The Origin of HIMU in the SW Pacific: Evidence from Intraplate Volcanism in Southern New Zealand and Subantarctic Islands
This paper presents field, geochemical and isotopic (Sr, Nd, Pb) results on basalts from the Antipodes, Campbell and Chatham Islands, New Zealand. New 40Ar/39Ar age determinations along with previous K–Ar dates reveal three major episodes of volcanic activity on Chatham Island (85–82, 41–35, 5 Ma)....
Main Authors: | , , , , , |
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Other Authors: | |
Format: | Text |
Language: | English |
Published: |
2005
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Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.598.3679 http://petrology.oxfordjournals.org/content/47/9/1673.full.pdf |
Summary: | This paper presents field, geochemical and isotopic (Sr, Nd, Pb) results on basalts from the Antipodes, Campbell and Chatham Islands, New Zealand. New 40Ar/39Ar age determinations along with previous K–Ar dates reveal three major episodes of volcanic activity on Chatham Island (85–82, 41–35, 5 Ma). Chatham and Antipodes samples comprise basanite, alkali and transitional basalts that have HIMU-like isotopic (206Pb/204Pb> 203–208, 87Sr/86Sr <07033, 143Nd/144Nd>05128) and trace element affinities (Ce/Pb 28–36, Nb/U 34–66, Ba/Nb 4–7). The geochemistry of transitional to Q-normative samples from Campbell Island is explained by interaction with continental crust. The volcanism is part of a long-lived (100Myr), low-volume, diffuse alkaline magmatic province that includes deposits on the North and South Islands of New Zealand as well as portions of West Antarctica and SE Australia. All of |
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