Host: Abstracts of Annual Meeting of the Geochemical Society of Japan
Name : Abstracts of Annual Meeting of the Geochemical Society of Japan
Number : 68
Date : September 01, 2021 - September 15, 2021
Pages 202-
The chondrite-normalized REE pattern, called the Masuda-Coryell plot, is one of the powerful researcher tools to understand the evolution of the Earth and planetary systems. Recently, Lee and Tanaka [1-3] developed a method to accurately measure the Eu isotope ratio using MC-ICP-MS, and also reported a geochemical application in the igneous rocks. REE tetrad effect with large Eu negative anomaly (Eu/Eu* ＜0.1) from highly fractionated granite is a specific geochemical feature of the chondrite-normalized REE patterns, which indicates an abnormal behavior of REE abundances in the Earth system. Since Masuda and Ikeuchi [4] reported the presence of REE tetrad effect from geological materials, several hypotheses have been proposed for the origin of the REE tetrad effect. However, its formation mechanism was not clarified clearly yet. In addition, another unsolved question is the relationship between extremely large negative Eu anomaly and REE tetrad effect. For example, highly fractionated granite with REE tetrad effect has very large Eu negative anomaly. However, there are no reports of an order between them. In this presentation, we will discuss REE tetrad effect with the Sr-Nd isotope system, the magnitude of Eu negative anomaly and the progress of Eu isotope fractionation, and so on.[1] Lee, S-G. and Tanaka, T. (2019) Determination of Europium isotopic ratio by multi-collector inductively coupled plasma mass spectrometry using a Sm internal standard, Spectrochm. Acta Part B, v.156, 42-50.[2] Lee, S-G. and Tanaka, T. (2021) Eu isotope fractionation in highly fractionated igneous rocks with large Eu negative anomaly Geochem. J. v.55, No.4, e9-e17. [3] Lee, S-G. and Tanaka, T. (2021) Gd matrix effects on Eu isotope fractionation using MC-ICP-MS: Optimizing Europium isotope ratio measurements in geological rock samples. Int.J.Mass.Spec.116668[4] Masuda, A. and Ikeuchi, Y. (1979) Lanthanide tetrad effect observed in marine environment. Geochem. J., v.13, 19-22.
