| Abstract |
Many Martian meteorites contain black-colored olivine grains. We observed these olivine grains by transmission electron microscope (TEM) and found that nano-particles of either Fe metal or magnetite (10-20 nm in diameter) are present, which is responsible for the black color. We performed shock experiments on olivine and successfully reproduced nano-particles at the shock pressure higher than 40 GPa, which is consistent with the estimated shock pressure of Martian meteorites containing black olivine.
The presence of two different nano-particle species can be explained by the difference of temperature increase during shock. The presence of nano-particles changes the reflectance spectra and magnetic susceptibility of olivine. Thus, it is necessary to consider the effect when we interpret the remote sensing data. |
