MAPPING THE UPPER PLUMBING SYSTEM OF ACTIVE AND INACTIVE GEYSERS WITHIN THE GREATER YELLOWSTONE GEOECOSYSTEM, WYOMING

There are approximately 1,600 geysers known on Earth, of which nearly half are found within the Greater Yellowstone Geoecosystem. The internal plumbing system of geysers has been difficult to examine due to high fluid temperatures, the presence of restrictions, and difficulty in obtaining permits for more invasive inspection methods. As part of an investigation to study geyser morphology with regards to hydrogeology and development, several active and inactive fountain geysers were surveyed by collecting measurements from the surface or by using various underwater data collection devices. At one of the inactive fountain geysers, surface stream incision into the plumbing system had cooled the water to around 30 °C allowing it to be physically inspected and surveyed using cave diving and underwater mapping techniques. The results of these surveys suggest that these geysers are mostly vertically integrated systems of complicated geometry and containing a series of irregular rooms and chambers. It is likely that these geysers began as sinter depositing hot springs, but due to internal modifications by dissolution and erosion, the geometry became favorable for geyser activity to begin. Inspections were conducted entirely from the upper plumbing within the sinter deposits to a maximum inspected depth of 25 meters. Our analyses from within this zone suggest that these systems could have formed as primary caves through the buildup of sinter around thermal vents, but have undergone modification from the onset by ascending thermal fluids, occurring in conjunction with the primary cave-forming process. This investigation provides new insights into geyser genesis and evolution through physical exploration and mapping within the plumbing system.