Report and Photos by Ray Pratt
Prior to the official start of the trip a number of us met up on Beacon Hill to get visual
bearings of our location. Well, that was the plan. Low cloud and rain impeded restricted this
to a short 5 minutes overview. The beacon Hill Formation, of which Beacon hill is composed
of, was the youngest of the Ediacaran aged rocks we were to look at on this weekend field
trip. These were composed of bedded tuffs, but due to the inclement weather pictures and
samples were not taken
folding of the rocks is near vertical. Ref Mel Leng, BGS. https://www.bgs.ac.uk/discovering-
geology/maps-and-resources/office-geology/beacon-hill-leicestershire/
Map Location 1: From here we headed west to Morley Quarry where we met up with our
field trip leader Nick Chidlaw, who had magically stopped the rain. The quarry was
composed of Tuffs of the Morely Lane Tuffs member of the Ives Head Formation., At C.
630mm years, these were the oldest rocks to be seen on this trip.
The detailed geological sketch map provided by the leader indicated that the general structure
of the Pre-Cambrian inlier was a southwards dipping antiform or even possible a dome. Here
the dips were northwards. A discussion was had re the apparent dips to be seen in outcrops
depending where the outcrop was on the structure. In this small exposure it was clear that the
apparent dip varied depending upon the strike of the surface being viewed.
Lane Tuffs and the Triassic continental sediments above.
pyroclastic nature of the tuffs with numerous large clasts of tuff to be
found within the finer grained tuff
Map Location 2: From here we headed south to Ludcloud Farm, Ives Head Hill exposure.
This consisted of finely bedded rocks of the Lubcloud greywackes member. The gross
thickness of this pale to medium grey, greenish grey, coarse grained sandstone is 550m. It
reportedly contains crystals and volcanic rock clasts, interbedded with subordinate mudrocks
and breccias, the latter containing much volcanic material. We were advised to look out for
upward fining and bedding within the sandstones, flat finely laminated mudrocks, small
slumps, load structures and local minor channels. The beds were reportedly laid down in a
proximal turbidite environment, a conclusion established by in depth studies of the area. This
was not obvious from this exposure.
strike to NW-SE / WSW-ESE. The coarse, near vertical cleavage dips at 71 degrees to the
north with an E-W strike
fossils. The visibility of these ichnofacies was very dependent upon lighting conditions.
The following day we met at Morley Quarry car park and car shared to our next location at
Whitwick where we took a circular walk to look at several rock types that compose the
Whitwick Volcanic Centre.
Map Location 5: On following the public footpath of Forest Rock Wood, we encountered
several very large blocks of Peldar Dacite Breccia. (Access to the quarry itself was not possible).
This unit is reportedly 520m thick composed of black, to dark grey dacite
containing rounded clasts, phenocrysts of plagioclase feldspar and quartz. The matrix is
medium grained, crystal rich and spherulitic.
Map Location 6: Following the footpath over Ratchet Hill a number of small Torrs were
seen, all but 1 were inaccessible. A sample from the accessible tor was of Grimley Andesite
phenocrysts. Locally intensely auto-brecciated
Auto brecciation simply implies that the magma was in part solidifying whilst still flowing.
The final stop 6b, within the Whitwick Volcanic Complex was an exposure of the fault
bounded Charnwood Lodge Volcanic Formation. The fault face was very clear with some
mineralisation seen. What was initially interpreted as fault breccia was seen to exist
throughout the rocks on both sides of the fault
As the walk progressed along the footpath of Forest Rock Wood the weather became warmer
and warmer until we were all down to shirt sleeves necessitating a refreshment stop at the
Three Horse Shoes in Whitwick with its amazing men’s toilet “70’s”retro artwork.
Duly refreshed we headed to Map location 3, One Barrow Plantation. The plan was to
examine exposures of Blackbrook reservoir Formation and adjacent natural crags in the South
Quarry Breccia member. We walked down the public footpath to the reservoir passing some
Blackbrook reservoir Formation exposures poking through the vegetation on the right side
without stopping to examine. At the bridge at the southern end of the reservoir, the rain
began, lightly at first. Hoping it was a passing shower we took refuge in the nearby trees but
the weather deteriorated rapidly turning to torrential rain, thunder and lightning, (which
persisted for the next 3 hours). We aborted this visit without examining the rocks, returning
to the cars along a flowing river that was a shortly before, a footpath. The plan is to return for
a day trip to finish off the study.
The Geology of the Charnwood Forest area is very complicated and identification of the
rocks and their history is not easy. Thanks to Nick for his detailed field guide and his expert
knowledge of this fascinating locality.