HR: 1340h
AN: V53B-1332    [Abstracts]
TI: Twenty Five Years of Chloride Flux Data From the Yellowstone River Drainage: Temporal Trends and Spatial Distribution
AU: * Eagan, S M
EM: sean_eagan@nps.gov
AF: Yellowstone Center for Resources, National Park Service, Building 27, Yellowstone NP, WY 82190, United States
AU: Heasler, H P
EM: henry_heasler@nps.gov
AF: Yellowstone Center for Resources, National Park Service, Building 27, Yellowstone NP, WY 82190, United States
AU: Jaworowski, C
EM: cheryl_jaworowski@nps.gov
AF: Yellowstone Center for Resources, National Park Service, Building 27, Yellowstone NP, WY 82190, United States
AU: Mahony, D
EM: dan_mahony@nps.gov
AF: Yellowstone Center for Resources, National Park Service, Building 27, Yellowstone NP, WY 82190, United States
AB: Chloride flux is one component of Yellowstone National Park's Geothermal Monitoring Plan. It has been used as a measure of volcanic and geothermal activity by a variety of researchers. Chloride flux is a measure of the mass of chloride, predominately from the magmatic system, leaving a basin during a given time period and is determined by multiplying chloride concentrations from river samples by USGS stream discharges values. Yellowstone's four major drainages (Yellowstone, Madison, Falls and Snake) have been sampled approximately 25 times a year since 1983. The Yellowstone River drainage above Corwin Springs encompasses an area of 6,800 km² and ranges in elevation from 1,550 to 3,400 meters. The andesitic Absaroka Range makes up the majority of the basin, but there is a significant area of Quaternary rhyolite associated with the Yellowstone Volcano. It is a snowmelt- dominated system with a mean annual flow of 88 m³ sec^-1 (3,100 cfs). Yellowstone Lake (350 km²), accounts for five percent of the drainage area and is the dominant water source during base flow periods. High-chloride and acid-sulfate, thermal springs predominately are found near the Yellowstone Caldera boundary and within the Norris-Mammoth corridor. Within the Yellowstone River drainage, chloride flux has been measured at the outlet of Yellowstone Lake, Lamar River, Gardner River and Boiling River. Each of these sites has different chloride concentrations and different temporal trends. We have observed that instantaneous chloride flux increases with increased discharge in the Yellowstone River at Corwin Springs and at the Yellowstone Lake outlet. Years with greater total water yield correspond to years with greater total chloride flux. The chloride flux data show that the variation in chloride flux within one year is greater than the variation in total chloride between years. Synoptic sampling of Yellowstone River tributaries and transects of chloride concentrations along the Yellowstone give insight into the surface locations that produce the approximate 1.7 x 10¹⁰ grams of chloride that flow down the Yellowstone River each year.
DE: 1830 Groundwater/surface water interaction
DE: 1860 Streamflow
DE: 8419 Volcano monitoring (7280)
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting