Ground Penetrating Radar

Ground-Penetrating Radar (GPR) is the process of sending radiowaves through the ground. As these radiowaves pass through the ground, any change in the subsurface materials will cause some energy to be reflected back to towards the surface while the remaining energy continues deeper. This information is recorded by a receiver which records the time it takes the wave to travel from the source, reflect off the buried object or disturbance, and travel back to the surface. The receiver converts this signal into a depth for the disturbance or object under the ground.

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Figure 1: Brian Leslie walking a transect with the GPR

The ability to map and record information below the earth’s surface without excavating is a valuable tool to an archaeologist. The excavation of archaeological sites is a destructive process, so having a non-invasive way to analyze and interpret sites is sometimes necessary. This is particularly important when dealing with sensitive cultural remains and unmarked graves.

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Figure 2: Corey Cookson and Liam Wadsworth surveying for unmarked graves

As part of an Archaeological Society of Alberta project, Tree Time Services Archaeologists, Corey Cookson and Brian Leslie, and University of Alberta Graduate Student, Liam Wadsworth, completed a GPR scan of an area identified by a local community as having possible unmarked graves. The team spent the afternoon surveying a grid to identify possible grave-shaped anomalies. The data was analyzed and the GPR scans revealed several clear grave-shaped anomalies 1.5 m beneath the surface. Some of the grave-shafts were narrow and may have contained a single individual (Figure 3, #1), while others were wider and may represent a burial pit with multiple individuals (Figure 3 #2, at least 5 m wide). This larger internment may have been the result of mass burial. It was speculated that these graves were dug around the time of the First World War and the Spanish Flu pandemic.

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Figure 3: Radargram with pit-shaped anomalies

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Figure 4: Same Radar gram with interpretation of pit-shaped anomalies

Purple Glass = Pre World War I

When we find post-European contact sites in Alberta we find a variety of historic resources including: cabins, ceramics, metal, and glass. The style of each of these can be a good indication of age and, in particular, glass has several features we look for. This includes molds, pontil marks (Figure 2), lip forms (Figure 1), and colour.

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Figure 1: Bottle lips crudely applied by hand prior to 1880s when lipping tools invented (Source: Wikimedia Commons)

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Figure 2: Pontil mark on the bottom of glass bottle on all bottles dated before 1860 (Source: Wikimedia Commons)

This year, while assessing a gravel pit along the North Saskatchewan River, we found a multi-component site (FcPs-14) with both a pre-European contact First Nations campsite and a post-European contact dwelling. In addition to the typical lithic debitage, we found a cabin depression, ceramics (Figure 3), metal (Figure 4), and glass artifacts. One shard of glass caught my eye because of the purple tint to the glass (Figure 5).

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Figure 3: Ceramic recovered from FcPs-14

M1182_modifiedFigure 4: Nail recovered from FcPs-14

 

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Figure 5: Purple glass recovered from FcPs-14

From 1885 to 1914, manganese dioxide was used as a clearing agent by glass makers to make sure the glass remained clear. However, when exposed to the sun over time, the manganese dioxide in the glass will cause the glass to turn a purple tint. The main source of this clearing agent was Germany. This supply was cut off with the outbreak of World War I. After World War I, selenium became the preferred clearing agent. When exposed to the sun’s rays, selenium will turn glass yellow.

By recovering this piece of glass, we can make a reasonable interpretation that this component of the site dates to before, or shortly after, 1914. Even a seemingly commonplace artifact like a shard of glass can tell us a lot about a site.

Rat’s Nest Cave – Pictographs

Last year I visited a very interesting site located near Canmore, AB. The Rat’s Nest Cave is accessible through the touring company, Canmore Cave Tours, and can be visited all year round. With the help of my guide, Brent, I rappelled 18 m into the cave and squeezed through many tight water carved gaps and tunnels. Eventually you reach “the grotto” where you can hang out by a crystal clear pool and several beautiful stalagmites and stalactites.

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Left: Repelling into the cave.  Right: One of the many squeezes you will experience!

Also in the cave are many animal bones dating to approximately 7000 years ago and, although I didn’t see any while on the tour, several stone tools dating to 3000 years ago. One of the most fascinating aspects of the cave are the pictographs located at the entrance of the cave. Inside the cave, are several small rock paintings that indicate the cave was of cultural significance for the First Nations people possibly for thousands of years. My guide also informed me that there are several pictographs on the outside of the cave above the entrance but due to years of weathering they are not visible to the naked eye.

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Assemblage of animal bones found in the cave
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One of the rock art images inside the entrance to the cave

Luckily, recent advances in technology allow us to digitally enhance rock art paintings. A process called Decorrelation Stretch or simply D-Stretch is currently being used by archaeologists and rock art researchers to enhance even the faintest of pictographs. The process works by increasing differences in hue and stretching the contrast for each colour variance. When D-stretch is used to enhance the image of the entrance of the Rat’s Nest Cave, a series of handprints can be seen going up the wall.

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Left: Normal image of the wall above entrance.  Right: D-Stretch image of wall above entrance
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One of the handprints isolated (Photo Credit: Jack Brink)

Continuity – Buffalo and Sucker Lake Region

Before 2013, archaeological survey in the Sucker and Buffalo Lake regions only identified three sites.  In contrast, just 5 km east, in the Logan and Clyde River systems, around 25 sites had been found. This is likely due to the location of developments being surveyed, but it may also reflect older archaeological survey methods.  The dense river systems and the sandy sediments typical to these two areas really increase the archaeological potential.  This means there are numerous sites that have yet been identified by archaeological survey.

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When Millar Western Boyle and Alberta-Pacific submitted new forest plans for this region, we knew we could improve the archaeological understanding of the area. Over two field seasons we put in 477 shovel tests and surface inspections. We increased the sites in the area by 14 sites!

Not only did we find sites, but we found two artifacts that really help us understand the people who used this area by helping us determine a date and possible trade connections. Two artifacts, one projectile point and one knife, were the most interesting finds of the survey.

  • The projectile point is the base of a dart thrown by an atlatl. This is an older technology than the bow and arrow, used prior to 2000 years ago. The point is likely Scottsbluff style which is dated up to 8,000 years ago. This atlatl dart point is also made of Knife River Flint. Knife River Flint is a very significant material that only comes from a quarry site in North Dakota (over 1300 km away!).
  • The knife is an asymmetrical corner notched siltstone knife. The only known knife typologies in Alberta belong to the Cody Complex; however, unlike this knife, the stems of Cody knives are usually straight and have a flat base. Further research at this site and about this artifact may significantly alter our knowledge about knife manufacture and technology in Alberta. The style may also be representative of a knife style found in other regions of North America which would suggest travel or trade.

Cabins and historic trails were also identified during the assessment. These are from late 19th to early 20th century occupation of the area, possibly associated with First Nation or Metis use and of cultural significance. At site GgOw-10, two cabins were present, one older than the other. We know this because of the way the two cabins were constructed: one with chainsawn logs and the other with an axe. This is indicative of significant, long-term land use in the Buffalo Lake area. At this site, many metal and glass artifacts were also observed, including a wagon wheel hoop, cans, pots, pans, and a cast iron stove. In addition, we identified wagon trails used to travel along between Buffalo Lake and other nearby settlements such as Philomena.

The area is still being used today and remains an area of importance to local First Nations. A prayer tree was identified while surveying a cutblock along a tributary stream. The cutblock was dropped from the harvest plan due to the presence of the prayer tree. The tree was a jackpine with a red and white pieces of fabric tied to the trunk. The prayer tree can indicate an area where a ceremony took place or an area with medicinal plants. A photo of the tree was not included out of respect for Indigenous traditions.

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Reid documenting an area near the prayer tree

We always look forward to returning to areas we have surveyed in the past.  Continuous archaeological survey helps us better predict where other sites are likely to be and fills out our understanding of how landscapes were used over time.

Gear Review – Load-Bearing Equipment

Anyone that works all day in the wilderness knows the importance of having a quality piece of Load Bearing Equipment (LBE) that accommodates all the odds and ends that are required of your profession, while being comfortable enough to wear for prolonged periods. LBE comes in a variety of styles, from the standard Cruise Vest, to the more tacticool modular equipment based off military style plate carries and H-harnesses that employ MOLLE attachment systems. Archaeologists at Tree Time Services Inc. have tried and tested a whole gambit of systems over the years, and everyone but a few outliers (Reid loves his cruise vest), have adopted the True North Aero Vest – Wildland as our LBE of choice.

Before I start the review section, there is one important aspect of our job that influences what type of LBE we prefer. We need to carry more gear than can be accommodated by LBE alone, so that a good backpack (30-50 Litre) is a necessity. Even though some people have tried to fit all the required equipment in their cruise vest, you can only fit the bare minimum of what we need to bring, and have to abandon some items that aren’t necessarily required, but are extremely valuable in certain situations. Things like rain gear, extra thermal layers, extra socks, survival kits, extra food and extra water will not easily fit in a cruise vest when it is filled with all the items that are required for archaeological survey in the boreal forest. Also, if you do try to fit all those things in your cruise vest, you will no longer be able to work effectively while wearing it. Furthermore, attaching your screen to your backpack with a bungie cord is arguably the best way to carry your screen for long hikes, and allows you to stow things such as a hoodie or jacket between the screen and backpack. For these reasons, almost every archaeologist at TTSI uses a combination of some type of LBE and a backpack.

The Cruise Vest

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Cruise vests have been around for a long time, are widely available, and come in a variety of colour and materials. In my opinion, they are fine if your profession requires you to be mobile in the field and your profession does not require much equipment. Reid uses a cruise vest made from a plastic mesh and considers this to the best vest as it is durable and breathable. Cruise vests can be expensive ($100+), and even more so if they have an internal frame. Yet they still don’t accommodate all the extra gear needed for adverse conditions. Teresa and Tim have both used the cruise vest with internal backpack frame, but Teresa has since switched to the True North Aero and hasn’t looked back.

  • Pros
    • Comfortable if not carrying much equipment
    • Variety of colours and fabrics
    • Widely available
  • Cons (With no backpack feature)
    • Not enough storage space
    • Very uncomfortable when overloaded
    • Very uncomfortable while riding ATV
    • Cannot wear while digging
    • Secondary HiVis still needed
    • Bad screen attachment
  • Cons (With backpack feature)
    • Less gear retention
    • Uncomfortable with backpack
    • Full pockets impede pack waist straps
    • Not adjustable for winter layers
    • Flimsy and wear out quickly
    • Non-breathable and hot

The Modular Vest

Modular vests have been around since the 1990’s and have generally replaced what was typically referred to as “web gear” by many Armed Forces groups around the world. They employ a Pouch Attachment Ladder System (PALS), also referred to as MOLLE, which allows the user to change what types of pouches they use based on personal needs without changing the base vest. Most modular vests also act as plate carriers (body armour) and allow the user to change their load-out while still utilizing their body armour as a base. Although modular vests are widely available, most are in neutral colours or camoflage and are therefore not suited to working with a HiVis requirement. With hunters in mind, a few companies have produced modular vests that are blaze orange, and thus work as HiVis provided the rules concerning HiVis clothing are not super strict (some companies would not consider any of these options to be sufficient HiVis clothing). Kurt used a modular vest for a couple field seasons, but has since switched to the True North Aero. He provided the following list of pros and cons:

  • Pros
    • Modular and adaptable
    • Very durable
    • Equipment-specific pockets
    • Can wear while digging
    • Very adjustable and can fit winter layers
    • No zippers
    • Super Tacticool!
  • Cons
    • Expensive
    • Most are not HiVis
    • Non-breathable and hot
    • Heavy
    • Bulky
    • Not comfortable with backpacks

True North Aero – Wildland

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True North is a company that primarily produces gear for Wildland Fire Fighters and First Responders. The True North Aero was designed as a primary piece of LBE that could be worn comfortably with a backpack. Although True North makes specific products that compliment the Aero, we at TTSI have found that this particular LBE to work with a variety of backpacks. The Aero has a specific spot for radios, GPS, flagging, tape measure and has a fleece lined pocket that fits a iPad Mini perfectly. Essentially, the Aero can accommodate all the equipment need while actually working, and in conjunction with a 30-50 L backpack, provides all the space you will ever need. A further benefit of using the Aero in conjunction with a backpack is that since all your survey equipment fits in the vest, one does not have to unpack their backpack to survey a target. Kurt was able to obtain several Aero vest in blaze orange, but unfortunately they seem to have discontinued so only the black version is widely available. While wearing the black version, TTSI employees usually opt to wear a HiVis work shirt.

  • Pros
    • Very durable
    • Lightweight
    • Comfortable to wear with backpacks
    • Breathable and cool
    • Fits all survey equipment
    • Holds gear secure
    • Can wear while digging
    • Protected inner fleece pockets
    • Few zippers, but high quality
    • Sheds water and dries out fast
    • Very adjustable and can fit over winter layers
  • Cons
    • Not true HighVis
    • Zippers can get clogged with mud

There are many options when it comes to LBE and like most things, not everyone will agree on what is the best. Reid stands fast as a die hard proponent of the mesh style cruise vest as it is durable, breathable and works well with his system. Similarly, Tim continues to use the internal frame cruise vest even though he has had the option to switch. However, the rest of us archaeologists at TTSI have chosen the True North – Aero as our LBE champion and never looked back. I personally think it will be a very sad day when my blaze orange version finally wears out and I am unable to get a replacement. On that day, I will regrettably don a HiVis undershirt, strap on a black True North – Aero and head off into the boreal wilderness.

Muddy Lab Secrets

The mud we slog through in the field doesn’t always stay in the field. It’s wrapped around a lot of the artifacts we find, and ends up in our sample bags. Once we get back from the field, we start the process of washing all the artifacts. As the sediment is brushed away, some of the artifact’s secrets are slowly revealed!

The mud can really hide what colour an artifact is. This flake was a dull grey brown until a “wet brush” made it’s way across one side. Underneath this layer is a beautiful pale quartzite that transitions into a orange-reddish pink the further washing was completed.
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Washing all artifacts in water is not possible. Bone just absorbs the water, which makes it take longer to dry fully. Putting wet bone into a bag will ultimately end up destroying the artifact with mold. Tools we find in the field are also only “dry brushed”. This helps preserve any residue left on tools, which can be used in various residue analyses. A good brushing will help pull out little details though. This thumbnail scraper has been worked around almost its entire edge. The brushing (left) really helps it stand out.
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Sometimes, however, a tool is only discovered after washing the mud away. Retouched flakes (as opposed to a formed tool) are often only discovered as the edges are cleaned, allowing the knapped edge to be fully exposed.  The same goes for a utilized flake.  These are flakes that look like a regular flake, but with closer inspection the edge has been chipped and worn from use.  These are often called expedient tools.  The flake’s sharp edge is used until it is dull, after which it is discarded.
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Fort Edmonton Park Expansion

As part of the upcoming expansion of Fort Edmonton Park, an Indigenous Peoples Experience exhibit is being added. The multimedia exhibit will educate visitors about the Indigenous histories and cultures of the Edmonton region in an engaging and interactive way. The exhibit will include an outdoor amphitheatre, teepees, campsite recreations, and an indoor arena show.

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Conceptual Design of Indigenous People’s Exhibit (subject to change). Photo Credit: Sandra Green.  Featured Image above – Bird’s Eye view of Indigenous People’s Exhibit (subject to change. Photo Credit : Brittany Cherweniuk.

For the purposes of authenticity, the park contracted Corey and Brittany, with another independent contractor, Alexandra Burchill, to do historical research on the Edmonton region during the period of 1600-1850 AD. Their research will be used to inform the exhibit content and educate the interpretive staff. The team analyzed several different source materials including: primary sources, secondary sources, archaeological reports, archival records, and recorded oral histories.

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The Research Team presenting at Fort Edmonton

The team also took part in a training program for the interpretative staff. Corey, Brittany, and Alex spent two evenings with the Fort Edmonton Park interpreters presenting their research. They also had several artifact reproductions for the staff to touch and ask questions about. Several staff took the opportunity to try ancient tool technologies such as the bow drill and atlatl throwing.

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Corey demonstrating tool use for the Fort Edmonton Interpretive Staff

As part of the research process, Treaty Six Elders were consulted and collaborated with to ensure the accuracy of research and identify areas that conflict with Indigenous knowledge, oral traditions, and culturally sensitive topics. Several stories told to us by the Elders were incorporated into the synthesis report including a story of an Elder that remembered his mother using a sharp obsidian flake to make small incisions on his temples to relieve headaches. We found this story to be an interesting addition to our discussion of the persistence of stone tool technologies after the introduction of European goods.

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Conceptual image of the Treaty Lodge (subject to change). Photo credit: Brittany Cherweniuk.

The project was a very educational experience for the research team learning a lot about the history of the Edmonton river valley. But more importantly, the project brought us together with many different people, all united by a love of history and respect for the Indigenous past of the place we all call home.