Submicron polyphase inclusions in garnet from the Tananao Metamorphic Complex, Taiwan: a key to unravelling otherwise unrecognized metamorphic events |
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| Authors: | S L Hwang T F Yui H T Chu P Shen |
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| Institution: | Department of Materials Science and Engineering, National Dong Hwa University, Hualien, Taiwan;Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan;Central Geological Survey, PO Box 968, Taipei, Taiwan;Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan |
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| Abstract: | Kyanite and staurolite occur in the Tananao Metamorphic Complex as submicron inclusions in almandine‐rich garnet from a metamorphosed palaeosol weathering horizon, near Hoping, eastern Taiwan. Quartz, rutile/brookite and zircon are also found as associated submicron inclusions in garnet. Employing the reaction ilmenite+kyanite+quartz=almandine+rutile, and the breakdown of staurolite and quartz as thermobarometers, these submicron‐scale minerals formed at >8.3–8.8 kbar and < 660–690 °C. This P–T estimate is different from that (i.e. 5–7 kbar and 530–550 °C) derived from matrix minerals, which include almandine‐rich garnet, muscovite, chlorite, chloritoid, plagioclase, quartz and ilmenite. These results suggest that submicron inclusions in garnet‐like materials may record portions of the otherwise undocumented prograde path or provide information about previous metamorphic events and thus yield new insights into orogenic belts. |
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| Keywords: | analytical electron microscopy (AEM) kyanite staurolite Tananao metamorphic complex Taiwan |
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