Distribution, characterization, and genesis of mordenite in Miocene silicic tufts at Yucca Mountain, Nye County, Nevada.

摘要

Tuffs at Yucca Mountain in the southwestern Nevada volcanic field are being investigated as a possible deep repository for high-level radioactive wastes. A sequence, as much as about 3000 meters thick, of Miocene silicic ash-flow tuffs, bedded tuffs, lavas, and flow breccias was derived chiefly from the Timber Mountain-Oasis Valley caldera complex. Previous studies by others of core from several drill holes have shown that much of the original vitric material of the volcanic and volcaniclastic rocks was altered during diagenesis to clay minerals, silica minerals, zeolites, and feldspars. Unaltered glass still persists in the upper part of the sequence, but zones characterized by clinoptilolite and mordenite, analcime, and albite follow in succession with depth. 28 refs., 16 figs., 5 tabs.