气候变化领域集成服务门户(CCPortal): Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications

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DOI	10.1016/j.precamres.2017.12.045
	Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications
	Tong, Laixi; Liu, Zhao; Li, Zheng-Xiang; Liu, Xiaohan; Zhou, Xin
通讯作者	Tong, LX (通讯作者)
发表日期	2019
ISSN	0301-9268
EISSN	1872-7433
起始页码	385
结束页码	398
卷号	326
英文摘要	A rare garnet-bearing mafic granulite boulder has recently been identified from the Larsemann Hills, East Antarctica, with the development of two-stage decompression textures. Detailed petrographic study and P-T estimates suggest three distinct metamorphic stages: (1) peak ultrahigh-temperature (UHT) stage (M1) represented by coarse-grained garnet-orthopyroxene-bearing porphyroblastic assemblage, with P-T conditions of similar to 9.3 kbar and 900-950 degrees C; (2) post-peak decompression stage I (M2) represented by relatively coarse-grained orthopyroxene-plagioclase-ilmenite-bearing corona assemblage, with P-T conditions of 7.2-7.6 kbar and 810-830 degrees C; and (3) post-peak decompression stage II (M3) represented by fine-grained orthopyroxene-plagioclase-ilmenite-bearing symplectite assemblage on garnets and along garnet cracks, with P-T conditions of 6.2-6.9 kbar and 730-770 degrees C. Combined with P-T pseudosection calculation in the NCKFMASHTO system, these P-T data define a clockwise P-T path with post-peak two-stage decompression accompanied by important cooling. LA-ICP-MS zircon U-Pb age dating results show two weighted mean ages of 927 +/- 13 Ma and 547 +/- 30 Ma, suggesting that M1 UHT stage occurred in the early Neoproterozoic Rayner orogeny (990-900 Ma), whereas M2-M3 stages occurred during the early Palaeozoic Pan-African tectonic event (550-500 Ma). The peak P-T conditions, post-peak two-stage decompression P-T path and age data resemble those of the early Neoproterozoic garnet-bearing mafic granulite on Sostrene Island. It is inferred that the mafic granulite boulder may have been derived from the bedrock under inland ice sheet of the Larsemann Hills. Thus, the early Neoproterozoic metamorphism (M1) may reflect crustal thickening followed by post-orogenic extension likely associated with the assembly of Rodinia continent, while the overprinting of early Palaeozoic metamorphism (M2-M3) may reflect an extensive intra-continental reworking.
关键词	PRINCE-CHARLES MOUNTAINS PRYDZ-BAY FACIES METAMORPHISM BRATTSTRAND BLUFFS RAUER GROUP CONSTRAINTS EVOLUTION TEMPERATURE AREA GEOCHEMISTRY
英文关键词	Garnet-bearing mafic granulite; Poly-phase metamorphism; P-T path; Zircon U-Pb ages; Larsemann Hills; East Antarctica
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000469157300022
来源期刊	PRECAMBRIAN RESEARCH
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259592
推荐引用方式 GB/T 7714	Tong, Laixi,Liu, Zhao,Li, Zheng-Xiang,et al. Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications[J]. 中国科学院青藏高原研究所,2019,326.
APA	Tong, Laixi,Liu, Zhao,Li, Zheng-Xiang,Liu, Xiaohan,&Zhou, Xin.(2019).Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications.PRECAMBRIAN RESEARCH,326.
MLA	Tong, Laixi,et al."Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications".PRECAMBRIAN RESEARCH 326(2019).