Love Thy Nonsuch

By Dr. Graham Young, past Curator of Palaeontology & Geology

I have often been told by members of the public that, “it must be so exciting to do paleontological fieldwork.” This is true, it can be very exciting to visit new places, to discover and collect fossils that were previously unknown to science. But often the conditions are such that the fieldwork is more of a necessary evil. It is a step that must be passed to acquire essential specimens, rather than a pleasure in itself.

Last week was a case in point. I had planned to travel to the Grand Rapids Uplands of central Manitoba with Dave Rudkin (Royal Ontario Museum) and Michael Cuggy (University of Saskatchewan) to carry out a bit of additional collecting at some unusual fossil sites. We had chosen late September because (1) the weather is often dry and clear, and (2) the mosquitoes and blackflies have generally been depleted by this time of year.

It turned out that we were only partly right on just one of these assumptions: I don’t think I saw a single mosquito. Their absence was, however, compensated by the swarms of blackflies that descended whenever the wind died down. And that merciful wind was a chill, damp one, associated with rains that were at times heavy.

We first arrived at the main site on Wednesday afternoon. Under a relatively pleasant overcast sky, we spent several hours splitting rock, but found little in the way of specimens worth taking back to the Museum. By Thursday morning the torrential downpours had begun. These died off by the time we arrived at the site, but we discovered that the gently sloping limestone had been replaced by a “water garden” that combined both pond and waterfall features.

By Friday the rain had ceased, but much of its moisture seemed to have attached itself to any clay that remained on and adjacent to the bedrock, resulting in large patches of wonderfully glutinous mud. Our crawling in this mud was at least worthwhile, as we came upon an area of rock that was very rich in fossils. We hauled out nine partial eurypterids (“sea scorpions”), along with other associated bits and pieces. By the end of the day Michael and I looked rather disgusting, encrusted with mud as we were. We were also disgusted with Dave, because he somehow managed to avoid getting mud on himself!

Saturday we had planned to do quick stops at several sites, prior to returning to Winnipeg in the afternoon. Of course, by now the weather had improved and we were greeted by a sunny, mild day with patchy cloud. Nevertheless, we were not unhappy that we had finished heavy collecting on the main site, as the blackflies had returned in profusion.

So if paleontologists tell you they are off to do fieldwork, you should not immediately imagine a romantic, exciting “dig”, in a setting reminiscent of that at the start of Jurassic Park. The specimens are often worth the pain, but the pain is often genuine!

By Dr. Graham Young, past Curator of Palaeontology & Geology

Following on from my recent post about the geology of the Canadian Museum for Human Rights, it seems entirely appropriate timing that another piece of architectural geology work has just been published. Last week, a guidebook to the geology of the Manitoba Legislative Building, by Jeff Young, Bill Brisbin, and me, finally appeared in downloadable form. The entire file (20 megabytes) can be found here.

This book was published as part of a series of field trip guides for the Geological Association of Canada – Mineralogical Association of Canada annual meeting, which took place in Winnipeg in May. Jeff Young (University of Manitoba) and I had the pleasure of leading an afternoon tour of the Legislative Building; it is such an interesting and beautiful structure, and it is always a pleasure to see people’s reactions to its geological features. The guidebook is based on research Jeff and I did with Bill Brisbin (also of U of M) almost a decade ago.

In addition to the Legislature guidebook, I also enjoyed assisting with a field trip on the Ordovician to Silurian geology of southern Manitoba. The guidebook for that trip (26 megabytes), by Bob Elias et al., can be downloaded here.

By Dr. Graham Young, past Curator of Palaeontology & Geology

Columnar jointing is a term used to describe the polygonal columns seen in many volcanic rocks. These developed as a result of stresses, when lava cools from a molten form. Famous columnar basalts can be seen in places like the Giant’s Causeway in Northern Ireland, and at many sites around the Bay of Fundy in eastern Canada (columnar-jointed bedrock in the Lake Nipigon area of Ontario has a similar appearance, though much of it may have actually formed from magma that was intruded between other rocks, rather than erupted onto the Earth’s surface).

By Dr. Graham Young, past Curator of Palaeontology & Geology

Having received a tour of the interior construction site in April, followed up more recently by careful examination of the building’s exterior, I have to respond to this question with a full-voiced “yes.” The CMHR does not contain as great a variety of building stones as some older buildings in downtown Winnipeg, but some of the materials are of types not readily seen in other structures, and the immense scale of the structure permits a geological experience that may be unparalleled elsewhere in this town.

The following descriptions are based largely on my brief observations of a building still very much under construction, along with what I could glean from the web and some information received from helpful staff at CMHR. Since a thorough examination is not possible at this stage, and since surfaces were still being installed when I saw them, it is entirely probable that I have missed or misinterpreted some of the geological materials. I am also, for the moment, ignoring the site geology and materials other than stone. At some point in the future I hope that we can write a detailed consideration of CMHR’s geology, comparable to our work on the Manitoba Legislative Building (a pdf can be found here).

To a Winnipegger walking outside the CMHR, the immense surfaces of Manitoba Tyndall Stone are both familiar and obvious. Since this stone is locally ubiquitous, I will instead begin with the more unusual materials in the museum’s interior. As you enter the building, some of the introductory areas seem dark and low, walled largely with ochre-coloured concrete along with feature walls of other materials. Passing upward into more open spaces, you have your first glance of the extensive ramp system that allows visitors to walk through the many museum areas.

The walking surfaces of the ramps are concrete, but the sides are Spanish alabaster, quarried in Zaragoza, Aragon, Spain. Alabaster is a translucent, lustrous stone, long used by humans because it is beautiful and easy to work with. The CMHR alabaster is cut quite thin, about 2 cm (or 3/4″), and with the natural light it glows magically when backlit.

Geologically, two major types of material are considered as “alabasters”: gypsum (hydrous sulfate of calcium) and calcite (calcium carbonate). Neither kind of alabaster is resistant to rain and moisture, so both are only suitable for indoor use. The CMHR alabaster is of the gypsum sort; it is quite a soft material, but the crystals are tiny and tightly bound together, permitting both the polish and the translucent quality. Pure alabaster is white, and the beautiful colours and patterns actually come from impurities such as clays.

The Aragonese alabaster was quarried from near-horizontal beds in the Ebro Basin of northeastern Spain. It formed during the Oligocene and Miocene epochs (roughly 34 to 5 million years ago). During this interval, the Ebro Basin was endorheic (i.e., it had internal drainage and was not connected to the sea). As a result the water often became very saline (briny), and salts were precipitated out to form bedded chemical rock, most notably the gypsum that makes up this alabaster. The Aragonese alabaster is quarried by Alabaster New Concept.

Manitoba also has considerable gypsum deposits in our Jurassic sedimentary rocks. These can be seen at places such as Gypsumville and Amaranth, but as far as I know there is none of alabaster grade.

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Part 2 of this geological tour will follow soon, with an explanation of the dark stone that can be seen in the spectacular Garden of Contemplation and other places in the museum’s interior.