The BGS Lexicon of Named Rock Units — Result Details

Sarn Complex

Computer Code: SRN Preferred Map Code: Srn
Status Code: Pending Upgrade
Age range: Ediacaran Period (AD) — Ediacaran Period (AD)
Lithological Description: Locally foliated granites, granodiorites, diorites and hornblende gabbros with garnetiferous gneiss in places.
Definition of Lower Boundary: None.
Definition of Upper Boundary: None.
Thickness: Unknown.
Geographical Limits: Lleyn Peninsula, Sheet 113 (Aberdaron and Bardsey Island), although the complex probably extends offshore. The boundaries of the intrusive complex are largely sheared along the Lleyn Shear Zone.
Parent Unit: Not Available (!)
Previous Name(s): SARN GRANITE
Alternative Name(s): RHOS HIRWAIN SYNENITE
Stratotypes:
Reference Section  Mynydd Cefnamlwch. 
Reference Section  Flanks of Pen y Gopa. 
Reference Section  Hilltop east of Meillionydd Farm. 
Reference Section  Afon Fawr, 600 m downstream from Pont Llangwnnadl. 
Reference Section  Craig Fael.. 
Reference Section  Foreshore 150 m south of Penrhyn Nefyn. 
Reference(s):
Gibbons W, Tietzch-Tyler D, Horak J M and Murphy F C. 1994. Precambrian rocks in Anglesey, southwest Llyn and southeast Ireland. 75-84 in A revised correlation of Precambrian rocks in the British Isles. Gibbons W and Harris A L [editors]. Geological Society of London Special Report No 22. 
Matley C A. 1928. The Pre-Cambrian complex and assocciated rocks of south-western Lleyn (Carnarvonshire). Quarterly Journal of the Geological Society of London, Vol. 84, 440-501. 
Matley C A and Smith B. 1936. The age of the Sarn Granite. Quarterly Journal of the Geological Society of London, Vol. 92, 188-200. 
Shackelton R M. 1956. Notes on the structure and relations of the Precambrian and Ordovician rocks of south-western Lleyn (Carnarfonshire). Geological Journal, Vol. 1, 400-409. 
Gibbons, W and McCarroll, D. 1993. Geology of the country around Aberdaron, including Bardsey Island. Memoir for 1:50 000 Geological Sheet 133. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E133 E134