NORTH DAKOTA STATE UNIVERSITY - FARGO, N D


GLACIAL OUTWASH IN BARNES COUNTY, N.D.



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The glacial sediments exposed in this gravel pit at Valley City, N.D., demonstrate both bedding (layering) and sorting of particles by size. They were deposited by meltwater rivers transporting water and sediment away from the ice margin. Note the cross-bedding (inclined minor beds within the master beds), which indicate deposition within a current. The "down-dip" direction of the cross-beds is the "down-current" direction of the water flow in which they were deposited. In this case, the cross-beds indicate that water flowed from right to left across the region of the photo.

Because the sediments have been cleaned of clay and fine silts, outwash is favored as a source of sand and gravel. In eastern and northern North Dakota, most sand-and-gravel operations tap outwash as a resource.

The other type of glacial drift (sediment) found in North Dakota is till. In contrast to outwash, till demonstrates no bedding and no sorting.

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



[ Glacial Landforms of North Dakota ]