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Quaternary Environments: Research & Projects

Postglacial Palaeoenvironments of Alberta

Introduction

Palaeoenvironmental work at the Royal Alberta Museum focusses on the investigation of landscape and vegetation changes during the last 12,000 years or so, especially as these relate to the human history of the Province. Several substantial projects are under way, on various sites from different parts of Alberta.

These investigations usually involve examination of plant remains, especially seeds and pollen, that may be preserved in lake muds and peats. These remains can often be identified according to the plants that produced them. Knowing the types of plants that were growing on the landscape in the past can provide information on past climates and climate change. This information is of value to archaeologists trying to piece together a picture of the landscape around their site. In addition, palaeoenvironmental data provide analogues for what conditions in the Province may be like if, as most experts predict, climate warming continues.

Fletcher Site (DjOw-1) macrofossil analysis

The Fletcher archaeological site is located near Taber in southern Alberta and is the subject of the Bison Kill diorama in the Syncrude Gallery of Aboriginal Culture at the Royal Alberta Museum. In addition to bison bone, the sediments at about 250 - 300 cm depth in the site, dated around 9300 years ago, contain plant remains, most of which are seeds. So far, about 33 different plant types have been identified from these seeds. The plants are mostly wetland or aquatic plants, such as bulrushes and pondweeds. Besides the seeds, the mud also contains many shells from pond snails. About 33,000 seeds and about 79,000 snail shells have been counted and identified for this project. Together, the plant and snail remains show that around 9300 years ago, the site was a permanent wetland or small lake. This indicates that there has been considerable change in the environment of the area during the last 9000 years because today there are very few surface water sources in this area, especially in the summer.

Wood Bog, Grande Prairie

This beaver-chewed wood, probably of aspen (<em>Populus</em> sp.) was found about 2 m below the ground surface at the &amp;quot;Wood Bog&amp;quot; site, east of Grande Prairie. Wood at this site has been radiocarbon dated and is around 9000 years old. <p>Sampling the sediments at the Wood Bog palaeoenvironmental site, just east of Grande Prairie, Alberta. The sediments in this section provide a continuous record of environmental conditions at the site for the last 9000 years.</p><p>Just below the water level in the dugout, there is a wood layer containing beaver-chewed wood. This material has been radiocarbon dated and is about 9300 years old. The whitish layer just by the seated figure's shoulder contains abundant mollusc (snail) shells. The upper part of the section consists of peat. Thousands of seeds and shells have been recovered from samples from this site. The seeds can be identified according to the plants that produced them and therefore provide information on the plants growing around this site through time.</p><p><em>Source: Photo CD 8020 3162 2906, Image &amp;#35; 001. Image source: Archaeological Survey collections, Royal Alberta Museum</em></p>

Some years ago, a landowner east of Grande Prairie started finding buried wood during excavation of a dugout. When this wood was radiocarbon dated, it was found to be about 9000 years old. Some of the wood had tooth-marks showing that it had been cut down by beaver. Subsequent investigation has shown that the sediments at the dugout preserve a continuous record of environments during the last 9000 years. Besides wood, the sediments have yielded rich and abundant plant remains, mainly seeds, and also shells from freshwater snails and insect remains.

<p>These seeds are about 9,200 years old and are from bulrushes (<em>Scirpus validus</em> or <em>Scirpus acutus</em>). They are about 2.5 mm in length and came from sediment at 255 - 265 cm depth at 'Wood Bog'.</p><em>Photographed by A. B. Beaudoin</em> <p>These four shells are from a freshwater pond snail called <I>Gyraulus</I>. This is a type of 'ramshorn snail', so called because of the tightly coiled shell. The shells are about 2 - 4 mm across and came from sediment at 205 - 210 cm depth at 'Wood Bog'. They are about 9,200 years old.</p><em>Photographed by A. B. Beaudoin</em>

The seeds show that the site was originally a pond, perhaps dammed by the beavers, which slowly filled in. Archaeological investigations at the nearby Saskatoon Mountain site (GhQt-4), west of Grande Prairie, have shown that people have been living in this area for at least 9500 years. The information on the changing environments obtained from the "Wood Bog" site provides valuable data which allows archaeologists to compile a more complete picture of the landscape seen by the people who once occupied the Saskatoon Mountain site.

References

Beaudoin, A. B. (1993) Seeds, Shells and Sediments: 9,000 Years of Environmental History Near Grande Prairie. Alberta Past 9(3):6-7.

Beaudoin, A. B., M. Wright and B. Ronaghan (1996) Late Quaternary Landscape History and Archaeology in the 'Ice-Free Corridor': Some Recent Results from Alberta. Quaternary International 32:113-126. DOI: 10.1016/1040-6182(95)00058-5

Wright, M. (1992) Saskatoon Mountain: 9500 Years of Human Occupation in the Grande Prairie Region. Alberta Past 7(3) (Winter 1991-1992), pp. 8-9.

Other Related Research Projects

Since 1995, many graduate students, researchers, and visiting scholars have worked in the Quaternary Environments Laboratory and used the Reference Collections, carrying out many different projects. Here is a selection of the projects, reports, and publications that have resulted from that work.