摘要: A wide variety of geophysical methods were employed to study a proposed nuclear waste site at Syncline Ridge on the Nevada Test Site, Nevada. Detailed and regional gravity work revealed complex structure at the site. Magnetics hel... 展开 A wide variety of geophysical methods were employed to study a proposed nuclear waste site at Syncline Ridge on the Nevada Test Site, Nevada. Detailed and regional gravity work revealed complex structure at the site. Magnetics helped only in identifying small areas of Tertiary volcanic rocks because of low magnetization. Seismic refraction assisted in identifying near surface faulting and bedrock structure. Difficulty was experienced in obtaining good quality reflection data, implying significant structural complexity. Electrical methods were used for fault identification and for mapping of a thick argillaceous unit of the Eleana Formation in which nuclear waste was to be emplaced. The geophysical studies indicate that major faults along the axis of Syncline Ridge and on both margins have large vertical offsets displacing units so as not only to make mining difficult, but also providing potential paths for waste migration to underlying carbonate aquifers. The Eleana Formation appeared heterogeneous, which was inferred to be due to structural complexity. Only a small region in the northwest part of the study area was found to contain a thick and relatively undisturbed volume of host rock. Deep electrical soundings identified a very conductive region in the crust below Syncline Ridge at depths shallower than 10 km. Similar conductive regions have been observed associated with geothermal systems in the western United States and imply the potential for a blind geothermal system below Syncline Ridge. The geophysical studies provided negative evidence for the suitability of the site for a nuclear waste repository. (ERA citation 07:049398) 收起