Basalt, Lava and Lichen at Gooseberry Falls State Park
November 29, 2018
Photographer: Dale Hugo
Summary Author: Dale Hugo
This pillar of basalt was erected in about 1940 at Gooseberry Falls State Park, Minnesota, by the Civilian Conservation Corp (CCC). It evidently holds chains to keep people from wandering over a cliff into big, cold Lake Superior. Basalt exists here because of an ancient geologic rift -- part of a mid-continent rift system from the middle Proterozoic Eon (Precambrian, around 1.1 billion years ago). Of the many original basalt pillars, about 20 can be found today.
The rock platform that the pillar sits on is part of a lava shelf. Note the advancing headlands of resistant lava rock off in the distance. This shelf extends several of hundred yards out into Lake Superior.
The orange-colored lichen seen on the pillar have been slowly growing for some 80 years, if we assume they were first established soon after the pillar was put in place. Photo taken in late summer of 2018.