Lithospheric control on geochemical composition along the Louisville Seamount Chain

Beier, C., Vanderkluysen, L., Regelous, M., Mahoney, J. J. and Garbe-Schönberg, D. (2011) Lithospheric control on geochemical composition along the Louisville Seamount Chain Geochemistry Geophysics Geosystems, 12 . DOI Q0am0110.1029/2011gc003690.

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Abstract

Major and trace element and Sr, Nd, and Pb isotope data for lavas from 12 seamounts along the western (older) 1500 km section of the Louisville Seamount Chain in the southwest Pacific show remarkably uniform compositions over a similar to 30-40 Myr period of volcanism. All 56 samples analyzed are alkalic to transitional in composition. Unlike Hawaiian volcanoes, Louisville volcanoes appear not to pass through a sequence of evolutionary stages characterized by older tholeiitic basalts overlain by incompatible element enriched alkalic and silica-undersaturated lavas. The youngest lavas from a given Louisville seamount tend to have the least enriched incompatible element compositions. This unusual chemical evolution may be the result of re-melting of heterogeneous hot spot mantle that was partially depleted during the earlier, age progressive stages. The oldest Louisville seamounts were constructed close to the extinct Osbourn Trough spreading center, located north of the chain, but age-progressive lavas from these older seamounts are not significantly different to lavas from younger seamounts. This may indicate that spreading at this fossil ridge ceased several tens of millions of years before the oldest Louisville seamounts were constructed. Large fracture zones apparently had no significant effects on the composition of Louisville magmatism. However, lavas from the central part of the Louisville Seamount Chain, where volcanoes are smaller and more widely spaced, tend to have more variable and more enriched compositions. We suggest this may reflect smaller degrees of melting resulting from greater lithosphere thickness, and hence a shorter melting column for this section of the Louisville Seamounts.

Document Type: Article
Keywords: Louisville Seamount Chain lithosphere thickness melting dynamics plume evolution spreading centre plume-ridge interaction pacific plate motion emperor seamounts southwest pacific hawaiian hotspot hollister ridge osbourn trough oceanic-crust samoan lavas mantle
Research affiliation: Kiel University > Kiel Marine Science
OceanRep > The Future Ocean - Cluster of Excellence
Kiel University
Refereed: Yes
DOI etc.: Q0am0110.1029/2011gc003690
ISSN: 1525-2027
Projects: Future Ocean
Date Deposited: 15 Dec 2011 05:28
Last Modified: 11 Apr 2018 11:59
URI: http://eprints.uni-kiel.de/id/eprint/15614

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