Tectono-metamorphic evolution and significance of shear-zone lithologies in Akebono Rock, Lützow-Holm Complex, East Antarctica

Baba, Sotaro and Hokada, Tomokazu and Kamei, Atsushi and Kitano, Ippei and Motoyoshi, Yoichi and Nantasin, Prayath and Setiawan, Nugroho Imam and Dashbaatar, Davaa-Ochir (2021) Tectono-metamorphic evolution and significance of shear-zone lithologies in Akebono Rock, Lützow-Holm Complex, East Antarctica. Antarctic Science, 33 (1). 52 – 72. ISSN 09541020

[thumbnail of Sotaro_TK.pdf] Text
Sotaro_TK.pdf - Published Version
Restricted to Registered users only

Download (3MB) | Request a copy

Abstract

We describe a major shear zone exposed at Akebono Rock and discuss its deformation and metamorphic history, with a view to providing a better understanding of the geological history of the Lützow-Holm Complex. Three deformation episodes are recognized: D1 produced open folds (F1), boudinage and a regional ductile foliation, whilst the related metamorphic facies is characterized by stable garnet. F1 folding is dominantly preserved in the eastern part of the study area. During D2, an isoclinal to tight asymmetric F2 folds developed mainly in the west part of the region, accompanied by an S2 shear, under biotite facies retrograde metamorphism. The D3 episode involved the formation of the major shear zone, characterized by mylonite and L-tectonite fabrics, which took place at ~610-660°C and 4-5 kbar. Large, sigmoidal garnet core domains have S-shaped inclusion trails, suggesting that syntectonic garnet growth occurred before the formation of the shear zone. Estimated P-T conditions suggest that the sigmoidal garnet-bearing amphibolite was recrystallized at a deeper crustal level and was brought to a higher level during the formation of the shear zone. Crustal-scale deformation involving syntectonic recrystallization and shearing of Akebono Rock is a key issue for reconsidering the evolution of the Lützow-Holm Complex. Copyright © Antarctic Science Ltd 2020.

Item Type: Article
Additional Information: Cited by: 3
Uncontrolled Keywords: Antarctica; East Antarctica; Lutzow-Holm Bay; amphibolite; crustal deformation; garnet; lithology; metamorphism; recrystallization; shear zone; tectonic evolution
Subjects: G Geography. Anthropology. Recreation > GB Physical geography
Divisions: Faculty of Engineering > Geological Engineering Department
Depositing User: Sri JUNANDI
Date Deposited: 30 Aug 2024 02:05
Last Modified: 30 Aug 2024 02:05
URI: https://ir.lib.ugm.ac.id/id/eprint/5521

Actions (login required)

View Item
View Item