Natural (Mg,Fe)SiO3-ilmenite and -perovskite in the Tenham meteorite

Science. 1997 Aug 22;277(5329):1084-6. doi: 10.1126/science.277.5329.1084.

Abstract

The minerals (Mg,Fe)SiO3-ilmenite and -perovskite were identified in the shock-induced veins in the Tenham chondritic meteorite. Both phases are inferred to have transformed from pyroxene at high pressures and temperatures by shock metamorphism. Columnar-shaped ilmenite grains, one of two types of morphologies, have a topotaxial relationship with neighboring pyroxene grains, indicating shear transformation. Granular-shaped perovskite grains showed a diffraction pattern consistent with orthorhombic perovskite, but these grains were not stable under the electron beam irradiation and became amorphous. The higher iron concentration in both phases compared with those experimentally reported may suggest their metastable transition from enstatite because of shock compression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Compounds / analysis*
  • Calcium Compounds / chemistry
  • Iron / analysis*
  • Iron / chemistry
  • Iron Compounds / analysis*
  • Iron Compounds / chemistry
  • Magnesium Compounds / analysis*
  • Magnesium Compounds / chemistry
  • Meteoroids*
  • Microscopy, Electron
  • Oxides / analysis*
  • Oxides / chemistry
  • Pressure
  • Silicates / analysis*
  • Silicates / chemistry
  • Temperature
  • Titanium / analysis*
  • Titanium / chemistry

Substances

  • Calcium Compounds
  • Iron Compounds
  • Magnesium Compounds
  • Oxides
  • Silicates
  • ilmenite
  • perovskite
  • olivine
  • Titanium
  • Iron