Table 3  Whole rock K-Ar dating of the ejecta of Takamatsu crater

sample # locali Rock name  Isotope ag  40Ar*     %40Ar*      %K
                               Ma    scc/gm*10-5
TK21-3-G   1      glass    12.8�}3.8   0.138      9.5       2.92
                                       0.153      9.3       2.91
94070205   2   biotite daci14.2�}0.7   0.163      74.1      2.97
                                       0.166      73.7      2.97
TKC-2-07   1   aphyric rhyo14.0�}0.7   0.167      74.4      3.02
                                       0.163      78.6      3.03
TKC-2-20A  1   aphyric rhyo13.8�}0.7   0.162      67.0      2.99
                                       0.159      69.3      2.98
TKC-2-20B  1      glass      <19.5     0.218      4.4       2.86
                                       0.219      4.5       2.87
TKC-2-21A  1      glass      <21.7     0.241      4.6       2.87
                                       0.246      4.8       2.87
TKC-2-21B  1   aphyric rhyo14.2�}0.7   0.170      71.6      3.06
                                       0.168      69.6      3.05