Econ. Environ. Geol. 2017; 50(3): 181-193
Published online June 30, 2017
https://doi.org/10.9719/EEG.2017.50.3.181
© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY
Correspondence to : seongyu@korea.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.
Mn-Fe phosphate mineral complexes included within the pegmatite are observed at Jurassic Cheolwon two-mica granite in Gyeonggi Massif, South Korea. The genetic evolution between the Cheolwon two-mica granite and pegmatite, and various trend of Mn-Fe phosphate minerals is made by later magmatic, hydrothermal, and weathering process based on mineralogical, geochemical analysis. The Cheolwon two-mica granite is identified as S-type granite, considering its chemical composition (metaluminous ~ peraluminous), post-collisional environment, low magnetic susceptibility, and existence of biotite and muscovite. The K-Ar age (ca. 153 Ma) of pegmatite is well coincident with age of the Cheolwon two-mica granite (151±4 Ma). It indicates that these two rocks are originated from the same magma. Pegmatite indicates the LCT geochemical signature, and was classified as muscovite-rare element class / Li subclass / beryl type / beryl-columbite-phosphate subtype pegmatite. The triplite {(Fe2+0.4,Mn1.6)(PO4)(F0.9)} is dominant phosphates in later magmatic stage which partly altered to leucophosphite {KFe3+2(PO4)2OH·2H2O} and jahnsite {(Fe3+0.7,Mn2.3)(PO4)2OH·4H2O} by hydrothermal alteration. In particular, near fractures, the triplite has been separatelty replaced by the phosphosiderite (Fe3+PO4·2H2O) and Mn-oxide minerals during weathering stage.
Keywords Pegmatite, phosphate mineral, triplite, leucophosphite, jahnsite, phosphosiderite
김규보1 ·최선규1* ·서지은1,2 ·김창성1 ·김지원3 ·구민호3
1고려대학교 지구환경과학과, 2경북대학교 지질학과, 3한국광물자원공사
Econ. Environ. Geol. 2017; 50(3): 181-193
Published online June 30, 2017 https://doi.org/10.9719/EEG.2017.50.3.181
Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.
Gyoo Bo Kim1, Seon Gyu Choi1*, Jieun Seo1,2, Chang Seong Kim1, Jiwon Kim3 and Minho Koo3
1Department of Earth and Environmental Sciences, Korea University, Seoul 02841, Korea
2Department of Geology, Kyungpook National University, Daegu 41566, Korea
3Korea Resources Corporation, Wonju 26464, Korea
Correspondence to:seongyu@korea.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.
Mn-Fe phosphate mineral complexes included within the pegmatite are observed at Jurassic Cheolwon two-mica granite in Gyeonggi Massif, South Korea. The genetic evolution between the Cheolwon two-mica granite and pegmatite, and various trend of Mn-Fe phosphate minerals is made by later magmatic, hydrothermal, and weathering process based on mineralogical, geochemical analysis. The Cheolwon two-mica granite is identified as S-type granite, considering its chemical composition (metaluminous ~ peraluminous), post-collisional environment, low magnetic susceptibility, and existence of biotite and muscovite. The K-Ar age (ca. 153 Ma) of pegmatite is well coincident with age of the Cheolwon two-mica granite (151±4 Ma). It indicates that these two rocks are originated from the same magma. Pegmatite indicates the LCT geochemical signature, and was classified as muscovite-rare element class / Li subclass / beryl type / beryl-columbite-phosphate subtype pegmatite. The triplite {(Fe2+0.4,Mn1.6)(PO4)(F0.9)} is dominant phosphates in later magmatic stage which partly altered to leucophosphite {KFe3+2(PO4)2OH·2H2O} and jahnsite {(Fe3+0.7,Mn2.3)(PO4)2OH·4H2O} by hydrothermal alteration. In particular, near fractures, the triplite has been separatelty replaced by the phosphosiderite (Fe3+PO4·2H2O) and Mn-oxide minerals during weathering stage.
Keywords Pegmatite, phosphate mineral, triplite, leucophosphite, jahnsite, phosphosiderite
김규보1 ·최선규1* ·서지은1,2 ·김창성1 ·김지원3 ·구민호3
1고려대학교 지구환경과학과, 2경북대학교 지질학과, 3한국광물자원공사
Seok-Jun Yang, Sung-Won Park and Sang-Mo Koh
Econ. Environ. Geol. 2012; 45(6): 709-719