Abstract

Lens shaped and stratiform titanomagnetite orebodies in the Boreumdo iron mine are closely associated with amphibolite which intruded into Precambrian metasediments. Mineralogical and petrochemical analyses of amphilbolite and titanomagnetite ores were carried out in order to interpret the origin of amphilbolite and the genesis of titanomagnetite ore deposits. Amphibolites belong to orthoamphilbolite interms of Niggli value and mineralogy, and are characterized by the occurrence of relict olivine. The amphilbolites responsible for titanomagnetite mineralization have extremely high content of $TiO_2$, ranging from 2.12 to 4.59 wt.% with the average value of 3.43 wt.%. Amphibole minerals in amphibolites are consist mainly of calcic amphiboles such as hornblende, ferroan pargasitic hornblende and tremolite. Most plagioclases belong to andesine ($An_{30-50}$\ulcorner). The metamorphic temperature and geobarometric pressure which are calculated by the calcic amphibole-plagioclase geothermometer and calcic amphilbole geobarometer are estimated to be 537$^{\circ}C$~579$^{\circ}C$(avg. 555$^{\circ}C$) and 2.9~6.6 kbar (avg. 4.5 kbars), respectively. It shows a typical amphibolite facies. Based on the mineral chemistry and petrochemisty of amphibolites and iron ores which are composed mainly of titanomagnetite and ilmenite in the Boreumdo iron mine, the titaniferous oxide melts could be immiscibly separatd from the titaniferous ultrabasic magma. The genesis of the Boreumdo titanomagnetite ore deposits are analogous to the Soyeonpyeongdo and Yonchon iron ore deposits in terms of their mineralogy, mineral chemistry and geologic setting.

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1. 대한광산학회지 v.2 no.2 불음도 함티탄자철광의 현미경에 의한 광물학적 조사 및 선광시험 최형섭;황기엽
2. 광상시추조사보고 no.10 대한광업진흥공사
3. 물리탐광 no.2 대한광업진흥공사
4. 연천, 가평, 포천지역 기본조사 보고서 대한광업진흥공사
5. 자원환경지질 v.27 no.4 소연평도 함티타늄 자철광상의 암석 지구화확적 연구 김규한;이정은
6. 자원환경지질 v.27 no.1 연천 고남산지역에 분포하는 반려암의 암석화학과 관입시기 김규한;이현주
7. 자원환경지질 v.27 no.2 연천 함티타늄 자철광상의 성인 김규한;이현주;전효택
8. 소연평도 함티타늄자철광상의 암석 지구화학적 연구 이정은
9. 남한에 분포하는 현생화강암류의 기원에 대한 광물 및 암석화학적 연구 조등룡
10. Contr. Min. Pet. v.104 Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer Blundy, J.D.;Holland, T.J.B.
11. The hematite-ilmenite+rutile oxybarometers: Experimental calibration v.68 Brothers, S.C.;D.H. Lindsley;Hadjigeorgiou, C.
12. Canadian J. Earth Sci. v.19 Volcanism of shoshonite to high-K andesite affinity in an Archean arc environment, Oxford Lake, Manitoba. Brooks, C.;J.Ludden;Y. Pigeon;Hubregtse, J.J.M.W.
13. Contr. Min. Pet. v.14 The iron-titanium oxides of salic volcanic rocks and their associated ferromagnesian silicates Carmichael, I.S.E.
14. Canadian J. Earth Sci. v.22 Geochemistry of Precambrian basaltic rocks from the Central African Republic (Equatorial Africa) Dostal, J.;C. Dupuy;Poidevin, J.L.
15. Econ. Geol. v.52 Geochemical and mineralogical investigations of titaniferous iron ores, west coast of Norway Gjelsvik, T.
16. Am. Min. v.71 Aluminum in hornblende: an empirical igneous geobarometer Hammarstrom, J.M.;Zen, E.
17. Am. Min. v.59 Amphibole pairs, epidote minerals, chlorite and plagioclase in metamorphic rocks, Northern Sierra Nevada, California Hietanen, A.
18. Am. Min. v.72 Confirmation of the empirical correlation of AI in hornblende with pressure of solidification of calcic0alkaline plutons Hollister, L.S.;G.C. Grissom;E.K. Peters;H.H. Stowell;Sisson, V.B.
19. Chem. Geol. v.67 Geochemistry and petrogenesis of early Proterozoic amphibolites Westcentral Colorado, U.S.A. Knoper, M.W.;Condie, K.C.
20. Econ. Geol. v.77 Mineralogy and geochemistry of Fe-Ti oxide and apatite deposits and evaluation of the liquid immiscibility hypothesis Kolker, A.
21. Am. J. Sci. v.281 Pressure, Temperature and time indicator in mafic schist Laird, J.;Albee, A.L.
22. Am. Min. v.63 Nomenclature of amphiboles Leak, B.E.
23. Michigan: Mineral. Soc. America Oxide minerals: Petrologic and magnetic significance Lindsley, D.H.
24. Am. J. Sci. v.274 Experimental studies of the phase relations between greenschist and amphibolite in a basaltic system Liou, J.G.;S. Kuniyoshi;Ito, K.
25. Geochim. Cosmochim. Acta. v.38 Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous and ordinary chondrites Nakamura, N.
26. Geol. Soc. Am. Abstracts Program v.8 Effects of magnesium on iron-titanium oxides Pinckney, L.R.;Lindsley, D.H.
27. Geol. Soc. Am. Abstr. Prog. v.6 Amphibolites and pyroxenes : characterization of other than quadrilateral components and estimates of ferric iron from microprobe data Papike, J.J.;K.L. Cameron;Baldwin, K.
28. The ore minerals and their intergrowths 2nd ed. v.2 Ramdohr, P.
29. Contr. Min. Pet. v.110 Amphibole composition in tonalite as a function of pressure : an experimental of the Alin-hornblende barometer Schmidt, M.W.
30. Am. J. Sci. v.281 An experimental study of hornblende stability and compositional variability in amphibolite Spear, F.S.