Nd AND Sr ISOTOPE CHARACTERISTICS OF THE PLUTONIC ROCKS IN THE S∅R RONDANE MOUNTAINS, EAST ANTARCTICA
スポンサーリンク
概要
- 論文の詳細を見る
Plutonic rocks in the S∅r Rondane Mountains, East Antarctica comprise early Paleozoic granitic rocks and late Proterozoic tonalite. The former is further classified into two types (volcanic arc type and within plate type). The initial εNd values for the analyzed granitic rocks (six samples from volcanic arc type and one from within plate type) fall in a limited range (-1.48 to +0.62) and Nd model ages (T_<DM>) for the granitic rocks were estimated to be 900-1000 Ma which agree well with the ages of basement rocks. Taking Sr isotope data and element compositions into account, volcanic arc type granites (Dufek, Lunckeryggen and Mefjell) are explained by a fractional crystallization from an isotopically homogeneous magma which was generated from late Proterozoic lower (to middle) crustal rocks, whereas the within plate type granites (Vikingh∅gda, Rogerstoppane and Pingvinane) are assumed to have been formed mainly by mixing between crustal rocks with high Sr isotope ratios and mafic (to intermediate) parental magma originated in the upper mantle or lower crustal source. The presence of extremely high Sr isotope ratios for the within plate type granites suggests the involvement of more older crustal rocks (early to middle Proterozoic) beneath the S∅r Rondane Mountains. Changes of magma sources and a dominant process of magma formation from within plate type granites (early) to volcanic arc type granites (late) reflect the change of tectonic situation in this region during the early Paleozoic. The late Proterozoic Nils Larsen tonalite was generated in a depleted mantle and evolved without large crustal contributions.
- 国立極地研究所の論文
著者
-
Arakawa Yoji
Earth Science Division Faculty Of Education Saitama University
-
TAINOSHO Yoshiaki
Department of Natural Environment, Faculty of Human Development, Kobe University
-
Takahashi Yuhei
Hokkaido Branch Geological Survey Of Japan
-
Tainosho Yoshiaki
Department Of Natural Environment Faculty Of Human Development Kobe University
関連論文
- PRELIMINARY RESULT FOR THE Nd AND Sr ISOTOPE CHARACTERISTICS OF THE ARCHAEAN GNEISSES FROM MOUNT PARDOE, NAPIER COMPLEX, EAST ANTARCTICA
- Sr-Nd isotopic systematics and geochemistry of intermediate plutonic rocks from Ikoma Mountains, Southwest Japan : evidence for a sequence of Mesozoic magmatic activity in the Ryoke Belt
- Continental basalts in the accretionary complexes of the South-west Japan Arc : Constraints from geochemical and Sr and Nd isotopic data of metadiabase
- Zircon U-Pb sensitive high mass-resolution ion microprobe dating of granitoids in the Ryoke metamorphic belt, Kinki District, Southwest Japan
- Nd AND Sr ISOTOPE CHARACTERISTICS OF THE PLUTONIC ROCKS IN THE S∅R RONDANE MOUNTAINS, EAST ANTARCTICA
- Preliminary result for the Rb-Sr whole-rock age and initial Nd isotope ratios from the Closepet granite in Karnataka, Southern India
- PETROCHEMICAL STUDY OF THE GNEISS FROM MOUNT PARDOE AND TONAGH ISLAND IN THE NAPIER COMPLEX, EAST ANTARCTICA
- Sm-Nd isochron ages of mafic igneous rocks from the Ryoke Belt, Southwest Japan: Remains of Jurassic igneous activity in a late Cretaceous granitic terrane
- MODE OF PLAGIOCLASE TWIN LAWS IN THE GRANITIC ROCKS IN THE S∅R RONDANE MOUNTAINS
- PRELIMINARY RESULT FOR THE Sm-Nd WHOLE-ROCK AGE OF THE METAMORPHIC ROCKS FROM MOUNT PARDOE IN THE NAPIER COMPLEX, EAST ANTARCTICA
- AMMONIUM CONTENT OF BIOTITES FROM GRANITIC AND METAMORPHIC ROCKS IN THE S∅R RONDANE MOUNTAINS, EAST ANTARCTICA
- Nd-isotopic composition of Phanerozoic sediments in the Inner Zone of Southwest Japan Arc : implications on provenance characteristics and contribution to formation of mature island arc system
- Rb-Sr isochron ages of the Cretaceous granitoids in the Ryoke belt, Kinki district, Southwest Japan