HR: 0800h
AN: V31E-0717 [Abstracts]
TI: Multiple Eruptive Phases and Deposits of a Monogenetic Volcano: Tabernacle Hill Volcano, Utah, USA
AU: * Hintz, A (
EM: arleonar@mail.usf.edu
AF: University of South Florida, 4202 E. Fowler Ave
SCA 528, Tampa, Fl 33620, United States
AU: Connor, C B
EM: cconnor@cas.usf.edu
AF: University of South Florida, 4202 E. Fowler Ave
SCA 528, Tampa, Fl 33620, United States
AB:
Tabernacle Hill volcano, located near the eastern edge of North America's great basin, is one of a group of
monogenetic small-volume (0.47 km3) basaltic volcanoes forming a long-lived (~ 1 Ma) north-south
trending alignment in Utah's Black Rock Desert. Initial phreatomagmatic eruptions at Tabernacle Hill are reported
to have begun 14,320 ± 90 years ago. The initial eruptive phase produced a tuff cone approximately 80 m
high (1,511 m a.s.l.) and 1.5 km in diameter with distinct bedding layers. Recent mapping and sampling of
Tabernacle Hill's lava and tuff cone deposits has been aimed at better constraining the sequence of events,
physical volcanology, rheology, and geochemistry of this eruption. Blocks located on the rim of the tuff cone of
mid-crustal and near-surface origin were mapped and analyzed to yield preliminary minimum muzzle velocities of
70-100 m/s. After the initial phreatomagmatic explosions, the eruption style transitioned to a more effusive phase
that partially filled the tuff cone with a semi-steady state lava lake 200 m wide and 15 m deep. Eventually, the tuff
cone was breached by the impinging lava resulting in large portions of the cone rafting on top of the lava flows
away from the vent. Eruption onto the Lake Bonneville lake bed allowed the Tabernacle Hill lava flows to flow
radially from the tuff cone and cover an area of 18.1 km2, producing a very uniform high aspect ratio (100:1)
flow field. Tabernacle Hill lava flows are pâhoehoe flows with many large phenocrysts of olivine and plagioclase
(>1 cm) and have an average thickness of 26.3 m. Subsequent eruptive phases cycled several times between
effusive and explosive, producing scoria cones and more lava flows, culminating in an almost complete drainage
of the lava lake through large lava tubes and drainback.
DE: 8415 Intra-plate processes (1033, 3615)
DE: 8425 Effusive volcanism
DE: 8427 Subaqueous volcanism
DE: 8429 Lava rheology and morphology
DE: 8486 Field relationships (1090, 3690)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting