Genesis of Volcanic Rocks, Heard IslandEntry ID: ASAC_400
Abstract: Metadata record for data from ASAC Project 400
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Taken from one of the referenced papers:
Oceanic basalts are produced by melting of the Earth's mantle and are widely used to probe its composition. The observation of systematic, coupled variations in the neodymium, strontium and lead isotopic compositions of ... these basalts has been widely interpreted as reflecting the mixing of identifiable mantle components. White and Zindler and Hart have suggested that the isotopic compositions of mid-ocean-ridge and ocean island basalts (MORB and OIB) can be considered as mixtures of a depleted MORB-type mantle component with a few other components reflecting long-term enrichment of Rb/Sr, Nd/Sm and/or U/Pb ratios. It remains unclear whether these components should be considered as hypothetical mixing endmembers, or whether they exist physically as mantle reservoirs. This question may be addressed if the mixing endmembers of individual mantle plumes can be identified. To this end, we report linear Pb-Pb and curvilinear Pb-Nd and Pb-Sr isotopic covariations in Recent lavas of Heard Island, southern Indian Ocean, indicating binary mixing. The hyperbolic relationships are unique among oceanic basalts and tightly constrain the isotopic compositions of the plume source components, which do not coincide with the mantle endmember components of ref. 3. If our results are generally applicable to other plumes, they call into question the existence of large mantle reservoirs corresponding to these components, and indicate that actual oceanic basalt source reservoirs have intermediate isotopic compositions.
Start Date: 1986-09-30Stop Date: 1995-03-31
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Quality Values provided in temporal and spatial coverage are approximate only.
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Please follow instructions listed in the citation reference at the provided URL when using these data.
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Distribution Media: HTTP
Distribution Size: 1,298 kb
Distribution Format: pdf
Role: TECHNICAL CONTACT
Phone: +61 3 9905 4894
Email: ian.nicholls at sci.monash.edu.au
Department of Earth Sciences Monash University
Province or State: Victoria
Postal Code: 3168
Role: DIF AUTHOR
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: dave.connell at aad.gov.au
Australian Antarctic Division 203 Channel Highway
Province or State: Tasmania
Postal Code: 7050
Barling J., Goldstein S.L. (1990) Extreme isotopic variations in Heard Island lavas and the nature of mantle reservoirs. Nature 348. 59
Barling J. (1990) Heard and McDonald Islands. Volcanoes of the Antarctic Plate and Southern Oceans 48. 435-441
Barling J. (1990) The Petrogenesis of the Newer Lavas of Heard Island, Southern Indian Ocean;
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Creation and Review Dates
DIF Creation Date: 2000-10-12
Last DIF Revision Date: 2014-01-10