At the Zhangye Danxia Landform Geological Park in Gansu, China, tourists flock to see China's own version of the Grand Canyon: A mountain range of densely packed layers of minerals and rock that are dramatically striated into a layer cake of magenta, maroon, and lemon-colored stone.
As a new UNESCO World Heritage Site, Danxia is become far more popular these days than it was just a few decades ago, with tourists drawn to the remarkable forms of the mountains here.
How did Danxia come to be, in the geological sense? Here's the story, as we understand it: Over millions of years, layers of different types of rock—including red sandstone and a whole lot of mineral deposits—formed on top of one another. Normal so far. But then, 40 or 50 million years ago, gigantic force of tectonic plates forced an island—the future India—into a collision course with the rest of Eurasia.
The catastrophic impact took place in slow motion: Over 50 million years, India—moving at about 27 feet per century—crushed into the larger continent, creating rifts of fractured rock and creating mountain ranges like the Himalayas. Over in the future Chinese province of Gansu, the collision disrupted the layer cake of red rock and minerals, too. Imagine a piece of paper with lines drawn on it—then imagine crumpling it up. The "rainbow" patterns we see at Danxia are the result of a similar crumpling, which explains their perfect striation.
Danxia was mapped by Chinese archaeologists in the 1920s and 30s, and it remained relatively unknown outside of the region—but that's quickly changing. It received protection as a UNESCO heritage site in 2009, and though Gansu is landlocked and lesser populated than more easterly provinces, it hasn't been immune to the rapid development of its neighbors, either—and the boom in tourism reflects that.
Danxia isn't the only instance of such dramatic coloration. There are a couple of similar examples in North America. For example, there's the Spectrum Range, in British Columbia. Further south towards the U.S., there's the Chilcotin Plateau—also known as the Rainbow Range. This range, too, is a huge shield volcano (19 miles wide!) that's mostly made up of a type of rock called Peralkaline—which have less aluminum and more sodium and potassium, part of what gives them their vibrant hue.
Still, there's little else like Danxia's uniquely perfect lines of minerals and red rock. It's enough to make you wonder what other geological wonders are out there!