Glacial Boulders on the Arctic Coast of Alaska

Abstract

Reports incidental observations made in the Barrow-Cape Simpson area 1949-50. Pleistocene glaciers of Alaska did not extend north beyond the northern foothills of the Brooks Range, yet glacial boulders have been reported near and along the coast. Altogether 56 such erratic boulders from sheltered spots on the shore, as far as 8-9 mi inland on the tundra and a few from the present sea floor were examined. Their location and size, rock type with field description and petrographic analysis are tabulated. Of granite (16), diabase (17), quartzite (10), etc., they range in weight from 2-3 lbs. to 4-5 tons. They are thought to represent morainic material left by melting icebergs, and the bergs to have been produced from glaciers in widely separated areas.