North Sister, also known as "Faith," is the oldest and most eroded of the three, with towering rock pinnacles and glaciers. It has not erupted since the late Pleistocene. It is the most dangerous climb of the Three Sisters, due to its level of erosion, and thus rockfall.
North Sister is a shield volcano consisting primarily of basaltic andesite and is estimated to have last erupted over 100,000 years ago and is considered extinct. The North Sister possesses more dikes than any similar Cascade peak. Many dikes were pushed aside by the intrusion of a 300 meter wide plug dome that now forms the mountain's summits of Prouty Peak and the South Horn. The remainder of the peak is chiefly loose debris held in place by the dike system.
Read more about this topic: Three Sisters (Oregon)
Famous quotes containing the words north and/or sister:
“Biography is a very definite region bounded on the north by history, on the south by fiction, on the east by obituary, and on the west by tedium.”
—Philip Guedalla (1889–1944)
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Chanting faint hymns to the cold fruitless moon.
Thrice blessed they that master so their blood
To undergo such maiden pilgrimage.”
—William Shakespeare (1564–1616)