The National Parks of the United States protect some of the most unique geologic wonders in the world. Billion of years of weather, life and plate tectonics has shaped the United States into this unbelievable landscape we know today. While all of the lands are special some regions are just a little extra special. You do not have to be a geologist with an advanced degree to appreciate the geological forces that have created some of our most spectacular national parks. Here are a few of my favorite geologic wonders and a BRIEF intro into the geology that created them.
Geologic Wonders of the National Parks
Old Faithful Geyser
Old Faithful Geyser is arguably the famous geyser in the world. Old Faithful is located in Yellowstone National Park and is part of the Upper Geyser Basin. The geyser is named for its predictability. US Ranger Naturalist Harry Woodward first described the mathematical relationship between the duration of Old Faithful’s eruptions and the interval between eruptions. On average, Old Faithful erupts every 65 or 91 minutes ±10 minutes. This number depends on if the previous eruption was more or less than 2.5 minutes.
Yellowstone National Park is located on a “hot spot.” A hot spot is a volcanic region that occurs independently from the tectonic plate boundaries. Geologist do not fully understand what or how hot spots are created. But what is know is that for some reason, basaltic magma rises through the continental crust and can violently burst into the surface in the form of a volcano. Yellowstone is one giant supervolcano and volcanic caldera. There is a great cove of magma below the surface of Yellowstone’s caldera. This magma superheats the water and creates the geothermal features of the park.
Old Faithful Geyser is created by water soaking into the earth. The water is collected in porous sections of the rock and is superheated. Then the water moves back towards the surface where the pressure drops and some of the water turns to steam and forces it upward and out. Old Faithful’s predictability is due to the fact that its water cycle is not depended on any other geothermal features in the area.
Great Sand Dunes
Colorado is famed for its mountains but the southeast quadrant of the state holds a few surprising spots. One of those spots is the Great Sand Dunes of Great Sand Dunes National Park and Preserve. This massive dune field is located at the western base of the Sangre de Cristo Range. These dunes are the tallest in North American. The highest dune in the park is 750 ft tall and the dunes cover 30 square miles of land in the San Luis Valley. It is estimated that there is 5 billion cubic meters of sand in the dune field.
The dunes were created by a unique mixture of mountains and wind. An ancient lake once covered the San Luis Valley floor. The lake left a large deposit of fine sediment. Over time, the southwest winds would blow the sediment towards the Sangre de Cristo Range. The wind would funnel towards three mountain passes and the sand starts to accumulate. Not all the sand would accumulate at the natural pocket between the mountains. Some would be blown up the mountains. Later storms would blow the sand back down and with each change of the wind, the dunes would grow a little higher.
The Grand Canyon is a massive canyon which is 277 miles long and up to 18 miles wide and depth of a mile. It is one of the world’s largest canyon. Located in northwestern Arizona, the canyon is spread between Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation.
Standing at the rim of the Grand Canyon is looking at two billion years of history. At the bottom of the Grand Canyon is the Colorado River. For millions of years, the Colorado River and associated tributaries have flowed thru this area. With each passing year, the river channel got a little wider and a little deeper. The exact time frame it took the Colorado River to carve the Grand Canyon is up for debate but as the river carved the earth in revealed layer upon layer of geological history.
Imagine a giant lake on top of an ancient volcano. With Crater Lake, one doesn’t have to imagine. Crater Lake is a lake that has formed in the caldera of the Mount Mazama volcano. This bright blue lake is located in southwestern Oregon. The lake has a recorded depth of 1,949 ft and is 316 acres in size.
Mount Mazama sits on the North American Tectonic Plate where the Juan de Fuca Tectonic Plate is slipping below the North American Plate. This slippage has created a series of volcanos called the Cascade Range. Over 400,000 years, various volcanic eruptions created an 11,000 ft stratovolcano. Suddenly about 7,700 years ago, Mount Mazama violently erupted. During the eruption, the mountain collapsed inward creating the caldera. Over the next 250 years, rain and snow accumulated in the caldera and created the brilliant blue lake known as Crater Lake.
Have I peaked your interested in the Geological Wonders of the US National Parks?
If you would like to learn more about our national parks check out Wonders of the National Parks: A Geology of North America. This 36 part series is taught by Professor
Ford Cochran, Master of Philosophy in Geology. Dr. Cochran is the Director of Programming for National Geographic Expeditions. Over his more-than-20-year career with National Geographic, Professor Cochran has written for National Geographic magazine, served as principal contributing writer for its Historical Atlas of the United States, helped launch nationalgeographic.com and directed content development and programming for the website, and documented numerous Society-funded research expeditions in the field. His work online has earned multiple Webby, CODiE, and People’s Voice Awards, along with the American Association of Museums’ Gold MUSE Award.
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