RE: [meteorite-list] Meteorite crater or crumbling of ground ?
Hello Pierre, the hole is most probably a sinkhole, created by the collaps of a cave. I think limestone is very common in the area, underlying the soil. A impact pit of this size probably wouldn't show such a sharp rim and there would be much mud thrown around. Best wishes Dennis From: Pierre-Marie PELE Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: [meteorite-list] Meteorite crater or crumbling of ground ? Date: Sat, 20 Mar 2004 20:26:37 +0100 (CET) Hello to the list ! During my prospecting trip to Spain hunting for the meteorite of the 4th january 2004, I saw once in a field this circular phenomenon. You can see the picture at this address : http://www.meteor-center.com/dossier/espagne2004/crater.jpg The terrain contains no stones, only mud and grass. There's no track to reach this place. That's the only hole of this kind we found during our one week trip. Also, it is situated on the trajectory of the meteor. According to you, what is this ? I thank you in advance for your help. Pierre-Marie PELE www.meteor-center.com -- Faites un voeu et puis Voila ! www.voila.fr __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list _ Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] impactite vs. impact glass
Hello Bob and all, Probably this nomenclature is applicable to all kinds of impact related rocks, as are meteorites. It seem to me that the term 'impact melt breccia' should be discarded, because it is usually NOT a brecciated impact melt rock set in a clastic or igneous matrix, but clasts of non melted rock set in a molten matrix. Usually the term accompaning 'breccia' refers to the nature of the clasts itselves, not to the nature of the matrix. So themore correctterm for 'impact melt breccia' would be 'impact melt rock' or 'impact melt rock with lithic clasts'. That´s how I understood it. In a singles impact eventthe melting and solidification of a rock can not predate the formation of a breccia of this materialdue to the same impact event. So truly (impact) brecciated impact melt rocks (=impact melt breccias) are extremly rare on earth, but elsewhere (an impact melt rock may be brecciated by another impact event, if it is monomict, it is an impact meltbreccia, if it is polymict it is something else, maybe a lithic breccia or a regolith breccia...). Well, I hope I got it right, scientists seem to love that ;-) Best wishes Dennis Harries *NO WAR* http://www.bgs.ac.uk/SCMR/docs/paper_12/scmr_paper_12_5.pdf Hello Dave and Dennis and all, This USGS paper raises more questions. Under the term "Impact Melt Breccia" it recommends that it's use be "discarded"! It doesn't suggest a replacement term. It's not obvious to me what the new term should be, so could someone tell me, what is the "preferred" term? Since the author is Stoffler, I'm assuming these terms are applicable for use in describing meteorites. But this may not be the case. I may be wrong in my assumption, and this list of terms may be only applicable for metamorphic processes involving Terran, Lunar, and Martian impact events and their resultant impactites. Is there a separate list of "approved" terms for asteroidal impact events and meteorites? More questions still, BOb V. MSN 8 helps ELIMINATE E-MAIL VIRUSES. Get 2 months FREE*. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] impactite vs. impact glass
Hi Dave, I think these are the most official definitions on impact rocks (by IUGS): http://www.bgs.ac.uk/SCMR/docs/paper_12/scmr_paper_12_5.pdf Impactite is the general term for rocks affected by impact metamorphism, including breccias, melt rocks, impact glasses, tektites .. Best wishes Dennis Harries Dear List; Is there a defined difference between impact glass and impactite? I see one picture of an impact glass that was hard to discern from impactite. So, lost as usual, is there a definition, or is it just a difference in the melt degree? Thank you, Dave Freeman __ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list STOP MORE SPAM with the new MSN 8 and get 2 months FREE* __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
