- 著者
- Masayo Minami Akimasa Masuda
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.31, no.3, pp.125-133, 1997-06-20 (Released:2008-04-08)
- 参考文献数
- 20
- 被引用文献数
- 4 9
Here is presented a mathematical method which enables us to evaluate the degrees of lanthanide tetrad effects from the data involving all of REE. Each of the four spans corresponding to four subgroups, La-Nd, Pm-Gd, Gd-Ho, and Er-Lu, is approximately fitted to a quadratic function and the resultant quadratic coefficient is employed as a numerical indicator for the tetrad effect. For the purpose of approximation by a quadratic function, the least-squares method is used under the constraint that the first and second quadratic curves intersect at the middle point between Pm and Sm, and that the third and fourth ones intersect at the middle point between Ho and Er. Since, mathematically, the subject is a problem on the conditional extremum, the method of Lagrange undetermined multipliers should be used. It is noted that the degrees of four tetrad effects can be evaluated simultaneously. This method can lead us to the mathematically well-defined estimation of the tetrad effect.
- 著者
- Tasuku Akagi Shun'ichi Nakai Akimasa Masuda
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.32, no.2, pp.135-141, 1998-04-20 (Released:2008-04-08)
- 参考文献数
- 22
- 被引用文献数
- 1 1
Rare earth elements in REE-rich minerals were determined accurately by isotope dilution mass spectrometry (IDMS). The chondrite normalized REE patterns of some specimens showed regular relative aberrations, which are similar to that of the “tetrad effect”. We have introduced a background curve passing normalized values of La, Nd, Gd, Er and Lu, to measure the aberrations. The relative differential variations of some of the minerals are not small, but have been overlooked due to large overall variations of the chondrite normalized values.
- 著者
- 増田 彰正 田中 剛 朝倉 純子 清水 洋 Akimasa MASUDA Tsuyoshi TANAKA Junko ASAKURA Hiroshi SHIMIZU
- 雑誌
- 南極資料 (ISSN:00857289)
- 巻号頁・発行日
- vol.58, pp.197-203, 1977-03
やまと隕石(j),(k)および(m)の中の希土類元素(REE),Ba,Rb,Srを安定同位体希釈法によって定量した.(j)については,任意に二つの部分をとって分析した(提供された試料は,やや粗い粉末試料だった).最も代表的な希土類元素相互存在度を示すと考えられるLeedeyコンドライトの値で規格化すると,(k)は最も小さい分化を示すが,Euによく見られる異常は別として,GdとDyとの間に不連続性が見られるのが特徴である.(m)と(k)は,成因的な関連が深いと判断された.(j)の二回の定量値の間には,興味深い,系統的な差がある.(m)と(k)との関連,および(j)の内部的分化は,共に,もとの母体小惑星内での溶融と結晶分化の効果を強く示唆すると解釈できる.