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A fine-grained light gray volcanic rock consisting primarily of quartz, plagioclase feldspar, and potassium feldspar, and also containing biotite, hornblende, or pyroxene.

[After Dacia.]


an igneous, volcanic rock characteristically light in colour with relatively high silica content
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.dacite - a grey volcanic rock containing plagioclase and quartz and other crystalline minerals
oligoclase, plagioclase - any of a series of triclinic feldspars that form rocks
volcanic rock - extrusive igneous rock solidified near or on the surface of the Earth
References in periodicals archive ?
The rocks are very similar and comparable in geochemistry to Bezow adakitic dacites (Modjarrad, 2015a).
The collected rock samples lie in Volcanic Formation" which consists of dolerites, andesite, dacites, dacitic tuff, rhyolites and rhyolitic tuff.
On the basis of whole rock geochemistry the rocks of Deosai volcanics are classied as dacites to rhyodacite and the meta-volcanics of Burji-La Formation have basalt to basaltic-andesite composition.
Also in this south sector (Cordon del Portillo) there is a plutonic association of gabbros and tonalites to granodiorites, and a volcanic sequence of andesites and dacites to rhyodacites and rhyolites (Polanski, 1972).
Of the three Quaternary volcanoes in Panama, El Valle is the easternmost volcano and is composed mostly of andesites and dacites, which spans a smaller compositional range than the rocks at La Yeguada, where there are some basalts as well as rhyolites.
The foot-wall rocks are slightly calc-alkaline-transitional dacites, whereas the hanging-wall rocks are calc-alkaline rhyodacites.
2] concession, Khandiza is a classic volcanic-hosted massive sulphide deposit within a sequence of Visean submarine sediments, rhyolitic volcanics and pyroclastics, capped by barren, post mineralisation dacites.
The mineralization is considered to be of volcanic-sedimentary origin intimately associated with felsic volcanic rocks, primarily sodic to potassic rhyolites and spilitized dacites (Schermerhorn, 1970).
The area contains recent postmineral andesites and dacites underlain by Tertiary acid-volcanics with 22 myodacite porphyry intrusives and 21 myolatite dikes identified thus far.
Verma (1999) reported that andesites and dacites from the Sierra de Chichinautzin volcanic field (central MVB) were derived from partial melting of a heterogeneous mafic granulite from the lower crust.
Petrological studies of lava flows show several varieties of andesites and dacites, which include hypersthene, hornblende, lamprobolite andesites and hornblende biotite dacite.
Along the thrust fault several dacite domes are exposed, dated 20 to 23 million years old, similar to dacites in other parts of the district.