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
[meteorite-list] impactite vs. impact glass
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. --- [meteorite-list] impactite vs. impact glass Dennis Harries [EMAIL PROTECTED] Thu, 20 Mar 2003 08:42:37 + htmldiv style='background-color:'DIV PHi Dave,/P PI think these are the most official definitions on impact rocks (by IUGS):/P PA href=http://www.bgs.ac.uk/SCMR/docs/paper_12/scmr_paper_12_5.pdf;http://www.bgs.ac.uk/SCMR/docs/paper_12/scmr_paper_12_5.pdf/A/P PImpactite is the general term for rocks affected by impact metamorphism, including breccias, melt rocks, impact glasses, tektites ../P PBest wishes/P PDennis Harries/P PBR __ 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
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
[meteorite-list] impactite vs. impact glass
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 __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] impactite vs. impact glass
http://www.ctlab.geo.utexas.edu/imagefolio/igmet/ Hey Dave, Check out the above web page. I'm not sure about the correct terminology, but the images might be what you are more interested in. Other interesting images: http://www.mintek.ac.za/pubs/geobook/Impactglass.htm http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1353.pdf http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1416.pdf http://presolar.wustl.edu/ref/DaG.pdf http://www.star-bits.com/aouelloul.htm http://www.star-bits.com/ldglass.htm Bob V. - [meteorite-list] impactite vs. impact glass David Freeman [EMAIL PROTECTED] Wed, 19 Mar 2003 19:34:35 -0700 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
