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Evidence from zircon U-Pb age spectra for crustal structure and felsic magma genesis at Taupo volcano, New Zealand

Charlier, B. L. A.; Wilson, C. J. N. and Mortimer, N. (2010). Evidence from zircon U-Pb age spectra for crustal structure and felsic magma genesis at Taupo volcano, New Zealand. Geology, 38(10) pp. 915–918.

URL: http://geology.geoscienceworld.org/content/38/10/9...
DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1130/G31123.1
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Abstract

U-Pb zircon age spectra from a metasedimentary xenolith and a young dacite provide evidence for rapid episodes of crustal melting and eruption at Taupo volcano, as well as unexpected crustal structure beneath the Taupo Volcanic Zone. Ages from the xenolith in a 28 ka rhyolite dome match those from Early Cretaceous Pahau Terrane graywackes that crop out >75 km east of the volcano and were underthrust and partially melted during the penecontemporaneous accretion process. Boundaries between graywacke terranes in the North Island are thus more complex than implied from map views. In contrast, ages from zircons in the 20 ka Omega dacite match the nearby surficial graywacke of the Jurassic Kaweka Terrane (55% of grains), Quaternary plutonic sources (39%), and Pahau Terrane graywacke (6%). Five of 72 grains analyzed contain graywacke cores and Pleistocene rims. Survival of euhedral xenocrystic zircons through the generation processes for Omega dacite magma reflects wholesale melting of crustal protoliths (including varieties not previously considered for petrogenetic modeling), open-system behavior, and crustal melts being generated and erupted within ~1–10 yr.

Item Type: Journal Article
Copyright Holders: 2010 Geological Society of America
ISSN: 0091-7613
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNot SetNERC
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 32116
Depositing User: Bruce Charlier
Date Deposited: 03 Feb 2012 10:14
Last Modified: 20 Mar 2014 14:26
URI: http://oro.open.ac.uk/id/eprint/32116
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