The BGS Lexicon of Named Rock Units — Result Details

Garn Bach Dacite

Computer Code: GBDA Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Porphyritic dacite with phenocrysts of andesine and glomeroporphyritic plagioclase clots, rare microdioritic xenoliths, minor amounts of zircon, apatite and altered mafics in a finely recrystallized felsitic groundmass.
Definition of Lower Boundary: Not seen.
Definition of Upper Boundary: Not seen.
Thickness: Unknown.
Geographical Limits: Not specified.
Parent Unit: Carn Fadryn Suite (CAFA)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Young, T P, Gibbons, W and McCarroll, D. 2002. Geology of the country around Pwllheli. Memoir of the British Geological Survey, Sheet 134 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used: