Origin of rhyolites by anatectic melting of granitic crustal rocks
- Cite this article as:
- Keller, J. Bull Volcanol (1969) 33: 942. doi:10.1007/BF02596758
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Rhyolitic pumice deposits on some East Aegean Islands are the remnants of a tuff sheet which covered formerly more than 2500 km2. The rhyolites originated by melting of granitic crustal rocks.
-mineralogical composition of the pumice being 60 wt % of glass and 40 % of relictic granitic minerals (quartz, plagioclase, potash feldspar, biotite) in «phenocrysts» up to 1 cm Ø.
-phenomena of strong corrosion, resorption and melting of all light colored «phenocrysts» in the rhyolitic pumice.
-mineralogical and chemical identity between pumice and granitic xenolites found in great quantity in the pumice tuff.
-structurally transitional types between pumice and the granites in different state of melting.
-eutectic composition of the pumice glass for a pressure of 2 kb.