^<40>Ar-^<39>Ar Dating : Investigation of some Technical Problems and its Application to the Deccan Trap Rocks and a Unique Meteorite from Antarctica

• Main Authors: Kaneoka Ichiro, Iwata Naoyoshi, Takigami Yutaka
• Format: Report
• Language: English
• Published: Tohoku University 1997
• Subjects: Trap Rocks; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10097/28698; https://tohoku.repo.nii.ac.jp/?action=repository_uri&item_id=47221; https://tohoku.repo.nii.ac.jp/?action=repository_action_common_download&item_id=47221&item_no=1&attribute_id=18&file_no=1

In order to get more reliable ages and extend the application of ^<40>Ar-^<39>Ar dating for terrestrial and exterrestrial samples, some technical problems such as the examination of the efficiency of Cd-shielding to reduce the interference thermal neutron flux and the laser heating method were investigated. It has been reconfirmed that Cd-shielding is effective to reduce the interference ^<40>Ar produced by thermal neutron from potassium. Further the laser heating method has been successfully developed in our laboratory and give reasonable ages for some age standard and Deccan Trap samples. Application of ^<40>Ar-^<39>Ar dating method gives ages for Deccan Trap samples which range from less than 60 Ma to about 70 Ma. The clast in a unique meteorite from Antarctica gives a in ^<40>Ar-^<39>Ar age of about 490 Ma which corresponds to a degassing event and concordant with that of the host meteorite. ^<40>Ar-^<39>Ar age Cd-shielding Laser heating Deccan Traps Meteorite Antarctica