2001年
大分県杵築地域に分布するNbに富む安山岩(共著)
山口大学機器分析センター報告
- ,
- ,
- 巻
- 9
- 号
- 9
- 開始ページ
- 27
- 終了ページ
- 32
- 記述言語
- 日本語
- 掲載種別
- 出版者・発行元
- 山口大学
Nb-rich andesites (NRAs ; Nb 27-15ppm) are found in the Miocene Usa Formation which distributes in Kitsuki area, Oita Prefecture. Phenocrysts of the NRAs are euhedral olivines, orthopyroxenes, clinopyroxenes, hornblendes and plagioclases. The NRAs posses SiO_2 contents of 58.1 62.6 and FeO^*/MgO ratios of 1.39 - 2.19,and are rich in TiO_2,K_2O, Ba, Nb, Rb, Pb, Th, Zr and light rare earth elements as well as the alkali basalts. N-MORB-normalized incompatible element patterns of the NRAs are similar to those of the SW Kyushu alkali basalt (JB-1a) and the Oninomi alkali basalt (within-plate type alkali basalt) rather than the Kuju-type basalts (island arc type basalt) and Yabakei-type basalt (intermediate between island arc and within-plate type basalts). The above chemical characteristics suggests that alkali basalt magmas or magma sources might play an important role of the origin of the NRAs.
- リンク情報
- ID情報
-
- CiNii Articles ID : 110000483492
- CiNii Books ID : AN1046804X