Formation of andesite melts and Ca-rich plagioclase in the submarine Monowai volcanic system, Kermadec arc

Journal article
(Original article)


Publication Details

Author(s): Kemner F, Haase K, Beier C, Krumm S, Brandl P
Journal: Geochemistry Geophysics Geosystems
Publisher: American Geophysical Union (AGU)
Publication year: 2015
Volume: 16
Journal issue: 12
Pages range: 4130-4152
ISSN: 1525-2027
Language: English


Abstract


Andesites are typical rocks of island arcs and may either form by fractional crystallization processes or by mixing between a mafic and a felsic magma. Here we present new petrographic and geochemical data from lavas of the submarine Monowai volcanic system in the northern Kermadec island arc that display a continuous range in composition from basalt to andesite. Using petrology, major, trace, and volatile element data, we show that basaltic magmas mostly evolve to andesitic magmas by fractional crystallization. Our thermobarometric calculations indicate that the formation of the large caldera is related to eruption of basaltic-andesitic to andesitic magmas from a magma reservoir in the deeper crust. Small variations in trace element ratios between the caldera and the large active cone imply a homogeneous mantle source. Contrastingly, resurgent dome melts of the caldera stagnated at shallower depths are more depleted and show a stronger subduction input than the other edifices. The Monowai basaltic glasses contain less than 1 wt % HO and follow typical tholeiitic fractionation trends. High-An plagioclase crystals observed in the Monowai lavas likely reflect mixing of HO-saturated melt batches with hot and dry tholeiitic, decompression melt batches. The result is a relatively HO-poor mafic magma at Monowai implying that partial melting of the mantle wedge is only partly due to the volatile flux and that adiabatic melting may play a significant role in the formation of the parental melts of the Monowai volcanic system and possibly other arc volcanoes.



FAU Authors / FAU Editors

Beier, Christoph PD Dr.
Lehrstuhl für Endogene Geodynamik
Brandl, Philipp
Lehrstuhl für Endogene Geodynamik
Haase, Karsten Prof. Dr.
Lehrstuhl für Endogene Geodynamik
Kemner, Fabian
Lehrstuhl für Endogene Geodynamik
Krumm, Stefan Dr.
Lehrstuhl für Endogene Geodynamik


How to cite

APA:
Kemner, F., Haase, K., Beier, C., Krumm, S., & Brandl, P. (2015). Formation of andesite melts and Ca-rich plagioclase in the submarine Monowai volcanic system, Kermadec arc. Geochemistry Geophysics Geosystems, 16(12), 4130-4152. https://dx.doi.org/10.1002/2015GC005884

MLA:
Kemner, Fabian, et al. "Formation of andesite melts and Ca-rich plagioclase in the submarine Monowai volcanic system, Kermadec arc." Geochemistry Geophysics Geosystems 16.12 (2015): 4130-4152.

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Last updated on 2018-25-11 at 13:53