The BGS Lexicon of Named Rock Units — Result Details

Haystacks Andesite Member

Computer Code: HAYS Preferred Map Code: Hys
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Andesite lavas with flow banding and columnar jointing, interdigitated with massive and bedded breccias in upper part of unit. Also some bedded volcaniclastic sedimentary rocks.
Definition of Lower Boundary: At the base of the andesite lava sequence resting on volcaniclastic rocks within the Birker Fell Andesite Formation.
Definition of Upper Boundary: Defined by the base of overlying bedded breccias, sandstones and tuffs of the Round How Member.
Thickness: About 500m
Geographical Limits: North Lake District, near Buttermere.
Parent Unit: Birker Fell Andesite Formation (BFA)
Previous Name(s): Haystacks Andesite (-951)
Haystacks Member (-4698)
Alternative Name(s): none recorded or not applicable
Reference Section  Crags on Hay Stacks. 
Reference Section  Crags on Seat. 
McConnell, B J and Kneller, B C, 1993. The Lower Borrowdale Volcanic Group of Ennerdale and upper Borrowdale. British Geological Survey Technical Report WA/93/38. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: