Colorful mountain range

DANIEL PRUDEK/ALAMY STOCK PHOTO

Where in the World?: Rainbow Mountain

Andes Mountains, Peru

The Andes Mountains stretch 8,900 kilometers (5,500 miles) near the western coast of South America. For 1,600 years, a glacier covered a mountain in Southern Peru. But over the past few decades, warm temperatures have caused the mass of ice to melt, uncovering a surprise: thick stripes of color, like those on a rainbow cake.

 Rainbow Mountain, or Vinicunca, gets its colors from minerals in the rock. The region was once a desert valley with red sandy walls. Over time, sand filled the valley and compacted into rock. Chemical elements in the rock reacted with different substances, creating wild colors.

For much of Earth’s history, these rainbow rocks sat in flat layers. Then, 180 million years ago, tectonic plates shifted. That caused a huge landmass to split into many landmasses, including today’s South America. Six million years ago, two plates pushed together, forming the Andes Mountains. The rainbow rock was forced upward, and the long-buried stripes turned sideways. Cold temperatures tranformed rain and snow into ice. The stripes were only revealed when it melted away.


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