South Charnwood Diorite - Bradgate House (SK 5346 1013)

The South Charnwood Diorites represent the final episode of Precambrian magmatism in Charnwood Forest.
The exposures near Bradgate House, home of Lady Jane Grey, are in medium- to coarse-grained, inequigranular
diorites, with a highly distinctive mottled pink-grey texture. The rock consists mainly of feldspars altered to sericite,
some showing relict twinning. The dark areas are aggregates of mafic minerals, mainly secondary amphiboles and chlorite.
Granophyric intergrowths of quartz and K-feldspar are also visible. The South Charnwood Diorites were named `markfieldite'
by Hatch (1909), but Wills and Shotton (1934) preferred `granophyric diorite' as the more accurate term.
(Excerpts from: BGS From: Occasional Report: OR/10/041 GUIDE TO THE GEOLOGY OF BRADGATE PARK AND SWITHLAND WOOD, CHARNWOOD FOREST. J N Carney)

Thin section under cross polars

Granophyric texture showing intergrowths of quartz and alkali feldspar Back to thin section thumbnails	Polished section of Bradgate Park Diorite