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F.M. Byers

Publications and source records attributed to F.M. Byers.

At least 37 records · Page 2Linked to original sources
USGS1968

Subsurface geology of the Silent Canyon caldera, Nevada Test Site, Nevada

Deep drilling in the vicinity of Silent Canyon on eastern Pahute Mesa, Nevada, has revealed a Tertiary volcanic section locally thicker than 14,000 feet. The area drilled covers most of the Silent Canyon caldera and some of the surrounding area. The caldera is rudely elliptical in plan and measures 10 by 14 miles. Except on its east edge, the caldera is completely obscured by younger volcanic rocks, including ash-flow sheets from several other centers. The structure, originally inferred from surface mapping and a 20-mgal gravity low, has been confirmed by drilling at 21 sites. Petrographic, chemical, and magnetic studies of more than 4,000 feet of drill core have revealed a complex sequence of volcanic rocks. Precaldera rocks include thick talc-alkalic lavas and tuffs. Peralkaline lavas and tuffs of the Silent Canyon center include the Belted Range Tuff (13-14 m.y.), eruption of which resulted in caldera collapse. The Belted Range Tuff has been downdropped 5,000-7,000 feet in the caldera. Subsequently, the depression was partially filled in the eastern part by genetically related peralkaline lavas and tuffs and in the western part by later calc -alkaline lavas and tuffs apparently genetically unrelated to the peralkaline rocks of the Silent Canyon center. Renewed subsidence probably occurred during their eruption. Isopach maps of younger tuffs show that the caldera was topographically low during deposition of later (12.5-7 m.y.) ash-flow sheets from other volcanic centers.

Nevada↗
USGS1959

Geological Survey investigations in the U12e.05 tunnel, Nevada Test Site

The papers comprising the various parts of this report contain the preliminary results of the U. S. Geological Survey investigations in the U12e.05 tunnel at the Atomic Energy Commission's Nevada Test Site, Nye County & Nevada (fig. 1). Reports on electrical resistivity, natural radioactivity, and heat required to raise the rocks to 100°C will be issued later. A preliminary report on the geologic effects of the Blanca event is being prepared. The U12e.05 tunnel, one of two laterals from the main U12e tunnel, trends west and connects with the main tunnel about U960 feet from the portal (fig. 2). The U12e.05 tunnel was driven for the nuclear test, code name Blanca, which took place on October 30, 1958. Before the explosion, the tunnel was 8 feet high and 8 to 9 feet wide and consisted of 990 feet of workings, a shot chamber, and an alcove (fig. 2). The original shot chamber, at the west end of the tunnel, was 19 feet long, 10 feet wide, and 15 feet high. The vertical and minimum cover over the original shot chamber are 1,150 and 950 feet, respectively. After detonation of the nuclear device in the test, code named Logan, in the U12e.02 tunnel on October 15, 1958, the U12e.05 tunnel, locally, was damaged severely.

Nevada↗