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| portion of the earth's surface consisting of disintegrated rock and humus |
| process where the surface of the earth is worn away by the action of water, glaciers, winds, waves |
| base level | |
| —n | |
| the lowest level to which a land surface can be eroded by streams, which is, ultimately, sea level | |
base level
in hydrology and geomorphology, limit below which a stream cannot erode. Upon entering a still body of water, a stream's velocity is checked and thus it loses its eroding power; hence, the approximate level of the surface of the still water body is the stream's baselevel. If a stream enters the sea, its baselevel is sea level; this is known as ultimate baselevel. If a stream enters a lake, the lake level acts as a temporary baselevel for all parts of the stream above that elevation. All continental areas tend to be eroded down to ultimate baselevel, or sea level, but uplifting of the Earth's crust and variations in sea level prevent this from happening except in rare, small areas
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