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Phlogopite-Bearing Orthopyroxenite in Andong Ultramafic Complex

안동 초염기성암 복합체의 함금운모 사방휘석암

  • Received : 2012.12.03
  • Accepted : 2012.12.23
  • Published : 2012.12.31

Abstract

Phlogopite-bearing orthopyroxenite occurs in Andong ultramafic complex in a planar body of about 1 meter thick, and consists mostly of coarse subhedral to euhedral orthopyroxene crystals. Minor minerals are clinopyroxene, phlogopite, and plagioclase with trace chromian spinel, pentlandite, apatite, and zircon. Clinopyroxene occurs as either exolution lamella or interstitial fillings with phlogopite and plagioclase. Electron microprobe analysis showed that orthopyroxenes are entatite, while clinopyroxenes are diopside with little chemical variation through samples. Hydrous alteration resulted in the formation of talc, amphibole, and serpentine from orthopyroxene, clinopyroxene, and plagioclase, respectively. The orthopyroxenite was probably formed by the fractional crystallization of the ultramafic magma. Radiogenic dating of phlogopite and zircon of the orthopyroxenite would reveal the age of the Andong ultramafic complex.

Keywords

Ultramafic;orthopyroxenite;Andong;phlogopite;zircon

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Cited by

  1. Mineral ages and zircon Hf isotopic composition of the Andong ultramafic complex: implications for the evolution of Mesozoic subduction system and subcontinental lithospheric mantle beneath SE Korea vol.151, pp.05, 2014, https://doi.org/10.1017/S0016756813000757

Acknowledgement

Grant : 행성자원 지화학 분석용 표준물질, 계측기 및 모사토 개발

Supported by : 한국지질자원연구원