Dacite

Rock type: 
Age: 
66 millions years

Gray dacites. Forms an extensive cover. Phenocrysts: oligoclase, orthoclase, sanidin, quartz, biotite. Phenocrystal sizes: 0.1 - 2 mm, rarely 3-4 mm. Upper Cretaceous - Low Paleocen. Thickness: 500-600 metres.