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Journal of Geography (Chigaku Zasshi), 2015 Vol.124 No.3

2015 Vol.124 No.3

Photomicrograph of a Mantle Dunite

Xenolith in alkali basalt from Takashima, Saga Prefecture. Dunite, a kind of peridotite, is representative of the uppermost part of the Earth’s upper mantle layer. It occurs frequently as xenoliths in volcanics, e.g., in Cenozoic alkali basalts from Southwest Japan. It is almost completely composed of olivine, the main mantle mineral, and can be formed by deep-seated magmatic processes, such as crystal accumulation from magma or a reaction between pyroxene-bearing peridotite and magma. Although it has a simple mineral assemblage, its genesis is difficult for us to specify. Some olivine grains are kinked to show kink bands (e.g., upper right of the center), due to deformation after magmatic formation. If we observe a thin section, ca. 0.03 mm in thickness, of peridotites under crossed-polarized light with a polarizing microscope, beautiful stained-glass patterns made by olivine grains are visible. The colors observed under crossed-polarized light with a microscope are called interference colors. The vivid interference colors from the 0.03-millimeter thin section in this photo are characteristic of olivine because of its optical properties.

(Photograph & Explanation: Shoji ARAI)

 


Special Issue: The Forefront of Mantle Material Research

Overview of the Special Issue “The Forefront of Mantle Material Research”

Shoji ARAI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 309.

DOI:10.5026/jgeography.124.309

Introduction to the Special Issue “The Forefront of Mantle Material Research”

Shoji ARAI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 315.

DOI:10.5026/jgeography.124.315

New Insights from Seismic Images of the Oceanic Plate in the Northwestern Pacific(Review Article)

Shuichi KODAIRA and Gou FUJIE

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 321.

DOI:10.5026/jgeography.124.321

Ancient Melting Residual Peridotites Producing Variable Source Mantle beneath Mid-ocean Ridges: Detection and Geodynamic Implications(Review Article)

Tomoaki MORISHITA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 333.

DOI:10.5026/jgeography.124.333

Residues of Hydrous Peridotites in the Deep Earth's upper Mantle: Implications of Melting Experiments at High Pressures and High Temperatures(Review Article)

Kyoko N. MATSUKAGE

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 355.

DOI:10.5026/jgeography.124.355

Rheological Properties of Serpentinite and Their Tectonic Significance(Review Article)

Ken-ichi HIRAUCHI and Ikuo KATAYAMA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 371.

DOI:10.5026/jgeography.124.371

Olivine Crystallographic Fabrics and Their P-wave Velocity Structures within Peridotites in the Uppermost Mantle(Review Article)

Katsuyoshi MICHIBAYASHI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 397.

DOI:10.5026/jgeography.124.397

Ultramafic Pseudotachylytes: A Rosetta Stone for Seismogenic Processes in the Upper Mantle(Review Article)

Masaaki OBATA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 411.

DOI:10.5026/jgeography.124.411

Fluid Inclusions in Mantle Xenoliths: A Probe for the Physical and Chemical State of the Lithospheric Mantle(Review Article) 

Junji YAMAMOTO, Kohei TAKAHATA, Junji TORIMOTO and Hidemi ISHIBASHI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 429.

DOI:10.5026/jgeography.124.429

Traces of Slab-derived Fluids Revealed by Halogens in Mantle-derived Rocks(Review Article)

Masahiro KOBAYASHI, Hirochika SUMINO and Chiaki TOYAMA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 445.

DOI:10.5026/jgeography.124.445

Chemical Composition of Mantle Wedge Fluids(Review Article)

Tatsuhiko KAWAMOTO

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 473.

DOI:10.5026/jgeography.124.473

Origins of Carbon and Nitrogen in Mantle Xenolith(Review Article)

Yoshinori TAKANO and Naohiko OHKOUCHI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 503.

DOI:10.5026/jgeography.124.503

The 100s: Significant Exposures of the World (No. 11)

Ultrapotassic Magma from the Deep Mantle, Leucite Hills Lamproite, Wyoming USA

Akira ISHIKAWA and Kenji KAWAI

Journal of Geography (Chigaku Zasshi), 2015, 124(3), 515.

DOI:10.5026/jgeography.124.515

Pictorials

1:Mantle Materials as Xenoliths in Volcanics

Shoji ARAI, Makoto MIURA, Norikatsu AKIZAWA and Akihiro TAMURA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), xi.

DOI:10.5026/jgeography.124.xi

2:Mantle Materials Found as Solid-intrusive Rocks

Shoji ARAI, Makoto MIURA, Norikatsu AKIZAWA and Akihiro TAMURA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), xii.

DOI:10.5026/jgeography.124.xii

3:Photomicrographs of Mantle Materials

Shoji ARAI, Makoto MIURA, Norikatsu AKIZAWA and Akihiro TAMURA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), xiii.

DOI:10.5026/jgeography.124.xiii

4:Similarities between Meteorites and the Earth's Mantle

Shoji ARAI, Makoto MIURA, Norikatsu AKIZAWA and Akihiro TAMURA

Journal of Geography (Chigaku Zasshi), 2015, 124(3), xiv.

DOI:10.5026/jgeography.124.xiv

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