At first glance, White Sands National Park in southern New Mexico and Great Sand Dunes National Park and Preserve in southern Colorado look similar. Geologically, however, they tell completely different stories.
White Sands and Great Sand Dunes demonstrate one of geology's greatest lessons: Landscapes that look alike can form through completely different processes. One formed from the remnants of an ancient tropical sea, while the other is the product of mountain uplift, erosion, rivers, and wind.
Let's take a look!
J. Alexandra Sloan
Founder and Principal Geologist, 4J Resources
White Sands National Park, New Mexico
Galyna Andrushko/ Shutterstock.com
White Sands is home to the largest gypsum dune field on Earth, covering nearly 275 square miles within the Tularosa Basin.
Area geology: Its story begins approximately 280 million years ago, when a shallow Permian sea deposited thick layers of gypsum across southern New Mexico.
Millions of years later, uplift of the San Andres and Sacramento Mountains exposed these rocks to weathering.
Rainwater dissolved the gypsum and carried it into ancient Lake Otero.
As the lake expanded and dried during the Ice Ages, gypsum crystals accumulated across the lakebed.
Wind eventually broke the crystals into sand-sized grains and built the white dunes that continue migrating today.
White Sands exists because the Tularosa Basin has no outlet, allowing the gypsum to remain trapped and continually recycled by wind.
The result is one of the most unusual landscapes in North America and an outstanding natural laboratory for studying evaporites, active dune migration, desert ecology, and Quaternary climate change.
The Classic Desert Aire Hotel: This artisanal lodge features a New Mexico-style boutique and cafe, as well as everything you need to plan your time near Alamogordo, New Mexico.
Tavares Inn: This is a great option for those who love to golf (it's near the Alamogordo Public Gulf Course).
Other activities:
Hike the Alkali Flat Trail and go dune sledding
Spend an afternoon in nearby Cloudcroft, a hub for winter sports.
Great Sand Dunes National Park and Preserve, Colorado
Kit Leongt/ Shutterstock.com
About four hours north lies another remarkable dune field—but with a completely different origin.
Area geology: Great Sand Dunes National Park contains thetallest sand dunes in North America, rising more than 700 feet above the San Luis Valley.
Instead of gypsum, these dunes consist primarily of quartz and feldspar derived from the surrounding Sangre de Cristo Mountains.
Over millions of years, streams carried sediment into the San Luis Valley.
Strong southwesterly winds transported the sand back toward the mountain front, where seasonal winds and Medano Creek continually recycle it into massive dunes.
This ongoing interaction between mountains, rivers, and wind makes Great Sand Dunes one of North America's most active eolian systems.
The park also offers visitors an opportunity to experience several geologic environments in one location—from alpine peaks and glacial valleys to alluvial fans, wetlands, and active dune fields.
Where to stay: I recommend The Windsor Hotel (Del Norte). Its elevated accommodations are a historic piece of the West. The hotel was established in 1874.
Other activities:
Sandboard or sled the dunes
Hike to High Dune, then cool off in Medano Creek in the late spring.
Visit Zapata Falls, a 25-foot fall inside a cave.
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