“Charnwood Forest is important geologically because it is one of the few parts of
England where there are exposures of Precambrian rocks which are usually buried beneath kilometres of younger strata. These rocks are amongst the most important in Charnwood Forest because they give clues to the types of volcanic eruptions that took place.” (From BGS Open Report: OR/10/044 GUIDE TO THE GEOLOGY OF MOUNT St. BERNARD, CHARNWOOD LODGE, WARREN HILLS AND BARDON HILL, CHARNWOOD FOREST: J N Carney)
The thin section taken from Warren Hills (at about
SK458152) is from the Charnwood Lodge Volcanic Formation
which consists of a suite of fragmental volcanic rocks dominated by massive or stratified coarse-grained tuff and lapilli tuff
with minor proportions of volcanic breccia. The section shows a volcanic breccia consisting of
feldspar fragments, minor amounts of pyroxene fragments (some chloritized) and epidote?
set within a tuffaceous matrix.
Plane polarised light 1mm
Cross polarised light 1mm