Skip to main content
SpringerLink
Log in

Submicroscopic alteration of hornblende in the amphibolitic schists, northwestern Okchon metamorphic belt

  • Published:
Geosciences Journal Aims and scope Submit manuscript

Abstract

Alteration phenomena in hornblende crystals of the northwestern Okchon metamorphic belt were investigated in detail using high-resolution transmission electron microscopy (HRTEM). HRTEM images of hornblende commonly show submicroscopic intergrowths of a variety of sheet silicates; chlorite is the most abundant sheet silicate within hornblende, and biotite is also frequently observed along with chlorite. Although the angle between (001) of chlorite and (100) of hornblende is variable, the (001) planes of both chlorite and biotite parallel the c axis of hornblende. Microstructural evidences indicate that both sheet silicates intergrown with hornblende are produced by retrogression of hornblende. Biotite apparently formed by early hydration reaction in the presence of fluids enriched with K+, and chlorite at a later stage of retrograde reaction when K+ was consumed. In addition, hornblende crystals contain numerous etch pits and poorly crystalline silicates as filling materials, which are the product of weathering. Such submicroscopic intergrowths of sheet silicates may result in somewhat high Al contents in the hornblende analysis, producing imprecise result in geothermobarometric calculations. Furthermore, submicroscopic alteration of hornblende deteriorates the Ar retentivity and consequently affects the K−Ar isotopic ages or the40Ar/39Ar age spectra of hornblende. It is thus evident that the HRTEM characterization of hornblende is prerequisite for the correct interpretation of P-T estimates and age data.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Ahn, J.H. and Cho, M., 1996, High-resolution electron microscopy of structural defects in hornblendes of Ogcheon amphibolites. Journal of the Geological Society Korea, 32, 334–344.

    Google Scholar 

  • Ahn, J.H. and Peacor, D.R., 1986, Transmission and analytical electron microscopy of the smectite-to-illite transition. Clays and Clay Minerals, 34, 165–179.

    Article  Google Scholar 

  • Ahn, J.H., Cho, M., Jenkins, D.M. and Buseck, P.R., 1991, Structural defects in synthetic tremolitic amphiboles. American Mineralogist, 76, 1811–1823.

    Google Scholar 

  • Akai, J., 1982, Polysomatization process of biopyriboles in metasomatism at the Atakani ore deposit, Japan. Contributions to Mineralogy and Petrology, 80, 117–131.

    Article  Google Scholar 

  • Banfield, J.B. and Barker, W.W., 1994, Direct observation of reactant-product interfaces formed in natural weathering of exsolved, defective amphibole to smectite: evidence for episodic, isovolumetric reactions involving structural inheritance. Geochimca et Cosmochimica Acta, 58, 1419–1429.

    Article  Google Scholar 

  • Banfield, J.F., Karabinos, P. and Veblen, D.R., 1989, Transmission electron microscopy of chloritoid: intergrowth with sheet silicates and reactions in metapelites. American Mineralogist, 74, 549–564.

    Google Scholar 

  • Berner, R.A., Sjöberg, E.L., Velbel, M.A. and Krom, M.D., 1980, Dissolution of pyroxene and amphiboles during weathering. Science, 207, 1205–1206.

    Article  Google Scholar 

  • Berner, R.A. and Schott, J., 1982, Mechanism of pyroxene and amphibole weathering II: observations of soil grains. American Journal of Science, 282, 1214–1231.

    Google Scholar 

  • Cressey, B.A., Whittaker, E.J.W. and Hutchison, J.L., 1982, Morphology and alteration of asbestiform grunerite and anthophyllite. Mineralogical Magazine, 46, 77–87.

    Article  Google Scholar 

  • Droop, G.T.R., 1994, Triple-chain pyriboles in Lewisian ultramafic rocks. Mineralogical Magazine, 58, 1–20.

    Article  Google Scholar 

  • Graham, C.M. and Powell, R., 1984, A garnet-hornblende geothermometer and application to the Pelona schist, southern California. Journal of Metamorphic Geology, 2, 13–32.

    Article  Google Scholar 

  • Hammarstrom, J.M. and Zen, E., 1986, Aluminum in hornblende: an empirical igneous geobarometer. American Mineralogist, 71, 1297–1313.

    Google Scholar 

  • Hanson, G.N., Simmons, K.R. and Bence, A.E., 1975,40Ar/39Ar spectrum ages for biotite, hornblende and muscovite in a contact metamorphic zone. Geochimica et Cosmochimica Acta, 39, 1269–1277.

    Article  Google Scholar 

  • Harrison, T.M., 1981, Diffusion of40Ar in hornblende. Contributions to Mineralogy and Petrology, 78, 324–331.

    Article  Google Scholar 

  • Harrison, T.M. and Gerald, J.D.F., 1986, Exsolution in hornblende and its consequences for40Ar/39Ar age spectra and closure temperature. Geochimica et Cosmochimica Acta, 50, 247–253.

    Article  Google Scholar 

  • Harrison, T.M. and McDougall, I., 1980, Investigations of an intrusive contact, northwest Nelson, New Zealand: II. diffusion of radiogenic and excess40Ar in hornblende revealed by40Ar/39Ar age spectrum analysis. Geochimica et Cosmochimica Acta, 44, 2005–2020.

    Article  Google Scholar 

  • Holland, T.J.B. and Blundy, J., 1994, Non-ideal interaction in calcic amphiboles and their bearing on amphibole-plagioclase thermometry. Contributions to Mineralogy and Petrology, 116, 433–447.

    Article  Google Scholar 

  • Hollister, L.S., Grissom, G.C., Peters, E.K., Stowell, H.H. and Sisson, V.B., 1987, Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calcalkaline plutons. American Mineralogist, 72, 231–239.

    Google Scholar 

  • Lee, J.H., Peacor, D.R., Lewis, D.D. and Wintsch, R.P., 1984, Chlorite-illite/muscovite interlayered and interstratified crystals: a TEM/STEM study. Contributions to Mineralogy and Petrology, 88, 372–385.

    Article  Google Scholar 

  • Min, K. and Cho, M., 1998, Metamorphic evolution of the northwestern Ogcheon metamorphic belt, South Korea. Lithos, 43, 31–51.

    Article  Google Scholar 

  • Min, K., Cho, M., Kwon, S.T., Kim, I.J., Nagao, K. and Nakamura, E., 1995, K−Ar ages of metamorphic rocks in the Chungju area: late Proterozoic (675 Ma) metamorphism of the Ogcheon belt. Journal of the Geological Society of Korea, 31, 315–327. (in Korean with English abstract)

    Google Scholar 

  • Onstott, T.C. and Peacock, M.W., 1987, Argon retentivity of hornblendes: a field experiment in a slowly cooled metamorphic terrane. Geochimica et Cosmochimica Acta, 51, 2891–2903.

    Article  Google Scholar 

  • Peacor, D.R., 1992, Diagenesis and low-grade metamorphism of shales and slates. Reviews in Mineralogy, 27, 335–380.

    Google Scholar 

  • Sharp, T.G. and Buseck, P.R., 1988, Prograde versus retrograde chlorite-amphibole intergrowths in a calc-silicate rock. American Mineralogist, 73, 1292–1301.

    Google Scholar 

  • Smith, D.J., Barry, J.C., Bursill, L.A., Petford, A.K. and Wheatley, J.C., 1986, Atomic resolution imaging of crystalline defects and surfaces. JEOL News, 24E, 2–6.

    Google Scholar 

  • Veblen, D.R. and Buseck, P.R., 1979, Chain-width order and disorder in biopyriboles. American Mineralogist, 64, 687–700.

    Google Scholar 

  • Veblen, D.R. and Buseck, P.R., 1980, Microstructures and reaction mechanisms in biopyriboles. American Mineralogist, 65, 599–623.

    Google Scholar 

  • Veblen, D.R. and Buseck, P.R., 1981, Hydrous pyriboles and sheet silicates in pyroxenes and uralites: intergrowth microstructures and reaction mechanisms. American Mineralogist, 66, 1107–1134.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Earth and Environmental Sciences, Chungbuk National University, 361-763, Cheongju, Korea

    Jung Ho Ahn

  2. Department of Geological Sciences, Seoul National University, 151-742, Seoul, Korea

    Moonsup Cho

Authors
  1. Jung Ho Ahn
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Moonsup Cho
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jung Ho Ahn.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ahn, J.H., Cho, M. Submicroscopic alteration of hornblende in the amphibolitic schists, northwestern Okchon metamorphic belt. Geosci J 2, 165–174 (1998). https://doi.org/10.1007/BF02910162

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02910162

Key words

Search

Navigation