Hello All, Speaking of Mercury: I'm sure Pete and some others have already read the article "Mercury's Marvels" in the April 2012 issue of Sky & Tel., pp.26-33.
On pp. 28-29, S&T senior contributing editor and list member J.K. Beatty describes the three ideas (or notions) of how 'iron-hearted' Mercury formed 4.5 billions years ago. On p. 29, you find a passage that may be a bit confusing, at least I think so: "A third notion is that, somehow, Mercury was never Earthlike but instead assembled from metal-rich building blocks. Such bodies exist: metal-rich meteorites called CV chondrites. But what Messenger is seeing on Mercury isn't a good match to those meteorites' composition. An iron-poor type known as aubrite is a better fit (see the box on page 31)." It's these words "metal-rich meteorites called CV chondrites" that may lead to misunderstandings (especially among readers who are not overly familiar with meteorites. A closer look at Allende will show what I mean: The Allende CV3.2 chondrite does have 23.85 % total iron but that should not be mistaken for its FeNi content, which is a mere 0.5% according to a post by Jeff Grossman many years ago. Jeff wrote on Monday, 19 Apr 1999: "In fact, Allende has almost no metal, if what you mean is metallic Fe-Ni. Jarosewich (1990) measured ~0.5 wt% metallic iron plus nickel in Allende. Most of the metal in these oxidized CV3 chondrites is the high-Ni alloy awaruite." Another example: The CR2 chondrite Renazzo has 24.93 % total iron but a metal content of only 7.4 wt%. Cheers, Bernd ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
