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dc.contributor.author
Marxer, Felix
dc.contributor.author
Ulmer, Peter
dc.date.accessioned
2019-10-21T11:25:22Z
dc.date.available
2019-10-20T03:02:51Z
dc.date.available
2019-10-21T11:25:22Z
dc.date.issued
2019-10
dc.identifier.other
10.1007/s00410-019-1619-x
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/371752
dc.identifier.doi
10.3929/ethz-b-000371752
dc.description.abstract
The understanding of the geochemical and petrophysical evolution of magmas forming intermediate calc-alkaline batholiths at shallow crustal levels critically depends on knowledge of the phase equilibria relations along the liquid line of descent. Here, we present experimental results for a tonalitic system at a pressure of 200 MPa and under water-saturated conditions. Melting experiments were performed at temperatures between 700 and 1000 °C in externally heated HCM pressure vessels, with oxygen fugacity controlled close to the Ni–NiO buffer equilibrium (NNO) employing an argon–methane mixture as pressure medium and Co–Pd redox sensors to verify fO2 conditions. Natural rock powder of a medium-K tonalite from the Adamello Batholith in Northern Italy served as experimental starting material. Based on compositional data of stable phases in the run products and images of entire run charges, mass balance calculations as well as image processing were performed to investigate the evolution of the crystal/melt ratio with respect to temperature. Furthermore, compositional trends of minerals as well as the liquid line of descent of residual melts were obtained. Orthopyroxene, clinopyroxene and plagioclase were identified as near-liquidus phases (below 990 °C). At 900 °C, amphibole joins the solid-phase assemblage at the expense of clinopyroxene, indicating the existence of a peritectic relationship. After an initial near-linear decrease with temperature, residual melt fractions exhibit a plateau of 45–55 vol. % between 750 and 850 °C, followed by a rapid decrease coinciding with quartz saturation at 725 °C. Compositions of residual liquids evolve along a typical calc-alkaline differentiation trend with decreasing temperature (increasing SiO2 and decreasing TiO2, Al2O3, CaO, MgO and FeO contents) and become peraluminous below 900 °C. Intermediate to acidic rocks from the Adamello follow the experimental liquid line of descent indicating that the observed compositional spread of the natural intermediate composition rock record can be explained by low-pressure magma differentiation and liquid extraction. Experimentally determined zircon saturation levels are at low temperatures distinctly lower compared to existing and often used Zr-saturation models, but fully consistent with observed and modelled Zr-evolution trends from the natural rock record of the Southern Adamello Batholith inferring that zircon saturation in these intermediate to felsic plutonic rocks occurred at 800–830 °C corresponding to a melt fraction of about 50 vol. %.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Springer
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
Arc magmatism
en_US
dc.subject
Equilibrium crystallisation
en_US
dc.subject
Crystal/melt ratio
en_US
dc.subject
Upper crustal plutons
en_US
dc.subject
Calc-alkaline intrusion
en_US
dc.subject
Tonalite
en_US
dc.subject
Adamello
en_US
dc.subject
Zircon saturation
en_US
dc.title
Crystallisation and zircon saturation of calc-alkaline tonalite from the Adamello Batholith at upper crustal conditions: an experimental study
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
dc.date.published
2019-10-03
ethz.journal.title
Contributions to Mineralogy and Petrology
ethz.journal.volume
174
en_US
ethz.journal.issue
10
en_US
ethz.pages.start
84
en_US
ethz.size
29 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Berlin
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier::08786 - Ulmer, Peter (Tit.-Prof.)
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier::08786 - Ulmer, Peter (Tit.-Prof.)
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
ethz.date.deposited
2019-10-20T03:02:59Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2019-10-21T11:25:37Z
ethz.rosetta.lastUpdated
2019-10-21T11:25:37Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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