A pair of red / blue 3D glasses is required to view this anaglyph. Please note that the red lens should be over the left eye.

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This image was produced by Ray Sterner of the Applied Physics Laboratory at Johns Hopkins University using USGS DEM data.

The east-west distance across the image is approximately 350 miles, and the north-south distance is about 190 miles. The vertical exaggeration induced by this 3-D processing is 150X.

The region of North Dakota generally east and northeast of the Missouri River contrasts profoundly in its physiography to the region west and southwest. The path of the Missouri River parallels the approximate limit of continental glaciation. Glaciers scoured much of the northeastern two-thirds of the state and then buried it under glacial debris, leaving a rather "soft" topography. The southwestern third of the state, in comparision, was largely unaffected by glaciation and today has a more rugged, bedrock-controlled topography.

Where glacier ice encountered major topographic obstructions, internal stresses within the ice caused it to shear as it passed over these obstructions. Multiple episodes of shearing within the ice caused these topographic features eventually to become thickly covered with both ice and glacial debris. Later, as the ice melted, the features were still left as topographic highs but deeply buried under glacial sediments. This occurred where the ice crossed over and onto the Turtle Mountains, Prairie Coteau, and Missouri Coteau (marked at its eastern margin by the Missouri Escarpment). Hummocky "pothole" topography today characterizes these areas, which include some of the finest waterfowl breeding areas in the United States.

West of the Missouri River, the topography of North Dakota is controlled by bedrock, largely of Tertiary age. This Tertiary-aged bedrock, spectacularly exposed in the Little Missouri River badlands (Theodore Roosevelt National Park), consists largely of sediments derived from the erosion of the ancestral Rocky Mountains. In some portions of North Dakota, particularly south of Bismarck and in the extreme southwest corner of the state, bedrock of Cretaceous age outcrops; a number of dinosaur finds have been made in these sediments.

A north-south continental divide trends across the state. Waters from eastern North Dakota drain northward via the Red River of the North, ultimately being delivered into Hudson Bay via the Nelson River. Waters from central and western North Dakota drain southeastward via the Missouri River, ultimately to arrive at the Gulf of Mexico via the Mississippi River.

Contrary to popular, regional belief, the Red River is not the only river in the contiguous United States to flow northward. Indeed, there a quite a number of such northward-flowing rivers in the lower 48-states.

For those of you clicking to enlarge the image, a prominent east-west line is impressed at 48° N. lat.   Another trends southward from the top of the image at 102.5° W. long. These are artifacts of suturing two datasets together to make this image and do not reflect any real changes in topographic expression.

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