SISSVoc Default


broader original
narrower dacite original original
narrower dacite original
definition Fine grained or porphyritic crystalline rock that contains less than 90 percent mafic minerals, between 20 and 60 percent quartz in the QAPF fraction, and has a plagioclase to total feldspar ratio greater than 0.65. Includes rocks defined modally in QAPF fields 4 and 5 or chemically in TAS Field O3. Typcially composed of quartz and sodic plagioclase with minor amounts of biotite and/or hornblende and/or pyroxene; fine-grained equivalent of granodiorite and tonalite. more like this
example rhyodacite more like this
source LeMaitre et al. 2002 more like this
Resource original
Concept original
in scheme simplelithology original
is primary topic of dacite