Conch Shell

At our Archaeology Roadshow event in Lac La Biche, in fall 2015 Allan and Juanita Gaudreault brought in several conch shell fossils. These shell fossils were heavily worn and most were down to the central spiral. This made them difficult to identify at first. These are very unusual specimens because these type of marine shells are not found in Alberta. They are native to the Gulf of Mexico. Our initial interpretation (as archaeologists, not palaeontologists) was that this could possibly be a discarded souvenir or a fossil from the Cretaceous period when an ancient seaway stretched from the Arctic to the Gulf of Mexico.

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Shell fossils from Gaudreault collection

Tree Time Services reached out to Alwynne Beaudoin, Curator of Earth Sciences and Quaternary Environments at the Royal Alberta Museum (RAM), for an answer. The RAM had a conch shell, also found in the Lac La Biche region, donated to the museum in 2011. She has been researching this conch shell and “has not been able to find another record of a conch in prehistoric context from Alberta, though there are records of other marine shells (and) they are unlikely to be Cretaceous.”
Furthermore, the specimen in the Royal Alberta collection was radiocarbon dated to “slightly more than 1000 years before present.” That specimen’s age debunks the discarded tourist souvenir theory. The most likely explanation for the RAM’s shell is prehistoric trade from the Caribbean to Alberta 1000 years ago. There are some artifacts found in Southwestern Manitoba, such as this shell gorget, made from a species of shellfish native to the Gulf of Mexico. However, evidence of prehistoric trade networks between the Canadian Plains and the Gulf of Mexico is extremely rare in Alberta and this would be an artifact of significant information potential.

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The Gaudreault collection of shell fossils and ancient bone fragments.

The potential that the 2015 shells represented trade or travel 1000 years ago, rather than palaeontology from millions of years ago, was pretty exciting. On September 7, 2016 Corey Cookson, Project Archaeologist at Tree Time Services, and Christina Barron-Ortiz, Assistant Curator at the Royal Alberta Museum, made the trip up to the Gaudreault’s home to view the rest of their collection. Upon another viewing of the conch fossils it was clear that our first interpretation was right, and these are remains from the Cretaceous period about 65 million years ago. With permission from the Gaudreaults, a representative sample of the shells were taken by Christina Barron-Ortiz for further study. We will post a future blog once we receive confirmation of the age of the shell fossils. Also stay tuned for another post about some other interesting fossils from the Gaudreault collection.

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Bison Jaw and Horse Tooth

At our Archaeological Roadshow event in Lac La Biche, AB Allan and Juanita Gaudreault brought in a collection of fossils. The fossils were fragments of a darkly stained bison jaw and a set of blueish grey horse teeth. Mr. Gaudreault told us the specimens were found in a low area near a lake. We came up with two possible interpretations of these specimens: they may have been permineralized due to being in a place with very hard groundwater; or could be dated to the early Holocene.

It is quite rare to find animal remains in the boreal forest in central and northern Alberta. The acidic soils of the boreal forest make for very poor preservation conditions. Animal bone is therefore rare, and these finds could help teach us about past environments in the region.

Tree Time Services reached out to Chris Jass, Curator of Quaternary Palaeontology at the Royal Alberta Museum (RAM), for more information on determining a possible age for the specimens. Jass confirms that “you can get fairly dark staining and mineralization fairly quickly depending on the depositional environment. However, if there’s a horse there, (the Gaudreaults) may be finding some older material.” Horses were native to North America, but went extinct sometime between 13,000 and 11,000 years ago (North American horse teeth were also recently found at the Brazeau Archaeological Survey project ). The horses that are ubiquitous in North America today were introduced by the Spanish in the late 15th and early 16th centuries. Due to the fossilized nature of the specimen and the recovery of the teeth from a possible relic lake bed, these horse teeth may be from the extinct North American horse.
Chris Jass goes on to state that he has “been working with a diver who has been pulling bones out of Cold Lake, and we’ve got Pleistocene dates (>11,700 years ago) on a bison that he’s recovered from the lake. I think there is considerable potential for recovery of late Pleistocene/early Holocene (ca. 11,700 years ago) material in many of the lakes in Alberta.”horse

On September 7, 2016 Corey Cookson, Project Archaeologist at Tree Time Services, and Christina Barron-Ortiz, Assistant Curator at the Royal Alberta Museum, made the trip up to the Gaudreault’s home to view the rest of their collection. Christina Barron-Ortiz is a specialist in horse and bison teeth. She confirmed that the horse tooth has the characteristics of several specimens the Royal Alberta Museum recovered from the lake bed near Cold Lake, AB. She also suspected that the bison jaw bone represented ancient bison but could not be as sure as the horse. With permission from the Gaudreaults, the bison jaw and horse tooth were collected and results from carbon dating are expected in the Spring.

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.

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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.