thumbnail

Evaluation of evidence pertaining to the origin of vein deposits exposed in trench 14, Nevada Test Site, Nevada

By:
Edited by:
Anon

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

Large vein-like deposits of calcite and opaline silica that infill the Bow Ridge fault are exposed by Trench 14 at the Nevada Test Site. The origin of the deposits has been the center of considerable controversy because the deposits occur on the edge of Yucca Mountain, which is being characterized geologically as a possible site for the nation's first high level nuclear waste repository, and the various proposed modes of origin have differing implications for the performance of a geologic repository. Isotopic data for oxygen, carbon, strontium, and uranium in the carbonates preclude deposition by upwelling waters by any mechanism from either of the regionally extensive aquifers known to exist beneath Yucca Mountain. Data from the adjacent Ash Meadows flow system further suggest that the isotopic compositions of ground water in southern Nevada have not changed markedly during the last 300 to 600 ky, and that therefore, conclusions based on present-day water compositions are probably valid for at least the last 600 ky. Geologic and paleontologic data are inconsistent with a shallow perched water spring origin for the veins, but are consistent with a pedogenic origin. Mineralogic and isotopic data match well with those for pedogenic deposits with perhaps minor modification from entrained or reacted wall rock. Taken as a whole, the data show that the carbonate and opaline silica deposits exposed in Trench 14 must have formed by a pedogenic process. Preliminary results suggest that veins in the sand ramps west of Busted Butte formed by the same mechanism.

Additional Publication Details

Publication type:
Conference Paper
Publication Subtype:
Conference Paper
Title:
Evaluation of evidence pertaining to the origin of vein deposits exposed in trench 14, Nevada Test Site, Nevada
ISBN:
0872628310
Year Published:
1991
Language:
English
Publisher:
Publ by ASCE
Publisher location:
New York, NY, United States
First page:
1429
Last page:
1438
Number of Pages:
10
Conference Title:
Proceedings of the 2nd Annual International Conference on High Level Radioactive Waste Management
Conference Location:
Las Vegas, NV, USA
Conference Date:
28 April 1991 through 3 May 1991