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

The distances across the image are approximately 200 miles by 120 miles. Although the actual vertical relief across the image is only about 1600 feet, the vertical exaggeration perceived in the image is much higher (150X).

All of the region shown was intensively glaciated during the Pleistocene ice ages. Glacier ice last withdrew from this region about 12,000 years ago, leaving behind a landscape today thickly draped by glacial (and glacial lake sediments). Only along portions of the Pembina Escarpment do bedrock outcrops appear. Here, they represent marine shales of Cretaceous age.

The Red River Valley trends north-south through the eastern quarter of this image image. The Valley is actually the bed of glacial Lake Agassiz, an enormous ice-dammed lake that developed at the end of the last ice age. The Red River of the North drains northward along the axis of the Valley. The clay-rich soils that underlie the Valley are among the richest in the world, supporting crops that include wheat, barley, sugar beets, and sunflowers. Using the 3D glasses, one should be able to pick out the faint traces of the margins ("beaches") on both sides of the lake basin.

At the southwest corner of the image is part of the Missouri Coteau, a surface of dead-ice moraine bordered to the northeast by the prominent northeast-facing Missouri Escarpment.

Like the Missouri Coteau, the Turtle Mountains are a hummocky upland of dead ice moraine, formed where ice was forced up a steep, bedrock escarpment. The Turtle Mountains are today covered by woodlands - the most extensive zone of forested lands in North Dakota.

To the southwest of the Turtle Mountains is the plain of Glacial Lake Souris: a large lake that formed at the end of the last ice age. Unlike Lake Agassiz, Lake Souris was not ice-dammed. It, however, occasionally received massive floods from releases of ice-dammed lakes to the north --- particuarly from Glacial Lake Regina (in Saskatchewan) via the Des Lacs and Souris River spillways (see 3D Anaglyph of North-Central ND).

A north-south continental divide passes between the Sheyenne and James River valleys in this image. Northeast of this divide, waters drain northward via the Sheyenne-Red River system, ultimately being delivered into Hudson Bay via the Nelson River. Waters southwest of this divide drain southeastward via the James-Missouri River system, ultimately to arrive at the Gulf of Mexico via the Mississippi River.

Devils Lake occupies an enclosed depression formed by extensive glacial thrusting. The thrust mass, itself, is visible in the 3D image immediately south of the lake itself (Sully's Hill). Because Devils Lake is totally enclosed and has no natural outlet, its level rises and falls with changing climatic conditions. At present, the lake is the most areally extensive that it has been since Euro-American settlement.

The prominent lines impressed at 48° N. lat. and 100° W. long. represent artifacts from suturing DEM datasets together to make this image. They do not reflect any real structure. In addition, some of the flat step-like areas are due to the contours on the original maps that were digitized by USGS to obtain the elevation data and therefore do not represent real topography.

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