Volcanic suites and related cauldrons of Timber Mountain-Oasis Valley caldera complex, southern Nevada

Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

“…It may correspond with the Fraction Tuff (Orkild and Maldonado, unpublished report), or it may be a previously unrecognized unit of the Crater Flat Tuff (B. Crowe, personal communication, 1978). It is somewhat similar, petrographically, to the Redrock Valley Tuff (Byers et al 1976; Marvin et al, 1970), but a positive correlation cannot be made on the basis of the limited petrographic data. B. Crater Flat Tuff 1.…”

Bulk, thermal, and mechanical properties of the Topopah Spring Member of the Paintbrush Tuff, Yucca Mountain, Nevada

“…The source is inferred to be the Claim Canyon Cauldron (Byers et al, 1976), which lies to the north of Yucca Mountain. In general, both the maximum degree of welding and the average degree of welding decrease away from the source, so that matrix porosity should increase with distance from the source.…”

Drift Degradation Analysis

“…The Paintbrush Group includes a sequence of four formations: the Tiva Canyon, Yucca Mountain, Pah Canyon, and Topopah Spring Tuffs, each of which consist primarily of large-volume, pyroclastic-flow deposits with minor amounts of pyroclastic-fall deposits (Byers et al 1976 [DIRS 104639];Christiansen et al 1977 [DIRS 157236];Broxton et al 1993 [DIRS 107386]; Buesch et al 1996 [DIRS 100106]) . At Yucca Mountain, two of these formations, the Topopah Spring and Tiva Canyon Tuffs, are voluminous, mostly densely welded, compositionally zoned, outflow sheet, pyroclastic-flow deposits (also referred to as ignimbrites) that grade upward from rhyolite composition to quartz latite composition (Lipman et al 1966 [DIRS 100773]; Byers et al 1976 [DIRS 104639]; Schuraytz et al 1989 [DIRS 107248]). The formations of the Paintbrush Group are interbedded with bedded tuffs, which consist of thinner pyroclastic-flow and pyroclastic-fall deposits, and, locally, a few lava flows (Byers et al 1976 [DIRS 104639];Christiansen et al 1977 [DIRS 157236];Broxton et al 1993 [DIRS 107386]; Buesch et al 1996 [DIRS 100106]; Day et al 1998 [DIRS 100027]).…”