NORTH DAKOTA STATE UNIVERSITY - FARGO, N D


GLACIAL ERRATIC IN MORTON COUNTY, N.D.



Click on the photo for an enlarged image. (81K)


Canada's bedrock was deeply scoured during continental glaciation. The glaciers later deposited their incorporated rock debris at sites generally well away (in this case, several hundred km southwest) from the bedrock source area. This debris includes cobbles and boulders (erratics), such as this boulder northwest of New Salem, N.D.

By examining the rock type of an erratic, geologists often can trace back to its bedrock source. Geologists thus utilize erratics to determine ice-flow directions.

(Photo by D.P. Schwert, North Dakota State University).



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