Quarry of the Ancestors

Editor’s note: All images in the post below were sourced from a report developed by the Archaeological Survey, Lifeways and Stantec.

Written by: Matthew Wangler, Executive Director, Historic Resources Management Branch

For decades, northeastern Alberta has been home to large-scale industrial activity in the region’s massive petroleum deposits. A remarkable discovery in the midst of the oil sands revealed that the same area of the province also accommodated another significant industry in ancient times; that historic and contemporary land use share a common origin in an epic event that profoundly shaped our province’s past.  This blog post will explore how historic resource management in Alberta helped reveal a lost chapter of our province’s history, how the discovery illuminated both the remarkable richness and depth of the Alberta story, and the surprising connections between past and present.

Protecting the past in the Oil Sands

Under Section 37 of the Historical Resources Act, the Minister responsible for heritage in Alberta can require industry to undertake assessments of any activity that is likely to damage historic resources, including archaeological sites. The Minister may also order industry to undertake any salvage, preservation or protective measures deemed necessary. The extraction of oil from the bituminous deposits of northern Alberta has evolved into a massive undertaking, and oil sands operators are frequently required to conduct archaeological investigations in areas with archaeological resources in advance of development activities. Industry studies have been indispensable in advancing our understanding of the fascinating history of this part of our province.

The Mystery

These investigations have revealed over 1,000 archaeological sites across the region and millions of artifacts. The density of archaeological sites discovered in the oil sands is one of the richest in Alberta—indeed, in North America—and has shone a light on ancient way of life in the province’s boreal forest. Many of the artifacts collected from archaeological sites in northeastern Alberta are made of Beaver River Silicifed Sandstone, a material well suited to the manufacturing of stone tools and other implements. Beaver River Silicified Sandstone artifacts are also found across western and northern Canada; they have been recovered in the Northwest Territories and near Kindersley, Saskatchewan.  While archaeologists had identified some sources of Beaver River Sandstone in the 1980s, they noted that the artifacts they were uncovering were typically made of a very fine-grained form of the material, whereas the known quarry sites at the time contained coarse-grained stone.  An essential question remained—where was the mother lode?

The Discovery

In the early 2000s, two large industrial projects were being proposed in an area near Fort McKay: a limestone quarry and the expansion of an oil sands mine. As the development area was in close proximity to known archaeological sites, and possessed landscape features that often yield artifacts, industry undertook archaeological investigations in advance of initiating industrial activities. It did not take long for archaeologists to appreciate that they had found something special. Over the course of the following few years, assessments at the proposed limestone quarry and the adjacent oil sands mine revealed an astonishingly rich complex of archaeological sites deposited on the landscape over millennia of occupation and use. The sites contained enormous collections of fine-grained Beaver River Sandstone tools and the flakes produced during the production of stone tools, known as debitage. They had found one of the primary sources of the material—and possibly the main quarry for artifacts scattered across the region. Given its clear significance as a quarry for some of our province’s earliest occupants, the site was named the Quarry of the Ancestors.

The Quarry of the Ancestors

The Quarry of the Ancestors possesses a number of features that distinguish it as a site of rare significance.

Quarry Deposits

Two large sites within the Quarry of the Ancestors consist of exposed formations containing Beaver River Silicified Sandstone and abundant associated cultural materials, reflecting primary extraction and initial processing of these stone formations.

 

Affiliated Sites

Twenty other archaeological sites at the Quarry of the Ancestors represent where raw materials were mined and used in stone tool production and subsistence-related activities.

Stratified Deposits

One of the archaeological sites at the Quarry of the Ancestors occurs in a deeply buried context with multiple soil layers, reflecting an accumulating sediment sequence. This site provides a rare opportunity to investigate archaeological deposits that embody sequential human occupations. Through analysis we can develop an understanding of how ancient land use, resource extraction, trade networks and other cultural phenomena in the region may have evolved through time.

Microblade Technology

Microblade technology is most commonly expressed in the Arctic and in coastal and interior British Columbia, and is thought to have developed as a means of conserving limited supplies of stone raw materials. There are several known occurrences in the oil sands region of archaeological sites containing this technological tradition.

Sub-Muskeg Deposits

Several sites within the Quarry of the Ancestors have provided evidence that archaeological remains extend into water-saturated muskeg landforms. The oxygen-depleted nature of these saturated burial environments hold great potential for the rare preservation of organic components of the archaeological record, such as bone, wood and leather artifacts.

Blood Residue

Analysis of one of the diagnostic projectile points recovered from the muskeg at the Quarry of the Ancestors produced organic residue identified as proboscidian (likely mammoth or mastodon). Additional residue testing of Beaver River Sandstone tools for an exhibit about the Quarry of the Ancestors at the Royal Alberta Museum returned positive matches for bison, deer and fish. The point with proboscidian blood was re-tested, but no additional residues were found.

Cultural Diagnostics

Although most artifacts obtained to date from the Quarry of the Ancestors are large quantities of quarry-related stone production debris, a substantial number of chronologically and culturally diagnostic specimens have been recovered. Projectile points recovered to date suggest that the principal period of site occupation occurred between roughly 9,800 and 1,000 years ago.

The Connection between Ancient and Modern

The scale and depth of the discovery prompted an inescapable question—why was this particular place such a hub for ancient quarrying and tool-making activities? The answer to that question lies in an epic event that transformed Alberta, and laid the foundations for two intensive forms of resource extraction separated by thousands of years.

15,000 years ago, two ice sheets covered most of Canada: the Cordilleran ice sheet extended from the western coast to the Rockies, while the Laurentide ice sheet extended from the Rockies to the Atlantic and Arctic Oceans. Around 12,000 years ago, a warming climate began to melt the ice sheets. As the Laurentide ice sheet receded, massive glacial lakes were formed in its wake. The largest of these was Lake Agassiz, a massive body of water that measured over 1 million square kilometres in extent and 200 metres in depth. It would have dwarfed the largest lakes in existence today.

Scientists think that roughly 13,000 to 10,000 years ago, the lake breached its banks and unleased a catastrophic outflow of water near the headwaters of the Clearwater River. A rapidly moving and enormous discharge of water into the Arctic Ocean significantly raised global sea levels and quite literally tore the top off the landscape in present-day northeastern Alberta. Forests were uprooted and sedimentary layers were obliterated, replaced with braided channel deposits, gravel bars, and sinuous ridges that would in time evolve into a well-drained, gently rolling, treeless plain within a vast forested region. The sinuous nature of the ridges, coupled with the potentially water-saturated condition of the channel features, would have produced ideal places to entrap or surround animals. Although subsequent establishment of modern environmental conditions led to the rapid development of forests, muskegs, fens and small lakes or ponds within former channel areas, these features can clearly be identified at the Quarry of the Ancestors.

When the outflow from Lake Agassiz scoured the landscape, it uncovered two resources that were to become essential to Alberta’s economy: the Beaver River Silicified Sandstone that was so vital to ancient Albertans and the oil sands deposits that have become so essential to modern Alberta. The epic flooding from Lake Agassiz binds together two chronologically distant uses of the landscape that bear surprising similarities. In both ancient and modern times, the region north of Fort McMurray was a site of intensive resource extraction and processing, and a hub for trade and social networks.

Site Protection

As the significance of the Quarry of the Ancestors became evident, Culture, Multiculturalism and Status of Women worked with stakeholders across the region to ensure its long-term protection. Extensive engagements with other Government of Alberta departments, with industrial operators and trappers, and with Indigenous communities resulted in the definition of a very large area— almost 200 hectares—to be preserved. In 2012, the site was designated a Provincial Historic Resource. Designation ensures that this invaluable resource—which represents one of the most intensive uses of a boreal environment yet identified—will be preserved for future generations, and that it will continue to reveal compelling new layers of Alberta’s history.