image The Geology of Yellowstone National Park

Yellowstone National Park is a place where Nature created so many wonders, that visitors from all over the world come every year to be captivated and amazed. Yellowstone is a World Heritage Site and encompasses 2.2 million acres in the states of Wyoming, Montana, and Idaho.

The secret of Yellowstone’s wonders originates from its geologic history. Yellowstone National Park sits over an active volcano, a hot spot. In Yellowstone molten magma is located very close to the Earth crust. In some places it is only 3 miles below the surface. Thanks to this giant underground furnace below and an abundance of water such as rivers, creeks, waterfalls and lakes on the surface, Yellowstone has the largest collection of geysers, hot springs, mudpots and fumaroles in the world.

This super volcano has had three mega eruptions. The first occurred 2.1 million years ago.  After this eruption the underground chamber of magma emptied and the ground over it sunk under its own weight, creating a caldera. The second occurred 1.3 million year ago and the third occurred 640,000 years ago. These eruptions were huge and spewed out tons of ash and rocks and also large amount of lava and gases.  During these eruptions, wildlife thousands of miles away from the epicenter perished due to the poisonous gases and volcanic ash in the air. After the last mega eruption, 640,000 years ago, the crater’s walls collapsed, forming a 30 by 45 miles caldera. Most of the central part of Yellowstone, including the northern part of Yellowstone Lake, lies over this caldera.

Scientists discovered a 500 miles chain of more than 100 calderas, stretching from the intersection of Nevada, Oregon, and Idaho through the Southern Idaho to Yellowstone. The volcanic activity started 16.5 million years ago and created the first caldera at the intersection of Nevada, Oregon, and Idaho. The North American tectonic plate was slowly moving in a northwest direction over the hot spot.  The rest of the volcanic chain was created by this movement, with the most recent eruptions occurring in Yellowstone. These volcanoes were created by the same forces of nature as were the Hawaiian Islands. Both were formed by a slowly moving tectonic plate over a hot spot.

Scientists agree that the most plausible explanation of the force which moves tectonic plates is the convectional currents in the asthenosphere. The asthenosphere is a semi-molten layer of the mantle and is located underneath of the lithosphere (upper mantle) and the Earth’s crust.


  1. Interesting! I hadn’t realised quite how extensive the volcanic activity is (or was) in Yellowstone. I mean geysers, yes, but how odd to find a whole landscape I associate with Iceland in the middle of the US.

    Liked by 1 person

    • Yes, Yellowstone is huge and full of fascinating hydrothermal features and wildlife. The supervolcano is still active and the landscape changes constantly. It might take a few weeks to see the most popular geysers, hot spring, lakes and waterfalls.


  2. Love this national Park! I never understood the geology behind it, but then again I visited as a 6 year old. Loved my experiences with the sights and smells in this park. So much wildlife roaming and waterfalls a plenty, and also loved the bubbling pits of different colors. Would love to go back as an adult. I imagine it’s pretty memorable as an adult too.

    Liked by 1 person

    • I agree, Yellowstone is awesome. I’ve got lots of unforgettable impressions that I am going to write about in my next posts. I found that geology of the park is pretty complicated, but was fascinated by it too.


  3. Wow, very technical information. Do you work in a technical field? I am looking forward to going to Yellowstone, and now I have more technical background. I will bookmark it to re-read when we go. Thanks!

    Liked by 1 person

    • You are welcome and I am glad you like it. I knew very little about geology until we visited a few National Parks. I became interested in the geology of the places we visited and found fascinating patterns. It’s just a hobby.


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