From Seas to Sands:

On its surface, Morocco’s landscape couldn’t be more distinct from that of Manitoba: towering snow-capped mountains, vast desert regions of exposed rock, and precious few lakes. And yet, when one peers deeper, these two regions have profound linkages in terms of their geological history. Both Manitoba and Morocco were once located close to the equator and largely submerged beneath vast seas during the early to middle Paleozoic Era, roughly 540 to 300 million years ago. The inundation of these distant continents was notably due to higher sea levels, thanks to less polar ice and tectonic processes occurring at that time. Owing to their similar past environments, there are also many connections in the fossils which can be found in these regions.

The destination for our field trip was a broad region of the Anti-Atlas Mountains along the edge of the Sahara Desert. Reaching them meant crossing over the High Atlas Mountains, a journey which took the better part of a day. Along the way, we passed villages nestled into the high peaks, majestic kasbahs (the Moroccan equivalent of castles), and roadside tourist stands showcasing a bewildering array of clothing, souvenirs, minerals, and fossils (many of them forgeries or highly altered). The rain shadow produced by the Atlas Mountains is straight out of a textbook; it was close to zero degrees, overcast, and snowing as we traversed the mountain pass, but transitioned to bright sun and up to 30 degrees as we descended into the desert beyond. Upon glimpsing the desert landscape, it’s no mystery why Morocco has been a filming site for many iconic movies and shows. As we broke for the night, we snacked on dates, biscuits, and tea served on polished stone tabletops sporting gorgeous fossil cephalopods.

Over time, oxygen built up in the atmosphere and oceans, leading to wide ranging effects such as the generation of the ozone layer that protects us from UV radiation, the oxidation of iron, producing most of the iron ore that we rely on today, the formation of thousands of new kinds of minerals which contain oxygen, and ultimately the evolution of more complex living cell types and the earliest multicellular organisms, which rely on oxygen for their metabolism. Ironically, the evolution of the first herbivorous animals seems to have led to a rapid decline in stromatolites around the beginning of the Cambrian Period. While less abundant, stromatolites still survive to this day in environments that are inhospitable for their herbivores, such as the famous Shark Bay site in Australia. Fossils of some of these post-Cambrian survivors also occur widely in Manitoba.

After driving for a few hours, we had an opportunity to visit the Fezouata Shale, which dates to the early Ordovician Period, around 477 million years ago. This site is world renowned for its fossilization of soft tissues and has been compared to other famous localities like the Burgess Shale. It also shares this type of preservation with three slightly younger sites in Manitoba: Cat Head, William Lake, and Airport Cove. This exceptionally preserved fossil deposit was first explored and recognized by Moroccan fossil collector Mohamed Oussaid Ben Moula. Ben Moula’s contributions to science have since been widely acknowledged, including through the naming of a species after him. We had the opportunity to visit Ben Moula’s family home and view some of his most recent collections, laid out in his yard! The fossils included beautiful trilobites preserving their antennae, giant marine filter feeders called radiodonts, armoured bristle worms, branching colonies of graptolites, and bizarre extinct echinoderms called stylophorans, to name just a few. Some of the fossils even represented new species (at least one that I spotted was acquired for a local museum collection). It will be exciting to see if any of the species found at Fezouata can also be found at sites in Manitoba. After the collection visit, we drove off the highway into the desert to one of the dig sites and were able to spend a short time searching for fossils. The group found some very nice trilobites and echinoderms, though none of the rarer species made an appearance.

After spending the night near Erfoud, we ventured forward in time to the Devonian Period, viewing a variety of sites ranging from about 400 to 360 million years old. The Devonian has been referred to as the “age of fishes,” and given the topic of our conference, our main goal was to survey the occurrence of these animals in the region. Two groups of fishes are particularly abundant in the region: early sharks and placoderms. The latter are thought to have been the first vertebrates to evolve jaws and teeth and include giant species like Dunkleosteus terrelli (a replica of which is on display in our Earth History Gallery) as well as more modest-sized Elmosteus lundarensis from Manitoba.

Our first Devonian site, Hamar Laghdad, preserves spectacular mud mounds – gigantic reef-like structures – teeming with fossilized life. As we ascended the peak from where our cars parked, we stepped over thousands of fossilized corals, brachiopods, cephalopods, and trilobite parts. In certain places, ancient crevices within the mud mounds were occupied by huge numbers of trilobites, possibly as safe havens for moulting their hard exoskeletons. Elsewhere, a quirk of fossil preservation caused by the movement of iron rich fluids through the rock has tinted the trilobites red and their eyes faintly green. Huge pits and caverns excavated by commercial collectors pointed the way to the richest fossil beds, and many fragments could be seen in the discard piles nearby. Slightly further along, in the youngest part of the outcrop section, we finally found fish remains. While stopping to chat with a colleague, I noticed a cylindrical chunk of fossil bone lying next to my boot. This turned out to be a section of the lower jaw of a placoderm fish called Alienacanthus malkowskii. This remarkable species had one of the most extreme “underbites” known from any animal! Shortly after, another member of our group found a large piece of bone belonging to Titanichthys termieri, a giant filter feeding placoderm. As we prepared to depart the site, we noticed several rock fragments on the desert floor near the cars which resembled stone tools, hinting at the long history of human occupation of this region.

The following day we were guided to two Devonian sites by local expert Moha Mezane. Mezane was first fascinated by fossils close to his home as a young boy and his keen eye for significant finds led to a number of important research contributions. His house also boasts an impressive display of fossils of all ages, ranging from trilobites and fish to ancient whale teeth and fossil trackways. Mezane led us into the desert near his house to a small outcrop featuring incredible trace fossils including trilobite trackways, fish swimming traces, and various invertebrate burrows. Further out, near El Atrous, we saw limestone beds tilted upright at an impressive angle. Scaling the piles of sand up to the exposed rock surfaces was a challenge, but well worth the effort. At the top we were greeted by partial skeletons of Alienacanthus and the shark Maghriboselache mohamezanei (named after Mezane). Such remains of sharks are particularly rare, since excepting their teeth, their skeletons are composed primarily of cartilage which is less resistant to decay than bone. The fossils were well-weathered by the desert wind and sand – it took a keen eye to spot them – but they still had many recognizable anatomical details. After wrapping up here, we finished the day with a very long, bumpy, off-road drive to our next hotel. We spent the night at Auberge Camping Oasis El Mharech, which is located in the heart of the dessert – it’s so remote its address is provided as GPS coordinates!

Waking early again, we journeyed on into the mountainous region between Tafraoute and El Maharch. Our next stop involved another steep climb to observe a variety of different geological layers, each with its own assortment of fossils. The bottom of the section, around 370 million years old, featured the “thylacocephalan layer,” which is named after the distinctive, extinct, big-eyed crustacean fossils that commonly occur there. The fossils were preserved inside concretions made of reddish ironstone and can be found by splitting open the concretions with a hammer. In addition to the thylacocephalans, rare fossil fishes can be found. One member of our group found an intact fin from a shark. Further up the slope, we crossed into different rock layers containing abundant cephalopods, brachiopods, and pieces of the bony armour of Dunkleosteus.  The top of the section featured a distinctive black shale consisting of sediment laid down 359 million years ago during a major extinction pulse (the Hangenberg event), characterized by widespread depletion of oxygen in the oceans, which wiped out placoderm fish and a range of other groups of organisms at the tail end of the Devonian Period. Pondering this dramatic shift in environment which fundamentally reshaped life on Earth seemed a fitting way to conclude our desert explorations.

After another long ride back to the road, we had the opportunity to see the personal collection of another significant local collector, Saïd Oukherbouch from Tafraoute, showcasing many intact shark and placoderm fossils found in this area. After taking in the sights here, it was time to begin our long journey back across the Atlas Mountains towards home.

Geologic time is truly staggering. It is hard to comprehend even for geologists, so we often rely on analogies to convey the vastness of time. If you could count one year per second, it would take an hour and 17 minutes until you had counted the age of the oldest Egyptian pyramids. Keep going, and it would take over 2 years before you reached the end of the age of dinosaurs. You would have to keep going for another 5 and a half years to get to the age of the earliest dinosaurs and another 12 on top of that to reach the earliest animals. It would be impossible to count to the age of the Earth, as it would take 144 years to get to 4.54 billion.

But, how do we actually know how old a particular specimen or event is? This is one of the most common questions I am asked as Curator of Palaeontology and Geology. It’s an excellent question, but not an easy one to answer in a concise way, so I will do my best to provide a more comprehensive answer here.

Manitoba has changed immensely over Earth’s history. While Churchill is now a cold, arctic environment close to 60 degrees north of the equator, about 450 million years ago it was equatorial and covered by a tropical sea. This is due to the shifting of the plates that make up the Earth’s crust, which move at about the speed that your fingernails grow.

You may have heard of carbon dating before. This approach relies on the radioactive decay of a naturally occurring form of the chemical element carbon. As with all elements, carbon atoms can come in several different forms, called isotopes. Isotopes share the same number of positive particles (protons) in their atomic nucleus, but differ in the number of neutral particles (neutrons). The majority of carbon on Earth is an isotope called carbon-12, which is stable. However, other forms of carbon exist, including an unstable form called carbon-14, characterized by two extra neutrons in its nucleus. Carbon-14 atoms decay over time, as one of their neutrons converts into a proton, releasing radiation and transforming the unstable carbon atom into a stable nitrogen atom. New carbon-14 is constantly being generated in the atmosphere by the action of cosmic rays from space which cause the conversion of nitrogen atoms into carbon-14.

Critically, the decay of carbon-14 happens at a predictable rate. By measuring this rate, we can predict that half of the carbon-14 that exists now will have decayed in 5,730 plus or minus 40 years. This length of time is known as the half life of carbon-14 and it is this concept that allows us to date materials made of carbon. Living organisms take in carbon, including carbon-14, either from carbon dioxide gas via photosynthesis or from feeding on other organisms. While organisms are alive, their supply of carbon-14 is continuously replenished. Once they die, carbon intake ceases and the carbon-14 “clock” is started. By measuring the amount of carbon-14 remaining in a sample of an ancient organism, we can calculate how long ago it died.

One of the oldest rocks on the surface of the Earth, called Acasta Gneiss, on display in the Earth History gallery. It is close to 4 billion years old and is found in Northwest Territories. The age of the Earth and Solar System are estimated to be even older based on measuring the age of meteorites and samples from the moon, which are less subject to processes that reset the radiometric “clock”.

Unfortunately, there’s a catch: if a sample is more than about 50,000 years old, the amount of carbon-14 remaining will be too small to permit an accurate age estimate. For older samples, scientists have to rely on different elements. For example, uranium-238 decays into lead-206 with a half life of about 4.47 billion years. Since uranium-238 is commonly trapped in in certain minerals when they form, it is ideal for measuring the age of older events in Earth’s history. Several other clocks, or more technically radiometric dating systems, exist and these can often be compared to each other to improve the accuracy of estimates.

Not every sample can be dated using an absolute method. For example, many fossils are too old for carbon dating and have insufficient uranium content for uranium-lead dating (although new approaches are pushing the boundaries of what is possible).

Similarly, sedimentary rocks like sandstones and limestones are formed of many different components including fragments of older rocks, fossils, and mineral crystals that have grown in between. Dating these components can give differing ages, sometimes producing misleading age estimates for samples. Further, alteration of rock under high heat and pressure or by the seeping of groundwater can enable atoms to move into and out of its crystalline structure (element mobility), which can “reset” the radiometric system.

This is where a second, complimentary approach called relative dating comes in. Even before there was a well-developed conception of evolution, scientists noticed that there was a regular pattern to the occurrence of different species throughout Earth’s rock record. We now know that this pattern is a consequence of the evolution and extinction of species. Mammoths, dinosaurs, and trilobites are all found only in particular rock layers and are absent from others. At a finer scale, careful examination reveals multiple successions of particular species, from which a comprehensive sequence can be built up. Since rock layers are deposited one on top of the other, the ordered succession of organisms gives us a clue about the relative age of the layers they are found in. If we can date rock layers above and below a particular fossil using radiometric dating, then we know that the fossil must be intermediate between those ages. If we then find the same fossil elsewhere, we have a relative idea of how old the rock it occurs in must be.

Fossils are not the only source of information that can be used for relative dating. Chemical and magnetic signatures also exhibit observable patterns of change through time that can be used to order rock layers by age. By combining insights from various relative and absolute dating methods around the world, the Earth’s timescale has been built up. The timescale is broken up into a number of named intervals, often based on particularly noticeable changes in the types of fossils. For example, the end of the Cretaceous Period is marked by the extinction of the dinosaurs, with the exception of birds.

Earth’s geological time scale should certainly be ranked among our most significant scientific achievements. This is the result of a long and fascinating history, with insights being drawn from multiple different disciplines of study around the globe. While we now have a pretty good idea of the age of key events throughout Earth’s history, new research is constantly refining dates, enabling us to understand events in the deep past with ever increasing precision.

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

The Deep History of the Churchill Quartzite 

As we pass through life we accumulate scars, each of which tells a story about an event that affected us. This white line on my hand shows where I fell hard on a tree stump in Nova Scotia when I was 19 years old. That pain in my ankle reminds me of an injury from another fall 30 years later, on an oil-slicked seashore. The older we get, the more of these old scars and injuries we will accumulate.  

It is the same in the natural world. Very old natural things, whether they are living or inanimate, carry many sorts of evidence with them. In the case of rocks, this evidence can tell us the stories of all the events that affected a rock between the time it was formed and the present day. 

Manitoba is home to many very old rocks; at least 2/3 of our province has bedrock that is about 1.7 to 3.5 billion years old, dating from the mid part of Precambrian time. Many of these rocks are beautiful and memorable – consider examples such as the granites and schists of the Whiteshell, east of Winnipeg – but to my eye the most memorable is the Churchill quartzite. This is the blue-grey to dove grey stone that forms the sculptural, sinuous “whaleback” ridges on both sides of the mouth of the Churchill River near Hudson Bay, so often seen as the backdrops in photos of polar bears. 

The Churchill quartzite has long been remarked upon by visitors to the Churchill area. It was first described and named by the Geological Survey of Canada geologist Robert Bell in 1880, and though the name “Churchill quartzite” was assigned so long ago, it has never received a formal scientific description, so the word ”quartzite” is not capitalized.  

The first waypoint of Churchill quartzite’s time travel was its formation. Although it is a “youngster” in comparison with some of the Precambrian rocks east of Lake Winnipeg, it is still deeply old. Somewhere around 1.8 billion years ago, what is now the Churchill area was covered by large rivers that flowed from newly rising mountains nearby. Since the riverbeds were steeply sloped, the rivers carried an abundance of coarse sediment: quartz grains, dark minerals such as mica and magnetite, and fragments of various rocks (some of which could be quite large). 

Where the flow of those rivers slowed, they deposited sediment. The Churchill quartzite contains evidence that it was deposited by flowing water, and that the flow was variable: features known as cross beds were formed as the sediment was laid down on angled or curved surfaces, in places such as river sandbars. Over long intervals of time, this deposited material was buried in more sediment, and pressure from the weight of that sediment turned it to stone. The sand, varied minerals, and rock fragments formed a dirty sandstone, known geologically as a greywacke. 

Through yet more geological time, this greywacke was buried ever deeper, where it was subjected to heat and pressure from the ongoing geological activity in this region. This welded the sediment grains together, giving the rock the remarkable toughness for which it is prized today by people building railways and airports. The greywacke had been metamorphosed and became a metamorphic (changed) rock, the metagreywacke that we call the Churchill quartzite. 

As time continued to pass, the nearby mountains were worn flat by erosion, and the tough, deeply buried Churchill quartzite was slowly uplifted until it was again exposed at the Earth’s surface. For many millions of years, this bedrock was subject to the forces of erosion in a desert-like landscape; the rock surfaces were smoothed and weathered, and large boulder fields developed at the bases of quartzite slopes. 

More than a billion years after the Churchill quartzite was formed, another waypoint was added to its time journey. The Churchill region was now near the equator, and a warm sea flowed in and covered the area. Water extended to the horizon in all directions, but the tough ridges of quartzite stood up above the water, so that they formed an archipelago of islands in that tropical sea. 

Around these islands, abundant sea life lived: creatures such as trilobites and giant cephalopods swam in the water, while corals proliferated in front of and against the quartzite shores. We see evidence of this sea life in Ordovician and Silurian age dolostones (rocks similar to limestones) and sandstones that date from about 450 to 440 million years ago; in some remarkable instances the fossil-rich rocks fill crevices in the quartzite surfaces!  

The sea became deeper, and during the Silurian and the subsequent Devonian Period, it is likely that the sculpted ridges of Churchill quartzite were again buried, with hundreds of metres of sedimentary rock laid down above them. An immense length of time passed, hundreds of millions of years, the sea was gone, and the thick sedimentary rocks above the quartzite were slowly eroded away by water and wind. 

About two and a half million years ago, a different erosional force arrived in the region. The Ice Age, also known as the Pleistocene glaciation, began, and large continental glaciers began to expand southward from the Arctic. These glaciers eventually covered much of North America, and in places they were two to four kilometres thick! The immense weight of this great thickness of ice gave it immense erosional power, and as it moved slowly southward across the land surface it deeply eroded and scoured the bedrock surfaces. 

As was the case during earlier erosion intervals, the immense toughness of the Churchill quartzite meant that it fared better than the other rocks around it. The dolostones that overlaid and abutted the quartzite were heavily ground down, to the extent that they can be observed in only a few select places in the Churchill area. The quartzite ridges themselves, in spite of their hardness, show considerable evidence of glacial erosion: in most places their surfaces were polished by the ice and show striations, lines and grooves that demonstrate the varied directions of ice flow as the rock fragments stuck into the bottom of the glacier scraped the top of the bedrock. 

In some locations you can see other features characteristic of glacial erosion: a roche moutonnée, or sheepback, shows where a large chunk was plucked out of the downstream side of a quartzite ridge, while the upstream side of the same ridge was smoothly polished. Chatter marks are smaller features, crescent-shaped gouges that show evidence of chipping by rock fragments on the base of the glacier; these are typically at right angles to the direction of ice flow (which is itself demonstrated by the striations, or lines on the bedrock surface). 

In southern Canada the Ice Age began to end roughly 12,000 years ago, and by 8,000 years ago the ice in northern Manitoba had melted to the extent that the Tyrrell Sea had formed – this forerunner of Hudson Bay was a huge body of water that covered the low-lying land that had been pushed down by the weight of the glaciers. Our ridges of Churchill quartzite were now again under deep salt water; old beach ridges show that the Tyrrell Sea extended many tens of kilometres south and west of Churchill. 

This region has been rising ever since, and even today the Churchill area continues to rise at a rate of almost a metre a century! This continued uplift is shown by the relationship between some human structures and the quartzite ridges. For example, old mooring rings at Sloop Cove, near the Churchill River, show where people were able to haul sloops (small ships) out of the river in the 18th century, to protect them from ice during the long northern winter. The cove has risen so much in the past 300 years that there is no way a ship could be hauled out in the same place today! 

Sloop Cove is one piece of the final chapter in the saga of the Churchill quartzite. The sinuous ridges have actually been associated with humanity for several millennia, ever since Pre-Dorset Inuit people living some 3500 years ago hunted marine mammals from what was then an archipelago of quartzite islands in the Tyrrell Sea. More recently, the men of the Hudson’s Bay Company quarried large blocks of this tough stone for construction of the impressive 18th century Fort Prince of Wales and Cape Merry Battery, which flank either side of the mouth of the Churchill River. Those men also carved the names of many men and ships into the cross-bedded quartzite at Sloop Cove. 

In the 20th and 21st centuries, Churchill quartzite has been put to many uses by enterprising humans: it makes superb ballast stone for the Hudson Bay Railway, it has been used to construct the large weir that controls flow of the Churchill River, it underlies the runways of Churchill Airport, and it appears as a backdrop in all those wonderful photos and videos of polar bears in their natural habitat! 

What does the future hold, I wonder, for such a remarkable and robust geological formation? In any case, it will be here for many millennia to come. 

This post draws on images and observations from our very successful August, 2022, Museum research trip to the Churchill area, which allowed our group to develop many ideas for new exhibit collaborations. A few of the photos are from earlier paleontological fieldwork in the Churchill area over the past 26 years.  

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

Bison rubbing stones are icons of the prairies. These large stones were originally transported south by Ice Age glaciers, then left behind on the prairies when the glaciers melted and receded roughly 12,000 years ago. They are therefore considered to be a form of fieldstone, and such large blocks of fieldstone are commonly called glacial erratics.

In the millennia since the glaciers left this region, rubbing stones have undergone a lengthy and intensive polishing process. These are boulders that were tall enough that they were made use of by itchy bison, who needed to shed their heavy winter coats or scratch after being bitten by flies and mosquitoes. The rubbing by bison over such a long time interval, along with the oils from the animals’ hides, gives rubbing stones a distinctive patina, and a rubbing stone is typically surrounded by a ring of flattened, eroded earth.

For our new Prairies Gallery, we knew that we wanted to include this sort of defining prairie element as a full-sized touchable piece, but we also knew that a cast or sculpted stone just wouldn’t do it. We had to acquire a real stone, and it had to be light enough that it could be moved into our gallery and placed safely on the gallery floor for an indefinite period of time. Since the gallery’s weight allowance is quite limited, how could this possibly be done?

As was the case for our fieldstone wall, we discussed this with stonemason Todd Braun quite early in the gallery development process. Although we thought that there should be a real boulder in the gallery, we also knew that it could not be a recognized rubbing stone, as those are heritage objects that should be left undisturbed in their original locations. Instead, Todd suggested that he could acquire a boulder of suitable size and rock type from gravel pits in the Morden area, and that he would prepare the boulder so that it could meet the floor loading limits and other requirements for placement in our gallery.

Todd told us that we were getting our money’s worth, since the job was more work than he had anticipated, but the hollowing out was completed by late November. He was also able to put a bit of a polish on the outer surface of the stone, to mimic the effect of rubbing by thousands of bison.

Todd used his tractor to lift the boulder into the back of his truck. Very early one morning, he drove to Winnipeg before there was significant traffic on the roads. The truck was backed into our loading dock, the hoist was attached to the heavy-duty straps that Todd had placed beneath the boulder, and the stone was lifted very smoothly onto a pallet jack. We were grateful at this stage that the boulder had lost so much of its original weight!

We had a crew of four on hand to assist Todd with moving the boulder into the gallery: an expert construction manager, and three curators to provide the grunt labour. Since we had measured all the doorways and halls in advance of this move, we knew that there would be a few tricky spots during the stone’s travel through the building, but that it should just fit through all of those.

First, we trundled it down a long corridor and through the Museum’s workshops, then out into the Welcome Gallery. Since there was new flooring in the galleries, we had to begin laying down sheets of board when we left the workshop space. There were several large plywood sheets, so it was a matter of laying down a row of boards along the planned path, then lifting each board after we passed over it, and moving it to the front of the other boards so that there would always be a safe surface for the pallet jack.

The stone turned out to have a bit of a “mind of its own” when it came to the direction our route would take, and there was some manoeuvring required to get it lined up with the doorway that would take us into the Winnipeg Gallery area. This gallery was another tight spot, and after some discussion and changing of direction, the boulder slipped through. We then had a clear run to its final location by the Pronghorn Diorama.

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

Beginning in 2012, The Museum’s curators worked together to plan exhibits for the Bringing Our Stories Forward project (BOSF). As we travelled around the grasslands region to prepare ideas for our new Prairies Gallery, we developed a list of topics that would be essential for a representation of this region. We rapidly agreed on some things that had to go into the Gallery: prairie vegetation, the importance of wind, Indigenous prehistory (and most particularly mound-building cultures), and several other topics. One of these was fieldstone. 

What is fieldstone, and why did we think it was essential? 

When European settlers arrived on the prairies, they wanted to build permanent houses and other buildings. They were now in a region where there were almost no trees away from the river valleys, so material for wooden houses could be scarce. Many settlers came from parts of Europe where houses were built from stone that was quarried from solid bedrock, but on the Manitoba prairie the bedrock was either buried far below the land surface, or it was soft Cretaceous shale that was useless as a building stone. 

There was however, a building stone resource that was readily available: loose fieldstone boulders, which lay on the land surface or could be readily found by digging near riverbanks. Fieldstone is a mixture of many kinds of stone. These stones formed as bedrock at  different times, under varied conditions, and include igneous, metamorphic, and sedimentary rock types. 

Like the settlers, fieldstone had immigrated to the prairies. During the Ice Age (Pleistocene Epoch), huge glaciers covered Manitoba. Glacial ice flowed southward, pulling blocks of stone out of solid bedrock. Blocks (glacial erratics), left behind when the ice melted, are used as fieldstone. Most fieldstone thus originated far to the north of where it is found today. 

Since fieldstone was a distinctive natural material seen across many parts of the prairies, and since it was used by settlers when they built many of the early buildings, it was clear to us that the fieldstone story should be included in our Prairies Gallery. We already planned to build an exhibit about the Brockinton National Historic site, a significant precontact bison kill site in the Souris Valley south of Melita, so it made sense that we also create an adjacent exhibit that would represent a wall of the Brockinton house, a late 19th century structure that sits at the top of the slope above the archaeological site. 

But how could we build this exhibit? Stone is really dense, and a mass of solid stone would have been far too heavy to be supported by the floor in our gallery space. Stone is also not really a topic that would have been suited to an animated video like our beautiful Prairies Mural Wall, and a flat panel display would have been just that: flat. We needed some way to allow visitors to observe and touch the genuine stone, in a setting that imitated a real fieldstone wall.  

Fortunately, in our various travels around southern Manitoba we had met Todd Braun, a stonemason who works in the Altona area. By consulting with Todd and with our exhibit design team, a plan took form: a frame would be fabricated from steel clad in plywood, and Todd would prepare the stones to attach to that frame, reducing their weight by slicing them thin. 

Todd and I selected stones to represent the great variety of fieldstone seen in southwestern Manitoba. Many of these came from boulders and cobbles that Todd had found during his visits to various gravel pits. A few were rocks that we found together, and in one or two instances I went to other geologists to request examples of very particular rock types.

Once we had agreed on the stones to be used, Todd prepared them using traditional techniques, breaking each rock with a hammer until it had a blocky shape. These blocks were laid out in their approximate relative positions for the wall. After a fitted layout was achieved, Todd patiently took each block and trimmed it with a saw so that the visible surface was effectively a “veneer” with only a few centimetres of thickness. These veneers were then attached to the steel and plywood frame using adhesives and metal hardware, and the space between them was covered in traditional mortar. The “corner stones” were a particular challenge, since they had to be cut in such a way that they would look like solid three dimensional blocks once the wall was assembled. 

To allow the wall to be assembled in Todd’s workshop prior to its installation in our gallery, the frame was actually built in three sections. This made each piece light enough to be readily moved, and small enough to fit through the smallest doorway between the Museum’s loading dock and our new Prairies Gallery. Very early one morning, Todd arrived at the Museum with the completed wall sections on his trailer. These were hoisted into the loading dock, and rolled through the Museum to the wall’s permanent gallery location. Todd and our construction team had created an ingenious hoist system that would allow each upper wall section to be lifted into position on the base section. Once the wall sections were in place, they were bolted together, and Todd covered the joins with fresh mortar. 

The finished wall looks very much like the walls you can see at Brockinton House and on other buildings in southwest Manitoba, and it beautifully demonstrates both fieldstone construction and the geological variety of this fascinating material. As is the case for some other Museum exhibits, there is no evidence of the incredibly complicated and lengthy development and construction process that allowed this structure to “look like the real thing.” 

Image above: In late autumn, the search for fossils in the Grand Rapids Uplands can be cold yet rewarding. Dave Rudkin of the Royal Ontario Museum visits a collecting site on a cold October morning.

Blog by Dr. Graham Young, past Curator of Palaeontology & Geology

This year, our Museum foyer has featured an exhibit of unusual fossils in the New Acquisitions Case. This exhibit, Finding the Impossible: Unique Tropical Fossils from William Lake, Manitoba, included a video “slide show” that documented the expeditions during which we collected these fossils. My colleague remarked to me the other day that this slide show should be shared widely using the Museum blog; this post, and some subsequent ones, will do just that!

The exhibit panel’s text gives a brief outline of the project:

How does an animal become a fossil? How is a fossil jellyfish even possible? Only bones, teeth and shells are commonly fossilized, while soft tissues rot or are eaten by scavengers. Jellyfish and other soft tissue fossils are not quite impossible, but they are very rare, preserved only in unusual environments.

The fossils at William Lake are 445 million years old, dating from the Ordovician Period of geological time. They represent creatures that lived along a tropical shore when Manitoba straddled the equator. The remarkable preservation resulted from low oxygen and high salt levels in lagoons.

These specimens were collected by a Manitoba Museum research team, collaborating with scientists from the Royal Ontario Museum and University of Saskatchewan, and students from the University of Manitoba. During fieldwork in central Manitoba in 2000, we discovered the first of these soft-tissue fossils. Through hard on-the-ground work, we located the site. We travelled there numerous times, excavating thin dolostone (limestone) layers to extract the specimens displayed here.

The first part of the accompanying slide show provided some background on Manitoba limestones, and shared the experience of travel to the Grand Rapids Uplands of northern Manitoba. I hope you will enjoy these images.

To be continued . . . next time I will talk about the fossil collecting process, with many graphic images of dusty and hot, or cold and wet paleontologists!

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

As we have worked our way through the pliosaur exhibit project, we have come up against a series of problems that have required novel solutions. About a month ago we carried out a very strange task, and one that none of us had ever had to do before: we needed to move the glyptodont. 

Before I explain how we did this, perhaps I had better backtrack a bit, as you probably have some questions at this point: “What is a glyptodont, anyway? Where did the Museum get its glyptodont and why did you need to move it?” 

Glyptodonts were creatures that lived during the Ice Age, that have been described as “fridge-size armadillos,” although the largest ones could perhaps have been called “armadillos the size of Volkswagen Bugs.” They were heavy, armoured creatures that weighed up to two tonnes. They spent their time lumbering around the forests and plains of South America and southern North America,  eating trees and grasses. Glyptodonts became extinct about 10,000 years ago during the “Quaternary Extinction Event,” at about the same time as giant ground sloths and other large mammals, probably as a result of climate change and hunting by humans. 

Our particular glyptodont is a replica of a fossil that belonged to the genus Glyptodon, and like our ground sloth it came to the Museum by a long and circuitous route. The glyptodont and the ground sloth were among the earliest casts of big vertebrate fossils, produced during the late 19th century by Ward’s Natural Science Establishment in Rochester, New York. Our ground sloth (Megatherium) was supplied to the Redpath Museum in Montreal in time for the opening of that institution in 1882, while the glyptodont joined it in Montreal some years later. 

By the 1960s, the Redpath was renovating, and these immense casts were removed and needed a home. The Manitoba Museum was under construction, so the casts were transferred to us and shipped to Winnipeg. They were assembled when the Earth History Gallery was constructed, and were there in time for the gallery opening in 1973. For the forty-plus years since then, both of these huge and historic casts have stood in place on the platforms that had been constructed for them. 

Now, in 2016, we are renovating that part of the gallery so that we can install our exciting fossil pliosaur, and to make space we have had to move the glyptodont. Since this replica had been in place since long before any of us worked here, we did not have any advance knowledge of how it should be handled, and since it is an irreplaceable artefact dating from  over a century ago, we considered this move with some trepidation. Since it turned out that the glyptodont is also immensely heavy, having been constructed of plaster, wood, and iron in the best 19th century fashion, our trepidation was well placed. 

As has been the case with handling the plesiosaur specimen, our technical staff love this sort of challenge, and Bert Valentin and Sean Workman had come up with solutions in the best “jury rigged” manner. Back when we installed our mineral exhibit, Bert had modified an engine hoist so that we could move our giant amethyst specimen, which weighs close to half a tonne. Now, with a fossil cast that weighs about the same amount (we weren’t able to weigh it, so this is a best guess), Bert re-modified that hoist as a glyptodont-lifter. The following sequence of photographs shows how it went – the process was much more nerve-wracking than it appears here! 

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

As you may know if you look at this page occasionally, for the past couple of years we have been working with a beautiful fossil of a pliosaurid plesiosaur, which was collected by Wayne Buckley from western Manitoba. We are now at the stage of preparing a permanent exhibit of the fossil, which will be installed in the Earth History Gallery this summer. So we have been very busy in the past little while!

Much of my own work involves the planning of the exhibit: writing copy for the panels, selecting images and graphics, collaborating with the designer, and working with grants and budgets to ensure that everything is on track. While I am doing this, some of the other staff are carrying out very creative and exciting work: the designer, of course, but also those who are building cases, engineering hanging mounts for a skeletal reconstruction, and figuring out lighting and other technical issues.

As these photos show, one of the most creative tasks is that of artist Debbie Thompson, who is making an artificial stone (shale) bed that will surround the original fossils so that they will look almost the same as they did when they were first discovered. When Debbie’s work is done, I think that many visitors will mistake her “rock” for the real thing, but as these photos show, this is only achieved through tremendous focus and patience.

If you want to read other posts related to this project, check out “Sea of Monsters” (here), “The Old Pliosaur and the Sea” (here), and “Flipping the Skull” (here).

By Dr. Graham Young, Curator Emeritus of Geology and Paleontology

It is exciting and interesting to work with the fossils of large vertebrate creatures, but this is a field with many complexities. During the fossilization of most vertebrates, the bone was replaced by other minerals, which makes the skeletal components both heavier and more brittle than they were during the animal’s life. For those of us working in the “back rooms” of museums, it can be very tricky to move these large, weighty, and fragile fossils as we prepare them, study them, or mount them for exhibit.

A few weeks ago, we had to perform one of the trickiest tasks associated with big vertebrates: flipping a skull. The large pliosaurid plesiosaur (read more in “Sea of Monsters”, here) that was donated to the Museum by Wayne Buckley (read more in “The Old Plesiosaur and the Sea”, here) had been fully prepared by Wayne, so that the bones are completely removed from bedrock; their weight is supported by mounts or cradles (structures similar to the plaster field jackets). This makes the fossil much easier to exhibit or study, but it means that we have to ensure that we are fully supporting the skull whenever we move it, so that it doesn’t collapse or break. Since this particular specimen is unique and scientifically important, and since it has survived the past 90 million years or so in remarkably good condition, it is imperative that we take extra care!

In late September, we were visited by Dr. Tamaki Sato (Tokyo Gakugei University) and Dr. Xiao-Chun Wu (Canadian Museum of Nature), who spent several days here studying the skeleton for a scientific publication. Before they arrived, Debbie Thompson had been making the final exhibit mount for the plesiosaur; to allow her to do that work, the skull was resting in a temporary support cradle, with its “back” side (the side hidden during exhibit) facing up. We knew that Tamaki and Xiao-Chun would want to thoroughly examine both sides of the skull, and that at the midpoint of the week we would need to flip it so that they could study the “front” side.

Knowing this in advance, Debbie had prepared a second cradle that would fit onto the the side that was currently up, making this support out of wood, plaster, burlap, and other materials. Unfortunately for us, Debbie was on vacation when the visiting scientists were here, so it was left to the rest of us to ensure that the cradle was used as she had intended.

On the Wednesday afternoon, Collections Specialist Janis Klapecki and I went to the room where the plesiosaur is laid out, and with Tamaki and Xiao-Chun we fitted Debbie’s second cradle over the skull. The fit was perfect, so we wrapped sturdy packing straps around the two cradles, then tightened them until there was no give and the wood supports were flexing a bit. This tightness would ensure that the bones would move as little as possible during the flip.

When we were ready, we were joined by several of our curatorial colleagues, who had kindly volunteered their assistance. The skull and cradles were not immensely heavy, but the operation had to be done very steadily and smoothly, so it was best to have two or three people on each end of it. Once we had everything in place, and once we had discussed how we would do it, it only took a couple of moments to actually flip the skull.