Hi All, Short opinion: manmade.
Reasoning: the inability to produce such a form purely through atmospheric ablation. Just to remind everyone, all of the so-called Franconia irons are nothing more than chondritic iron that has separated from an H-chondrite fall -- either during flight, or by terrestrial weathering processes on the ground. Thus it has always bothered me that these irons were given a separate meteorite name from the ubiquitous H-chondrites at Franconia from which they derive. If my information is outdated on this subject, someone please let me know. But many (most?) of the people I know who have hunted Franconia and found these irons do not pretend that they are from a separate iron fall -- they all accept that the iron nuggets were spalled from an H-chondrite. So, getting back to Larry's unusual, tiny iron find. If this iron did not start at the top of the atmospere as a very tiny piece of iron, there would be no way to ablate it, let alone punch a hole through it. Since the Franconia irons were once part of a massive chondritic meteoroid, there was no opportunity for these irons to experience independent, high altitude, high velocity ablation. Their ablation history wouldn't have started until the main H-chondrite body had fragmented on a gigantic scale (e.g. terminal burst), which of course would have occurred at comparatively low altitude. On a final note, the H-chondrite fall at Franconia was not a recent one. While this part of NW Arizona receives little seasonal rainfall, I don't imagine that a 0.1-gram piece of iron could survive more than a century. But a manmade piece of iron, dropped there in the last 50 years, might possibly survive terrestrial weathering. I would love nothing more than for Larry's find to have an extraterrestrial origin; but the physics and history of finds at Franconia argue strongly against it. Best wishes, Rob ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list