February 13 , 2013: Glacial Lakes
stadial: cold period within a glacial period
channelled scablands: holes 60 m deep
o caused by slow, normal erosion?
o caused by large volumes of water in a few days?
o doctrine of catastrophism?
o principle of uniformitarianism? (processes occurring in present are same as
those in the past)
o pro-glacial lakes
Wisconsinan was the last glacial advance of the Pleistocene
Columbia River formed from ice dam breaking from Cordillera ice sheet
most geologists through channeled scablands from normal erosion by normal
amounts of water
Bretz examined size/spacing/placement of features had to be caused by
movement of large volumes of water over short time periods
theory not accepted since no evidence & very close to catastrophism which would
source of catastrophic floods found