CompuServe Messages

Hi Doug, Here is yet some more information on ureilites. Ureilites are classified in two groups due to shock. They are low-moderate and very high degree of shock. Diamond and lonsdaleite found in the ureilites are obviously due to shock transformation of graphite requiring a minimum peak pressure of 13 GPa. The upper limit may be as high as 60 Gpa. Thats sound like a planetary strike to me <G>. Don't know if the ureilite – Venus association will be answered too soon but like a lot of other meteorites whos parent bodies need to be solved so does this association. Also it could be a mistake to assume it came from Venus not too long ago although possible it could have happened earlier in our systems history and the meteoroid could have floated near Earth and been flung in a outward orbit only to return just recently. Don't know if the cosmic radiation effect on this material supports that idea though. I do like having the Zagami knowing it is most likely from Mars. Now if the ureilite is from Venus then all I need is some lunar material (legal) to have the solar systems three closest bodies to Earth <G>. –AL