Structure and dynamics of a silicic magmatic system associated with caldera-forming eruptions at Batur Volcanic Field, Bali, Indonesia

Details

Serval ID
serval:BIB_BA41A692A24B
Type
Article: article from journal or magazin.
Collection
Publications
Title
Structure and dynamics of a silicic magmatic system associated with caldera-forming eruptions at Batur Volcanic Field, Bali, Indonesia
Journal
Journal of Petrology
Author(s)
Reubi O., Nicholls I.A.
ISSN-L
0022-3530
Publication state
Published
Issued date
2005
Peer-reviewed
Oui
Volume
46
Pages
1367-1391
Language
english
Abstract
The Batur volcanic field (BVF), in Bali, Indonesia, underwent two
successive caldera-forming eruptions that resulted in the deposition of
silicic ignimbrites. The magmas erupted during and between these
eruptions show a broad range of compositions from low-SiO2 andesite to
high-SiO2 dacite. On the basis of their geochemistry and mineralogy
these magmas may be assigned to six groups: (1) homogeneous andesites
with phenocryst compositions essentially in equilibrium With the
whole-rock composition; (2) remobilized crystal-rich low-SiO2 andesites
with resorbedphenocgsts in equilibrium with the whole-rock composition;
(3) mixed low-SiO2 dacite with a relatively large range of phenocryst
compositions, with most phenocrysts slightly too evolved to be in
equilibrium with the whole-rock; (4) extensively mixed low-SiO2 dacites
with a very large and discontinuous range of phenocryst compositions,
with most phenocrysts either more Mg-rich or more evolved than the
equilibrium compositions; (5) remobilized crystal-rich low-SiO2 dacites
with resorbed and euhedral phenocrysts; (6) homogeneous high-SiO2
dacites lacking evidence for magma mixing and showing narrow ranges of
phenocryst compositions in equilibrium with the whole-rock composition.
This range of silicic magmas is interpreted to reflect a combination of
closed- and open-system fractional crystallization, magma mixing and
remobilization of cumulate piles by heating. 7 he variety of magmas
erupted simultaneously during the caldera-forming eruptions suggests
that the magmatic system consisted of several independent reservoirs of
variable composition and degree of crystallization. The magmatic
evolution of individual reservoirs varied from closed-system fractional
crystallization to fully open-system evolution, thereby resulting in
simultaneous production of magmas with contrasted compositions and
mineralogy. Extensive emptying of the magmatic system during the
caldera-forming eruptions led to successive or simultaneous eruption of
several reservoirs.
Open Access
Yes
Create date
07/02/2013 8:02
Last modification date
20/08/2019 15:28
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