Uplift-driven expansion delayed by middle Holocene desiccation in Lake Winnipeg, Manitoba, Canada

Lewis, C F M; Forbes, Donald L.; Todd, B J; Nielsen, Erik; Thorleifson, Harvey; Henderson, P J; McMartin, I; Anderson, T. W.; Betcher, R N; Buhay, William M.; Burbidge, Susan M.; Schröder-Adams, Claudia J.; King, John W.; Moran, K.; Gibson, Carol; Jarrett, C A; Kling, Hedy; Lockhart, W.L.; Matile, G L D; Risberg, Jan; Rodrigues, Cyril G.; Telka, Alice M.; Vance, Robert E.

doi:10.1130/0091-7613(2001)029<0743:udedbm>2.0.co;2

Cited by 32 publications

(37 citation statements)

References 24 publications

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“…The deciduous forest boundary was north of its present location in the southern Great Lakes region (McMurray et al, 1978;Heide, 1984), the grassland and parkland boundaries remained somewhat north of their present locations on the Canadian prairies, and treeline remained above present elevations in the Colorado and Alberta Rockies and in the British Columbia Coast Range. Conditions were so dry on the prairies by 7.5 ka BP that there was insufficient inflow of water to the southern basin of Lake Winnipeg to fill the basin to overflow despite the fact that isostatic tilting was tending to raise water levels at the south end of the lake (Lewis et al, 2001). The moisture balance at Winnipeg may have been similar to that at Medicine Hat today.…”

Section: Ka Bpmentioning

confidence: 88%

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Dyke

2007

gpq

114

118

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AbstractBiome maps spanning the interval from the last glacial maximum to modern times are presented. The biome distributions at 18 ka BP were probably as nearly in equilibrium with climate as are the modern distributions, but deglacial biomes were probably in disequilibrium. Ice sheet configuration was a strong control of climate until 7 ka BP. Regional climate trends can be inferred from changing biome distributions, but during periods of disequilibrium, biome distributions under-represent summer warming. Because of summer cooling by 2-4 °C during the Holocene, largely in the last 3-5 ka, middle and certain early Holocene biome distributions and species compositions are reasonable analogues of future equilibrium displacements due to equivalent warming, at least in areas that were long-since deglaciated. Past biome migration rates in response to rapid regional warming during deglaciation were mainly in the range of 100-200 m per year. If these rates pertain in the future, biomes may shift 10-20 km in most regions over the next century. A major impediment to using former Holocene conditions as a guide to future conditions is that warmer Holocene summers were accompanied by colder winters, whereas warmer future summers will be accompanied by warmer winters.

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Section: Ka Bpmentioning

confidence: 88%

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Dyke

2007

gpq

114

118

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“…Even more conspicuous are the hydrological changes in large lakes located parallel to the direction of the tilting. The tilting is causing the southward expansion of Lake Winnipeg (Lewis et al 2001), while Lake Vättem, the second largest lake in Sweden, has tilted so that the water level at its southern end has risen 25 m during the last 8000 years (Norrman 1964;Nilsson 1968). Trangressions of such magnitude can often cause the formation of new outlets, as has occurred in Lake Saimaa, the largest lake in Finland, which originally drained into the Baltic Sea basin from its northwestern end, but whose outlet since 5700 calibrated years before present (cal yr BP) has been located in its southeastemmost end (Saamisto 1970).…”

Section: Introductionmentioning

confidence: 98%

Tilting of Lake Pielinen, eastern Finland – an example of extreme transgressions and regressions caused by differential post-glacial isostatic uplift

Seppä¹,

Tikkanen²,

Mäkiaho³

2012

Estonian J. Earth Sci.

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Tilting of large lakes due to differential isostatic uplift in the glaciated regions of the Northern Hemisphere is a well-documented process. With the help of accurate digital elevation models and spatial GIS analysis techniques, the resulting hydrological changes, including shifts in the outlets and changes in the size and configuration of lakes, can now be mapped and calculated more precisely than before. As a case study to highlight the magnitude of such changes in Fennoscandia, we investigated and reinterpreted the Holocene palaeogeography and palaeohydrology of Lake Pielinen in eastern Finland. This lake is currently 99 km long and located parallel to the direction of land uplift, being thus particularly sensitive to the impacts of tilting. Our results show that the lake was formed at the end of the regional deglaciation, following drainage of a local ice-dammed lake. In its initial stage until 10 200 cal yr BP, the outlet of the newly-formed lake was located in its northwestern end, but the tilting led to a major water level transgression in the basin, eventually causing formation of a new outlet over the southeastern threshold. The lake area was 143 km long and its area was 1998 km2 at the time of formation of the southeastern outlet at 10 200 cal yr BP. The lake level has been regressive throughout the basin during the last 10 200 years. This regression will continue for approximately another 10 000 years until all the glacial isostatic adjustment has occurred, after which Lake Pielinen will be only 89 km long and 565 km2 in area

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“…There is considerable evidence suggesting that maximum aridity occurred early in the Holocene and, thus, the onset of a more positive hydrologic budget in Lake Manitoba after 7700 14 C yrs BP corresponds with many paleolimnological records from the region (e.g., Radle et al, 1989;Dean and Stuiver, 1993;Haskell et al, 1996;Last et al, 1998;Yansa, 1998;Aitken et al, 1999;Last and Vance, 2002). In contrast, other paleoclimatic reconstructions in the northern Great Plains point toward much later aridity maximums (Last, 1990b;ValeroGarcés and Kelts, 1995;Smith et al, 1997;Xia et al, 1997;Teller et al, 2000;Lewis et al, 2001; see also Schwalb, 2003).…”

mentioning

confidence: 94%

Paleolimnology of Lake Manitoba: the Lithostratigraphic Evidence

Teller

2004

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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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Uplift-driven expansion delayed by middle Holocene desiccation in Lake Winnipeg, Manitoba, Canada

Cited by 32 publications

References 24 publications

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Tilting of Lake Pielinen, eastern Finland – an example of extreme transgressions and regressions caused by differential post-glacial isostatic uplift

Paleolimnology of Lake Manitoba: the Lithostratigraphic Evidence

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