Award Date

1-1-1996

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

Number of Pages

142

Abstract

Uranium concentrations and {dollar}\rm\sp{234}U/\sp{238}U{dollar} isotope ratios were determined for over 100 springs, wells and surface waters in areas on and surrounding the historical nuclear weapons testing range in southern Nevada, the Nevada Test Site (NTS). Uranium concentrations were less than 2 {dollar}\mu{dollar}g/liter in the Spring Mountains, where ground water enters the system, and between 2.5 and 5 {dollar}\mu{dollar}g/liter in waters discharging from the major springs at Ash Meadows, Nevada and the Death Valley-Furnace Creek area of southeastern California. Slightly higher levels of dissolved uranium (6-15 {dollar}\mu{dollar}g/liter) were associated with the weathering of susceptible rocks and the concentration of ground water by evaporation. The average concentration of uranium in ground water was 3.03 {dollar}\mu{dollar}g/liter (s.d. 2.1) and the highest measurement recorded was 69 {dollar}\pm{dollar} 5.8 {dollar}\mu{dollar}g/liter in water collected from Lower Pahranagat Lake in Lincoln County, Nevada. Uranium isotope ratios, ({dollar}\rm\sp{234}U/\sp{238}U{dollar}), ranged from close to one at NTS Well UE-6E (1.04 {dollar}\pm{dollar} 0.21) to more than seven at NTS Well J-13 (7.58 {dollar}\pm{dollar} 0.24). Isotope mixing diagrams suggest that about 70 percent of the water discharging from the regional springs at Ash Meadows in the southern Amargosa Desert may come from the nearby Spring Mountains, with the remainder possibly coming from the Hiko-Pahranagat region, northeast of the NTS. This is in agreement with earlier findings. Spring discharge in southern Death Valley is also related to regional ground water movement. Using data collected in this study, it is estimated that 80 percent of the water in southern Death Valley is a result of underflow from the Ash Meadows region to the east, while as much as 20 percent may originate from other areas.

Keywords

Ash; Basin; Flow; Groundwater; Investigation; Isotope; Meadows; Nevada; Patterns; Ratios; Regional; Southern; Uranium

Controlled Subject

Hydrology; Geology; Environmental sciences

File Format

pdf

File Size

3880.96 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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