The Contact Relationship of Glaucophane Schist and Meta-pillow lava in Juisui of eastern Taiwan

Tsung-Siang Chiu

Abstract

The glaucophane is a typical mineral in high pressure metamorphism. The Yuli belt was compared to a lower temperature and higher pressure metamorphism. Most scholars believe that the Yuli belt was result from a subduction of Eurasia plate and Philippine plate. The study area Juisui is a typical area where outcrop the high pressure metamorphic rock. This area outcrops several similar rocks such as glaucophane schist, epidote-amphibole-quartz schist, and amphibole-quartz-garnet schist. But we find something strange that some glaucophane schist contact with meta-pillow lava directly.

This study was focus in the contract relationship of glaucophane schist and meta-pillow lave. According to the observation of petrology, the minerals in the contact zone were overgrowth. And we can’t find glaucophane in the pillow lava and some garnet belts seem folded under ductile deformation. But the glaucophane crystals were disordered. Several kinds of mineral were recognized, such as clino-zoisite, amphibole, garnet, pyrite, and glaucophane.

The following works are doing XRF (X-ray fluorescence) analyze to determine the bulk composition, and the using polarizing microscope to observe the detail structure, and then using the EPMA (electron probe micro analyzer) to determine the component of minerals. The final object is to build the P-T-t path model and to explain why this kind of rock appearance.

Reference

Chen, W.M., and Yang, C.N. (1997) Chemical characteristics of amphiboles in the mafic schist of the Juisui area: Proc. Geol. Soc. China., 40, pp.625-638.

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Liou, J.G., Ho, C.O., and Yen, T.P. (1974) Petrology of some glaucophane schist and related rocks from Taiwan: J.petrol., 2, pp.277-311.

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