity to examine rock samples from around the world. However, my research mainly involved samples of chalcedony, a variety of quartz, from the Pilbara region of Western Australia. The focus of my summer research was studying how elements, such as iron, move through this rock. For example, why only certain elements are incorporated into the rock’s structure.

Similarly, another question I explored is why the minerals grow the way they do, including the interesting behaviour of dendrites in chalcedony. A dendrite is a natural tree-like or moss-like formation on, or in, a piece of rock or mineral. A dendritic pattern forms when an element or mineral, starting from a point of origin, migrates and branches outward. A single dendritic branch extends until the mineral reaches a point where growing various new branches is, for some unknown reason, more favourable.

A piece of limestone with a darker tree-like dendrite pattern

A magnesium oxide dendrite in a limestone specimen from Solnhofen, Germany. Catalogue number CMNMC 34359. © Canadian Museum of Nature.

Dendritic branching is just one of the many natural phenomena scientists like myself hope to explain in the future. My museum internship was such a fun, amazing and memorable learning experience — one for which I am very grateful as I branch-out on my research career.

 

This entry was posted in Research, Rocks and minerals, Species Discovery and Change and tagged , , . Bookmark the permalink.

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