Nd同位体組成からみたマントルの不均質性

概要

論文の詳細を見る
The auther has examined mantle heterogeneity by using the neodymium isotope data of oceanic region. It has been stated that the ε_<Nd> values of MORBs originating from the most depleted mantle are characterized by the range between +9 and +12, However, from many collected data, it has been recognized that the ε_<Nd> values of +10 and over are rare. The most depleted MORBs are distributed in restricted region of the Northern Hemisphere. On the other hand, the MORBs of the Southern Hemisphere are characterized by low ε_<Nd> values as compared with those of the Northern Hemisphere, and form the isotopically anomalous zone. The most of new ε_<Nd> data concentrate between +7 and +10, and the ranges of those values are different in each ocean. The ε_<Nd> values of OIBs in the Southern Atlantic and the Indian Oceans are +1 to -2. They are lower than those of the other OIBs. It has been suggested that large-scale Pb and Sr isotopic mantle anomalies (Dupal anomaly) exist in the Southern Hemisphere. On neodymium isotopic composition, the auther also has been recognized the anomalous zone in the Southern Atlantic and the Indian Oceans. Furthermore, it has been clearly that the anomaly on OIBs is found in the same area on MORBs.
地学団体研究会の論文
1987-01-25