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Shades of Blue: Patagonia's Glacial Lakes
Credit: NASA

The glacial lakes of Patagonia are blue beacons standing between the richly forested islands and peninsulas of Chile and the high, arid plain stretches east from the Andes in this image taken by NASA's Terra satellite last month.

Most of the glacial lakes extend eastward onto the high plain. Like the lakes of the Qinghai-Tibet Plateau , these water bodies appear in multiple shades influenced by multiple factors, including depth and sediment content.

Lago Buenos Aires (also known as Lago General Carrera) is the darkest of the lakes, ranging in color from electric blue in the west to navy in the east.

In the south, Lago Cardiel and Lago Argentino are lighter. Lago San Martin and Lago Viedma are the palest lakes, and bear the color characteristic of thick glacial flour.

Like glaciers the world over, Andean glaciers have slowly pulverized the rocks below into fine-grained sediments. When pooled in glacial lakes, glacial (or rock) flour colors the water bright turquoise. Patagonian glaciers have been grinding rocks into flour for at least a few million years.