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  • Nature Publishing Group  (6)
  • Oxford University Press  (2)
  • Mineralogical Society of America  (1)
  • 1
    Electronic Resource
    Electronic Resource
    A mechanism for magmatic accretion under spreading centres (1984)
    [s.l.] : Nature Publishing Group
    Nature 312 (1984), S. 146-148 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It is reasonable, to a first approximation, to assume that the mantle is behaving as a viscous newtonian fluid, so we can expect the upwelling to be two dimensional with a maximum under the smoothed location of the spreading centre. If this is the case, we also postulate that a linear region of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/312146a0
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Formation of harzburgite by pervasive melt/rock reaction in the upper mantle (1992)
    [s.l.] : Nature Publishing Group
    Nature 358 (1992), S. 635-641 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Many mantle peridotite samples are too rich in Si02 (in the form of orthopyroxene) and have ratios of light to heavy rare earth elements that are too high to be consistent with an origin as the residuum of partial melting of the primitive mantle. Trace element studies of melt/rock ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/358635a0
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  • 3
    Electronic Resource
    Electronic Resource
    Nd and Sr isotope evidence linking mid-ocean-ridge basalts and abyssal peridotites (1994)
    [s.l.] : Nature Publishing Group
    Nature 371 (1994), S. 57-60 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Most studies of abyssal peridotite either assume a relationship with MORB, and thus cannot be used to demonstrate its existence11'12, or do not address this question at all13'14. The best evidence so far for this link comes from worldwide covariations in basalt and abyssal peridotite major-element ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/371057a0
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  • 4
    Electronic Resource
    Electronic Resource
    The oxidation state of the Earth's sub-oceanic mantle from oxygen thermobarometry of abyssal spinel peridotites (1989)
    [s.l.] : Nature Publishing Group
    Nature 341 (1989), S. 526-527 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have sampled abyssal spinel peridotites (n = 33) from fracture zones along the Central Indian, America-Antarctica, South-west Indian and Mid-Atlantic Ridge systems as well as the Cayman Trough. Although variably affected by hydrother-mal alteration, all of our samples contained fresh spinel (sp) ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/341526a0
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  • 5
    Electronic Resource
    Electronic Resource
    Migration of mid-ocean-ridge volcanic segments (1987)
    [s.l.] : Nature Publishing Group
    Nature 326 (1987), S. 835-839 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The propagation of small-offset volcanic spreading-centre segments along mid-ocean ridge crests may reflect absolute motion of the plate boundary relative to the underlying mesospheric frame. Such a relationship could be caused by a purely vertical flow of the mantle under spreading centres ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/326835a0
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  • 6
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    Jurassic zircons from the Southwest Indian Ridge (2016)
    Nature Publishing Group
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 6 (2016): 26260, doi:10.1038/srep26260.
    Description: The existence of ancient rocks in present mid-ocean ridges have long been observed but received less attention. Here we report the discovery of zircons with both reasonably young ages of about 5 Ma and abnormally old ages of approximate 180 Ma from two evolved gabbroic rocks that were dredged from the Southwest Indian Ridge (SWIR) in the Gallieni fracture zone. U–Pb and Lu–Hf isotope analyses of zircons were made using ion probe and conventional laser abrasion directly in petrographic thin sections. Young zircons and their host oxide gabbro have positive Hf isotope compositions (εHf = +15.7–+12.4), suggesting a highly depleted mantle beneath the SWIR. The spread εHf values (from−2.3 to−4.5) of abnormally old zircons, together with the unradiogenic Nd-Hf isotope of the host quartz diorite, appears to suggest an ancient juvenile magmatism along the rifting margin of the southern Gondwana prior to the opening of the Indian Ocean. A convincing explanation for the origin of the unusually old zircons is yet to surface, however, an update of the theory of plate tectonics would be expected with continuing discovery of ancient rocks in the mid-oceanic ridges and abyssal ocean basins.
    Description: This work was supported by the National Natural Science Foundation of China (41573046) to H.C. and the Chinese National Key Basic Research Program (2012CB417300) to H.Z.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 7
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    Trace element and isotopic evidences for recycled lithosphere at basalts from 48°E to 53°E, Southwest Indian Ridge (2020)
    Oxford University Press
    Details
    Publication Date: 2020-06-29
    Description: Mantle source heterogeneity and magmatic processes have been widely studied beneath most parts of the Southwest Indian Ridge (SWIR). But less is known from the newly recovered mid-ocean ridge basalts from the Dragon Bone amagmatic segment (53°E, SWIR) and the adjacent magmatically robust Dragon Flag Segment. Fresh basalt glasses from Dragon Bone segment are clearly more enriched in isotopic composition than the adjacent Dragon Flag basalts, but the trace element ratios of the Dragon Flag basalts are more extreme compared to the average mid-ocean ridge basalts (MORB) than the Dragon Bone basalts. Their geochemical differences can only be explained by source differences rather than variations in degree of melting of a roughly similar source. The Dragon Flag basalts are influenced by an arc-like mantle component as evidenced by enrichment in fluid-mobile over fluid-immobile elements. However, the sub-ridge mantle at the Dragon Flag segment is depleted in melt component compared to a normal MORB source due to previous melting in the subarc. This fluid-metasomatized, subarc depleted mantle is entrained beneath the Dragon Flag segment. In comparison, for the Dragon Bone axial basalts, their Pb isotopic compositions and their slight enrichment in Ba, Nb, Ta, K, La, Sr, Zr and depletion in Pb, Ti concentrations show resemblance to the Ejeda-Bekily dikes of Madagascar. Also, Dragon Bone Sr and Nd isotopic compositions together with the Ce/Pb, La/Nb and La/Th ratios can be modeled by mixing the most isotopically depleted Dragon Flag basalts with a composition within the range of the Ejeda-Bekily dikes. It is, thus, proposed that the Dragon Bone axial basalts, similar to the Ejeda-Bekily dikes, are sourced from sub-continental lithospheric Archean mantle beneath Gondwana, pulled from beneath the Madagascar Plateau. The recycling of the residual subarc mantle and the subcontinental lithospheric mantle could be related to either the breakup of Gondwana, or the formation and accretion of Neoproterozoic island arc terranes during the collapse of the Mozambique Ocean, and is now present beneath the ridge.
    Print ISSN: 0022-3530
    Electronic ISSN: 1460-2415
    Topics: Geosciences
    Published by Oxford University Press
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  • 8
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    Evidence for Multi-stage Melt Transport in the Lower Ocean Crust: Atlantis Bank Gabbroic Massif (IODP Hole U1473A, SW Indian Ridge) (2020)
    Oxford University Press
    Details
    Publication Date: 2020-08-10
    Description: The architecture of lower oceanic crust at slow- and ultraslow-spreading ridge is diverse, yet the mechanisms that produce this diversity are not well understood. Particularly, the 660-km2 gabbroic massif at Atlantis Bank (Southwest Indian Ridge) exhibits significant compositional zonation, representing a high magma supply end member for accretion of the lower ocean crust at slow and ultraslow-spreading ridges. We present the petrographic and geochemical data of olivine gabbros from the 809-meter IODP Hole U1473A at Atlantis Bank gabbroic massif. Structurally, the upper portion of U1473A consists of a ∼600-meter shear zone; below this, the hole is relatively undeformed, with several minor shear zones. Olivine gabbros away from the shear zones have mineral trace element compositions indicative of high-temperature reaction with an oxide-undersaturated melt. By contrast, olivine gabbros within shear zones display petrographic and chemical features indicative of reaction with a relatively low-temperature, oxide-saturated melt. These features indicate an early stage of primitive to moderately evolved melt migration, followed by deformation-driven transport of highly evolved Fe-Ti-rich melts to high levels in this gabbroic massif. The close relationship between shear zones and the reaction with oxide-saturated melts suggests that syn-magmatic shear zones provide a conduit for late-stage, Fe-Ti-rich melt transport through Atlantis Bank lower crust. This process is critical to generate the compositional zonation observed. Thus, the degree of syn-magmatic deformation, which is fundamentally related to magma supply, plays a dominant role in developing the diversity of lower ocean crust observed at slow- and ultraslow-spreading ridges.
    Print ISSN: 0022-3530
    Electronic ISSN: 1460-2415
    Topics: Geosciences
    Published by Oxford University Press
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  • 9
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    Magmatic srilankite (Ti2ZrO6) in gabbroic vein cutting oceanic peridotites: An unusual product of peridotite-melt interactions beneath slow-spreading ridges (2004)
    Mineralogical Society of America
    Details
    Publication Date: 2004-05-01
    Print ISSN: 0003-004X
    Electronic ISSN: 1945-3027
    Topics: Geosciences
    Published by Mineralogical Society of America
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