Melting Mountain Glaciers For many years it has been believed that Canada's western mountain glaciers, also known as the Cordilleran Ice Sheet, melted some 12.5 thousand years ago. A new study published in the Journal Nature by researcher Brian Menounos and his team is shedding new light on just when our mountains became ice-free. Deciphering the story of ice melt across western Canada's mountain has far-reaching implications. By understanding how ice melted thousands of years ago, we can also build better models to predict how current alpine ice sheets, like the one in Greenland, may melt in the future. It also helps to understand the challenges of previous theories of an "ice-free corridor" in terms of human migration to the North American Continent. And finally, it also is an important part of the story of ocean level fluctuations as a result of the increased meltwater. When we talk about landscapes we need to understand two concepts, inheritance and consistency. When we look at changing climates over the millennia, we also need to look at the associate landforms that each climate typically creates. In the mountain west, for instance, the mountain landscape was first carved by the power of water. Water dissects the land in a very specific way. It takes advantage of the contours as well as weaknesses in the rocks to guide its flow. Water passes over rocks of varying hardness including soft shales and harder limestones. Softer rocks will be worn down more quickly while harder rocks remain more resistant to the power of water. Cracks or fissures will be widened and over time, the landscape begins to be divided by mountain summits and intervening v-shaped valleys carved by water. When glaciers later inherited this water forged landscape, they inherited the same valleys previously carved by water and began to renovate them. Narrow V-shaped valleys were renovated into broad u-shaped valleys typical of valley glaciers. High on the mountains, glaciers also formed on cliff ledges and any area where snow could accumulate. As these glaciers moved, they enlarged the ledges upon which they sat and in many cases created round bowl-shaped depressions called cirques. I often refer to cirques as glacial nurseries as the ice usually formed there and then would overflow down the valley as it exceeded the ability of these bowls to contain the ever-increasing volumes of ice. Rock and debris fell onto the ice and some hitched a ride, just like a modern-day conveyor belt. It would later be deposited along the ice margins in linear ridges called moraines. Most of the rock becomes incorporated into the glacier and gets scraped and scoured along the base of the glacier. It's this action that allows glaciers to modify the landscape. Today, water has re-inherited this ice-modified mountainscape and is once again altering the cirques and u-shaped valleys. Consistency refers to the simple fact that processes acting on the landscape within a particular climate are the same processes that acted on the landscape at other periods of similar temperature and moisture. The way water changes the mountains today is the same way it would have done thousands or even millions of years ago. Each climate creates its own types of landforms but is always working with vistas carved by successive climatic periods. As a naturalist, this is what I love to look for in the surrounding peaks. Where can I find the impacts of previous climates and how are the current changes in climate affecting how water will shape the mountains long into the future. Brian Menounos' study helps climatologists to not only more accurately understand how our mountain glaciers melted, but also how similar landscapes today may react in the future. Just like looking at a star in the sky represents light that may have traveled for thousands or millions of years before it reached your eye, our mountains may represent a time capsule of how other mountain glaciers may melt in the future. One of the challenges facing this study was the fact that most previous studies found that the glaciers in western Canada only melted around 12.5 thousand years ago. This date was the result of Carbon dating. Carbon dating has been a tried and true way of dating materials for decades, but once you get into high mountain landscapes, it runs into problems; there's not a lot of carbon at high elevations. The carbon used for dating comes from ancient plants and once you hit the upper alpine environment, you find yourself in a land of rock and ice with little to no plant life. This may have added significant error to the dating. If you take a walk to the far end of Lake Louise in summer, you'll enter a land where winter is still king, and where glaciers have only recently revealed the landscape that was previously hidden by ice. You'll also notice that there is little regrowth on much of the lower valley as you hike up to the Plain of Six Glaciers Teahouse. Once glaciers disappear from a mountain valley, it may take a millennia or more before it becomes fully reclaimed by plant communities. This means that the carbon that was being measured in previous studies may have represented plants that colonized the valley long after the glaciers had disappeared. Newer dating methods that don't rely on carbon offered some additional ways to get a better date. Beryllium is a mineral most of us have never heard of. It's a highly toxic and carcinogenic mineral, but it's also one of the lightest metals in the world and has a correspondingly high melting point. These characteristics make beryllium very important in today's cell phones, aeroplanes and even missiles. One isotope, beryllium 10, like carbon 14 is radioactive. The radioactivity is created by cosmic rays colliding with atoms on Earth. In the case of beryllium 10, it's caused when cosmic rays hit oxygen atoms in the bedrock. A layer of ice acts to stop these rays and so measuring how much beryllium 10, which is found in the quartz rocks so common in the mountains, can help to tell us when the rocks were exposed by melting glacial ice. Menounos and his team measured 76 samples from 26 locations to see if dates could be more accurately determined using this new dating method. They visited glacial moraines across British Columbia in order to test the theory that many areas may have been ice-free much earlier than previously believed. The great ice age, the Pleistocene, ended some 14,700 years ago when climates suddenly warmed. At the peak of the Cordilleran Ice Sheet, the amount of ice was similar to what can be found in present-day Greenland. The results showed that the moraine samples fell into two age ranges, 12,800 to 15,000 years for the older locations and 9,800 to 13,000 for the younger sites. If we work with the average ages of 13,900 and 11,400 years respectively, the study showed that large areas of the mountain glaciers had already melted prior to earlier estimates of 12,500 years ago. It also shows that ocean waters off the coast of British Columbia would have risen by approximately 4C between 15,500 and 14,000 years ago. This would have melted most of the low-elevation glaciers, leaving only the highest mountain regions ice-free. Also during this period, meltwater would have contributed to sea level increases of 2.5 to 3 metres. In other terms, the mountain glaciers lost half of their mass in less than 400 years. This also changed the ice sheet into a series of interconnected alpine glaciers, and icefields, gradually leaving us with the landscape we recognize today, just on a much much more extensive scale. This study shows that vast amounts of ice had been lost from the mountain landscape at least 2,000 years earlier than previously thought. It also shows that ice sheets as large Greenland's can also melt at a very fast rate. Essentially, once the melt starts, it can take place very quickly. While it may seem that this actually adds to the possibilities of human migrations towards a possible "ice-free corridor", the study shows evidence that low elevation travel routes would have remained ice-choked until long after the migrations would have needed to occur. Way back in episode 6 I talked about some of the new evidence that was rendering the ice-free corridor to the dustbin of history. You can check it out at www.MountainNaturePodcast.com/ep006. The most recent archaeological evidence shows that people had already arrived in North and South America as far back as 14,500 years ago. Assuming that early migrants made it across the ice-free corridor even 13,000 years ago, there is little chance they would have spread to Monte Verde in southern Chile by 14,500 years ago, yet there are archaeological sites that date to that period. Essentially, it's out with the ice-free corridor and in with the kelp highway. What the heck is the kelp highway you ask? Well, it refers to a coastal migration rather than an inland one. It wasn't long ago that this was considered fringe science. All the archaeological eggs were in the ice-free corridor camp and there was little research into an alternative option. Over time though, ancient sites began to appear across the coastal areas of North and South America that kept pushing the tenure of first nations further and further back. Currently, the oldest sites are 14,500 years old in places like the Page-Ladson site in Florida. As far south as this site seems today, this underwater site revealed evidence of mastodon bones that showed signs of human butchering. Even much further south, on the southern end of Chile, lies the Monte Verde site. In 1975 the remains of a Gomphothere, an animal considered to be ancestral to modern-day elephants was found and this spurred further investigations. These revealed amazing artefacts well preserved in a peat bog that included butchered Gomphothere bones, stone hearths, the remains of other local animals, wooden house posts and even bits of animal skin clothing. To most archaeologists used to having to deal with hearths and stone tools, this site was incredibly rich, largely due to the preserving qualities of peat. Again, the dates stretch back to some 14,500 years. Prior to sites like this, the Clovis culture was considered to the be the oldest North American indigenous culture, but these and many more sites are now pre-dating the Clovis culture which was believed to have arrived via the ice-free corridor between 12,900 and 13,200 years ago. So how exactly did these pre-Clovis cultures find themselves in the New World - well that's the kelp highway? Essentially it refers to a coastal migration of peoples confident in traveling by boat along coastal areas taking advantage of plentiful supplies of kelp and seafood that was available. The ice-free corridor Clovis migration has been suffering a death by a thousand cuts over the past few years. Doubtless, Clovis people did take advantage of a corridor across the Bering Strait but it is now clear that they were the followers and not the leaders. They would still have arrived several millennia after the coastal regions had already been settled. In Episode 37, I talk about a new site off the coast of British Columbia that begins to add fuel to the kelp highway migration theory. One of the Achilles heels of this potential migratory route in the past has been the lack of evidence of a coastal migration. A newly announced site on Triquet Island has revealed artefacts at least 14,000 years old. This makes it the oldest archaeological site in Canada and helps to finally build a trail of breadcrumbs to support a coastal migration. We still need to push the chronology back further if we are to bring well-established populations of humans to the southern tip of South America by 14,500 years ago, but perhaps this is a good start. One of the great aspects of science is that until you actually look for something, it may be hiding in plain sight. Some science is the result of just plain luck…looking for one thing, and discovering another. Sometimes, we're just looking in the wrong place. With renewed interest in a coastal migration, there will be more and more resources focused on examining sites that might have been visited by our very oldest ancestors. While part of me laments the loss of a good story on an ice-free corridor migration right past my doorstep, another part of me loves the fact that an entirely new archaeological story is now unfolding. Just to throw another wrinkle into the equation. We're still assuming a migration across the Bering Strait that hugged the Pacific coast of North America. What if these paleo sailors were more adept than we give them credit for? We know that Aboriginal Australians were there by 50,000 years ago. They would have had a more challenging, open-water voyage in order to discover this new continent. Maybe we're just beginning to scratch the surface in a new whodunnit of New World migration. A really unique site in California shows the potential for some kind of early human as far back as 130,000 years ago. The site was found in 1992 beside a highway site near San Diego California. While archaeologists are quibbling about a few hundred years here and there when dating sites, this site has come in more than 100,000 years before anyone thought humans could be in the new world. The site features a partial skeleton of a mastodon that appears to have been butchered by paleo-humans. The outrageous preliminary dating of the site kept it on the fringes until new dating techniques to confirm early dating. This resulted in the new research being published in the Journal Nature just in April of 2017. Every new discovery leads to new rabbit holes of investigation, confirmation, peer review, and then new questions. This site is so wacky early that if it's confirmed by subsequent research, then all human migration theories on the planet will be up for grabs. It's so old that we would be talking about hominids as opposed to humans. I can't wait to see how this story ends. Perhaps we are just at the beginning of a new mystery? Stay tuned. Next up - The greatest land geographer to ever live David Thompson's early years The history of the exploration of Canada is filled with the names of great men. Names like Simon Fraser, Alexander Mackenzie, Samuel Hearne, Anthony Henday, and David Thompson. All of these men were great explorers but in the final tally of simple achievement, none could hold a candle to David Thompson, or as the first nations knew him, the man who looks at stars. Thompson was born on April 30, 1770, in Westminster, England. His family was poor and after his brother was born two years later, his father died leaving the family even the more destitute. The day before his 7th birthday he was enrolled in the Grey Coat School in Westminster. At the time, it was a school devoted to educating poor boys. Its goal was "to educate poor children in the principles of piety and virtue, and thereby lay a foundation for a sober and Christian life". By all accounts, Thompson was an able student and this brought him to the attention of the School Board. In the minutes of their December 30, 1783, meeting it states: "The Master also reports that application was made by the Secretary belonging to the Hudson's Bay Company, to know, if this Charity could furnish them with 4 boys against the month of May next, for their settlements in America. The Master, by order of the Treas (sic) wrote a letter informing the Governor and Directors that there were but two boys that had been taught navigation in the school, which two boys they desire may be qualified for them, vis: Samuel John McPherson and David Thompson." What an adventure for a boy of only 15…or was it? Apparently, Samuel McPherson didn't think so as he did a runner the following day rather than be packed off to the new world. Thompson, on the other hand, embraced the opportunity and on the minutes of the Grey School dated June 29, 1784, he was apprenticed to the Hudson's Bay Company. The minutes state: "On the 20th of May David Thompson, a mathematical Boy belonging to the Hospl (sic) was bound to the Hudson's Bay Company and the Trear then paid Mr Thos. Hutchins, Corresponding Secretary to the said Company, the sum of five pounds for taking the said Boy apprence (sic) for seven years". I can imagine that when the Company ship the Prince Rupert departed London in May of 1784 that many things must have been going through the mind of this bright 15 year old boy. Part of him must have been terrified to leave the only home he had ever known for a vast wilderness. Thompson reflected on his years at the Grey School writing in his journal: "Books in those days were scarce and dear and most of the scholars got the loan of such books as his parents could lend him. Those which pleased us most were the Tales of the Genii, the Persian, and Arabian Tales, with Robinson Crusoe and Gullivers Travels : these gave us many subjects for discussion and how each would behave on various occasions." Doubtless, stories of the hardships awaiting him must have reached his young ears, yet he embraced his fate and soon after, the new world for the rest of his life. As the ship approached the coast of North America he wrote: "We now held our course over the western ocean ; and near the islands of America saw several icebergs, and Hudson's Straits were so full of ice, as to require the time of near a month to pass them ; this being effected the three ships separated, one for Albany and Moose Factories, another for York Factory, and the third for Churchill Factory at which last place we arrived in the beginning of September 1784." Thompson continued: "Hudson's Bay, including Jame's Bay, may be said to be an inland sea, connected to the Atlantic Ocean by Hudson's Straits…On its west side it receives Seal, Churchill, the Kissiskatchewan (now known as the Nelson), Hayes, Severn, Albany, and Moose Rivers; on the east side Ruperts and several other Rivers, the names of which are unknown as they come from barren, desolate, countries." What a first impression it must have been for Thompson? Fort Churchill was isolated at what must have seemed like the end of the world, especially when he learned: "The Factory is supplied once a year with goods and provisions, by a Ship which arrives on the last days of August, or early September, and in about ten days is ready for her homeward voyage; the severity of the climate requiring all possible dispatch." Thompson saw adventure along with hardship. In autumn, just like they do today for the viewing pleasure of thousands of tourists, the polar bears arrive at Churchill. Thompson wrote: "The polar Bear now makes his appearance, and prowls about until the ice at the sea shore is extended to a considerable distance ; when he leaves to prey on the Seal, his favourite food : during his stay he is for plunder and every kind of mischief, but not willing to fight for it." While the cold and the wind bothered all, there was little snow until the latter part of December when: "a north east snow storm of three days continuance drifted the snow to the height of the stockades and over them, and filled the whole yard to the depth of six to ten feet, which could not be cleared, and through which avenues had to be cut and cleared of about four feet in width ; and thus remained till late in April, when a gradual thaw cleared the snow away. From the end of October to the end of April every step we walk is in Snow Shoes. The Natives walk with ease and activity, and also many of us: but some find them a sad incumbrance, their feet become sore and their ankles sprained; with many a tumble in the snow from which it is sometimes difficult to rise." The winds of Hudson Bay are legendary. Any snow that falls quickly forms in huge drifts. After spending three weeks on the Bay this fall, I can see how the stockades would catch the drifting snow and how it would fill the enclosed yard as well. The climate is the great arbiter in the north and he wrote: "The country, soil, and climate in which we live, have always a powerful effect upon the state of society, and the movements and comforts of every individual, he must conform himself to the circumstances under which he is placed, and as such we lived and conducted ourselves in this extreme cold climate. All our movements more, or less, were for self-preservation : All the wood that could be collected for fuel, gave us only one fire in the morning, and another in the evening…" "The interior of the walls of the House were covered with rime to the thickness of four inches, pieces of which often broke off, to prevent which we wetted the whole extent, and made it a coat of ice, after which it remained firm, and added to the warmth of the House, for the cold is so intense, that everything in a manner is shivered by it" When the summer sun arrived, so did the swarms of mosquitoes. Thompson wrote: "Summer such as it is, comes at once, and with it myriads of tormenting Musketoes ; the air is thick with them, there is no cessation day nor night of suffering from them. Smoke is no relief, they can stand more smoke than we can, and smoke cannot be carried about with us. The narrow windows were so crowded with them, they trod each other to death in such numbers, we had to sweep them out twice a day ; a chance cold northeast gale of wind was a grateful relief, and [we] were thankful for the cold weather that put an end to our sufferings. " "different Persons feel them in a different manner ; some are swelled, even bloated, with intolerable itching ; others feel only the smart of the minute wounds ; Oil is the only remedy and that frequently applied ; the Natives rub themselves with Sturgeon Oil, which is found to be far more effective than any other oil. All animals suffer from them, almost to madness, even the well-feathered Birds suffer about the eyes and neck. The cold nights of September are the first and most steady relief." At one point, Thompson began to wonder why he had been brought at all: "It had been the custom for many years, when the governors of the factory required a clerk, to send to the school in which I was educated to procure a Scholar who had a mathematical education to send out as Clerk, and, to save expenses, he was bound apprentice to them for seven years. To learn what ; for all I had seen in their service neither writing nor reading was required, and my only business was to amuse myself, in winter growling at the cold ; and in the open season shooting Gulls, Ducks, Plover and Curlews, and quarelling with Musketoes and Sand flies." After spending a year at Churchill, he was sent to York Factory after the supply ship had arrived at Churchill in 1785. He was sent out, accompanied by two natives, on foot, without provisions, to walk 240 km in the cold of autumn to bring mail that had arrived on the ship to another fort. He was accorded a single blanket to keep him warm at nights. At the same time, two natives would be sent from York Factory to Churchill. This would give each fort current information about the state of the other while also forming as a ready means of communicating between the forts. They were dropped at Cape Churchill and while Thomson was given a blanket, his guides were given a gallon of strong whiskey. Alas, the day was lost as they quickly set down to consume the spirits. Thompson always opposed the use of whiskey in the fur trade and banned it from any post that he was in control of. The next day they walked all day without breakfast or lunch, and in the evening his guides shot a goose and three ducks. He arrived on Sept 13 and spent the winter in the fort and quickly settled into a new routine. The natives that walked with him were given 3 gallons of brandy and 4 pounds of tobacco. The fall and winter are spent collecting all manner of food, fishing, snaring hares, hunting geese in the fall and ptarmigan in the winter, and basically trying to stay warm. The forts had to be completely self-sufficient. March and April seem to be the months when snow blindness is most prevalent. Thompson writes: "As I never had it, I can only describe the sensations of my companions. Accustomed to march in all weathers, I had acquired a power over my eyelids to open, or contract them as circumstances required, and to admit only the requisite quantity of light to guide me, and thus [I] prevented the painful effects of snow blindness. In the case of those affected the blue eye suffers first and most, the gray eye next, and the black eye the least ; but none are exempt from snow blindness ; the sensations of my companions, and others, were all the same ; they all complained of their eyes, being, as it were, full of burning sand ; I have seen hardy men crying like children, after a hard march of four months in winter. Three men and myself made for a trading post in the latter part of March. They all became snow blind, and for the last four days I had to lead them with a string tied to my belt, and [they] were so completely blind that when they wished to drink of the little pools of melted snow, I had to put their hands in the water. They could not sleep at night. On arriving at the trading Post, they were soon relieved by the application of the steam of boiling water as hot as they could bear it, this is the Indian mode of cure, and the only efficient cure yet known, but all complained of weakness of sight for several months after." The Bay men had mastered the north country. As they expanded their influence further west, they encountered the peoples of the Blackfoot Confederacy, in particular, the Peigan. He wasn't the first to visit the Blackfoot, that honour was reserved for Anthony Henday who visited the area in 1754. Henday was trying to sell an impossibility though. He was trying to convince them to go to the Bay to sell their furs. This was pretty much a non-starter for a population of the grasslands. He learned that, rather than travel long distances to the Bay, the Blackfoot would sell their furs to the Cree, who would, in turn, trade them to the Company at York Factory for a profit. An additional wrinkle was that the rival Northwest Company had built forts far more convenient to the Cree and they would get the best furs long before the remaining poorer quality pelts made their way to the Bay. The Northwest Company sent men out, onto the land, to meet, live with, learn the languages of, and in some cases, intermarry with the indigenous people of the hinterlands. The Blackfoot, while they enjoyed the whiteman's trade goods, they really didn't need them, and they definitely didn't want trading posts in their territory. They also were in a position to manage trade across the continental divide to British Columbia. Essentially, any Hudson's Bay Man wanting to visit B.C. would have to go through them. To negotiate with the Blackfoot, the company sent James Gaddy who spent three winters living with the Peigan in the foothills west of Calgary. In 1787, 17-year old David Thompson accompanied him. At this point, nobody had realized that David was no ordinary teenager. He kept a careful journal and decades later would use it to write his memoirs. Thompson described the people that he stayed with and the stories shared with him by them: "The Peeagan in whose tent I passed the winter was an old man of at least 75 to 80 years of age ; his height about six feet, two or three inches, broad shoulders, strong limbed, his hair gray and plentiful, forehead high and nose prominent, his face slightly marked with the small pox, and alltogether his countenance mild, and even, sometimes playfull ; although his step was firm and he rode with ease, he no longer hunted, this he left to his sons ; his name was Saukamappee (Young Man) ; his account of former times went back to about 1730…" Saukamappee was not of the Peigan, today referred to by the name Pikani. He was part of a Cree nation known as the Nahathaway with whom the Pikani were closely allied. Both nations were constantly at war with the Snake or Shoshone Indians to the south. Usually, they were very well matched in terms of weaponry and few people died in their skirmishes…at least in the early days. Saukamappee related how the arms race began to alter the balance of power as horses and guns began to appear. "By this time the affairs of both parties had much changed ; we had more guns and iron headed arrows than before ; but our enemies the Snake Indians and their allies had Misstutim (Big Dogs, that is Horses) on which they rode, swift as the Deer, on which they dashed at the Peeagans, and with their stone Pukamoggan (war clubs) knocked them on the head, and they had thus lost several of their best men. This news we did not well comprehend and it alarmed us, for we had no idea of Horses and could not make out what they were. Only three of us went and I should not have gone, had not my wife's relations frequently intimated, that her father's medicine bag would be honored by the scalp of a Snake Indian." Guns and horse began to change the landscape of the plains. The Pikani won with the help of the Nahathaway guns. Thankfully, the Snake Indians didn't have any horses with them in this battle. A few days later, Saukamappee saw his first horse, a dead one that had been killed in a different skirmish. The Peigan were able to keep the Snakes gun-poor as they were able to control access to the Hudson's Bay and Northwest Company supply of trade goods. This allowed the Peigan to expand greatly across the plains until they encountered an unstoppable foe - Smallpox. "While we have these weapons, the Snake Indians have none, but what few they sometimes take from one of our small camps which they have destroyed, and they have no Traders among them. We thus continued to advance through the fine plains to the Stag River when death ca
