Magnetotelluric Data, Rainier Mesa/Shoshone Mountain, Nevada Test Site, Nevada.

Williams, Jackie M. ; Sampson, Jay A. ; Rodriguez, Brian D. ; Asch., and Theodore H.

United States Geological Survey - Nevada, Henderson, NV

关键词: Management;    Security;    Testing;    Geologic Structures;    Geology;   

DOI  :  10.2172/895290
RP-ID  :  USGS OF 2006-1215
RP-ID  :  AI52-01NV13944
RP-ID  :  895290

美国|英语

来源: UNT Digital Library

【 摘 要 】

The United States Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) at their Nevada Site Office (NSO) are addressing ground-water contamination resulting from historical underground nuclear testing through the Environmental Management (EM) program and, in particular, the Underground Test Area (UGTA) project. From 1951 to 1992, 828 underground nuclear tests were conducted at the Nevada Test Site northwest of Las Vegas. Most of these tests were conducted hundreds of feet above the ground-water table; however, more than 200 of the tests were near or within the water table. This underground testing was limited to specific areas of the Nevada Test Site, including Pahute Mesa, Rainier Mesa/Shoshone Mountain, Frenchman Flat, and Yucca Flat. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology, and its effects on ground-water flow. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Rainier Mesa/Shoshone Mountain Corrective Action Unit (Bechtel Nevada, 2006). During 2005, the U.S. Geological Survey (USGS), in cooperation with the DOE and NNSA-NSO, collected and processed data from twenty-six magnetotelluric (MT) and audio-magnetotelluric (AMT) sites at the Nevada Test Site. The 2005 data stations were located on and near Rainier Mesa and Shoshone Mountain to assist in characterizing the pre-Tertiary geology in those areas. These new stations extend the area of the hydrogeologic study previously conducted in Yucca Flat. This work will help refine what is known about the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU – late Devonian to Mississippian-age siliciclastic rocks assigned to the Eleana Formation and Chainman Shale) from the Yucca Flat area and west towards Shoshone Mountain, to Buckboard Mesa in the south, and onto Rainier Mesa in the north. Subsequent interpretation will include a three-dimensional (3-D) character analysis and a two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for the twenty-six stations shown in figure 1. No interpretation of the data is included here.