The Geological Survey of Canada's Integrated Research and Monitoring Area (IRMA) projects: a contribution to Canadian global change research

Lemmen, D S; Dyke, L. D.; Edlund, S A

doi:10.1007/bf00680038

Cited by 13 publications

(3 citation statements)

References 19 publications

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“…However, beginning in the 1990's, the recognition of global change and the necessity to better understand the past climate of the region [ 296 ] caused an explosion of interest in the Holocene and late Pleistocene records of the lakes in the Great Plains. The major objective of many of these projects was to decipher the timing and severity of postglacial climatic changes and their geomorphic impact on the prairie landscape [ 58 , 297 - 302 ]. Clearly, investigation of the Holocene and late Pleistocene stratigraphic records preserved in the lakes of the region forms a pivotal role in accomplishing this objective.…”

Section: Northern Great Plains Paleolimnologymentioning

confidence: 99%

Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology

2005

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In much of the northern Great Plains, saline and hypersaline lacustrine brines are the only surface waters present. As a group, the lakes of this region are unique: there is no other area in the world that can match the concentration and diversity of saline lake environments exhibited in the prairie region of Canada and northern United States. The immense number of individual salt lakes and saline wetlands in this region of North America is staggering. Estimates vary from about one million to greater than 10 million, with densities in some areas being as high as 120 lakes/km 2 .Despite over a century of scientific investigation of these salt lakes, we have only in the last twenty years advanced far enough to appreciate the wide spectrum of lake types, water chemistries, and limnological processes that are operating in the modern settings. Hydrochemical data are available for about 800 of the lake brines in the region. Composition, textural, and geochemical information on the modern bottom sediments has been collected for just over 150 of these lakes. Characterization of the biological and ecological features of these lakes is based on even fewer investigations, and the stratigraphic records of only twenty basins have been examined.The lake waters show a considerable range in ionic composition and concentration. Early investigators, concentrating on the most saline brines, emphasized a strong predominance of Na + and SO 4 -2 in the lakes. It is now realized, however, that not only is there a complete spectrum of salinities from less than 1 ppt TDS to nearly 400 ppt, but also virtually every water chemistry type is represented in lakes of the region. With such a vast array of compositions, it is difficult to generalize. Nonetheless, the paucity of Cl-rich lakes makes the northern Great Plains basins somewhat unusual compared with salt lakes in many other areas of the world (e.g., Australia, western United States). Compilations of the lake water chemistries show distinct spatial trends and regional variations controlled by groundwater input, climate, and geomorphology. Short-term temporal variations in the brine composition, which can have significant effects on the composition of the modern sediments, have also been well documented in several individual basins.From a sedimentological and mineralogical perspective, the wide range of water chemistries exhibited by the lakes leads to an unusually large diversity of modern sediment composition. Over 40 species of endogenic precipitates and authigenic minerals have been identified in the lacustrine sediments. The most common non-detrital components of the modern sediments include: calcium and calcium-magnesium carbonates (magnesian calcite, aragonite, dolomite), and sodium, magnesium, and sodium-magnesium sulfates (mirabilite, thenardite, bloedite, epsomite). Many of the basins whose brines have very high Mg/Ca ratios also have hydromagnesite, magnesite, and nesquehonite. Unlike salt lakes in many other areas of the world, halite, gypsum, and calcite are relati...

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Section: Northern Great Plains Paleolimnologymentioning

confidence: 99%

Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology

2005

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“…The late Pleistocene and Holocene sediments preserved in these lakes collectively offer an exceptional opportunity to unravel the marked regional climatic and hydrologic variability that is inherent to this important agricultural area. Considerable recent effort has been made to decipher past regional environmental changes on the basis of multiple proxy investigations of these lacustrine records (Lemmen et al, 1993;Vance and Last, 1994;Lemmen, 1996;Vance, 1997;Lemmen and Vance, 1999a), however only a few of the lakes in the northern Great Plains of Canada have provided complete, uninterrupted Holocene sequences. As discussed by others (e.g., Schweger and Hickman, 1989;Yansa, 1995;Last, 1995Last, , 2002, fewer than a dozen continuous lacustrine stratigraphic sections in the entire interior plains region extend back to the early Holocene.…”

Section: Introduction and Previous Workmentioning

confidence: 99%

Paleolimnology of Lake Manitoba: the Lithostratigraphic Evidence

Teller

2004

gpq

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Lake Manitoba, the largest lake in the prairie region of North America, is one of the most intensively studied lacustrine basins in western Canada. New AMS 14C dating, together with mineralogical, geochemical, and lithostratigraphic analyses of the 14-m-thick, offshore sediment sequence, document a complex Holocene history in which water levels and limnological conditions were controlled by the interplay of changing climate, variable river and groundwater inflow, and differential isostatic rebound. Varves, ice-rafted debris, and clast-rich laminated sediment record deposition in the lake when the basin was part of proglacial Lake Agassiz. As Agassiz retreated northward, Lake Manitoba became isolated by about 8500 14C yrs BP, and for the next 800 years was characterized by mainly shallow water to dry conditions. Deeper and more stable water conditions returned to the Lake Manitoba basin by 7700 14C yrs BP probably due to the damming effect of differential isostatic rebound and decreasing aridity. For the next 3000 years, relatively stable lake levels and water compositions were maintained, reflecting a delicate balance between differential isostatic rebound, climate, inflow of the Assiniboine River, and groundwater contribution. At ~4500 14C yrs BP the Assiniboine River was rerouted to its present easterly path, by-passing Lake Manitoba, and resulting in loss of a significant component of the lake’s hydrologic budget. Water levels dropped and the offshore sediments were once again subaerially exposed. By 3700 14C yrs BP, a cooler and wetter climate, together with continued southward transgression of water, compensated for the loss of fluvial input, resulting in reflooding of the basin. By about 2000 years ago the lake had evolved from a shallow, saline, and alkaline pool to its present depth and extent.Le lac Manitoba, le plus grand lac des Grandes Plaines de l’Amérique du Nord, est l’un des bassins lacustres le plus intensément étudiés de l’Ouest du Canada. De nouvelles dates 14C SMA, ainsi que des analyses minéralogiques, géochimiques et lithostratigraphiques de la séquence sédimentaire de 24 m d’épaisseur au large du rivage témoignent d’une évolution complexe du lac, à l’Holocène. Au cours de cette période, les niveaux lacustres et les conditions limnologiques ont été influencés par les effets combinés des changements climatiques, de la variation des apports d’eaux lacustre et souterraine et d’un relèvement isostatique différentiel. Les varves, les débris glaciels et les sédiments en lamines riches en éléments détritiques ont constitué l’apport sédimentaire au lac lorsque le bassin faisait partie du Lac glaciaire Agassiz. Après la vidange du lac glaciaire vers le nord, le lac Manitoba a été isolé vers 8500 BP ; pendant les 800 années suivantes, le lac était caractérisé par des eaux peu profondes et un climat sec. Des eaux plus profondes et plus stables ont caractérisé le lac vers 7700 BP, probablement en raison de l’endiguement qu’a entraîné le relèvement isostatique différentiel et une moins grande aridité. Pe...

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“…I), the region for global change research in the Canadian prairies (Lemmen et al 1993). The landscapes from this region contain evidence of significant changes in postglacial geomorphic and pedologic process activity (Vreeken 1 9 9 3~) .…”

Section: Introductionmentioning

confidence: 99%

A Holocene soil-geomorphic record from the Ham site near Frontier, southwestern Saskatchewan

Vreeken¹

1994

Can. J. Earth Sci.

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The soil-geomorphic evolution of a hillslope in hummocky moraine terrain in one of the most arid parts of the Palliser Triangle is reconstructed from ca. 12 600 BP to the present. A transect from a moraine plateau into an internally drained basin provided evidence for seven postglacial landscape cycles. Each cycle includes a phase of land-surface instability, marked by erosional and depositional imprints, and a phase of stability, marked by pedologic imprints. Five cycles of slopewash-dominated erosion left behind four superposed downslope-thickening and downslope-fining sediment mantles and were followed by two eolian cycles, each of which left behind a loess mantle that accumulated from a local loess-dispersal system. Accumulation of long-range calcareous dust coincided with each of these loess cycles. The five complete buried soil catenas and the surficial catena have systematic textural differentiation, reflecting the preceding geomorphic regimen, and color differentiation, reflecting the soil-drainage continua. Changes in hillslope hydrology occurred repeatedly throughout the postglacial. The evidence indicates that each element from the 14 successive local soil landscapes reacted to environmental change as a component from a functionally integrated process -response system. L'tvolution gComorphique des sols sur le versant d'un terrain morainique, en creux et bosses, localisk dans une des parties les plus arides du triangle de Palliser, est reconstituke a partir de 12 600 ans Av.Pr. jusqu'i nos jours. Une coupe transversale du plateau morainique, faisant partie d'un bassin a drainage interne, documente sept cycles de paysages postglaciaires. Chaque cycle inclut une phase d'instabilitk de la surface du terrain marquke par des figures d'trosion et des dkpbts, et une phase de stabilitk rkvklke par des figures ptklologiques. Cinq cycles d'krosion domines par le ruissellement sur versant ont laissk en amont quatre kpaississements superposCs de bas de pente, lesquels sont recouverts de sediments fins, ils sont suivis par deux cycles d'krosion Coliennes, chacun ayant laissk derrikre lui une couverture de loess qui Ctait alimentte par un systkme local de dispersion du loess. Une accumulation Ctendue de poussikre calcareuse accompagnait chacun des cycles de loess. Les cinq catenas de sols totalement enfouies, et aussi la catena de surface, presentent une difftrenciation texturale systkmatique qui reflkte le rkgime gkomorphique prtckdent, et la diffkrence des couleurs exprime la continuitk skquentielle dans le drainage du sol. Des changements dans l'hydrologie des versants sont apparus de manikre rtpktitive durant tout le postglaciaire. Les resultats de l'ktude indiquent que chaque klkment des 14 paysages de sol locaux et successifs rkagissait au changement des conditions du milieu, en se comportant comme une composante fonctionnellement intkgrke dans un systkme de u processus -rCponse r.[Traduit par la rkdaction]Can.

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The Geological Survey of Canada's Integrated Research and Monitoring Area (IRMA) projects: a contribution to Canadian global change research

Cited by 13 publications

References 19 publications

Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology

Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology

Paleolimnology of Lake Manitoba: the Lithostratigraphic Evidence

A Holocene soil-geomorphic record from the Ham site near Frontier, southwestern Saskatchewan

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