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Author Pittarello, L.; Mckibbin, S.; Yamaguchi, A.; Ji, G.; Schryvers, D.; Debaille, V.; Claeys, P. pdf  doi
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  Title Two generations of exsolution lamellae in pyroxene from Asuka 09545 : Clues to the thermal evolution of silicates in mesosiderite Type A1 Journal article
  Year (down) 2019 Publication The American mineralogist Abbreviated Journal Am Mineral  
  Volume 104 Issue 11 Pages 1663-1672  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Mesosiderite meteorites consist of a mixture of crustal basaltic or gabbroic material and metal. Their formation process is still debated due to their unexpected combination of crust and core materials, possibly derived from the same planetesimal parent body, and lacking an intervening mantle component. Mesosiderites have experienced an extremely slow cooling rate from ca. 550 degrees C, as recorded in the metal (0.25-0.5 degrees C/Ma). Here we present a detailed investigation of exsolution features in pyroxene from the Antarctic mesosiderite Asuka (A) 09545. Geothermobarometry calculations, lattice parameters, lamellae orientation, and the presence of clinoenstatite as the host were used in an attempt to constrain the evolution of pyroxene from 1150 to 570 degrees C and the formation of two generations of exsolution lamellae. After pigeonite crystallization at ca. 1150 degrees C, the first exsolution process generated the thick augite lamellae along (100) in the temperature interval 1000-900 degrees C. By further cooling, a second order of exsolution lamellae formed within augite along (001), consisting of monoclinic low-Ca pyroxene, equilibrated in the temperature range 900-800 degrees C. The last process, occurring in the 600-500 degrees C temperature range, was likely the inversion of high to low pigeonite in the host crystal, lacking evidence for nucleation of orthopyroxene. The formation of two generations of exsolution lamellae, as well as of likely metastable pigeonite, suggest non-equilibrium conditions. Cooling was sufficiently slow to allow the formation of the lamellae, their preservation, and the transition from high to low pigeonite. In addition, the preservation of such fine-grained lamellae limits long-lasting, impact reheating to a peak temperature lower than 570 degrees C. These features, including the presence of monoclinic low-Ca pyroxene as the host, are reported in only a few mesosiderites. This suggests a possibly different origin and thermal history from most mesosiderites and that the crystallography (i.e., space group) of low-Ca pyroxene could be used as parameter to distinguish mesosiderite populations based on their cooling history.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000494707400014 Publication Date 2019-08-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-004x ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.021 Times cited Open Access  
  Notes Approved Most recent IF: 2.021  
  Call Number UA @ admin @ c:irua:164645 Serial 6331  
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Author Salje, E.K.H.; Buckley, A.; Van Tendeloo, G.; Ishibashi, Y.; Nord, G.L. openurl 
  Title Needle twins and right-angled twins in minerals: comparison between experiment and theory Type A1 Journal article
  Year (down) 1998 Publication The American mineralogist Abbreviated Journal Am Mineral  
  Volume 83 Issue Pages 811-822  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000074717900013 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-004x ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.021 Times cited 43 Open Access  
  Notes Approved Most recent IF: 2.021; 1998 IF: 2.124  
  Call Number UA @ lucian @ c:irua:25675 Serial 2288  
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Author Groat, L.A.; Kek, S.; Bismayer, U.; Schmidt, C.; Krane, H.G.; Meyer, H.; Nistor, L.; Van Tendeloo, G. openurl 
  Title A synchrotron radiation, HRTEM, X-ray powder diffraction, and Raman spectroscopic study of malayaite, CaSnSiO5 Type A1 Journal article
  Year (down) 1996 Publication The American mineralogist Abbreviated Journal Am Mineral  
  Volume 81 Issue 5/6 Pages 595-602  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Synchrotron radiation, high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction, and Raman spectroscopy were used to study the structure and thermal behavior of malayaite, CaSnSiO5. No indications of deviation from A2/a symmetry and no structural transitions were observed between 100 and 870 K. HRTEM revealed that the material is free of domains and antiphase boundaries. However, the lattice constants, cell volume, and Raman-active phonons show a thermal discontinuity near 500 K, which is possibly related to variation of the coordination sphere around the highly anisotropic Ca position.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos A1996UP41100006 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-004x ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.964 Times cited 19 Open Access  
  Notes Approved no  
  Call Number UA @ lucian @ c:irua:16862 Serial 3407  
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