| タイトル | Ar-39/Ar-40 systematics of Allende inclusions |
| 著者（英） | Bence, A. E.; Bender, J.; Schaeffer, O. A.; Maluski, H.; Eichhorn, G.; Herzog, G. F. |
| 著者所属（英） | Rutgers Univ.|State Univ. of New York |
| 発行日 | 1980-01-01 |
| 言語 | eng |
| 内容記述 | A laser microprobe was used to measure the Ar isotopic contents of individual mineral grains in four neutron-irradiated Allende samples: two coarse-grained Ca-Al-rich inclusions; one fine-grained Ca-Al-rich inclusion; and one sample with matrix and miscellaneous chondrules. The following K-Ar ages (G.y.) were obtained after degassing low Ar retentive sites by preheating the samples for one hour at 675 C: matrix, 3.5 + or - 0.2; three miscellaneous chondrules, 4.4 + or - 0.1, 4.0 + or - 0.1, and 4.4 + or - 0.1; and the fine-grained inclusion, 4.5 + or - 0.2. The minerals in the coarse-grained Ca-Al-rich inclusions have ubiquitous chlorine, less than 10 ppm K and apparent ages ranging upwards from 4.6 G.y. to well over 10 G.y. Possible explanations for these apparent ages are atmospheric contamination, the decay of K-40 prior to the formation of the solar system, and the trapping of radiogenic Ar-40 lost by the matrix. |
| NASA分類 | LUNAR AND PLANETARY EXPLORATION |
| レポートNO | 82A22304 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/411904 |
|
