Shock effects experiments on serpentine and thermal metamorphic conditions in Antarctic carbonaceous chondrite

• Main Authors: Akai,Junji, Sekine,Toshimori
• Format: Report
• Language: English
• Published: Department of Geology and Mineralogy, Faculty of Science, Niigata University/National Institute for Research in Inorganic Materials 1994
• Subjects: Antarctic; Murchison; Yamato; Antarc*
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=4639; http://id.nii.ac.jp/1291/00004639/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=4639&item_no=1&attribute_id=18&file_no=1

The unique Antarctic carbonaceous chondrites, Belgica (B)-7904,Yamato (Y)-86720,Y-82162,Y-793321 are thermally metamorphosed. However, the heat source of the thermal metamorphism is not known. Two strong possibilities are shock-induced heating and heating on the parent body. The explosive impact method was used to check the possibility of heating of phyllosilicates by shock compression. Examining the shocked specimens from the Murchison meteorite and terrestrial lizardite, the following were found : (1) Phyllosilicates in the shocked (>32.1GPa) specimens changed to nearly amorphous substances; (2) the phyllosilicates in specimens shocked at lower pressures were still crystalline and undamaged; (3) some void-like (bubble) textures were widely observed in the amorphous substances; (4) the other minerals such as pyroxenes and olivines which did not change to glass phases seem to be little affected by shock. These facts do not suggest that the unique Antarctic chondrites experienced significant shock.