During the decay of the Cordilleran Ice Sheet 10 000 -13 000 BP, glacial lakes developed within valleys that dissect the Interior Plateau of British Columbia. In this paper, we (1) illustrate a procedure for assessing paleo water planes that has general application, (2) document lake paleogeography and evolution in the Thompson Valley, (3) provide new data on the glacio-isostatic response of the central Cordillera, and (4) present new evidence of its late-glacial environment. We employ geomorphology and sedimentology, digital elevation models, and new technologies (differential global positioning systems, ground penetrating radar, and geographic information systems) to refine paleogeographic reconstructions of glacial lakes. Glacial Lake Thompson and Glacial Lake Deadman were ribbon-shaped (width to length ratio ≈ 3:100), deep (>>140 to -50 m) lakes that contained significant water volumes (84-24 km 3 ). They lengthened to the west and their water level lowered as ice decayed. Final ice dam failure resulted in an -20 km 3 jökulhlaup that eroded bedforms and deposited flood eddy bars within the lake basin, travelled -250 km along the Fraser River system, and may have deposited exotic mud offshore between 10 190 and 11 940 BP. Glacio-isostatic tilts of water planes are among the highest in the world (1.7-1.8 m km -1 ). Their orientations suggest that ice sheet loads were greater or longerlived to the north-northwest of the study area, lending support to the notion of an ice divide centred on the Fraser Plateau.Résumé : Durant la décroissance de l'inlandsis de la Cordillère, 10 000 -13 000 ans avant le présent, des lacs glaciaires se sont développés dans des vallées qui recoupent le plateau intérieur de la Colombie-Britannique. Dans le présent article, nous (1) décrivons une procédure d'application générale pour évaluer les paléonappes d'eau, (2) documentons la paléogéographie et l'évolution des lacs dans la vallée de la rivière Thompson, (3) fournissons de nouvelles données sur la réponse glacio-isostatique de la cordillère centrale et (4) présentons de nouvelles évidences de son environnement tardi-glaciaire. Nous utilisons la géomorphologie et la sédimentologie, des modèles numériques d'élévation et des nouvelles technologies (systèmes de positionnement global différentiels, géoradars et systèmes d'information géographi-ques) pour préciser les reconstructions paléogéographiques des lacs glaciaires. Les lacs glaciaires Thompson et Deadman avaient une forme rubanée (rapport largeur à longueur~3:100), ils étaient profonds (>> 140 à~50 m) et ils contenaient des volumes d'eau importants (84-24 km 3 ). Ils s'allongeaient vers l'ouest et leur niveau d'eau s'abaissait au fur et à mesure de la fonte de la glace. Une rupture finale de la digue de glace a causé un jökulhlaup~20 km 3 qui a érodé les fonds rocheux et a déposé des barres de tourbillons de crue dans le bassin du lac; cette masse d'eau s'est déplacée sur~250 km le long du système de la rivière Fraser et aurait pu avoir déposé des boues exotiques au large entre 1...

. The overall pattern of deglaciation of the southern part of the Scandinavian Ice Sheet has been considered established, although details of the chronology and ice sheet dynamics are less well known. Even less is known for the south Swedish Upland because the area was deglaciated mostly by stagnation. Within this area lies the conspicuous Vimmerby moraine, for which we have used the terrestrial cosmogenic nuclide (10Be) exposure dating technique to derive the exposure age of six glacially transported boulders. The six 10Be cosmogenic ages are internally consistent, ranging from 14.9 ± 1.5 to 12.4 ± 1.3 ka with a mean of 13.6 ±0.9 ka. Adjusting for the effects of surface erosion, snow burial and glacio‐isostatic rebound causes the mean age to increase only by c. 6% to c. 14.4± 0.9 ka. The 10Be derived age for the Vimmerby moraine is in agreement with previous estimates forthe timing of deglaciation based on radiocarbon dating and varve chronology. This result shows promise for further terrestrial cosmogenic nuclide exposure studies in southern Sweden.

2006 (February): The environment in and around ice-dammed lakes in the moderately high relief setting of the southern Canadian Cordillera. Boreas, Vol. 35, pp. 106 Á/125. Oslo. ISSN 0300-9483.During decay of the Cordilleran Ice Sheet, Â/13 000 Á/10 000 cal. yr BP, numerous ice-dammed, ribbon-shaped lakes developed within the moderately deep valleys of the Interior Plateau of British Columbia. We describe the pattern and characteristics of lake sediments within the Thompson Valley, propose a palaeoenvironmental model for glacial lakes Thompson and Deadman and explore their implications for the palaeogeography of Cordilleran Ice Sheet decay. Seventeen glaciolacustrine lithofacies are identified within deltas, subaqueous fans and lakebottom beds. Sediments accumulated at high rates and by a diversity of sediment dispersal and depositional processes: hyperpycnal and surge-type turbidity currents, grain flows and debris flows. Megascale subaqueous failures (tens of metres thick) were facilitated by high sedimentation rates. The palaeoenvironmental model highlights: (i) high rates of basin infilling; (ii) the dominant role of tributary rivers, rather than valley-occupying ice, in delivering water and sediment to lakes; and (iii) the role of melt cycles, jö kulhlaups and hyperpycnal flows in sediment delivery. These conditions, in combination with a lack of organics and a fining upward sequence in lake sediments, suggest that glacial lakes Thompson and Deadman were coeval with dwindling plateau ice.

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