Age and geochemistry of volcanic rocks from the Hikurangi and Manihiki oceanic plateaus

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doi: 10.1016/j.gca.2010.09.030
Author(s): Hoernle, Kaj; Hauff, Folkmar; van den Bogaard, Paul; Werner, Reinhard; Mortimer, Nick; Geldmacher, Jörg; Garbe-Schönberg, Dieter; Davy, Bryan
Author Affiliation(s): Primary:
Leibniz Institute of Marine Sciences, Kiel, Germany
Institute of Geological and Nuclear Sciences, New Zealand
Texas A&M University, United States
Christian Albrechts University, Germany
Volume Title: Geochimica et Cosmochimica Acta
Source: Geochimica et Cosmochimica Acta, 74(24), p.7196-7219. Publisher: Elsevier, New York, NY, International. ISSN: 0016-7037 CODEN: GCACAK
Note: In English. Includes appendices. 113 refs.; illus., incl. 3 tables, sketch maps
Summary: Here we present the first radiometric age data and a comprehensive geochemical data set (including major and trace element and Sr-Nd-Pb-Hf isotope ratios) for samples from the Hikurangi Plateau basement and seamounts on and adjacent to the plateau obtained during the R/V Sonne 168 cruise, in addition to age and geochemical data from DSDP Site 317 on the Manihiki Plateau. The 40Ar/39Ar age and geochemical data show that the Hikurangi basement lavas (118-96 Ma) have surprisingly similar major and trace element and isotopic characteristics to the Ontong Java Plateau lavas (ca. 120 and 90 Ma), primarily the Kwaimbaita-type composition, whereas the Manihiki DSDP Site 317 lavas (117 Ma) have similar compositions to the Singgalo lavas on the Ontong Java Plateau. Alkalic, incompatible-element-enriched seamount lavas (99-87 Ma and 67 Ma) on the Hikurangi Plateau and adjacent to it (Kiore Seamount), however, were derived from a distinct high time-integrated U/Pb (HIMU)-type mantle source. The seamount lavas are similar in composition to similar-aged alkalic volcanism on New Zealand, indicating a second wide-spread event from a distinct source beginning ca. 20 Ma after the plateau-forming event. Tholeiitic lavas from two Osbourn seamounts on the abyssal plain adjacent to the northeast Hikurangi Plateau margin have extremely depleted incompatible element compositions, but incompatible element characteristics similar to the Hikurangi and Ontong Java Plateau lavas and enriched isotopic compositions intermediate between normal mid-ocean-ridge basalt (N-MORB) and the plateau basement. These younger (∼52 Ma) seamounts may have formed through remelting of mafic cumulate rocks associated with the plateau formation. The similarity in age and geochemistry of the Hikurangi, Ontong Java and Manihiki Plateaus suggest derivation from a common mantle source. We propose that the Greater Ontong Java Event, during which ∼1% of the Earth's surface was covered with volcanism, resulted from a thermo-chemical superplume/dome that stalled at the transition zone, similar to but larger than the structure imaged presently beneath the South Pacific superswell. The later alkalic volcanism on the Hikurangi Plateau and the Zealandia micro-continent may have been part of a second large-scale volcanic event that may have also triggered the final breakup stage of Gondwana, which resulted in the separation of Zealandia fragments from West Antarctica. Abstract Copyright (2010) Elsevier, B.V.
Year of Publication: 2010
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 03 Geochronology; Absolute age; Alkaline earth metals; Ar/Ar; Bottom features; Cenozoic; Chemical composition; Cretaceous; DSDP Site 317; Dates; Deep Sea Drilling Project; East Pacific; Equatorial Pacific; Geochemistry; Gondwana; Hafnium; Hikurangi Trough; ICP mass spectra; Igneous rocks; Isotope ratios; Isotopes; Lead; Leg 33; Lithogeochemistry; Major elements; Manihiki Plateau; Mass spectra; Mesozoic; Metals; Nd-144/Nd-143; Neodymium; Ocean floors; Ontong Java Plateau; Pacific Ocean; Paleogene; Paleogeography; Pb-206/Pb-204; Petrology; Plate tectonics; Plateaus; Radioactive isotopes; Rare earths; Rifting; Seamounts; South Pacific; Southeast Pacific; Southwest Pacific; Spectra; Sr-87/Sr-86; Stable isotopes; Strontium; Tertiary; Trace elements; U/Pb; Volcanic rocks; West Pacific; X-ray fluorescence spectra
Coordinates: S110006 S110005 W1621546 W1621547
Record ID: 2011034484
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands