The BGS Lexicon of Named Rock Units — Result Details

Twt Hill Granite Pluton

Computer Code: TWTH Preferred Map Code: notEntered
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Homogeneous pale grey micro-syenogranite.
Definition of Lower Boundary: none recorded or not applicable
Definition of Upper Boundary: none recorded or not applicable
Thickness: none recorded or not applicable
Geographical Limits: Crags and quarries around Twt Hill, Caernarfon, North West Wales [248301 363138]. The outcrop as mapped extends to the NE as a fault bounded unit.
Parent Unit: Not Entered (?)
Previous Name(s): Arvonian Formation (-4435)
Twt Hill Granite Pluton (TWTH)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Schofield, D.I., Evans, J.A., Millar, I.L., Wilby, P.R. and Aspden, J.A. 2008. New U-Pb and Rb-Sr constraints on pre-Arcadian tectonism in North Wales. Journal of the Geological Society. 165, 5 891-894. 
Greenly E. 1944. The Arvonian rocks of Arvon. Quarterly Journal of the Geological Society, London, 100, 269-287. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E106 E118