SPACEPHOTOS

This south-southwest-looking, low-oblique photograph shows the central portion of the snow-covered Altai Mountains and the dry basin known as the Valley of the Lakes of northwestern Mongolia. The Altai Mountains are a complex, uplifted mountain system rich in deposits of gold, silver, mercury, iron, lead, zinc, and copper, but because of remoteness, many mineral resources have not been tapped fully. Precipitation in the basins is very sparse, but meltwater from glaciers feeds many small streams that descend into basins and form salt lakes. Winters are extremely cold, and summers can be very hot for short periods. Visible in this photograph are four salt lakes—Doroo Lake near the center of the photograph; Har Lake to its north; lobster-claw-shaped Har Us Lake, the largest of the lakes, whose length is almost 40 miles (64 kilometers); and Ayrag Lake to the far northeast into which the Dzavhan River empties.