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    Textures of mantle peridotite rocks revisited

    Tabor, B.E. and Downes, Hilary (2019) Textures of mantle peridotite rocks revisited. Lithos , p. 105203. ISSN 0024-4937. (In Press)

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    Abstract

    Characterisation of textures in mantle peridotites has long been a subjective method, lacking precise definition or quantification. In a continuing effort to quantify textures found in mantle peridotites, we have analysed thin-sections of a wide variety of spinel and garnet peridotite xenoliths from a range of locations, using a grain-section skeleton outline method. Peridotites from ultramafic massifs have also been analysed using the same methodology. The results for all these samples lie on the same linear trend in a plot of grain-section area vs standard deviation as seen in our previous study. This confirms the utility of the quantitative method, which provides observer-independent objective numerical descriptions of textures in peridotites. In addition, two spinel peridotite xenoliths have been disaggregated using an Electric discharge disaggregation technique and were sieved to produce a grain size distribution. SEM imaging has also been used to show that the 3-D shapes of grains of the constituent minerals have concave features. Computed Tomography (CT)-scanning of separated grains and peridotite rock cores has confirmed the concave features of the constituent minerals and their consequent interlocking structures. A ‘perimeter-area’ relation technique has been used to show that the two-dimensional grain-section skeleton outlines clearly display self-similarity (i.e. fractal characteristics). Images of thin-sections were compared with known Euclidian and fractal images; both the thin-section images and the known fractal images yielded fractal dimensions, whereas the Euclidian images did not. The self-similar or fractal nature of textures of mantle peridotite rocks has also been demonstrated by using Box counting, an alternative method for fractal assessment.

    Metadata

    Item Type: Article
    Keyword(s) / Subject(s): Textures, Peridotite, Fractal characteristics, Self-similarity, Electric discharge disaggregation, CT-scanning
    School: Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences
    Depositing User: Administrator
    Date Deposited: 14 Oct 2019 07:03
    Last Modified: 16 Oct 2019 18:31
    URI: http://eprints.bbk.ac.uk/id/eprint/29459

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