e-mail: dweis@eos.ubc.ca
phone / tél.: 1-604-822.1697
mobile: 778-386.4466
Ker 88 snowstorm Tete d'Homme

Kerguelen Mantle Plume and Other Large Igneous Provinces

After Hawaii and Iceland, the third largest oceanic island is the Kerguelen Archipelago. The origins of this island and the associated giant oceanic plateau, which is greater than 15 million km3, have been debated by the geological community for many years. The Kerguelen mantle plume has been active for the past 120 million years (e.g., Frey et al., 2002).

Baie Larose
Baie Larose, Kerguelen: The emperor penguins give the scale of the huge basaltic flow, >800m cliffs.

 

From 1997 – 2002, Dominique led a multi-national project on the study of this mantle plume and has published over 40 papers on the topic. Her primary contribution to this project has been the determination of the geochemical source characteristics and their evolution with time and tectonic settings. The results have allowed for quantitative modeling of the continental crustal contamination in Elan Bank among other Cretaceous plateau sites during the early stages of continental break-up (Weis et al., 2001; Ingle et al., 2002). The results have also led to the ability to model the relative proportion of the depleted mantle component in the basalts (Weis and Frey, 2002). In addition, her work defines the enriched component of the Kerguelen mantle plume (EM-I end-member) and demonstrates the absence of any continental component in the basalts on the archipelago (<34 Ma). These results are particularly important, in terms of overall mantle dynamics, by connecting EM-I and the African low-velocity zone (Weis et al., 2011).

Mantle Xenoliths
Mantle Xenoliths on the Southeast Province of the Kerguelen Islands, Presqu’île Jeanne d’Arc

 

Lava Flow
Kerguelen lava flow

 

We now have a better idea of the isotopic characteristics of the other major EM-I mantle plumes and the data puts constraints on the composition of the large low shear velocity provinces under Africa and under the Pacific.

Studies have expanded to other large igneous provinces (Wrangellia: Greene et al., 2008, 2009 a&b and Caribbean: Escuder-Viruete et al., 2006, 2007) and other hotspot tracks to further the constraints on the modes of formation and mantle sources of these major Earth’s features.

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Comparison of age-corrected (230 Ma) Sr-Nd-Hf-Pb isotopic compositions for Karmutsen flood basalts on Vancouver Island with age-corrected OIB and MORB and Nb-Zr-Y variation (Greene et al., 2009)

 

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Summary of ages and biostratigraphy in five areas of Wrangellia. Radiometric ages are white circles. Fossil ages are colored according to the formation they are found in the stratigraphic column. Circles that are multicolored green and blue indicate fossils from interflow sedimentary lenses, and other multicolored circles indicate fossils found near the contact between two formations (Greene et al., 2010).

 

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