西藏定结高喜马拉雅石榴辉石岩-镁铁质麻粒岩的岩石特征及其地质意义

廖群安; 李德威; 易顺华; 卢练

Volume 28 Issue 6

Nov. 2003

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LIAO Qun-an, LI De-wei, YI Shun-hua, LU Lian, 2003. Petrologic and Geologic Significance of Garnet Pyroxenite and Mafic Granulites from High Himalayan Region, Tibet. Earth Science, 28(6): 627-633.

Citation:

LIAO Qun-an, LI De-wei, YI Shun-hua, LU Lian, 2003. Petrologic and Geologic Significance of Garnet Pyroxenite and Mafic Granulites from High Himalayan Region, Tibet. Earth Science, 28(6): 627-633.

LIAO Qun-an, LI De-wei, YI Shun-hua, LU Lian, 2003. Petrologic and Geologic Significance of Garnet Pyroxenite and Mafic Granulites from High Himalayan Region, Tibet. Earth Science, 28(6): 627-633.

Citation:

LIAO Qun-an, LI De-wei, YI Shun-hua, LU Lian, 2003. Petrologic and Geologic Significance of Garnet Pyroxenite and Mafic Granulites from High Himalayan Region, Tibet. Earth Science, 28(6): 627-633.

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Petrologic and Geologic Significance of Garnet Pyroxenite and Mafic Granulites from High Himalayan Region, Tibet

Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

Received Date: 2003-05-15
Publish Date: 2003-11-25

Abstract

Abstract

HP garnet-pyroxenite and the mafic granulites formed by decompression have been found in the high-Himalaya crystallinites (HHC) from Kada-Zaxang near Dingri County, Tibet. The mineral assemblage of the HP garnet-pyroxenite in early stage, Grt+Cpx (rich in Al₂O₃) +Ru+Q, without any plagioclase, was formed in 845-896 ℃ and 1.2 GPa, with pressure as high as that in eclogitic phase. While the mineral assemblage of mafic granulite was Opx±Cpx (Al-poor) +Pl (An high up to 90) ±Grt (rim), of which the Opx, Cpx and Pl are symplectite which replaced the early Grt and Al-rich clinopyroxene in decompression condition: t=993-776 ℃, p=1.21-0.80 GPa. The latest mineral assemblage, Hb+Pl+Q, found to have replaced the assemblage of mafic granulite, was formed by retrograde metamorphism in amphibolitic phase. All of this show that the HHC have undergone an HP metamorphism and a stage of decompression retrograde metamorphism and that in early stage the temperature rose with the decompression, but in late stage it dropped with the decompression. Therefore, it can be assumed that the uplifting of the HHC was related to the hot source of the mantle.
- high-Himalaya,
- garnet-Nielamu,
- garnet-pyroxenite

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References(15)

References

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