Researchers Resolved Century-Old Yellowstone Naming Error
Archival letters from 1926 reveal that a hydrothermal explosion caused a permanent mislabeling of a park geyser.
Updated on Oct. 5, 2026 in Geology
The U.S. Geological Survey has identified the cause of a decades-long naming error involving the Black Pearl Geyser in Yellowstone National Park. Researchers used correspondence from 1926 to determine that a 1925 hydrothermal explosion in Biscuit Basin displaced the site's signage.
Why it matters
The discovery clarifies historical geological records in an area where lack of witnesses to the 1925 explosion left thermal features misidentified for nearly a century. Reconstructing these events helps scientists better understand the volatile history of the region's landscape.
The Black Pearl Geyser is characterized by unique dark, pearl-like spheres of sinter, distinguishing it from surrounding features. The initial 1925 explosion significantly tore through the fragile sinter crust located near the Firehole River.
The players
U.S. Geological Survey
This federal agency provides scientific data about the Earth's natural systems and monitors volcanic and seismic hazards in Yellowstone.
J.R. Van Pelt
He was a park ranger whose 1926 correspondence provided the first written evidence regarding the misplaced geyser sign.
J.E. Haynes
He was a historical figure in park documentation whose 1926 letter confirmed the specific location error of the signage.
The details
Researchers pieced together the history using letters written by Ranger J.R. Van Pelt and J.E. Haynes in 1926, which confirmed the signage error. The finding provides context to the area's ongoing thermal activity, which recently saw a separate hydrothermal explosion at the nearby Black Diamond Pool in July 2024.
Timeline
A hydrothermal explosion altered the landscape of Biscuit Basin in 1925.
Ranger J.R. Van Pelt wrote a letter regarding the sign error on August 15, 1926.
J.E. Haynes confirmed the signage error in a letter dated August 26, 1926.
A hydrothermal explosion occurred at Black Diamond Pool in July 2024.
The USGS confirmed the reconstruction of the historical naming error in October 2026.
Deeper Dive
This study follows a pattern set by the Yellowstone Volcano Observatory's historical thermal monitoring program by using past archives to contextualize modern geological changes.
Visitors to Biscuit Basin may now have a more accurate understanding of the geyser formations they observe while hiking near the Firehole River. The correction assists in correctly identifying the unique sinter spheres found at the Black Pearl Geyser site.
The takeaway
Historical archival records remain a critical tool for modern scientists attempting to decode the natural history of volatile landscapes. Understanding past errors allows for better management and interpretation of park features for future visitors.
Further reading
Learn more about local land formations in our Geology section.
Source note: This article includes information reported by The Times of India.
