Researchers from the University of Wyoming and the National Park Service made the discovery while excavating sediment from near the cone of Old Faithful. They found several pieces of mineralized wood that had fallen from trees and been partially burned by the geyser's heat more than 10,000 years ago. By measuring the level of carbon-14, a radioactive isotope of carbon, in the wood, the researchers determined that the trees were killed during the time when Old Faithful was quiet.
"This is a significant finding because it challenges our current understanding of Old Faithful's behavior," said Dr. Jamie Farrell, a geologist with the University of Wyoming. "We used to think that Old Faithful has been erupting continuously for the last 10,000 years, but now we know that it has had at least one major hiatus."
The researchers believe that the hiatus was caused by a change in the geyser's plumbing system. Old Faithful is fed by a shallow reservoir of hot water that is heated by the magma below Yellowstone. If the water level in the reservoir drops too low, the geyser will stop erupting.
"We think that the hiatus was caused by a decrease in the amount of hot water flowing into Old Faithful's reservoir," said Farrell. "This could have been due to a number of factors, such as a change in the temperature of the magma below Yellowstone or a shift in the geyser's plumbing system."
The hiatus lasted for several decades, according to the researchers. This is based on the fact that the carbonized wood found near the cone of Old Faithful is dated to between 10,000 and 9,500 years ago. This means that the trees were killed during the hiatus and that the geyser did not start erupting again until after 9,500 years ago.
The discovery of the hiatus at Old Faithful is important because it shows that the geyser's behavior is not as predictable as we thought. This could have implications for the management of Yellowstone National Park, as well as for our understanding of the geyser's role in the park's ecosystem.
"Old Faithful is one of the most popular tourist destinations in Yellowstone National Park," said Farrell. "This discovery shows that the geyser's behavior is not as predictable as we thought, which could have implications for the management of the park. It also shows that the geyser's role in the park's ecosystem is more complex than we thought."
The researchers are continuing to study the mineralized wood found near Old Faithful in an effort to learn more about the geyser's history. They hope to determine what caused the hiatus and how long it lasted.
