EGU Blogs

Matt Herod

Matt Herod is a Ph.D Candidate in the Department of Earth Sciences at the University of Ottawa in Ontario, Canada. His research focuses on the geochemistry of iodine and the radioactive isotope iodine-129. His work involves characterizing the cycle and sources of 129I in the Canadian Arctic and applying this to long term radioactive waste disposal and the effect of Fukushima fallout. His project includes field work and lab work at the André E. Lalonde 3MV AMS Laboratory. Matt blogs about any topic in geology that interests him, and attempts to make these topics understandable to everyone. Tweets as @GeoHerod.

Geology Photo of the Week #6 – Sept 30 – Oct 5

This is my first official post, besides the welcome post, at GeoSphere – EGU edition. It seems fitting to begin with a post that is part of a continuing series from my old home and is bridging the way to my new one.  The photo of the week, while still only six weeks old, is and will stay a regular fixture on my blog. The photo for this week is of some fantastic glacial striations in glacially polished marble located in Cantley, Quebec, which is about a 40 minute drive from Ottawa and is one of the most popular field trip sites for students from uOttawa.

Glacial striations are an interesting feature. They are pretty much ubiquitous across Canada, but rarely are they so defined as they are in Cantley. Striations form from the abrading action of rocks and sediment particles embedded in the base of a glacier. As the glacier slides across the bedrock it scrapes these sediments along the rock below making these striations. In order to form a striation the glacier must be sliding, which only occurs when there is a little water at the bed-glacier interface to lubricate things. Furthermore, if you look at striations under high magnification you can see that the sliding is discontinuous. In fact, it is a series of perfectly aligned slips of only a millimetre or two that are connected to form a perfectly straight groove up to several metres long. Another great feature about striations is that they can tell us the orientation of glacial movement. Indeed, the parallel lines in the rock below point the way to glacier was flowing. However, it is very difficult to tell the glacial flow direction from a striation since the glacier could have been flowing in either direction to make a straight line. In Ottawa we know from numerous other glacial features that the Laurentide Ice Sheet was flowing roughly from north to south. During the Pleistocene epoch, about 10,000 years ago, glaciers were covering pretty much all of Canada as well as most of Europe. The ice sheet at Cantley was ~2km thick.

Glacial striations at Cantley Quarry, Cantley, Quebec. Click for a larger image. (Photo: Matt Herod)

Thanks for reading!


Welcome to GeoSphere


I’d like to begin by welcoming you to GeoSphere, a part of the new European Geosciences Union blog network (). I hope you enjoy your visit and learn something about the incredible and varied world of geology while you’re here.

The header image you see at the top of this blog is a photo that I took and I believe it shows the whole Geosphere. The geosphere is defined as anything in the solid earth. This includes all rocks, mineral and fossils. However, I like to think of the geosphere more holistically. In my mind the geosphere represents an integration of seemingly separate parts of the Earth. For example, the interaction between rocks, water and bacteria could be viewed was part of the geosphere, hydrosphere and biosphere. The separation of these interconnected aspects of environment does us all a disservice by making things that are integrally linked appear unrelated. In my eyes the geosphere can be redefined as the intersection between the lithosphere, hydrosphere, biosphere and atmosphere as these Earth systems are all connected and it is certainly more awe-inspiring but also better for scientific thought to recognize the interconnectedness of these aspects and unify them. I see this unification as the true definition of the geosphere. So back to the header image that I think represents the true geosphere. It includes rocks, water, ice, the atmosphere and some of the biosphere all in one beautiful place and marries them all to form a varied and unique environment.

The picture itself was taken by me while I was doing field work in the Yukon Territory. It is in Tombstone Territorial Park during the end of the spring melt season and the start of summer and the river is called the North Klondike River. As you can see there is still quite a bit of melting that has to occur.

A view of the GeoSphere as I see it. The photo is of the North Klondike River overlooking the Tombstone Mountains in the Yukon Territory, Canada. (Photo: Matt Herod)

Science outreach is something that I feel very strongly about. I truly believe that scientists have a responsibility to the the public, our sponsors, to communicate what we do and our findings openly and honestly. Not only that, scientists also have a responsibility to educate. In my experience the science of geology is very poorly taught in elementary and high school, at least, far worse than many other sciences. The aim of this blog is to engage in geology outreach and attempt to rectify this problem one post at a time. For the past two years I have been attempting to take things in the geosciences that interest me and write explanations for a lay audience in order to bridge the communication gap and make the fascinating world of geology accessible to anyone and I will continue to do so here.

I am in the lucky position of being a Ph.D student which affords me a terrific opportunity to see how research is done and interact with geologists from all over the world at conferences. I am also fortunate enough to have free access to many scientific articles through the university library and labs in the department, which gives me the opportunity to blog about new research. Indeed, stay tuned for some updates from our labs at uOttawa.

I am looking forward to getting some real content up here and I can’t wait to get going! Stay tuned and subscribe. Also, I am on Twitter @GeoHerod.