Ice-sheet Sentence Examples
The deposits of the Post-Glacial period are represented throughout Russia, Poland and Finland, as also throughout Siberia and Central Asia, by very thick lacustrine deposits, which show that, after the melting of the ice-sheet, the country was covered with immense lakes, connected by broad channels (the fjarden of the Swedes), which later on gave rise to the actual rivers.
This lake drained southward into the Gulf of Mexico via the Minnesota and Mississippi rivers, until the ice sheet which had prevented its natural drainage to the north had melted sufficiently to allow it to be drained off into Hudson Bay by way of the Nelson River.
North America is bathed in frigid waters around its broad northern shores; its mountains bear huge glaciers in the north-west; the outlying area of Greenland in the north-east is shrouded with ice; and in geologically recent times a vast ice-sheet has spread over its north-eastern third; while warm waters bring corals to its southern shores.
After the continental ice sheet entirely disappeared from the state, local valley glaciers lingered in the Adirondacks and the Catskills.
This region presents no striking topographic features except the numerous small lakes which occupy the hollows created by the continental ice-sheet.Advertisement
As the part east of the river was once covered by the ice-sheet, its hills have been lowered and its valleys filled through the attrition of glaciers until the surface has a gently undulating appearance.
The prairies in this second table-land are gently rolling, and are covered with drift from the continental ice-sheet of the glacial period.
The ice-sheet wore down from the hills and filled the valleys with debris until the surface has a billowy appearance.
Certain extraordinary features were produced when the retreat of the ice sheet had progressed so far as to open an eastward outlet for the marginal lakes along the depression between the northward slope of the Appalachian plateau in west-central New York and the southward slope of the melting ice sheet; for when this eastward outlet came to be lower than the south-westward outlet across the height of land to the Ohio or Mississippi river, the discharge of the marginal lakes was changed from the Mississippi system to the Hudson system.
This peculiar feature is explained as the result of displacement of the river from a better graded preglacial valley by the Pleistocene ice-sheet, which here overspread the plains from the moderately elevated Canadian highlands far on the north-east, instead of from the much higher mountains near by on the west.Advertisement
Of these, the Kansan ice-sheet was the most extensive, and the later ones constitute a diminishing series.
In the ice-free belt, between the northern ice-sheet and the vastly extendedglaciers of the Alps, the two floras must have found a common refuge and congenial conditions of existence; and this view is confirmed by direct palaeontological evidence.
The greater richness of certain districts in the matter of species is partly due to the variety of soils encountered therein; but in part may be explained by the fact that these districts were the first to be freed from the ice-sheet at the end of the glacial period.
Some of them are relics of the longitudinal moraines of the ice-sheet, and they run north-west to south-east, parallel to the striation of the rocks and to the countless parallel troughs excavated by the ice in the hard rocks in the same direction; while the Lojo As, which runs from HangOudd to Vesi-jarvi, and is continued farther east under the name of Salpausellia, parallel to the shore of the Gulf of Finland, are remainders of the frontal moraines, formed at a period when the ice-sheet remained for some time stationary during its retreat.
The former of these, representing the bottommoraine of the ice-sheet, are covered with Glacial and post-Glacial clays (partly of lacustrine and partly of marine origin) only in the peripheral coast-region - or in separate areas in the interior depressions.Advertisement
It was entirely covered with the bottom moraine of the great ice-sheet of the Glacial Epoch, resting upon Silurian sandstones and limestones.
With the melting of the great ice-sheet the climate became milder, and the southern part of Sweden was covered with shrubs and plants now found only in the northern and alpine parts of the country (Salix polaris, Dryas octopetala, Betula nana, &c.).
The glacier or ice sheet overran all Maine, irregularly scouring out the bed rock to produce rock basins, damming up many river valleys with glacial deposits and completely disarranging the drainage lines.
The glacier or ice sheet, above referred to, deposited till or boulder clay, which was compacted under the enormous pressure of the ice sheet to form the " hard-pan " referred to later.
It contributes between 10% to 40% to the total ammonium deposited on the central Greenland ice sheet during the Holocene.Advertisement
One response to climate change has been the retreat of five ice shelves, floating extensions of the grounded ice sheet.
The most likely potential source for such an anomaly is meltwater from the antarctic ice sheet in a global warming scenario.
The illustrated site describes the advance and retreat of the Laurentide continental ice sheet.
The Antarctic has had a permanent ice sheet for the last 30 million years.
It is made inhospitable by extreme cold, a massive permanent ice sheet and floating ice shelves.Advertisement
Cosmogenic exposure ages from relict lateral moraines overridden by the Fennoscandian ice sheet in northern Sweden.
Well-defined mega-scale glacial lineations are present within the trough, produced by a palaeo-ice stream draining the Greenland Ice Sheet across the continental shelf.
Satellite remote sensing with aim of improving knowledge of ice sheet topography, ice dynamics and surface energy balance.
This will be carried out by detailed ice cap survey; ice sheet modeling; and subglacial process.