Late Pleistocene Collared Lemming (Dicrostonyx torquatus) from Northeastern British Columbia

Charlie Lake Cave is a terminal Pleistocene/Holocene archaeological and paleontological site in northeastern British Columbia (Driver, 1988; Fladmark et al., 1988; Driver et al., 1996). Located in the Peace River District to the east of the Rocky Mountains (56°16\u2735"N, 120°56\u27 15"W), the major feature of the site is a deep gully in front of a cave formed in a low sandstone escarpment. The gully runs parallel to the hillside, and has been filled with sediments moving down the hill since 10,500 B.P., resulting in up to 4.5 m thick deposits. The site is well stratified, and there is a strong correlation of radiocarbon age and depth, suggesting stratigraphic integrity. The site contains vertebrate assemblages deposited by natural agencies and human hunters, and there is also a long sequence of archaeological components at the site . The importance of the site was demonstrated by Fladmark\u27s excavations in 1983 (Fladmark et al., 1988). Further excavations at the site were undertaken in 1990-1991, and remains of collared lemming (Dicrostonyx torquatus) were recovered during the second series of excavations. The specimens are described and their significance evaluated.   Article Summary by Jonathan C. Driver, May 2015               This short paper provides information on an unexpected and unusual find from the lower layers at the site. After the 1991 excavations were finished we began to work on identifying the animal bones that were recovered. Somewhat to our surprise we found a few specimens of the collared lemming, an animal that today only inhabits the high tundra of the arctic. This wasn’t out of line with other species that indicated a cold and/or open unforested landscape during the earliest period of occupation – bison, ground squirrels and hares – but as collared lemming had not been found before in British Columbia it warranted a paper to itself.             The paper describes the specimens, noting that they were somewhat larger than modern lemmings, and then looks at the known distribution of lemmings at the end of the ice age. There are a number of specimens from fossil sites (mainly caves) well outside their modern distribution. This presumably suggests  lemming populations were able to colonize cold, open landscapes around the expanding ice sheets, and had enough time to move south as the ice sheets expanded and in turn created new habitat that was suitable for lemmings.             As the climate changed and as forests moved in, lemmings were unable to survive and their populations dwindled and soon became extinct in the Peace River region

Late Pleistocene and Holocene Vertebrates and Palaeoenvironments from Charlie Lake Cave, Northeast British Columbia

Excavations outside Charlie Lake Cave, Peace River District, British Columbia, revealed deposits dating from 10 700 BP to the present. The earliest fauna (10700 - 10000 BP) was deposited when the newly deglaciated landscape was largely unforested and included bison (Bison sp.), ground squirrel (Spermophilus sp.), a large hare (Lepus sp.), snowshoe hare (Lepus americanus), and a variety of birds, including the Cliff Swallow (Hirundo pyrrhonota). By 10000 BP snowshoe hare (Lepus americanus) was the most numerous mammal, indi cating the development of forested conditions. By 9000 BP the fauna resembled the modern Peace River fauna prior to European settlem ment, typical of a largely forested landscape, with wetland areas indicated by aquatic avian species. Subsequent Holocene climatic fluctuations are not evident in the faunal record.   Article Summary by Jonathan C. Driver, May 2015               This article provides a historical interpretation of the animals and natural environment of Tse’K’wa and surrounding regions. The animal bones from Tse’K’wa are special for a number of reasons. This is one of the few sites in northern BC or Alberta that preserves a complete record of animal bones from the end of the last ice age to modern times. As a result, we have a glimpse into the local and regional environment around the site. Furthermore, the bones and teeth are preserved very well, especially in the earliest (oldest) layers.             Because the animal bones tell us a lot about past environments, I decided to publish a description and interpretation in an earth sciences journal.  The paper complements the 1988 paper in American Antiquity that focused on the early archaeological materials. These are the two main journal articles that resulted from the 1983 excavations.             There are two major environmental periods represented. During the late glacial and early post-glacial period the landscape was less forested than today, and there do not seem to have been wetlands near the site. Animals present include an extinct form of bison, quite a large number of ground squirrels, and a few bones of a large hare that is not the common snowshoe hare found in the region today. These all indicate a largely treeless environment. However, this period was relatively short-lived, and the second period at the site reflects many thousands of years in which the landscape was mainly forested, and included nearby wetlands. The mammals and birds of the second period are typical of the region and, with the exception of passenger pigeon that became extinct in the 19th century, could all be found within a few kilometres of the site today

The Significance of the Fauna from the Charlie Lake Cave Site

Article Summary by Jonathan C. Driver, May 2015               This paper and The Prehistory of Charlie Lake Cave by Knut R. Fladmark, are excerpts from Early Human Occupation in British Columbia, an archaeological book published in 1996. In 1988 the annual meeting of the Canadian Archaeological Association was held in Whistler, B.C. As part of the meeting, Roy Carlson, a professor at SFU, organized a symposium on the early human presence in British Columbia. Knut Fladmark and I each gave a paper on our work at Tse’K’wa, based on the 1983 excavation season.             Although it was intended to publish the book quickly, there were various delays, and Fladmark and I went back to Tse’K’wa in 1990 and 1991 before the proceedings of the Whistler symposium were finally published in 1996. We updated our papers slightly based on the later excavations, but both of these papers really reflect our thinking prior to the full analysis of the material from 1990 and 1991.             Fladmark’s paper is a good introduction to the location and geology of the site, and it provides an account of the cultural materials recovered in 1983.             Driver’s paper summarizes the animal bones from the 1983 excavations, and devotes more time to considering how the wide variety of animals were brought to the site. I noted that the bison bone was found in locations with lower amounts of small mammals and birds and suggested that most of the smaller animals were brought to the site by non-human predators, such as owls

Raven Skeletons from Paleoindian Contexts, Charlie Lake Cave, British Columbia

Two raven skeletons were excavated from Charlie Lake Cave, British Columbia, in association with Paleoindian occupations dated at about 10,500 and 9500 B.P. The distribution and condition of  the bones, the association with  artifacts, the configuration and location of the site, and data from ethnographic and historic sources contribute to the argument that the two ravens were deposited deliberately by people.   Article Summary by Jonathan C. Driver, May 2015               This paper emerged from a series of personal experiences I had while working at Tse’K’wa. Fairly late in the 1991 season I was excavating a layer dating to about 9000 BC that didn’t appear to contain any humanly-made artifacts but, like many layers at the site, had a few animal bones scattered through it.  As I was digging I uncovered two bird bones lying in an “articulated” position – in other words, they were in the same relationship to each other as they would be when the bird was alive.   Leaving them in place, I began to dig carefully around them, and soon realized I was uncovering a complete bird skeleton. As I uncovered each bone I drew it onto a plan, numbered it and removed it, so by the end of the work I mapped an almost complete bird skeleton, with each bone numbered and bagged separately. The final part of the excavation was very delicate, as I uncovered and mapped the individual toe bones. In among the toe bones was a small rock, and as I removed it I realized that it was a rather unusual stone artifact known as a “microblade core”.  Made of very fine-grained stone, ancient people had carried it around so they could remove small, parallel sided flakes of stone, which could then be hafted in a variety of handles – rather like blades of utility knives that we use today. This technology is so distinctive that archaeologists make special note when it appears. The bird skeleton was lying in a small hollow, either natural or humanly made, so it appeared that someone had placed the dead bird in the hollow, with an artifact at its feet, and then covered it up so that it would not be disturbed.             As we excavated even deeper levels we uncovered a second bird skeleton, scattered across about a square metre. Although it was older by at least 1000 years, it was even better preserved. We also mapped the bones of this skeleton as they emerged, and confirmed that we had a second bird that seemed to have been buried as a complete individual.             During excavation seasons one is always concerned about getting as much done in the days available, so I didn’t spend much time trying to identify these birds. I assumed that once I was able to study the bones they would turn out to be some kind of waterfowl because remains of ducks and grebes are quite common at Tse’K’wa. Once I got back to the university at the end of the summer one of the first things I did was to check on the identification, and I quickly realized we had uncovered two raven skeletons.             For anyone living in British Columbia the connection between ravens and First Nations people is well known. Bill Reid’s massive cedar sculpture at the UBC Museum of Anthropology of Raven opening a clam shell is visited by tens of thousands of people every year, and his Jade Canoe, steered by Raven, is seen by millions at the Vancouver airport. Elementary school children all read stories about Raven the trickster.             This connection to BC’s First Nations would be reason enough to get excited, but I had a personal connection to ravens and Tse’K’wa that caused shivers to run up my spine as I made the identification of the bird skeletons in the bone lab. When we had finished our excavations in 1991 I spent a morning at the site by myself, mainly down in the bottom of the deep excavation finalizing some of the drawings, checking measurements and just thinking about the site before we started backfilling on the following day. It had been very quiet in the excavation hole, too deep to hear traffic noise from the Alaska Highway, no comments from an excavation crew, no scraping of trowels on rock, and no rattling as sediments were shaken through the screens. My companions throughout that morning were a pair of ravens who hung around the site, talking to each other and, as I liked to think, talking to me as well.  My experience with the ravens that morning filled my thoughts as soon as I had confirmed the identification of the bones.             I knew that there was a story to tell about the buried ravens, but it took me a while to sort it out, and quite a long time to get it accepted for publication. Like most scholars, archaeologists are most comfortable with the familiar. No one had found any evidence in North America for ritual behaviour this early, other than very rare human burials, and reviewers were reluctant to accept the interpretation that these two ravens were placed deliberately by people. I found this somewhat frustrating because the other region in which I work – the American Southwest – has thousands of examples dating from more recent times of “special” birds (mainly eagles, hawks, owls and parrots) found as complete skeletons. Often times these remains are in association with  buildings identified as places of ceremonial or ritual activity for ancestral Native Americans. Tse’K’wa clearly would have a been a special place on the landscape, and both caves and ravens have all kinds of spiritual importance around the world. Why was it so difficult for other scholars to accept that the combination of complete skeletons, a special place, and culturally significant birds  suggest that Tse’K’wa was a sacred location to the First Nations people who visited the site many years ago?              Eventually I was able to convince the editor of American Antiquity – arguably the best archaeology journal in North America – that there would never be agreement amongst reviewers. Some thought my manuscript was too speculative, and others thought it was worth publishing.             The published paper describes the location, configuration and age of the skeletons. It briefly describes the importance of ravens in cultures around the world. They are often seen as messengers, and are frequently connected to hunting. In some parts of North America Raven is both creator and trickster who has many human qualities.             I also noted that Tse’K’wa was likely a prominent feature of the landscape, not only because of the cave, but also because there was a very large vertical stone monolith in front of the cave that would have been much more visible than today. Caves are often entrances to the underworld, and the placing of spiritually important birds right in front of the cave mouth may suggest that they were seen as capable of communicating between the world of the living and the world of the spirits

Stratified Faunas from Charlie Lake Cave and the Peopling of the Western Interior of Canada

Article Summary by Jonathan C. Driver, May 2015               This article discusses the correlations between environmental change and human activity and the significance of Tse’K’wa to such research. In 1995 I attended an international conference in Berlin that looked at the archaeology of the transition period from the last ice age (the Pleistocene) to the modern period (the Holocene).  I gave a paper summarizing  archaeological data from western Canada for the period 11,000 BC to 9000 BC. At that conference it was suggested that we needed to have a second meeting that looked at changes in environment and hunting during this period of global environmental change. I therefore volunteered to organize a set of presentations within a conference on animal bone archaeology (zooarchaeology) that was held in Victoria, British Columbia, in 1998.             The paper that I presented included a discussion about when habitats would have been suitable for human habitation after deglaciation, but in view of the small number of sites and the differing intensities of archaeological fieldwork I did not feel confident in suggesting  (as I now believe) that colonization of the interior of western Canada took place from south to north.             The rest of the paper focused on Tse’K’wa because it was (and is still) the only archaeological site in the interior of western Canada where evidence for environmental change can be correlated with evidence for human activities. The animal bone data from Tse’K’wa clearly show a rapidly changing environment as the ice was ending and new habitats were being established. Building on the results of the 1983 excavations, adding data from the 1990 and 1991 excavations allowed a more detailed picture of the changing environments. For example, one diagram in the paper shows how quickly the local small mammals change from ground squirrels to snowshoe hare. It was also apparent that animals that live in or near water became more prevalent  once the forested environments were established

Tailoring polymer molecular weight distribution to pore size distribution using filtration and mechanical degradation

High molecular weight polymers are used for mobility control during oil recovery operations. The cost effectiveness of polymer solutions improves as the molecular weight of the polymer increases, but very high molecular weight polymers can be as large in solution as the throats of the pores that support transport. An envelope exists in pore size and permeability that marks the limits of transport without plugging for polymers of different sizes. The concept of a polymer’s “size” is a complicated one; polymers adopt non-spherical shapes in solution, a distribution of molecular weights is present in any given solution, and the exact relationship between a polymer’s apparent size and the size of pores as inferred from mercury injection capillary pressure is unclear. This study contends that filter plugging is the most practical measurement of the sizes of polymers in a polymer solution, and builds a quantitative theory to maximize the quality of the information extracted. Specifically, the most effective size characterization method is the filtration pore size assay, in which plugging of a polymer solution is measured on filters across a range of pore sizes. The utility of this assay is demonstrated in comparisons of polymer shearing, variations in salinity, post-hydrolysis, and filtration processing. It is shown that mechanical degradation of polymer solutions shifts the high molecular weight tail of the polymer size distribution without appreciably reshaping it, that swelling by salinity and hydrolysis has a differential effect on plugging at large and small pore sizes, and that serial filtration can produce high-quality, high-viscosity polymer solutions that cannot be produced from a single filtration. Furthermore, mechanical degradation and serial filtration can be used in combination to produce polymer solutions that can be filtered at extremely small pore sizes, down to one tenth of a micrometer in diameter, with surprising retention of viscosity that makes them suitable for chemical EOR core floods. Single phase core floods with HPAM and scleroglucan are used to assay the limits of transport without plugging, while a successful surfactant flood in a seventeen millidarcy reservoir carbonate core proves the power of the optimized tight-filtration technique.Petroleum and Geosystems Engineerin

A 10 500-Year Sequence of Bird Remains from the Southern Boreal Forest Region of Western Canada

The prehistoric avian fauna from the Charlie Lake Cave site, Peace River District, British Columbia, spans the last 10,500 years and includes birds from eleven orders. Prior to about 10,000 B.P. the fauna is sparse and the most common species is Cliff Swallow (Hirundo pyrrhonota), which probably nested at the site. The avian fauna from 10,000 B.P. to the present is dominated by wetland associated birds (mainly grebes and ducks) of the same species found in the area today and is consistent with the establishment of boreal forest by 10,000 B.P. From about 8000 B.P. Passenger Pigeon (Ectopistes migratorius) occurs and appears to have been a regular component of the local fauna. The assemblages demonstrate rapid colonization of boreal environments by bird populations by 10,000 B.P. and probably indicate that the modern patterns of migration were established early in the Holocene.Key words: British Columbia, fossil birds, Holocene, Passenger PigeonL’avifaune préhistorique du site de Charlie Lake Cave, dans le district de Peace River en Colombie-Britannique, couvre les 10 500 dernières années et comprend des oiseaux appartenant à onze ordres différents. Antérieurement à environ 10 000 BP, la faune est clairsemée et l’espèce la plus courante est l’hirondelle à front blanc (Hirundo pyrrhonota), qui nidifie probablement sur le site. L’avifaune couvrant de 10 000 BP au présent est dominée par des oiseaux associés aux terres humides (surtout des grèbes et des canards) appartenant aux mêmes espèces que l’on trouve actuellement dans la région, et cette prédominance correspond à l’établissement d’une forêt boréale d’ici 10 000 BP. A partir d’environ 8000 BP, la tourte (Ectopistes migratorius) fait son apparition et semble avoir été une composante régulière de la faune locale. Les assemblages indiquent une colonisation rapide des milieux boréaux par les populations d’oiseaux d’ici 10 000 BP et semblent indiquer que les schémas de migration actuels se sont établis au début de l’holocène.Mots clés: Colombie-Britannique, oiseaux fossiles, holocène, tourt

Rise and Fall of the Beringian Steppe Bison

The widespread extinctions of large mammals at the end of the Pleistocene epoch have often been attributed to the depredations of humans; here we present genetic evidence that questions this assumption. We used ancient DNA and Bayesian techniques to reconstruct a detailed genetic history of bison throughout the late Pleistocene and Holocene epochs. Our analyses depict a large diverse population living throughout Beringia until around 37,000 years before the present, when the population’s genetic diversity began to decline dramatically. The timing of this decline correlates with environmental changes associated with the onset of the last glacial cycle, whereas archaeological evidence does not support the presence of large populations of humans in Eastern Beringia until more than 15,000 years later.   Article Summary by Jonathan C. Driver, May 2015   This article explores the movement of North American bison and the special significance of Tse’K’wa in this research, shedding insight into how the first Paleoindian peoples of Canada arrived at the land. One of the fascinating aspects about archaeology today is the speed with which new scientific techniques are developed and applied to archaeological materials. This paper demonstrates why it is so important to keep material safely stored after it has been excavated – because you never know when it will be valuable to a future researcher or when it can yield new information about the past.   Quite a few years after the excavations at Tse’K’wa were finished I was approached by Alan Cooper and Beth Shapiro of Oxford University about the possibility of sampling early bison bones from the site, to see if they still had DNA preserved. Beth was writing her doctoral thesis on the evolution of bison, and she was being supervised by Alan, a highly accomplished researcher into ancient DNA. It turned out that the Tse’K’wa bison were well preserved, and Beth was able to extract DNA and include it in the study of hundreds of samples from North America and Asia. As an added bonus, Beth and Alan arranged for radiocarbon dates to be run on every bone they studied.This added to our understanding of the age of the site\u27s earliest material.   Beth summarized her doctoral research in this paper, published in the very prestigious journal “Science”. The many contributors to her research were listed as co-authors, recognizing that each of us had contributed in a small way to the research, by sharing samples and ideas.  While the paper mainly deals with Beth’s conclusions about the evolutionary history of bison, for those interested in Tse’K’wa and the history of the early peoples of Canada, there was a fascinating tidbit of information contained in the Tse’K’wa bison DNA – they were from two quite distinct populations.   To understand the significance of this, we must first consider the impact of the extensive ice sheets that formed across Canada about 20,000 years ago. The ice sheets separated North American bison into two populations. One group of bison herds lived to the south of the ice sheets, in what is today, the continental USA and very southern parts of Saskatchewan, Alberta and B.C. The other population lived in unglaciated regions of, what is today, Yukon, Alaska and northeast Asia. These two populations can be distinguished by minor differences in their DNA. When Beth studied the bison fossils from across the vast region of their ice-age distribution she found that in every location except one the bison were either northern or southern types. The one exception was Tse’K’wa where bison from both the north and south were found.   The explanation for this seems fairly straightforward. When the western Canadian ice sheets melted and new pastures were developed, northern bison began to move south through the Yukon and into northern and central BC and Alberta. At the same time, the southern bison began to move north, also following pastures that developed on the recently de-glaciated  landcapes.  Finally, the northern and southern populations met in the Peace River region. There is no evidence that they bred with each other, and, based on the genetics of modern bison in North America it appears that the southern form survived and evolved into the bison we are familiar with today.   The Tse’K’wa data suggest the meeting of bison populations must have occurred around the same time the site was first occupied by humans, as it is very unlikely that two genetically distinct populations of bison could have lived in the same environment without interbreeding or one of them becoming extinct. This means the establishment of a viable migration route for animals (and people) from Alaska through Yukon, B.C., Alberta and into continental USA must have happened after the dates of the earliest human presence in the continental USA and South America. Therefore, the first people to enter North America could not have migrated through an ice-free corridor along the eastern slopes of the Rockies. Assuming they entered the Americas during the last ice age, then the most likely route would be down the coast of Alaska and British Columbia. Interestingly, this hypothesis was proposed by the director of the 1983 Tse’K’wa excavations, Knut Fladmark, in a paper published in 1979!   The Tse’K’wa stone artifacts lend support to this scenario. The earliest spear point at the site – the “fluted point” – is stylistically very similar to artifacts found in the south, which date a little earlier than those at Tse’K’wa. This supports the notion that the earliest inhabitants of the site were part of a human population that began to move north (perhaps out of southern Alberta and northern Montana)  following the bison herds as they moved north to exploit the newly created grassland environments that formed as ice melted and glacial lakes drained away

The Paleoindian Component at Charlie Lake Cave (HbRf39), British Columbia

Charlie Lake Cave (HbRf 39) is a stratified site in northeastern British Columbia, Canada, containing a flutedpoint component at the base of the excavated deposits. The small artifact assemblage includes a fluted point, stone bead, core tool, and retouched flake. A diverse associated fauna includes fish, birds, and mammals, indicating a more open environment than exists today. Radiocarbon dates suggest that the artifact assemblage was deposited about 10,500 years ago.   Article Summary by Jonathan C. Driver, May 2015             This was the first major publication about Tse’K’wa and it focuses on what for many people was the most exciting find at the site – a very early occupation of so-called “Paleoindian” people.             There continues to be considerable debate about when the first people came to the Americas. In the 1980’s (and continuing today), the weight of evidence supports a long-held belief that the ancestors of the indigenous peoples of the Americas made their initial migration from somewhere in northeast Asia.  However, the timing of this movement, the context in which it occurred, and the date are still contentious. (It is, of course, a simplification to describe this as a single event. There is plenty of evidence for a number of major migrations across the Bering Strait, and it is likely that there was a flow of people and ideas in both directions over thousands of years).             In the 1980’s, as today, virtually all archaeologists agree that “Paleoindian” cultures dating to the end of the last glacial period (about 12,000 BC) indicate a well-established population throughout the Americas by that time, although there is still considerable debate about when the first ancestors of Paleoindians arrived in the Americas.             While the way of life of these peoples must have varied across different environments found in North and South America, the most distinctive Paleoindian artifacts in North America are a kind of stone spear point, known as “fluted points”.  Fluted points were chipped from fine-grained rocks, such as chert, jasper and obsidian, and generally had a long, lanceolate outline. In order to fit the base of the point into the shaft of the spear, it was thinned by striking off some flakes that ran from the base towards the sharp tip, creating a shallow channel or “flute” on one or both surfaces of the stone spearpoint.             Fluted points have been found in association with extinct animals, most commonly woolly mammoth and extinct forms of bison, but also with horse and camel, primarily  in the central and western half of the USA. Due to different geological and soil conditions in eastern USA, most fluted point sites there do not preserve animal bone. In 1983 when a fluted point was found at Tse’K’wa, there was only one site in all of Canada where fluted points had been found in association with organic material that could be radiocarbon dated – at Debert, in Nova Scotia where charcoal in the soil provided some dates. Tse’K’wa was the first site in Canada that produced a fluted point in association with animal bones that had clearly been butchered by people – in this case an extinct form of bison – and the first site in Canada in which a fluted point was found at the bottom of a long sequence of later cultural periods. The unique soil conditions at the Tse\u27K\u27wa site have enabled archaeologists to use radio carbon dating on fluted points and animal remains to gain further insight into the lifestyles and timeline of early human occupation of Canada.             Also of significance was the location of Tse’K’wa just to the east of the Rockies. Archaeologists had proposed that one route into the Americas during the late ice age was between the Rocky Mountain glaciers to the west and the massive ice sheets that covered Canada to the east – this so-called “ice-free corridor” might have allowed early hunters to move from unglaciated areas of Siberia and Alaska into the vast uninhabited continents to the south of the ice. Although fluted points had been picked up from ploughed fields in BC and Alberta, before the excavations at Tse’K’wa none of them had been radiocarbon dated, and so it was difficult to relate them to known dates of glaciers and post-glacial landscapes