The Yellowstone hotspot is millions of years older than previously thought. It was initially believed to have been about 17 million years old, but new studies have revealed that it is actually much older – at least 50 million years old and perhaps even older.
Yellowstone National Park measures 3,472 square miles and is mostly located in Wyoming (96% of it), while about 3% is in Montana and 1% is located in Idaho. The most famous geyser is Old Faithful which ejects boiling water every 60 to 110 minutes (an average of 74 minutes between intervals). It sends large amounts of boiling water (about 200 degrees Fahrenheit) approximately 130 feet into the air on average and the eruptions usually last between 1.5 and 5 minutes.
It sits above a “hotspot” that is “powered by a plume of hot (but not molten) material that may extend as deep as the boundary between the planet's mantle and core” as explained by experts from the U.S. Geological Survey (USGS).
They went into further details by stating, “As hot material rises buoyantly, it decompresses and melts near the surface, generating magma that feeds the magma chambers beneath Yellowstone and provides the heat that powers the many geysers and hot springs.”
Geologists have revealed that there is “a growing volume of geological evidence” like physical and chemical evidence of the Yellowstone hotspot in the Pacific Northwest part of the ocean which is hundreds of miles away from the National Park. This is how they figured out that it is millions of years older than first thought.
Experts already knew that the Yellowstone hotspot moved in the past millions of years because of our planet’s shifting tectonic plates. The experts from the USGS explained this further, “Through years of careful accumulation of data and evidence, however, the case has become quite strong – the Yellowstone hotspot is a long-lived feature that dates back to at least 50 million years ago, and perhaps even earlier,” adding, “This evolution in thought is a good example of how continued data collection and study are critical and can shift our view of geologic history, even changing our understanding of something as important as the Yellowstone magmatic system.”
The McDermitt volcanic system is around 17 million years old and since there weren’t any other older volcanic systems located to the southwest of it, experts believed that’s when the Yellowstone hotspot originated. There is new data that strongly suggests it was around much longer and originated off the western coast of North America such as a large volcanic eruption offshore from the coastal mountains of Oregon and Washington between 50 and 55 million years ago.
Volcanic eruptions drastically declined approximately 22 million years ago and completely stalled around 20 million years ago which was probably caused by a “slab of previously subducted ocean crust” that was caught under the continent. “This barrier effectively blocked the flow material from the Yellowstone hotspot to the surface,” the USGS experts explained. “The accumulated magma finally punched through 17 million years ago, breaking the ancient slab and resulting in the Columbia River Basalt eruptions.” “Then began the progression of volcanic calderas to present-day Yellowstone.”
The research was published in GSA Today where it can be read in full.