Date of this Version
ISOTOPE CONTENT AND TEMPERATURE OF PRECIPITATION IN SOUTHERN NEVADA, AUGUST 1983-AUGUST 1986 By W.K. Milne, L.V. Benson, and P.W. McKinley. U.S. GEOLOGICAL SURVEY Open-File Report 87-463. Denver, Colorado 1987
From August 1983 through August 1986, 429 precipitation samples of 112 precipitation events were collected at 12 stations in southern Nevada. Some of these samples were analyzed for oxygen-18, deuterium, and tritium. The results of these analyses as well as the air temperature and the precipitation measured at the collection sites are tabulated in this report. The sampling program provides a data base for future interpretive studies on the timing and origin of ground-water recharge in the Yucca Mountain region, of southern Nevada.
The stable-isotope composition of precipitation is the result of fractionation processes that occur in the atmosphere. Isotopic trends in precipitation have been phenomenologically related to latitude, altitude, distance from moisture source area, season, precipitation, and air temperature (Dansgaard, 1964; Fritz and Fontes, 1980).
Even though tritium (3H) concentrations are small and relatively uniform over the oceans throughout the year, over the continents 3H increases in the lowest 2 kilometers of the troposphere during summer (Ehhalt, 1971, 1974; Fritz and Fontes, 1980). Ehhalt has attributed the occurrence of the summer-precipitation 3H peak to re-evaporation of continental moisture.
This progress report presents oxygen-18 (δ18O), deuterium (δD), 3H and temperature data collected from 12 stations in southern Nevada from August 1983 through August 1986.