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Now showing items 1 - 16 of 5905

  • Hf-Nd input flux in the Izu-Mariana subduction zone and recycling of subducted material in the mantle RID A-1762-2011

    Chauvel, Catherine   Marini, Jean-Christophe   Plank, Terry   Ludden, John N.  

    In subduction zones, two major mass fluxes compete: the input flux of altered oceanic crust and sediments subducted into the mantle and the output flux of magma that forms the volcanic arc. While the composition and the amount of material erupted along volcanic arcs are relatively well known, the chemical and isotopic composition of the subducted material (altered oceanic crust and sediments) is poorly constrained and is an important factor in the mass balance calculation. Ocean Drilling Program Leg 185 in the Western Pacific used systematic sampling of the altered basaltic basement and sediment pile and the creation of composite mixtures to quantify the total chemical flux subducted at the Izu-Mariana margin. Here, we report Hf and Nd isotopic compositions of materials recovered from this Leg. The Hf and Nd isotopic compositions of altered basalts from Hole 801C are indistinguishable from those of recent unaltered Pacific mid-ocean ridge basalt, suggesting that hydrothermal alteration had no effect on either isotopic systems. The complete Site 1149 sedimentary pile has a weighted average epsilon(Nd) of -5.9 and epsilon(Hf) of +4.4, values similar to those of Fe-Mn crusts and nodules. Therefore, the Hf and Nd isotopic compositions of the sediments collected at Site 1149 indicate minimal contributions from continental detrital material to the rare earth elements and high field strength elements. However, the Hf isotopic budget of the oldest sediments is more influenced by continental material than the younger sediments, despite the large distances to continental masses 130 Ma ago. In the Izu subduction zone, we calculate a sedimentary input of less than about 2% in the volcanic lava source. In contrast, at least 85% of the sedimentary Nd and Hf are recycled into the mantle to affect its general composition. Assuming that sediments have been recycled in a similar manner into the mantle for millions of years, large chemical heterogeneities must be produced in the mantle. In addition, the depletion of the mantle due to the extraction of continental crust must be partly counterbalanced by the injection of vast quantities of enriched sedimentary material.
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  • Behaviour of rare earth elements during submarine weathering of tholeiitic basalt

    LUDDEN, JOHN N.   THOMPSON, GEOFFREY  

    Evidence is presented which shows that the rare earth elements (REE) in ocean floor basalts are affected by low temperature weathering processes. Specifically the light rare earths (especially Lalpha) show enrichments which may result in a basalt with a primary light-REE depleted pattern showing a flat or enriched light-REE pattern. This phenomenon is probably due to the uptake of the rare earths La to Sm from seawater
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  • The John N. Insall Award

    Young, Simon W.   Zhang, Mei   Moore, Grant A.   Pitto, Rocco P.   Clarke, Henry D.   Spangehl, Mark J.  

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  • 2018 John N. Insall Award

    Fleischman, Andrew N.   Crizer, Meredith P.   Tarabichi, Majd   Smith, Shelby   Rothman, Richard H.   Lonner, Jess H.   Chen, Antonia F.  

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  • Dr John N. Lunn OBE

    Harmer, M.  

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  • Dr John N. Lunn OBE

    Harmer   M.  

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  • Diakonia: In Conversation with John N. Collins

    Breed, Gert  

    The work of John N. Collins on the - word group makes an important contribution to understanding church ministry. Although it receives much attention and support, there is some criticism of Collins's exegesis. If his conclusions are accepted by churches, there will be an impact on their ministry. It is therefore important that his underlying assumptions be thoroughly tested. This article analyzes Mark 10:45 in the context of that Gospel and particularly in the context of Mark 8-10. Collins's supposition that is never done out of love or compassion for other people is found wanting. Rather, Mark describes Jesus's as done out of compassion and love for others, and as an envoy of God.
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  • John N. Deely: A Thomistic Voice for Semiotics

    Lanigan, Richard L.  

    The article presents John Deely's philosophical critique of Martin Heidegger's Being and Time from the perspective of Catholic theology defined by the work of Thomas Aquinas, John Poinsot, and Jacques Maritain. Deely's analysis centers on the philosophical definition of esse intentionale. A biographical context for the critique stems from the life-long friendship of John Deely and the author. The moral force of Deely's critique is now confirmed by the recent publication of Heidegger's personal diaries, the Black Notebooks.
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  • Rev. John N. Schumacher SJ, 1927–2014

    Ileto, Reynaldo C.; Rafael, Vicente L.; Barry, Coeli; Gealogo Chair, Francis A.; Baytion, Maricor M.; Aguilar, Filomeno V  

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  • John N. Warfield

    Kenley   Bob  

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  • Honored Life Member John N. Kraeuter March 28, 2012

    Bushek, David   Carnegie, Ryan   Flimlin, Gef  

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  • Honored Life Member John N. Kraeuter March 28, 2012

    Bushek, David; Carnegie, Ryan; Flimlin, Gef  

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  • John N. Collins, Diakonia Studies: Critical Issues in Ministry

    Methuen   C.  

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  • John N. Collins, Diakonia Studies: Critical Issues in Ministry

    Methuen, C.  

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  • Modern theoretical chemistry: the legacy of Prof. John N. Murrell

    Stace, Anthony J.   Clary, David C.  

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  • John N. Gathegi,The Digital Librarian’s Legal Handbook

    Review by: Jill A. Smith  

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