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- W2116080110 abstract "Compositional data for >400 pumice clasts, organized according to eruptive sequence, crystal content, and texture, provide new perspectives on eruption and pre-eruptive evolution of the >600 km3 of zoned rhyolitic magma ejected as the Bishop Tuff during formation of Long Valley caldera. Proportions and compositions of different pumice types are given for each ignimbrite package and for the intercalated plinian pumice-fall layers that erupted synchronously. Although withdrawal of the zoned magma was less systematic than previously realized, the overall sequence displays trends toward greater proportions of less evolved pumice, more crystals (0·5–24 wt %), and higher FeTi-oxide temperatures (714–818°C). No significant hiatus took place during the 6 day eruption of the Bishop Tuff, nearly all of which issued from an integrated, zoned, unitary reservoir. Shortly before eruption, however, the zoned melt-dominant portion of the chamber was invaded by batches of disparate lower-silica rhyolite magma, poorer in crystals than most of the resident magma but slightly hotter and richer in Ba, Sr, and Ti. Interaction with resident magma at the deepest levels tapped promoted growth of Ti-rich rims on quartz, Ba-rich rims on sanidine, and entrapment of near-rim melt inclusions relatively enriched in Ba and CO2. Varied amounts of mingling, even in higher parts of the chamber, led to the dark gray and swirly crystal-poor pumices sparsely present in all ash-flow packages. As shown by FeTi-oxide geothermometry, the zoned rhyolitic chamber was hottest where crystal-richest, rendering any model of solidification fronts at the walls or roof unlikely. The main compositional gradient (75–195 ppm Rb; 0·8–2·2 ppm Ta; 71–154 ppm Zr; 0·40–1·73% FeO*) existed in the melt, prior to crystallization of the phenocryst suite observed, which included zircon as much as 100 kyr older than the eruption. The compositions of crystals, though themselves largely unzoned, generally reflect magma temperature and the bulk compositional gradient, implying both that few crystals settled or were transported far and that the observed crystals contributed little to establishing that gradient. Upward increases in aqueous gas and dissolved water, combined with the adiabatic gradient (for the ∼ 5 km depth range tapped) and the roofward decline in liquidus temperature of the zoned melt, prevented significant crystallization against the roof, consistent with dominance of crystal-poor magma early in the eruption and lack of any roof-rind fragments among the Bishop ejecta, before or after onset of caldera collapse. A model of secular incremental zoning is advanced wherein numerous batches of crystal-poor melt were released from a mush zone (many kilometers thick) that floored the accumulating rhyolitic melt-rich body. Each batch rose to its own appropriate level in the melt-buoyancy gradient, which was self-sustaining against wholesale convective re-homogenization, while the thick mush zone below buffered it against disruption by the deeper (non-rhyolitic) recharge that augmented the mush zone and thermally sustained the whole magma chamber. Crystal–melt fractionation was the dominant zoning process, but it took place not principally in the shallow melt-rich body but mostly in the pluton-scale mush zone before and during batchwise melt extraction." @default.
- W2116080110 created "2016-06-24" @default.
- W2116080110 creator A5001131895 @default.
- W2116080110 creator A5075369838 @default.
- W2116080110 date "2007-03-29" @default.
- W2116080110 modified "2023-10-18" @default.
- W2116080110 title "Compositional Zoning of the Bishop Tuff" @default.
- W2116080110 cites W1864360925 @default.
- W2116080110 cites W1885235426 @default.
- W2116080110 cites W1964416837 @default.
- W2116080110 cites W1966876329 @default.
- W2116080110 cites W1968025245 @default.
- W2116080110 cites W1969319865 @default.
- W2116080110 cites W1971154777 @default.
- W2116080110 cites W1974291054 @default.
- W2116080110 cites W1978432636 @default.
- W2116080110 cites W1980688903 @default.
- W2116080110 cites W1981056431 @default.
- W2116080110 cites W1981756317 @default.
- W2116080110 cites W1982053720 @default.
- W2116080110 cites W1982630226 @default.
- W2116080110 cites W1986541024 @default.
- W2116080110 cites W1992815203 @default.
- W2116080110 cites W1993283790 @default.
- W2116080110 cites W1994532449 @default.
- W2116080110 cites W1994802915 @default.
- W2116080110 cites W1995202391 @default.
- W2116080110 cites W1998221897 @default.
- W2116080110 cites W1998640834 @default.
- W2116080110 cites W1999493995 @default.
- W2116080110 cites W2000190788 @default.
- W2116080110 cites W2002212057 @default.
- W2116080110 cites W2005107294 @default.
- W2116080110 cites W2007243168 @default.
- W2116080110 cites W2009678407 @default.
- W2116080110 cites W2012396908 @default.
- W2116080110 cites W2012433994 @default.
- W2116080110 cites W2012715340 @default.
- W2116080110 cites W2014510786 @default.
- W2116080110 cites W2018581667 @default.
- W2116080110 cites W2018961438 @default.
- W2116080110 cites W2019521934 @default.
- W2116080110 cites W2020931849 @default.
- W2116080110 cites W2021689808 @default.
- W2116080110 cites W2023320566 @default.
- W2116080110 cites W2023563727 @default.
- W2116080110 cites W2024806311 @default.
- W2116080110 cites W2029787791 @default.
- W2116080110 cites W2031433824 @default.
- W2116080110 cites W2032585463 @default.
- W2116080110 cites W2034937042 @default.
- W2116080110 cites W2038068172 @default.
- W2116080110 cites W2040659190 @default.
- W2116080110 cites W2041389048 @default.
- W2116080110 cites W2043877394 @default.
- W2116080110 cites W2045914082 @default.
- W2116080110 cites W2046488984 @default.
- W2116080110 cites W2048152287 @default.
- W2116080110 cites W2048562994 @default.
- W2116080110 cites W2049994227 @default.
- W2116080110 cites W2050053288 @default.
- W2116080110 cites W2050595494 @default.
- W2116080110 cites W2051199006 @default.
- W2116080110 cites W2051979453 @default.
- W2116080110 cites W2053118559 @default.
- W2116080110 cites W2053396208 @default.
- W2116080110 cites W2055595543 @default.
- W2116080110 cites W2055783005 @default.
- W2116080110 cites W2055921266 @default.
- W2116080110 cites W205659000 @default.
- W2116080110 cites W2056741239 @default.
- W2116080110 cites W2056886193 @default.
- W2116080110 cites W2057852429 @default.
- W2116080110 cites W2061605116 @default.
- W2116080110 cites W2062471418 @default.
- W2116080110 cites W2062890233 @default.
- W2116080110 cites W2064810596 @default.
- W2116080110 cites W2065855118 @default.
- W2116080110 cites W2067221143 @default.
- W2116080110 cites W2068542029 @default.
- W2116080110 cites W2069342962 @default.
- W2116080110 cites W2072506249 @default.
- W2116080110 cites W2074293173 @default.
- W2116080110 cites W2076406150 @default.
- W2116080110 cites W2076830276 @default.
- W2116080110 cites W2077385643 @default.
- W2116080110 cites W2077680773 @default.
- W2116080110 cites W2085941059 @default.
- W2116080110 cites W2087686567 @default.
- W2116080110 cites W2089684068 @default.
- W2116080110 cites W2090895097 @default.
- W2116080110 cites W2093002188 @default.
- W2116080110 cites W2093014852 @default.
- W2116080110 cites W2096680403 @default.
- W2116080110 cites W2108170961 @default.
- W2116080110 cites W2112606960 @default.
- W2116080110 cites W2118699879 @default.
- W2116080110 cites W2119893743 @default.