Abstract
During its 1800-year-long persistent activity the Stromboli volcano has erupted a highly porphyritic (HP) volatile-poor scoriaceous magma and a low porphyritic (LP) volatile-rich pumiceous magma. The HP magma is erupted during normal Strombolian explosions and lava effusions, while the LP one is related to more energetic paroxysms. During the March-April 2003 explosive activity, Stromboli ejected two typologies of juvenile glassy ashes, namely highly vesicular LP shards and volatile-poor HP shards. Their textural and in situ chemical characteristics are used to unravel mutual relationships between HP and LP magmas, as well as magma dynamics within the shallow plumbing system. The mantle-normalized trace element patterns of both ash types show the typical arc-lava pattern; however, HP glasses possess incompatible element concentrations higher than LP glasses, along with Sr and Eu negative anomalies. HP shards are generally characterized by higher Li contents (to ~20 ppm) and lower δ7Li values (+1.2 to -3.8‰) with respect to LP shards (Li contents of 7-14 ppm and δ7Li ranging between +4.6 and +0.9‰). Fractional crystallization models based on major and trace element compositions, combined with a degassing model based on open-system Rayleigh distillation and on the assumption that melt/fluidDLi > 1, show that abundant (~30%) plagioclase precipitation and variable degrees of degassing can lead the more primitive LP magma to evolve toward a differentiated (isotopically lighter) HP magma ponding in the upper conduit and undergoing slow continuous degassing-induced crystallization. This study also evidences that in March 2003 Stromboli volcano poured out a small early volume of LP magma that traveled slower within the conduit with respect to later and larger volumes of fast ascending LP magma erupted during the April 5 paroxysm. The different ascent rates and cooling rates of the two LP magma batches (i. e., pre- and post-paroxysm) resulted in small, but detectable, differences in their chemical signatures. Finally, this study highlights the high potential of in situ investigations of juvenile glassy ashes in petrologic and geochemical monitoring the volcanic activity and of Li isotopes as tracers of degassing processes within the shallow plumbing system.
| Original language | English |
|---|---|
| Pages (from-to) | 541-561 |
| Number of pages | 21 |
| Journal | Contributions to Mineralogy and Petrology |
| Volume | 159 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2010 |
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Keywords
- Degassing-induced crystallization
- Lithium isotopes
- Petrologic monitoring
- Stromboli
- Volcanic ash
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
Cite this
Degassing, crystallization and eruption dynamics at Stromboli : Trace element and lithium isotopic evidence from 2003 ashes. / Schiavi, Federica; Kobayashi, Katsura; Moriguti, Takuya; Nakamura, Eizou; Pompilio, Massimo; Tiepolo, Massimo; Vannucci, Riccardo.
In: Contributions to Mineralogy and Petrology, Vol. 159, No. 4, 2010, p. 541-561.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Degassing, crystallization and eruption dynamics at Stromboli
T2 - Trace element and lithium isotopic evidence from 2003 ashes
AU - Schiavi, Federica
AU - Kobayashi, Katsura
AU - Moriguti, Takuya
AU - Nakamura, Eizou
AU - Pompilio, Massimo
AU - Tiepolo, Massimo
AU - Vannucci, Riccardo
PY - 2010
Y1 - 2010
N2 - During its 1800-year-long persistent activity the Stromboli volcano has erupted a highly porphyritic (HP) volatile-poor scoriaceous magma and a low porphyritic (LP) volatile-rich pumiceous magma. The HP magma is erupted during normal Strombolian explosions and lava effusions, while the LP one is related to more energetic paroxysms. During the March-April 2003 explosive activity, Stromboli ejected two typologies of juvenile glassy ashes, namely highly vesicular LP shards and volatile-poor HP shards. Their textural and in situ chemical characteristics are used to unravel mutual relationships between HP and LP magmas, as well as magma dynamics within the shallow plumbing system. The mantle-normalized trace element patterns of both ash types show the typical arc-lava pattern; however, HP glasses possess incompatible element concentrations higher than LP glasses, along with Sr and Eu negative anomalies. HP shards are generally characterized by higher Li contents (to ~20 ppm) and lower δ7Li values (+1.2 to -3.8‰) with respect to LP shards (Li contents of 7-14 ppm and δ7Li ranging between +4.6 and +0.9‰). Fractional crystallization models based on major and trace element compositions, combined with a degassing model based on open-system Rayleigh distillation and on the assumption that melt/fluidDLi > 1, show that abundant (~30%) plagioclase precipitation and variable degrees of degassing can lead the more primitive LP magma to evolve toward a differentiated (isotopically lighter) HP magma ponding in the upper conduit and undergoing slow continuous degassing-induced crystallization. This study also evidences that in March 2003 Stromboli volcano poured out a small early volume of LP magma that traveled slower within the conduit with respect to later and larger volumes of fast ascending LP magma erupted during the April 5 paroxysm. The different ascent rates and cooling rates of the two LP magma batches (i. e., pre- and post-paroxysm) resulted in small, but detectable, differences in their chemical signatures. Finally, this study highlights the high potential of in situ investigations of juvenile glassy ashes in petrologic and geochemical monitoring the volcanic activity and of Li isotopes as tracers of degassing processes within the shallow plumbing system.
AB - During its 1800-year-long persistent activity the Stromboli volcano has erupted a highly porphyritic (HP) volatile-poor scoriaceous magma and a low porphyritic (LP) volatile-rich pumiceous magma. The HP magma is erupted during normal Strombolian explosions and lava effusions, while the LP one is related to more energetic paroxysms. During the March-April 2003 explosive activity, Stromboli ejected two typologies of juvenile glassy ashes, namely highly vesicular LP shards and volatile-poor HP shards. Their textural and in situ chemical characteristics are used to unravel mutual relationships between HP and LP magmas, as well as magma dynamics within the shallow plumbing system. The mantle-normalized trace element patterns of both ash types show the typical arc-lava pattern; however, HP glasses possess incompatible element concentrations higher than LP glasses, along with Sr and Eu negative anomalies. HP shards are generally characterized by higher Li contents (to ~20 ppm) and lower δ7Li values (+1.2 to -3.8‰) with respect to LP shards (Li contents of 7-14 ppm and δ7Li ranging between +4.6 and +0.9‰). Fractional crystallization models based on major and trace element compositions, combined with a degassing model based on open-system Rayleigh distillation and on the assumption that melt/fluidDLi > 1, show that abundant (~30%) plagioclase precipitation and variable degrees of degassing can lead the more primitive LP magma to evolve toward a differentiated (isotopically lighter) HP magma ponding in the upper conduit and undergoing slow continuous degassing-induced crystallization. This study also evidences that in March 2003 Stromboli volcano poured out a small early volume of LP magma that traveled slower within the conduit with respect to later and larger volumes of fast ascending LP magma erupted during the April 5 paroxysm. The different ascent rates and cooling rates of the two LP magma batches (i. e., pre- and post-paroxysm) resulted in small, but detectable, differences in their chemical signatures. Finally, this study highlights the high potential of in situ investigations of juvenile glassy ashes in petrologic and geochemical monitoring the volcanic activity and of Li isotopes as tracers of degassing processes within the shallow plumbing system.
KW - Degassing-induced crystallization
KW - Lithium isotopes
KW - Petrologic monitoring
KW - Stromboli
KW - Volcanic ash
UR - http://www.scopus.com/inward/record.url?scp=77952153004&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77952153004&partnerID=8YFLogxK
U2 - 10.1007/s00410-009-0441-2
DO - 10.1007/s00410-009-0441-2
M3 - Article
AN - SCOPUS:77952153004
VL - 159
SP - 541
EP - 561
JO - Contributions of Mineralogy and Petrology
JF - Contributions of Mineralogy and Petrology
SN - 0010-7999
IS - 4
ER -