A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation

Open-File Report 2014-1187
By: , and 

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Abstract

The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR).

 

In late September 2010, the U.S. Geological Survey (USGS) conducted a ground-based magnetic survey of the northeast portion of Frenchman Flat within the NNSS and within the adjacent NTTR. The survey was designed to address two questions of importance to the siting of new monitoring wells near (down-gradient of) or within groundwater-contaminant plumes resulting from the Milk Shake and Pin Stripe underground nuclear tests:

 

Question 1—What is the horizontal extent of the basalt flow (the Basalt lava flow aquifer or BLFA) encountered in three wells (UE5k, UE5i, and ER-5-3) within the alluvial section at depths ranging from 268 to 290 meters (m) (880 to 950 feet [ft]), and having a thickness between 9 and 21 m (30 and 70 ft)? Exploratory Hole UE5k is located near Emplacement Hole U5k, site of the Milk Shake underground nuclear test (U.S. Department of Energy, 2000). Characterization well ER-5-3 is located approximately 670 m (2,200 ft) west-northwest of the Milk Shake test.

 

Question 2—Does basin and range normal faulting observed in the hills north of Frenchman Flat continue southward under alluvium and possibly disrupt the Topopah Spring Tuff of the Paintbrush Group (the Topopah Spring welded tuff aquifer or TSA) east of the Pin Stripe underground nuclear test, which was conducted in Emplacement hole U11b?

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation
Series title Open-File Report
Series number 2014-1187
DOI 10.3133/ofr20141187
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Crustal Geophysics and Geochemistry Science Center
Description Report: vi, 144 p.; 1 Plate: 36.00 x 48.00 inches; USGS-474-216: 24 p.; Downloads Directory
Country United States
State Nevada
Other Geospatial Frenchman Flat
Datum North American Datum of 1927
Online Only (Y/N) Y
Additional Online Files (Y/N) N