Current status and future development of mineralogical studies on geochronometers
年代測定鉱物に関する研究の現状と今後の展開
阿部 健康
Abe, Takeyasu
希土類元素(REE: Y+LaLu)やアクチノイド元素(U, Th)を含有する鉱物は、ホストとなる岩石の生成過程を議論するために重要な地球化学的情報や地質年代を保持している(cf. Harlov, 2016 review article, Journal of the Indian Institute of Science)。変成岩の研究では、ジルコンやザクロ石, 燐灰石, モナズ石, ゼノタイムが主に重要とされ、多くの先行研究がこれまで行われてきた(e.g. Hoskin and Schaltegger, 2003, Reviews in Mineralogy and Geochemistry; Meagher, 1982, Reviews in Mineralogy and Geochemistry; Spear and Pyle, 2002, Reviews in Mineralogy and Geochemistry)。本講演では、それら年代測定鉱物に関する最近の研究動向と、それを踏まえた今後の研究の方向性について、モナズ石を中心に議論を行う。
REE- and actinide-bearing minerals contain geochemical and geochronological information, which is important to discuss rock-formation process (cf. Harlov, 2016 review article, Journal of the Indian Institute of Science). In metamorphic petrology, many researchers have focused on the minerals such as zircon, garnet, apatite, monazite and xenotime. Many previous studies of those minerals have been reported (e.g. Hoskin and Schaltegger, 2003, Reviews in Mineralogy and Geochemistry; Meagher, 1982, Reviews in Mineralogy and Geochemistry; Spear and Pyle, 2002, Reviews in Mineralogy and Geochemistry). Here, current understanding of REE- and actinide-bearing minerals is reviewed. Based on the review, future work direction of mineralogical studies on geochronometers is discussed focusing on monazite.