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Planetary Geology on Earth: Echo Amphitheater — Geocache of the Week

by hzoi
New Mexico, United States
N 36° 21.580′ W 106° 31.716′

Today’s featured EarthCache takes us to New Mexico and Mars, as part of the Planetary Geology on Earth Series. New Mexico’s “Land of Enchantment” moniker is well deserved for its breathtaking beauty on a grand scale. The area features stunning desert landscapes and impressive geological features like tall sandstone hoodoos, volcanic calderas, and lava plugs. Add to that bubbling hot springs, magnificent deep river gorges, the world-renowned Carlsbad Caverns full of spectacular formations and the largest cave room in North America, and you’re sure to feel enchanted too.   

Today we feature another fascinating EarthCache as our Geocache of the Week, Planetary Geology on Earth: Echo Amphitheater (GC652YV).

Echo Amphitheater is a big rounded hole carved deep into the colorful layers of sandstone by wind and rain. A peculiar feature about this amphitheater is the red stains that look like blood has dribbled down the rock face from the top. The stains have inspired legends of massacres taking place at the top, with the victims’ blood pouring over the edge. Of course, it isn’t blood at all. It is a natural coating on the rock, known as Desert Varnish.

Desert Varnish is formed when the wind blows sand and dust, which sticks to rock wet with runoff. With the help of bacteria living on the rock, it oxidizes and becomes red if the sand contains a lot of iron. The bacteria cement a thin layer of the colored dust onto the rock face and after thousands of years, the varnish accumulates to form dark blood-like stains as seen in Echo Amphitheater.

During your visit, pay close attention to the colors and textures in the layers of sandstone for the logging tasks. You’ll need to look for signs of weathering too. Above all, don’t miss out on the fun part, this formation is called Echo Amphitheater for a reason! Your voice bounces around the curved walls and you’ll hear a big echo in return. This is one of the few places where screaming and yelling is encouraged! 

The colors of the sandstone are easy to see if you step back a little. Sandstone layers are formed when an area is repeatedly flooded. The longer each layer is under water, the thicker the layer will be. This location was at the bottom of a huge salty lake 170 million years ago, and at other times it was covered with sand dunes that later compacted into a different layer of the sandstone.

The different colors of the sandstone are also visible in the sandstone cliffs adjacent to the amphitheater. However, colorful ribbons of sandstone are not limited to Earth!

These colorful sandstone layers are on Mars! The photo above is found inside the 87-mile (140 km) wide impact crater known as Holden Crater. The crater must have been flooded at one or more times, each time depositing a new different color of sediment. If you didn’t know this photo was from Mars, it would be easy to believe it was taken at one of Earth’s deserts.

“Second visit to this awesome site. First time logging the cache. Very interesting reading the description about the legend and the Earth Science lesson. Thank you for making this an earthcache and giving folks another reason to visit here.”

globetrotting medic

“I’m so glad we stopped here to view and play around in the echo amphitheatre! Very cool rock units and story in the description.”


“This place is amazing! We played around with echoes, but as we were leaving, there was a family coming up the trail with a little girl. That little voice echoed like crazy. It was adorable!! Thank you for this Earthcache! Dropping a fave point!”

Mama Simba 

Continue to explore some of the most amazing geocaches around the world.
Check out all of the Geocaches of the Week on the Geocaching blog. If you would like to nominate a Geocache of the Week, fill out this form.

Source: Geocaching

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