Formation Giant's kettle

giant s kettle illustration.

potholes vary in size few inches several feet in depth , diameter. commonly occur in shields, there ancient rocks (granite, gneiss) different resistances erosion, strong pebbles can fall small cavities in stream bottoms , swirl, making cavities wider , deeper. hardness of pebbles must same or higher rock @ bottom of stream kettle forming. in areas there diamonds , quartz pebbles, hardness of these carve potholes , remain trapped in bottom of them.

collection of pebbles shaped in giant s kettles

giant s kettles can formed while surface covered glacier. water, produced thawing of ice , snow, forms streams on surface of glacier, which, having gathered courses amount of morainic debris, flow down crevasse swirling cascade or moulin. sides of crevasse abraded, , vertical shaft formed in ice. erosion may continued bed of glacier; and, ice having left district, giants kettle formed seen empty shaft, or pipe filled gravel, sand, or boulders. such cavities , pipes afford valuable evidence former extent of glaciers.

similar holes encountered in riverbeds @ foot of cascades, , under other circumstances.