Department of Geology, Kochi University
Department of Geology, Kochi University
National Institute of Polar Research
抄録(英)
In the Austkampane area of the S∅r Rondane Mountains, East Antarctica, a meta-ultramafic rock occurs as a lenticular block enclosed within the host garnet-biotite gneiss of the granulite facies. The rock consists of olivine, orthopyroxene, amphibole, spinel, apatite, ilmenite, magnetite, chalcopyrite and pentlandite. The bulk rock analysis shows an ultramafic composition in a broad sense, but compared with mantle peridotites it is enriched in TiO_2,Al_2O_3,CaO, Nb and Zr, and has a slightly high ratio of FeO^*/MgO. This suggests a slightly differentiated basaltic cumulate as its precursor. After the igneous generation, the rock was incorporated within the original rock of the host gneiss (sedimentary quartzo-feldspathic rock), probably in the form of block-in-matrix, and then both rocks underwent the granulite facies metamorphism. The olivine-spinel geothermometer and Al_2O_3 content of orthopyroxene indicate metamorphic temperatures of about 780-820℃ and 750-800℃, respectively. Similar meta-ultramafic rocks have been reported from the Lützow-Holm Complex, suggesting that the similar association of original rocks such as oceanic lower crusts developed in these two granulite terrains.
雑誌書誌ID
AA1072335X
雑誌名
Proceedings of the NIPR Symposium on Antarctic Geosciences
META-ULTRAMAFIC ROCK FROM THE AUSTKAMPANE AREA OF THE SØR RONDANE MOUNTAINS, EAST ANTARCTICA
.png)
KJ00002409869.pdf
(899.55KB)
概要
