[meteorite-list] Origins

[mhutson at pdx.edu]

I'm not sure where the idea came from that enstatite chondrites might be 
samples of Mercury.  We know that Mercury has a large metallic core and an 
intrinsic magnetic field.  Therefore, it must be differentiated.  Surface 
material would be the silicate fraction of whatever chondritic precursor 
material went in to the accretion of the planet.  All of the metal would be in 
the core.  Enstatite chondrites contain a significant amount of metal and are 
undifferentiated (roughly solar in composition).  Enstatite chondrites cannot 
be surface material from any large (planetary) object.  A recent spectral study 
of the surface of Mercury (Sprague et. al -- LPSC 2004) shows no evidence for 
metal on the surface of Mercury.  Mercury's surface does not reflect sunlight 
in the same manner as an enstatite chondrite.