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:
“The battle of the North Atlantic is a grim business, and it isn’t going to be won by charm and personality.”
—Edmund H. North, British screenwriter, and Lewis Gilbert. First Sea Lord (Laurence Naismith)
“Sister Bernice: I have looked everywhere. In all of the usual places.
Mother Abbess: Sister Bernice, considering that it’s Maria, I would suggest you look in some place unusual.”
—Ernest Lehman (b. 1920)