Since 2014 a group of volunteers organised by the Earth Heritage Trust (EHT) has performed valuable work in maintaining geological sites, mostly in the Malvern area, in useful condition for demonstration to visiting geological parties. Funding and other support for the work is provided by the Malvern Hills AONB and the Malvern Hills Trust. EHT is very grateful to them both. Most of the work is completed in the winter to avoid disturbing nesting birds and the 2019-2020 session has just ended. Generally, six or seven sites are tackled each winter on the Malvern projects and some work for others has been done elsewhere in recent years.
To date forty sites have been dealt with of which ten have been visited more than once — in some places vegetation quickly regrows to begin to negate earlier clearance. Most of the sites are easily accessible, often from adjacent public footpaths. The number of active volunteers is currently about twenty-three and these are drawn from the several local geological organisations.
Volunteers at Dingle Quarry
The full report on the 2018-19 work is to be found on the EHT web site. In the most recent 2019-20 round fifteen sites were covered but some only briefly. Amongst the main locations were Martley Rock, ‘refreshed’ with the help of workers from DEFRA on an ‘away-day’, and a limestone pavement, eroded to the usual clints and grykes, on Little Doward in the Forest of Dean.
However, the most interesting sites were in the south Malverns, near Bronsil (east of Eastnor) and near Whiteleaved Oak. A roadside bank at Bronsil cuts one of the many local small igneous intrusions from Ordovician times. Especially good here are the examples of ‘onion-skin weathering’ on rounded rocks of the igneous material.
Onion skin (layered) weathering at Bronsil
At Whiteleaved Oak a small roadside quarry was cleared, resulting in what is currently the best publicly accessible exposure of the Cambrian Hollybush Sandstone.
One hundred and fifty metres to the north is the large Whiteleaved Oak Quarry. Here the principal interest lay in a low ridge of unquarried rock within the lower level of the quarry. Strangely, this ridge has never been investigated by earlier geologists. After the clearance of much moss it was found to be quite complex, with thin layers of at least four rock types. Possibly this structure is at the boundary between the Precambrian and Cambrian rocks, which lies somewhere within the quarry but, if so, the boundary here is very different in nature from that in the upper level of the quarry a few tens of metres away. There, the boundary is a simple unconformity. Investigation is needed.
Clearing the ridge of rock at Whiteleaved Oak Quarry
A further hundred and thirty metres north, another small quarry at the bottom of a spur of Raggedstone Hill shows a variety of metamorphic rocks: schist, mylonite and a metadolerite intrusion. Most of these are very rich in silica. This leads to the possibility that these rocks stem from the country rock into which the plutonic igneous rocks of most of the Malvern Hills were intruded. If this is true, these rocks represent the oldest ones in the Malverns and perhaps the oldest exposed rocks in England.
New volunteers for this work are always welcome. Please contact John Payne via the EHT office.
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