A time when "Old Faithful" wasn’t so faithful !

In Yellowstone National Park, the "Old Faithful" geyser in the Upper Geyser Basin received its unique name in the 19th century due to the regularity and predictability of its eruptions.

A sample of mineralized (silicified) wood was discovered in his mouth, as evidenced by a Journal published over 60 years ago. Its radiocarbon dating has just been confirmed in a study that was just published in October 2020, on 41 dates: 1233-1362 CE.

This date corresponds to a series of severe regional droughts, which lasted for many decades, at the end of the Middle Ages climate anomaly, before the onset of the Little Ice Age.

Murray pines (Lodgepole pine) were able to thrive in the mouth of an active natural geyser only during a period of great drought that affected much of the United States, and affected the native cultures of Anasazi, Fremont and Lovelock . The remains of trees were then preserved by mineralization in an alkaline water rich in silica ... to reveal to us today the mysteries of the "Old Faithful".

Natural geysers are rare on the planet, because they require special conditions to form: heat input from active or recent magmatism, and adequate geometry of rock fractures underground to ensure episodic discharge. These parameters can change following earthquakes modifying the fractures, or by regional variations in precipitation, which feed underground reservoirs.

Climate change forecasts, which include regional droughts for the middle of the 21st century, suggest less frequent eruptions of these geysers, and even the end of their activity.

Happy are those who were able to see them in great shape!

Sources:

- USGS - Caldera chronicles - A time when Old Faithful wasn’t so faithful

- Geophysical Research letters - Yellowstone's Old Faithful Geyser Shut Down by a Severe 13th Century Drought