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dc.contributor.author le Roux, PJ
dc.contributor.author le Roex, AP
dc.contributor.author Schilling, JG
dc.contributor.author Shimizu, N
dc.contributor.author Perkins, WW
dc.contributor.author Pearce, NJG
dc.date.accessioned 2011-10-06T10:19:16Z
dc.date.available 2011-10-06T10:19:16Z
dc.date.issued 2002-10-15
dc.identifier.citation le Roux , P J , le Roex , A P , Schilling , J G , Shimizu , N , Perkins , W W & Pearce , N J G 2002 , ' Mantle heterogeneity beneath the southern Mid-Atlantic Ridge : Trace element evidence for contamination of ambient asthenospheric mantle ' Earth and Planetary Science Letters , vol 203 , no. 1 , PII S0012-821X(02)00832-4 , pp. 479-498 . DOI: 10.1016/S0012-821X(02)00832-4 en
dc.identifier.issn 1385-013X
dc.identifier.other PURE: 171489
dc.identifier.other PURE UUID: 681eba99-dc43-4e67-ac24-f15848813a42
dc.identifier.other dspace: 2160/7606
dc.identifier.uri http://hdl.handle.net/2160/7606
dc.description le Roux, P. J., le Roex, A. P., Schilling, J. G., Schimizu, N., Perkins, W. W., Pearce, N. J. G. (2002). Mantle heterogeneity beneath the southern Mid-Atlantic Ridge: trace element evidence for contamination of ambient asthenospheric mantle. Earth and Planetary Science Letters, 203 (1), 479-498. Article Number: PII S0012-821X(02)00832-4. en
dc.description.abstract We report new trace element data for an extensive suite of quench basalt glasses dredged from the southern Mid-Atlantic Ridge (MAR) between 40°S and 52.5°S. Ratios between highly incompatible trace elements are strongly correlated and indicate a systematic distribution of incompatible element enriched mid-ocean ridge basalt (MORB) (E-type: Zr/Nb=5.9–19, Y/Nb=0.9–8.4, (La/Sm)n=1.0–2.9) and incompatible element depleted MORB (N-type: Zr/Nb=30–69, Y/Nb=11–29, (La/Sm)n=0.48–0.79) along this section of the southern MAR. A notable feature of N-type MORB from the region is the higher than usual Ba/Nb (4–9), La/Nb (1.2–2.4) and primitive mantle normalised K/Nb ratios (>1). Ba/Nb ratios in E-type MORB samples from 47.5 to 49°S are especially elevated (>10). The occurrence and geographic distribution of E-type MORB along this section of the southern MAR can be correlated with the ridge-centred Shona and off-axis Discovery mantle plumes. In conjunction with published isotope data for a subset of the same sample suite [Douglass et al., J. Geophys. Res. 104 (1999) 2941], a model is developed whereby prior to the breakup of Gondwana and the opening of the South Atlantic Ocean, the underlying asthenospheric mantle was locally contaminated by fluids/melts rising from the major Mesozoic subduction zone along the south–southwest boundary of Gondwana, leaving a subduction zone geochemical imprint (elevated (K/Nb)n and 87Sr/86Sr ratios, decreased 143Nd/144Nd ratios). Subsequent impingement of three major mantle plume heads (Tristan/Gough, Discovery, Shona) resulted in heating and thermal erosion of the lowermost subcontinental lithosphere and dispersal into the convecting asthenospheric mantle. With the opening of the ocean basin, continued plume upwelling led to plume–ridge interactions and mixing between geochemically enriched mantle derived from the Shona and Discovery mantle plumes, material derived from delamination of the subcontinental lithosphere, and mildly subduction zone contaminated depleted asthenospheric mantle. en
dc.format.extent 20 en
dc.language.iso eng
dc.relation.ispartof Earth and Planetary Science Letters en
dc.rights en
dc.subject Mid-Atlantic Ridge en
dc.subject mantle en
dc.subject heterogeneity en
dc.subject trace elements en
dc.subject magma contamination en
dc.subject SOUTHWEST INDIAN RIDGE en
dc.subject BOUVET TRIPLE JUNCTION en
dc.subject GEOCHEMICAL VARIATIONS en
dc.subject HOTSPOT INTERACTIONS en
dc.subject BASALT GEOCHEMISTRY en
dc.subject CONTINENTAL-CRUST en
dc.subject OCEAN en
dc.subject PLUMES en
dc.subject ISLAND en
dc.subject MORB en
dc.title Mantle heterogeneity beneath the southern Mid-Atlantic Ridge : Trace element evidence for contamination of ambient asthenospheric mantle en
dc.type /dk/atira/pure/researchoutput/researchoutputtypes/contributiontojournal/article en
dc.identifier.doi http://dx.doi.org/10.1016/S0012-821X(02)00832-4
dc.contributor.institution Institute of Geography & Earth Sciences en
dc.description.status Peer reviewed en


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