Why do we survey gravel pits?

Aggregate pit applications, even renewals, are regularly triggered for Historic Resources Impact Assessments in Alberta.  This is mostly due to two factors: their location, and their impact levels.  Good sand and gravel deposits are often located near watercourses, especially major rivers, and the presence of coarse parent sediment usually gives them better drainage than surrounding terrain. High, dry ground next to water is exactly the kind of place people have been camping for thousands of years.

Reid taking notes after testing a high potential landform in a planned gravel pit.

The second factor is the expected impact.  Other development types, like forestry or seismic, may disturb sites, but will leave some or most of them intact.  By their nature, aggregate pits will result in complete destruction of any archaeological sites that may be in their footprint.  Once an archaeological site is destroyed, it’s gone forever.  This means the province only gets one chance to find, understand and protect sites if they’re in a planned gravel pit.  The survey intensity and mitigation standards are therefore more stringent.
Gravel pits also have a high potential to contain quaternary (ice age) mammal fossils.  Bones and tusks from ice age animals like mammoths, extinct bison and sabre toothed cats were often deposited in gravel bars along ice-age rivers.  These gravel bars are the gravel seams that the modern aggregate industry targets.
Alberta Culture released new guidelines for gravel pit Historical Resources Act compliance two years ago.  In short, pits under 5 ha require an HRIA if there’s a known site in the immediate area.  Pits over 5 ha require an HRIA if there’s a known site, or if the land is deemed to have high archaeological or palaeontological potential.
The 2004 Code of Practice for sand and gravel pits says that gravel pits “may be required to shut down if artefacts are discovered during operation of the pit” (section 8.3.6).  This is very rare. Usually if an archaeological site is found during the HRIA, it can be avoided or archaeological digs (mitigative excavation) can be done to salvage a sample of the site before development.  If archaeological or palaeontological resources (for example arrowheads, stone tools, ice age mammal or dinosaur bone) are found during operation, the pit operator is required to report it (this post explains how), and some salvage may be done, but it’s unlikely the pit will be shut down.  Alberta Culture and historic resource management professionals like us work to balance economic development for Alberta’s future with preservation of it’s past.



The Archaeology of Wildfire

This is a guest post by Christina Poletto, a Master’s student with the Institute of Prairie Archaeology at the University of Alberta Department of Anthropology. She’s studying the palaeoenvironmental signature of wildfire, to look for signs of pre-historic controlled burning by indigenous societies in northeastern Alberta.

Fire is almost a constant in Alberta’s north, and its impact can be felt not only on the environment but on populations. In recent years’ fire has been seen in a negative light due to extreme fires that have impacted communities in northern Alberta. The 2016 fire in Fort McMurray has had a devastating impact on people in the area, displacing thousands and damaging houses and buildings. However, fires were not always this large and destructive.

Fire Map
Wildfires from 1930 to 2014. This map only presents 84 years of fires in the area, but it shows the frequency and scale of fires in the region. (Fire history from Canadian Forest Service. 2011. National Fire Database – Agency FireData. Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta. http://cwfis.cfs.nrcan.gc.ca/en_CA/nfdb.; map created by C. Poletto)

As part of the boreal forest’s natural cycles, fires allowed for a diverse mosaic of landscapes to be re-established and helped support animal communities in the area. These natural fire cycles also help to remove ‘dead’ organic materials like fallen trees and overgrown plants. If these materials are left to build up, they become another fuel source for fire and make fires more intense. This has led fire scientists to argue that the more the forest is regulated and the more fires are suppressed, the more intense and dangerous fires become. In the years before fire suppression, fires were a crucial and positive part of the success and diversity of the boreal forest.

Dense forest cover can be both fun and challenging when accessing sites. For fires though, this can mean a faster moving and more intense burn (image C. Poletto)

In addition to natural fires, northern Alberta First Nations groups had traditions of cultural burning. These fires were highly regulated; they were only started under specific circumstances and were dependent on factors like weather conditions and the amount of fire fuel in an area. Early spring was the preferred season because the ground was dry enough to burn but damp enough to prevent the fire from getting too large, whereas during the fall it was drier, making it more dangerous to begin burning. When all the conditions were right, fires would be used to create landscape features like hay meadows or to form and maintain trails, and to promote plant and animal communities re-entering into an area. Ethnographic studies like ones conducted by Henry T. Lewis and Theresa Ferguson with the Dene-Tha (Slavey) in northwestern Alberta documented the longstanding tradition of controlled burning. Elders commented that these practices would not only promote the movement of people but would encourage vegetative communities to thrive and entice animals to revisit areas. In the forest, ensuring the availability of food resources for the months ahead and for years to come was the primary goal of these activities, which is why such great care was taken with the burning process.

In an archaeological site with deep deposits, records of these traditions could be noted by multiple layers of charcoal related to occupation periods. However, in many parts of the boreal forest, the soil deposits are shallow and make it challenging to see these patterns. Instead, researchers can look at soils in lake basins to help recreate these parts of the record. With these ancient and modern records, we can understand how different plant species respond to different fire types, and model the regrowth and response of animal communities. Understanding how First Nations groups manipulated these environmental relationships enhances our understanding of past groups living in the boreal forest. IN addition to its archaeological value, this knowledge can be integrated into modern forest management practices. In some parts of Alberta, highly regimented cultural burning through collaborative efforts has been reintroduced as a way to help minimize fire risk and to promote a healthy, diverse boreal forest.

This map of the Clear Lake – Eaglesnest Lake area in the Birch Mountains shows how we can use current vegetation data to see how the boreal forest responds to fire. It also serves as a baseline for future research to attempt to interpret the boreal forest’s story of fire from lake records (created by C. Poletto).




Archaeology on Deer Mountain

On Friday, April 15th at 7 PM Tree Time Services Sr. Project Archaeologist Kurtis Blaikie-Birkigt will be presenting  at the High Prairie and District Museum on ongoing research on Deer Mountain, Alberta.  On the weekend, Tree Time will be at the High Prairie Gun & Sportsmen’s show with a display of artifacts and replicas to help identify your finds.

Figure 1. Stemmed projectile point found by Darryel Sowan of Swan River First Nation during archaeological survey by Western Heritage Services for Alberta Plywood Ltd. (From Cloutier, 2006. Courtesy of Western Heritage Services)


Early archaeological research on northern Alberta was focused on big lakes. Large campsites were found on major lakeshores and were assumed to be related to seasonal fisheries. It was assumed that past people’s hunting forays into the hills and hinterlands wouldn’t have left much of an archaeological trace. When we started doing archaeological surveys for forestry cutblocks in 2001, we didn’t expect to find very much. The typical sites we’d find would be small scatters of stone chips and flakes left from making stone tools like arrowheads. Even those sites were almost always very close to major streams or other waterbodies.

Figure 2. Location of Deer Mountain. Note the distance from major waterbodies.

In 2005, I was part of a crew that did some pre-harvest archaeology surveys for Alberta Plywood on Deer Mountain (Figure 2). Earlier surveys had found a few sites there, more than would be expected in a place so far from major waterbodies. Even knowing there were sites there, our findings in 2005 surprised us. We found quite a few sites, they were richer than expected, included a unique local stone called Grizzly Ridge Chert (Figure 3), and we found a spear point similar in style to ones that date to 8000 years ago (Figure 1). Deer Mountain was an unusual place, archaeologically speaking, and was very eye opening to me.

Figure 3. Grizzly Ridge Chert retouched / utilized flake found on Deer Mountain in 2015.

Last year, I got to revisit some of the same areas for Alberta Plywood, with the benefit of another 10 years of experience, high resolution LiDAR imagery, and significant improvements in survey and site evaluation methods. We found more sites, bigger sites, and more interesting sites in places we didn’t even think to look in 2005. I came away with an even greater appreciation for how interesting Deer Mountain is, and for how much I’ve learned over the intervening years.

In this talk, I’ll touch on careers in archaeology, archaeological methods, how industry and government manage risks to archaeological sites, and a really interesting area in Alberta archaeology that’s barely been studied.

Figure 4. View to significant site GfPt-3 on Deer Mountain.



Cloutier, Riel

2006      Heritage Evaluation of West Fraser Slave lake (Alberta Plywood Ltd. Division) 2005/2006 Annual Operating Plan Forest Harvest Developments, Slave Lake, Alberta. Archaeological Research Permit No. 2005-378. Report on file, Archaeological Survey of Alberta, Edmonton.


Archaeology of the Marten Creek valley

Last year (2015) archaeologists from Tree Time Services conducted surveys of a number of areas on the Marten Creek valley, from near the mouth of the creek at Lesser Slave Lake to the headwaters at Marten Lakes.  These surveys were done in advance of forestry operations by Alberta Plywood and Tolko Industries Slave Lake mill.  We found several clusters of precontact archaeological sites that show the Marten Creek valley has been occupied and traveled through for thousands of years.

Point found at GjPr-8 on Marten Creek. Probably 3500 to 1350 years old.

Near the mouth of the creek, we surveyed areas on the north and south sides of the valley for Tolko.  A little survey had been done in this area before, for a pipeline that crossed the creek valley just east of Highway 88.  This survey found two small scatters of stone flakes on south facing terraces over the creek.  We flagged those sites for avoidance, and we found several other small sites.  At two of these sites (GjPr-8 and 10), we found small, side-notched points. If you found these, you’d probably call them arrowheads, but based on the size, they were probably attached to a shaft bigger than an arrow, for a javelin-like small spear. We call these spears ‘darts’. They were thrown with a throwing stick called an atlatl, that gave them a lot more range and force than a spear thrown by hand.  We know that atlatls were used in Alberta from about 8000 years ago up to 1300 years ago.  These points are similar to Besant or Bracken style points that date to the end of this period, from about 3500 to 1350 years ago.

Broken dart point from GjPr-10, overlooking Marten Creek. Probably 3500-1350 years old.

Further upstream, on the north side of Marten Lakes, we found several small sites and a couple much more extensive campsites.  We didn’t find any diagnostic tools, like projectile points, that would give us a time of occupation, but we did find some other tools and cores that give a sense of what people were doing here.  A lot of the debitage, or flakes and chips from making tools, are from the early to middle stages in the tool making process and are of quartzite, which is present in the local glacial gravel.  This tells us that one of the things people were doing in the valley was making tools from local stone. The local quartzites are fairly coarse-grained, and very strong. They’re good for making things like stone choppers, hide scrapers,and expedient (quick, disposable) knives, and we have found a couple tools like this in the area. We also found some cores and flakes of materials other than quartzite. These include a fine grained siltstone core and a flake of chalcedony or silicified peat, which is a material similar to flint. These were probably brought here from elsewhere because people knew it would be difficult to find nice fine-grained stone here to make smaller, sharper tools with.

The biggest site on Marten Lakes (GjPp-4) had multiple components, identifiable occupations from different time periods.  There were stone flakes buried about 20 cm down; some stone flakes and moose bone fragments about 5 cm down, below the moss and duff; a pit feature, cans and moose bone in the duff, and an ATV trail and bullet casings on the surface.  We didn’t do enough excavation to get specific dates for the occupations, but our preliminary interpretation is that we have a precontact occupation of unknown age, maybe another more recent precontact / protohistoric (fur trade era) occupation, an early 20th century occupation (maybe a trapping cabin), and recent traditional or recreational use.

There’s another, very interesting historic site at Marten Lakes, an old ranger cabin with a marked grave. We revisited this to make sure that it wouldn’t be disturbed by the forestry operations, and to update the government on it’s status since it was last reported in 2007.

Known archaeological sites on the Marten Creek valley, as of 2016.

All of these sites tell us that that the Marten Creek valley has been occupied and traveled through for at least 2000 years, and probably a lot longer. We didn’t do enough digging to interpret any of these sites in detail, but based on the types of tools we found: points, scrapers and expedient knives; moose hunting was probably a major activity here. Marten Lakes might also have had a very productive spawning season fishery. The Marten Creek valley and Willow River valley also form a natural travel corridor through the muskeggy country from Lesser Slave Lake to Wabasca, and this probably also played a role in its occupation during the precontact and historic periods.

Early archaeology on Lesser Slave Lake

From 1979 to 1982, Dr. Ray LeBlanc, then Boreal Archaeologist with the Archaeological Survey of Alberta, conducted baseline surveys of the Lesser Slave Lake region.  Before that time there were less than 1000 archaeological sites recorded in the entire Green Zone of northern Alberta (including the Grande Prairie region).  Within the Lesser Slave Lake basin there were only 39 known sites (Figure 1, in yellow).  These were mostly surface scatters of stone artifacts identified by members of the public and the Archaeological Survey during early reconnaissance work.  Known sites included scatters at the Marten Mountain and Deer Mountain fire towers, several sites in Lesser Slave Lake Provincial Park, and a few sites scattered around the shores of the lake.  Besides their locations, very little was actually known about these sites, because little to no testing or excavation was done.

Figure 1. Known archaeological sites in the Lesser Slave Lake region, as of 1989.


Starting with preliminary surveys in 1979, followed by systematic surveys in 1980 and ’81 and test excavations in 1982 Dr. LeBlanc recorded 89 new sites on the shores of Lesser Slave Lake and the surrounding area.  The majority of these sites were located on the northwest shore of the lake, and on the north side of Buffalo Bay.  Most of the sites were identified in surface exposure, including some large collections of artifacts from ploughed fields.  Private collections west of Lesser Slave Lake included some rare artifacts from the earliest occupation of the province, such as Clovis period macroblades and large lanceolate points (Figure 2).  Some examples of these finds can be seen today in the High Prairie & District Museum.

Large spearpoints from the Burley site. These lanceolate bifaces may date to the Palaeoindian period, 8-12,000 years ago. (from LeBlanc 2004, p.35)

Some other notable finds came from a site on the south shore of the lake, near Joussard.  Mr. Frank Madsen had collected a large number of artifacts from his farm on the shore.  His collection included a number of projectile points (arrowheads and spear points) from the middle and late periods of occupation of the province (about 5000 to 250 years ago), as well as a number of oval tools made from quartzite cobbles. These tools had worked ends and chipped notches on the sides.  They’ve been interpreted two ways.  They may have been stone axe or adze heads. Archaeologists call these celts when we don’t know if they were hafted parallel to the handle, as axes, or perpendicular, as adzes.  Alternatively, they’ve also been interpreted as stone net sinkers or weights, with the notches used to tie them to the bottom of fishing nets.
The most interesting finds in the Madsen Collection are examples of ground-stone artifacts, which are rare in Alberta: a jade adze, and a steatite (soapstone) pipe bowl (Figure 3).  The jade adze is typical of the type made and found in British Columbia.  Only about a dozen of these have been found in Alberta, and the current Boreal Archaeologist, Todd Kristensen, is researching them.

Figure 3. Jade adze and steatite (soapstone) pipe bowl from the Madsen Collection. (From LeBlanc 2004, p.25)

These surveys in the early 1980’s made the Lesser Slave Lake region one of the best studied parts of Alberta’s boreal forest, but we still knew very little about the history of human occupation in the region, and how people lived at various times in the past.  We would start getting the answers to some of these questions in the later 1980’s, when Dr. LeBlanc, as a professor at the University of Alberta, returned to some of these sites with students for a field school excavation.


LeBlanc, 2004  Archaeological Research in the Lesser Slave Lake Region. Mercury Series Archaeology paper 166, Canadian Museum of Civilization. Gatineau, Quebec.

More archaeological research in the Lesser Slave Lake region

From 1979 to 1990 Dr. Raymond Le Blanc conducted archaeological surveys and excavations in the Lesser Slave Lake region, first as a member of the Archaeological Survey of Alberta, and later with an archaeological field school with the University of Alberta. These projects are one of the largest archaeological bodies of work in Alberta’s boreal forest outside of the oilsands region. The Mercury paper published from them,
“Archaeological Research in the Lesser Slave Lake Region”, is one of very few monographs on northern Alberta prehistory.

Since 1990, nearly all archaeological research in the region has been conducted under Cultural Resource Management projects, primarily for the forestry sector. These projects have focused our interest away from the lakeshore into the uplands and hinterlands of the region. We have identified hundreds of new archaeological sites in these hinterlands, giving us new perspectives on land-use patterns and settlement systems, long-distance trade, and regional travel and trade networks.

I’m going to be sharing my thoughts on these sites at the 2016 Canadian Archaeological Assocation conference in Whitehorse Yukon this May, in a special session in Honour of my graduate supervisor, Dr. LeBlanc.  I hope to see some of you there.  If you can’t make it, watch this site for the full paper.

How are Historic Resources like Environmental Contaminants?

Tree Time Services is proud to sponsor the breakfasts at the 2016 Edmonton and Calgary ESAA Regulatory Forums.

I attended the Environmental Services Association of Alberta regulatory forum in Edmonton on January 11th, 2016 with Mike Toffan, our Reclamation Coordinator. None of the regulatory updates dealt directly with Historical Resources Act concerns, but our work often occurs in the broader environmental regulation context, so it’s good to have a general understanding of things like the Environmental Protection and Enhancement Act and the Environmental Site Assessment Standards. The presentations by Gordon Dinwoodie and Brian Lambert of Alberta Environment and Parks were of particular interest to me. Throughout Brian Lambert’s overview of the updated standards on Environmental Site Assessment (ESA), I was struck by the parallels between Environmental Site Assessment and Historical Resources Impact Assessment (HRIA).

Continue reading “How are Historic Resources like Environmental Contaminants?”