CHARACTERIZATION AND MONITORING OF HOT SPRINGS IN THE LOWER GEYSER BASIN, YELLOWSTONE NATIONAL PARK

Monitoring hot springs can provide valuable indirect evidence to changes in sub-surface magmatic systems. During the past 3 summers, the EIU Geology Field Camp has collected data on about 150 hot springs in the Lower Geyser Basin of Yellowstone National Park. Data is collected from 3 different areas known as the Sentinel Meadows Thermal Area, Rabbit Creek area, and the White Creek Group. During a 48 hour period, teams of about 4-5 students and one professor collect Geographic Positioning System (GPS) location data, temperature, and pH for individual hot springs. In addition, a digital photograph is taken of each data collection site. Most springs in the study areas have been measured annually beginning in June 2000. Data from each year (2000, 2001, and 2002) was entered into a Geographic Information System (GIS) database for analysis. Microsoft Access was used to compile and analyze the data, while ArcView GIS was used to plot data and generate maps. Each hot spring was then evaluated for changes in temperature, pH, and appearance during the monitoring period. Springs in the Sentinel Meadows Thermal Area are consistently the hottest, with temperatures typically ranging from 85-96°C. During the past 3 years, many springs have shown 3-4°C temperature increases with one spring increasing as much as 11°C. In addition, a few new pools have become active, and the level of one particular pool has varied significantly from year to year. The pH ranged from 6.5-9.5 in Sentinel Meadows and exhibited a positive correlation with temperature. The Rabbit Creek area has had greater temperature variability, ranging from about 40-95°C. A temperature increase was noted at about 60% of the pools, while the others remained unchanged. The overall temperature increase in these springs was typically 3-7°C and as high as 10°C. During the study period, one spring has been intermittently active and a few new springs have also developed. The pH in the Rabbit Creek area ranged from 6.0-9.5 and there was no correlation with temperature. Analysis of The White Creek Group is in progress.