(Answer to question 1 ) Hudson Bay was the center of the North American ice sheet during past glacial episodes. This was the
area where ice was thickest and hence heaviest. The weight of that ice depressed the lithosphere
beneath it to below sea level. The evidence for this is the existence of Hudson Bay itself, which lies
well within the interior of the continent. Melting of the ice was sudden, in the sense that it happened
faster than the underlying lithosphere could elastically adjust. This adjustment, or rebound, is still
happening via uplift at the rate of about a meter per century. Portions of Hudson Bay have uplifted by
over 250 meters.
(Answer to question 2 ) Many rivers and streams are able to flow year round because of water stored in glacial ice. The ice is
basically a natural reservoir that slowly releases its stored volume during the summer. Without this ice,
it is likely that many rivers would cease to flow during the dry portion of the year
(Answer to question 3 ) Sea level would rise by as much as 40 meters. This would flood most of the major population centers
of the world and would eliminate large areas used for agricultural purposes
(Answer to question 4 ) A terminal moraine is an accumulation of glacial debris that marks the farthest point of advance of a
glacier. Recessional moraines form by similar processes but mark the stepwise retreat of a glacier.
They can form as the result of a state of temporary equilibrium or of temporary advan