[SCG59-P08] Thin section etching of zircon for micro thermochronology by fission track method: A trial
Keywords:Fission Track, etching, zircon
To avoid the destruction of a thin section during the etching by high temperature alkali eutectic etchant, pinpoint etching only on zircon was tried. In order to perform pinpoint etching, a pipette tip made of polypropylene or Teflon was tried, but dropping of the etchant on the sample was impossible, because of the rapid solidification during the experiment. Dropping the etchant using a Teflon coated spoon on a sample was possible, but the control in amount of etchant was difficult. A photosetting resin was used as a material for bonding the rock and the slide glass. As a result of trial with several etchants, it was found that rocks came off with an etching solution at 160℃ or higher. The KOH:NaOH eutectic mixture used in the conventional zircon fission track method was found to be unsuitable because it had a melting point of about 170℃. On the other hand, the KOH:NaOH:LiOH eutectic mixture used as an alternative etchant has a melting point of about 140℃ and has higher etching efficiency than the KOH:NaOH eutectic mixture. Zircon in thin section was able to be etched using a KOH:NaOH:LiOH eutectic mixture at 150℃.