Hi The etching is genuine. The statement that 'if etching was terrestrial then the whole surface would be etched' is incorrect.You have to remember that different surfaces have been exposed to different conditions. Some surfaces simply have no stresses and lines of weakness for chemical attack to occur and if it does occur then it is more even on these surfaces. The posterior smooth surface, which was not exposed to re-entry heating, generally survives very well. The spalled areas or bald areas again have no lines of weakness and often avoid etching. The anterior surface which suffered re-entry heating and then rapid cooling has many lines of weakness and is readily attacked. If you take the stretch tektites then the exterior surface was cooled, re-heated and then rapidily cooled. The interior stretch part was exposed late on - either due to impact breakage or more likely thermal breakage when the tektite had lost its inherited cosmic velocity and shock wave and then rapidly cooled. This exposed stretch surface simply cooled. The two surfaces are very different in terms of thermal history and weaknesses, hence one is heavily etched and the other lightly or not etched. If you don't believe that pitting can form by natural etching then study ancient soda glass. Islamic glass jeton is great as it can be accurately dated. This material, sometimes over 1000 years old will sometimes show pitting. Soda glass is a lot lower in quality compared with tektite glass and so the process of etching is quicker. Etching is genuine, but is not random - this is the key point. It attacks cracks and weaknesses caused as the tektite cooled then re-entered the atmosphere. If you want to study etching then start with moldavites and then work towards the more recent Australasian tektites. Etching is a tricky subject btw. Etching is, strictly speaking, alkaline attack that targets the silica network. This usually creates v-grooves. Leaching is the acid attack which is more common as tektites usually occur reworked in porous and permeable gravels exposed to meteoric waters. Acid attack targets the alkaline component in the glass. The acid attack usually results in rounded pitting and u-grooves. The two processes can also act in parallel if conditions are right. The geological and reworking history of an individual specimen is often complex and, combined with abrasion from transportation, can result in a diversity of sculpture and morphologies. I know that etching is genuine, but I still wondered if some of the anterior sculpture on indochinites was original. I don't think it is. Another way to study etching is to collect half a ton of different tektites with various stages of sculpture. Your wife will be happy with that suggestion. Also, tektites are glass, quenched very quickly - no crystals or crystallites here! Regards, Aubrey Whymark
From: Daniel <[email protected]> To: [email protected] Sent: Saturday, 25 February 2012, 19:26 Subject: Re: [meteorite-list] Steves unproven tektite theory by Steve lol! Hi Carl, I don't agree with everything about this theory, I just thought it was interesting. There all still a lot of unknowns when it comes to tektites. Are you a tektite collector? Best Regards, Daniel Sutherland On Feb 25, 2012, at 9:45 AM, <[email protected]> wrote: > Daniel, Steve, > All due respect to this theory. > I'd like to hear more about this theory because he says; > "Theories about chemical etching and spalling as the major creators of > surface sculpturing have been proven unlikely." > He does not explain this statement. How has this been proven unlikely? > If his theory is true. How do you explain all of the glass rocks found that > have the same surface features as tektites but, have been ruled out as > tektites based largely on the amount of H2O within them? > Arizonaites( Saffordites) ?, Columbianites?, etc. > > Carl > meteoritemax > > -- > Cheers > > ---- Daniel <[email protected]> wrote: >> Hi all, >> >> Take a look at this website. >> >> http://www.edamgaard.dk/Copy%20of%20VietnamTektites%20edj.htm >> >> >> Cheers, >> Daniel Sutherland >> >> Sent from my iPhone >> >> On Feb 24, 2012, at 11:19 PM, "Dan Wray" <[email protected]> wrote: >> >>> Steve, >>> >>> I am a tektite collector and I agree with you about the so called etching. >>> If you look at broken fragments of hollow tektites the inside surface is >>> smooth and the outside textured. You can also see this on stretched >>> specimens, the stretched area is smooth. This so called etching is bogus. >>> >>> Dan Wray >>> ----- Original Message ----- From: "Steve Dunklee" <[email protected]> >>> To: <[email protected]> >>> Sent: Friday, February 24, 2012 1:41 PM >>> Subject: [meteorite-list] Steves unproven tektite theory by Steve lol! >>> >>> >>>> >>>> I believe the features on most tektites are produced during formation and >>>> not by etching. As the molten material reaches the upper atmosphere they >>>> reach a verry cold environment with low atmospheric pressure. The skin of >>>> the material is outgassing while being exposed to sub zero temps. this >>>> outgassing while freezing causes the skin to crystalize in strange shapes. >>>> then they are smoothed off during re entry which reaches speeds over the >>>> speed of sound. when wet limestone mud freezes in winter it causes similar >>>> crystal formations. when you mash them down they look like the surface of >>>> tektites. the molten material travels up to 4 or 5 miles in a molten state >>>> where it is quenched by sub zero tempratures causing crystalization. then >>>> re heated during its fall back to earth. the deep sharp grooves made >>>> during cooling are rounded off during re melting. I have a teardrop with >>>> smooth glassy surface on one end with no etching. if the etching was >>>> terestrial the >>>> whole tektite would be etched. >>>> Cheers >>>> Steve Dunklee >>>> ______________________________________________ >>>> >>>> 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 >>> >>> >>> ______________________________________________ >>> >>> 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 >> ______________________________________________ >> >> 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 ______________________________________________ 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 ______________________________________________ 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
