岩石鉱物科学
Online ISSN : 1349-7979
Print ISSN : 1345-630X
39 巻 , 4 号
July
選択された号の論文の2件中1~2を表示しています
原著論文
  • クラッシャイ ジタ
    原稿種別: 原著
    2010 年 39 巻 4 号 p. 115-135
    発行日: 2010年
    公開日: 2010/09/04
    [早期公開] 公開日: 2010/07/10
    ジャーナル フリー
      Large-scale igneous activity characterised the development of the Carpathian-Pannonian Region, Central Europe from Late Cretaceous to Pleistocene times, with a peak of activity during the Miocene. The magmatism is considered to have been caused by the closure of the Tethys Sea and consequent collision between the African and Eurasian plates, but the exact mechanism for magmageneration is still a matter of debate. In order to get a better understanding of magmageneration and differentiation processes, a new set of bulk chemical data, including trace and rare earth elements has been presented on igneous rocks from the NE part. Together with published data, igneous rocks from the three regions of the research area (Tokaj-Slanske Mts., Great Plain and Transcarpathia) cover a wide spectrum of the calc-alkaline series and reveal close similarities in both petrography and geochemistry. No significant spatial differences could be revealed in terms of major element chemistry but Nb and Zr trends slightly differ in Tokaj-Slanske Mts. -Great Plain and Transcarpathia. Felsic rocks formed mainly at the earlier stages, the most mafic sample at the latest stage of the igneous activity. Alkali basaltic activity (generally characterising the development of the Carpathian-Pannonian Region from 11.7 Ma) has not been observed at the NE part.
      The results of crystallization and mixing calculations on igneous rocks from the area of research show that geochemical characteristics of most rocks cannot be explicitly explained by crystallization processes alone and they reflect the involvement of various (upper crustal, lower crustal, upper mantle and alkali basaltic) source materials through magma mixing, assimilation and contamination. The different spatial Nb and Zr trends may be interpreted as the outcome of mainly crustal contamination in the case of rocks from Transcarpathia, as opposed to the joint effects of upper crustal contamination and the involvement of alkali basaltic magma in the case of rocks from the Tokaj-Slanske Mts. Thus, alkali basaltic magma may have been involved in the formation of calc-alkaline igneous rocks not only as heat source, but in the case of basaltic rocks, also as material.
総説
  • 門馬 綱一, 泉 富士夫
    原稿種別: 総説
    2010 年 39 巻 4 号 p. 136-145
    発行日: 2010年
    公開日: 2010/09/04
    [早期公開] 公開日: 2010/07/10
    ジャーナル フリー
      VESTA is a three-dimensional visualization system for both structural models and volumetric data such as electron and nuclear densities, Patterson functions, electrostatic potentials, and wave functions. VESTA represents crystal structures by ball-and-stick, space-filling, polyhedral, wireframe, stick, dot-surface, and thermal-ellipsoid models. A variety of crystal-chemical information is extractable from fractional coordinates, occupancies, and oxidation states of sites. Volumetric data are displayed as isosurfaces, bird's-eye views, and two-dimensional maps. Isosurfaces can be colored according to other physical quantities such as electrostatic potentials. Translucent isosurfaces and/or slices can be overlapped with a structural model. Collaboration with external programs enables the user to standardize crystal data, simulate X-ray and neutron powder diffraction patterns, and calculate site potentials and Madelung energies. Electron densities determined experimentally are convertible into their Laplacians and electronic-energy densities.
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