Hello Graham, All, On the contrary, the typical pieces of "shrapnel" found were in my opinion formed exclusively on impact - the force of the explosive impacts was certainly adequate to drive sizable fragments through practically any tree (well, let's exclude things like Sequoias...).
There are two types of Sikhote-Alin fragments, though. There are the pieces that show atmospheric fragmentation - these typically exhibit surfaces that appear torn but are not technically "shrapnel." Then there are the specimens that formed upon impact - the torn, jagged "shrapnel" pieces. Here are examples of each: Atmospheric Tear: www.aerolite.org/.../ sikhote-alin-aaa-33-2.htm http://upload.wikimedia.org/wikipedia/commons/archive/a/ab/20050827232208!SikhoteAlinMeteorite.jpg http://sk.wikipedia.org/wiki/Súbor:SikhoteAlinMeteorite.jpg Then you have the impact fragments: http://www.carionmineraux.com/mineraux/mineraux_decembre_2008/meteorite_sikhote_alin_top_1.jpg http://lh6.ggpht.com/_4j-MWz4xHuI/SU-HOSQNOgI/AAAAAAAAAII/CwiJw7cjXTw/Sikhote_Alin_78gram_01.jpg Right - I just got Jeff's message...mhm. Regards, Jason On Tue, Nov 17, 2009 at 4:09 AM, <ensorama...@ntlworld.com> wrote: > Hi Fred, List, > > How does that explain all the shrapnel found in the sides of the trees or > holes straight through standing trees? Surely shrapnel was produced both on > the way down and on impact? > > I have pieces that seem to have no sign of ablation, just lots of shear lines. > > Graham, Uk > > ---- debf...@att.net wrote: >> List, I have searched many Kilos of SA shrapnel without ever finding ONE >> without some surface melting. From what I have seen shrapnel is ALL air >> shredding with subsequent atmospheric frictional melting. >> Cheers, Fred Olsen >> -------------- Original message ---------------------- >> From: <ensorama...@ntlworld.com> >> > >> I did not know heat was needed at all to form shrapnel...surely it is just >> due >> to shearing of fragments from the dramatic collisions of fragments on impact >> or >> during exposive events on the way down that did not leave enough time for >> > ablation? >> > >> > Graham UK >> > >> > ---- Maurizio Eltri <maurizio.el...@libero.it> wrote: >> > > Hi all, >> > > >> > > I ask to those who are more experienced >> > > than me,clarification about Sikhote Alin's >> > > splinters formation. >> > > In my opinion there can be two ways to >> > > justify the origin of the fragments found in >> > > the vicinity of the largest craters, >> > > 1) The kinetic energy released at the contact >> > > surfaces of meteorite/ground was enough to >> > > melt the frontlayer of the meteorite with >> > > the subsequent violent expulsion of fragments, >> > > fused or partially fused. >> > > 2) Having the meteorites reached the retardation >> > > point at only 5 km of altitude, they would arrived >> > > at an impact with their hot surfaces, this would >> > > facilitate the expulsion of splinters. >> > > I apologize for my bad English. >> > > Maurizio Eltri >> > > >> > > ______________________________________________ >> > > http://www.meteoritecentral.com >> > > Meteorite-list mailing list >> > > Meteorite-list@meteoritecentral.com >> > > http://six.pairlist.net/mailman/listinfo/meteorite-list >> > >> > ______________________________________________ >> > http://www.meteoritecentral.com >> > Meteorite-list mailing list >> > Meteorite-list@meteoritecentral.com >> > http://six.pairlist.net/mailman/listinfo/meteorite-list >> >> >> >> >> > > ______________________________________________ > http://www.meteoritecentral.com > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
