• Wetland and Eolian Features [MOV, 888.2 kb, player]
• Marine Mollusc Zones [MOV, 2.3 Mb, player]
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GSC Open File 3296 open file presents preliminary drafts of time-slice plots of paleoenvironmental features and parameters generated from a series of computer databases based largely on radiocarbon dates. The databases were assembled as part of GSC's Global Change initiative. The databases (approximate number of records) are as follows: vegetation (4500), sea level (4000), eolian (1100), alpine glaciers (1400), wetland inception (1000), permafrost (600), lake sedimentation (2000), mammals (2000), and marine molluscs (3100). The databases were assembled from detailed literature and database searches under the direction of H. Jetté (vegetation to be released later) and A.S. Dyke (others). They are maintained and updated by the GSC. The preliminary drafts were released because of continued national and international demand for these products and because of considerable apparent duplication of effort in creating similar databases. Detailed discussions of various aspects of these maps are being prepared for release as scientific papers. The entire set of maps and associated databases will form the basis of a GSC publication: "Paleogeographic Atlas of Glaciated North America".

The database on marine molluses has been interpreted in detail in "Marine molluses as indicators of environmental change in glaciated North America and Greenland during the last 18 000 years" by A.S. Dyke, J.E. Dale, and R.N. McNeely (1996); Géographie physique et Quaternaire, v. 50, p. 125-184. Other papers resulting from this study are "A history of sea ice in the Canadian Arctic Archipelago based on Postglacial remains of the Bowhead whale", by A.S. Dyke, J. Hooper and J. M. Savelle (1996); Arctic, v. 49, p. 235-255 and "Changes in driftwood delivery to the Canadian Arctic Archipelago: The hypothesis of Postglacial oscillations in the Transpolar Drift", by A.S. Dyke, J. England, E. Reimnitz, and H. Jetté; Arctic, v. 50, p. 1-16.

The paleogeographic plots display the data in various combinations. For example sites of former eolian activity are plotted on the same maps as sites of wetland inception, which may distinguish areas with positive moisture balances from areas with low or negative moisture balances. Dates on alpine glacier advances and retreats are plotted on the same maps as are data pertaining to former permafrost distributions because both represent largely responses to temperature changes. The sea level data are synthesized in an independent series of isobase maps, and lake sedimentation data are displayed independently as contoured maps of lake sedimentation rates. The marine mollusc data are interpreted in terms of paleofaunistic zones, which correspond to water-mass temperatures and shifting ocean-surface current patterns. Mammals are interpreted in terms of either water-mass affinities (e.g. narwhal as "maritime arctic") or terrestrial vegetational environment (e.g., collared lemming as "arctic tundra"; mastodon as "coniferous woodland").

Author: A.S. Dyke