The BGS Lexicon of Named Rock Units — Result Details

Lubcloud Microgranite

Computer Code: LUMG Preferred Map Code: FG
Status Code: Index Level
Age range: Ordovician Period (O) — Ordovician Period (O)
Lithological Description: Brick-red, fine-grained microgranite with a saccharoidal, quartzo-feldspathic groundmass in which are set larger idiomorphic plagioclase crystals. Plagioclase and lath-shaped chlorite form c.2mm size phenocrysts; the latter are concentrated in the central part of the intrusion, where they comprise up to 15% of the rock.
Definition of Lower Boundary: Not applicable, but the microgranite occupies a northwest-trending subvertical sheet, up to 9m wide, the actual contacts being obscured by vegetation. It is emplaced into grey, cleaved, thinly bedded to laminated volcaniclastic strata of the Charnian Supergroup (Ives Head Formation).
Definition of Upper Boundary: Not applicable. (see Lower Boundary discussion.)
Thickness: c.9m
Geographical Limits: The intrusion follows a northwesterly trend and is exposed discontinously from about 350m westnorthwest of Ives Head trig point, to a narrow wooded ridge about 400m east of Lubcloud Farm, the latter being now much overgrown.
Parent Unit: Not Available (!)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Discontinuous natural exposures on the southwestern slopes of Ives Head hill, about 700m northnorthwest of Lubcloud Farm, Charnwood Forest. Carney, 1994. 
Reference(s):
Carney, J N, 1994. Geology of the Thringstone, Shepshed and Loughborough districts (SK41NW, SK41NE and SK51NW). British Geological Survey Technical Report WA/94/08. 
Carney, J N, Ambrose, K, Brandon, A, Royles, C P, Cornwell, J D and Lewis, M A. 2001. Geology of the country between Loughborough, Burton and Derby. Sheet Description of the British Geological Survey, 1:50 000 Series Sheet 141 Loughborough (England and Wales). 
Watts, W W, 1947. Geology of the ancient rocks of Charnwood Forest, Leicestershire. Leicester: Leicester Literary and Philosophical Society. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E141