Geology of Canadian Wetlands

GEOSCIENCE CANADA Volume 31 Number 2 June 2004 57 géologues n’ont pas prêté suffisamment paleoecological tools. Further, these d’attention aux terres humides. Cela tools can be applied to elucidate more tient en partie à une mauvaise precisely what and how the geological connaissance de la géologie des terres connections are with wetlands, and what humides et de ce que sont ces éléments if any, the relationships are between the géomorphologiques. Comme éléments vast array of different wetland types. géomorphologiques, les terres humides Wetlands are intimately connected to the ont ceci de particulier qu’elles sont surroundings of their individual basins principalement constituées de matériaux and to their watersheds. The geology of biologiques issus de processus wetlands focuses on understanding these biologiques, et non de minéraux et de relationships (Moore, 2001). Geology of Canadian roches formées par des processus The importance of geology in Wetlands physiques. Il existe deux grands groupes wetland science seems to have escaped de terres humides, soit les terres the attention of most geologists, despite humides minérales, généralement situées covering about 15% and being a Barry G. Warner en milieux de hautes énergies, et les distinctive part of the Canadian land- Wetlands Research Centre tourbières, situées en milieux de basses scape. Part of the problem is that University of Waterloo énergies, et dont le développement wetlands have long been an enigma. Are Waterloo, Ontario N2L 3G1 comporte une étape de terrestrialisation they landforms, soil units, water features [email protected] ou de tourbification. or vegetation communities? The answer Tant comme élément topo- is yes, to all of the above. Wetland SUMMARY graphique que ressource économique, science can be thought of as an amalga- Wetlands have not gained as much les terres humides ont été et demeurent mation of all of these disciplines. Up attention as they ought to by geologists importantes au Canada. Des savoir- until a decade or two ago, it was not despite being so prevalent in the faire techniques nouveaux et plus possible to provide clear answers to Canadian landscape. Some of this stems spécialisés seront nécessaires pour these questions. Today, wetland science from a poor understanding of wetland concevoir et édifier des infrastructures has become more refined and widely geology and what wetland landforms are. en milieux humides. On devrait voir les accepted as a distinct and unique Wetlands constitute unusual landforms terres humides comme une ressource discipline in the environmental sciences. in that they are formed of biological économique devant être gérer avec A wetland classification system, begun in material predominantly shaped by sagesse. Il est nécessaire que des the 1970s, was an important develop- biological processes rather than being technologies douces soient inventées ment for defining and recognizing formed of minerals and rock shaped pour conserver la ressource et en tirer wetlands in Canada (Warner and Rubec, more by physical processes. There are un meilleur parti tout en protégeant la 1998). Though much remains to be two main groups of wetlands: mineral santé humaine. learned about the intricacies of wetland wetlands, commonly situated in high- hydrology, biogeochemistry, and biology, energy settings; and peatlands, situated and its linkages with other environ- in low-energy settings that undergo INTRODUCTION mental phenomena such as climate, either terrestrialization or paludification Wetlands occur where an excess natural and human-induced during the course of their development. of water saturates soils and collects at disturbances, and global sea levels, little Wetlands, as both a landscape shallow depths on the land surface long advancement can be made in wetland unit and economic resource, have enough to sustain waterlogged science without regard for the important historically been and will continue to be conditions. Geological characteristics role of geology. important in Canada. New and more determine how the water reaches the Canadian geologists were once specialized skills and engineering designs land surface and where it is distributed far more involved with wetlands than will be required to build infrastructure in watersheds. Where and how water is today, and indeed, played a leading role in wetland terrain. Wetlands should be situated within wetlands, especially in wetland studies in the early 1900s. regarded as an economic resource that peatlands, is controlled by physical The early interests revolved around requires wise use and management. characteristics of the peat. Origins, geological surveys and economic Nature-sensitive technologies need to be composition and stratigraphy of wetland evaluations of peat resources in the invented for use with wetlands to deposits depends on dissolved chemicals country. There is as much need today as conserve and enhance the resource to and materials derived from erosion and there was in the early 1900s for serve the needs and protect the health of deposited from their surroundings. The Canadian geologists to be involved with human society. rate and mode by which the sediment wetlands and to re-assume their leading and peat has accumulated and role, especially in view of current RÉSUMÉ decomposed through time, and how this environmental and economic issues, Bien qu’elles constituent un trait carbon-rich material is stored are such as climate change, landscape dominant du paysage canadien, les addressed using common geological and rehabilitation, sustainable wise use of 58 economic resources, surface water and EARLY WORK IN CANADIAN OCCURRENCE AND DISTRIBUTION groundwater conservation and WETLAND GEOLOGY The general pattern and geographic protection, and public and occupational Much of the early work on extent of wetlands became much better health concerns. Perhaps the wane in wetlands in Canada focused on understood once a scientific definition interest in wetland geology in recent peatlands. Initial interests were and a wetland classification framework decades may be due to the narrow primarily from entrepreneurs and were developed for Canada (Canadian historical perception that geologists engineers who investigated ways to National Wetland Working Group, need only play a role with regard to peat mine and process peat for fuel (Warner 1988; Warner and Rubec, 1998). as an economic resource and not with and Buteau, 2000). The first Inventories reveal that about 14% of the much broader issues such as commercial peat mining operation was Canadian land surface and 125 X 106 understanding the origin, character, establishing in 1864 on a bog near ha is covered by wetlands, about 12% development, and management of the Victoriaville, east of Montreal, Quebec. and 110 X 106 ha of which are overall wetland resource in a country Individual operations were started in peatlands, making Canada the most like Canada, whose wetlands are vast Ontario, Newfoundland, and elsewhere peatland-rich country in the world and varied. in Quebec, but all of these operations (Fig. 1; Tarnocai et al., 2000, 2001). Wetlands have historically been ceased by 1877. About 18% of the world’s wetlands regarded as obstacles to development. Interest in the use of peat for occur in Canada (Tarnocai et al., 2001). Their widespread occurrence in this fuel was renewed in the 1890s but this These figures for the most part do not country has made it nearly impossible interest was temporary. The fledgling include freshwater wetlands along the to avoid them. Technical and peat industry at the turn of the century shores of lakes, banks of rivers, in engineering skill, ingenuity, and luck lobbied the federal government for estuaries and along the marine coasts. have been instrumental in shaping assistance. This action prompted the There is a striking match Canada as it has come to be today. Geological Survey of Canada to between the peatland map of Canada Engineers are moving away from their investigate the peat industry in Europe (Fig. 1) and a map showing areas early and more traditional approaches (Nyström 1908). The government covered by proglacial lakes and inland that focussed on draining wetlands. purchased a small peat mining plant seas (Fig. 2). The flat till plains and Plans and designs now ensure that from Sweden for $50,000 and set it up clay, silt and sand glaciolacustrine and wetlands remain intact, and indeed, in 1907 on the Alfred bog near Ottawa. glaciomarine plains laid down in large engineers are restoring and creating Scandinavian geologists were hired by inland lakes and seas created poorly wetlands. This new outlook indicates the Geological Survey of Canada to drained areas that have contributed to an acceptance of the challenges of undertake national surveys of Canada’s the widespread wetlands in Canada working with wetlands in the landscape peatland resources. A series of reports today. A notable example is in the and inventing new, more nature- were published over the next 25 years southern parts of the Hudson and James sensitive technologies and codes of or so (e.g. Anrep, 1914, 1915, 1927; Bay basins, where proglacial lake and professional practice. Auer, 1930; Haanel, 1923, 1925; seabed deposits have contributed to This paper examines what Moore, 1908; Nyström, 1908; Nyström development of one of largest peatland wetland geology is and points out how and Anrep, 1909). There was so much complexes in the world. geology is related to wetland landforms interest in peatlands during this period There are obvious anomalies, in the Canadian context. There is that a Canadian Peat Society was notably in the south-central Prairies, discussion of some of the engineering formed in 1911. This early society had southern Ontario, and the Ottawa- and environmental applications of no connection with the current St. Lawrence valleys, where there are till wetland geology. Wetland geology is far Canadian Society for Peat and plains and glaciolacustrine and glacio- more relevant than is typically assumed. Peatlands, which began in the 1970s. marine clay, silt and sand deposits but More geology needs to be included in There was little interest in few peatlands today.

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