Chapter 17 Flashcards
cirque
a bowl-shaped amphitheater-like depression formed by glacial plucking and abrasion at the head of a glacier
tarn
a small lake in a cirque
paternoster lakes
a series of tarns connected together by streams
horn
the resulting feature of a point when three or more cirques carve out opposite sides of a mountain
arete
when two adjacent valleys carve a sharp ridgeline between them, the spine is called an arete
hanging valleys
when smaller tributary glaciers join a larger main valley their valleys are distinctively more shallow because the glaciers in the smaller valleys were not as heavy and did not carve as deep
kettle holes
in outwash of glacier, large block of ice has been buried by sediments and later melts; forms hole
kettle lakes
kettle holes that fill with water
kames
stratified sediment deposits formed when a stagnant glacier melts
esker
long, sinuous ridges of sand and gravel deposited by streams that formerly ran under or in a glacier
drumlins
smooth, elongated forms created under a glacier
eccentricity
a 100,000 year cycle where Earth’s orbit changes from a perfect circle to an ellipse and back again
aphelion
the point in its orbit when Earth is farthest from the sun
perihelion
the point in its orbit when Earth is closest to the Sun
obliquity
then angle of Earth’s axis of spin which changes from 21.5 to 24.5 degrees every 41,000 years
precession
the wobbly action of Earth’s spin which causes it to wobble to and from the sun approximately every 19,000 to 23,000 years
