Beckford Gravel Pit SSSI – the third in a series about top Earth Heritage sites in Herefordshire and Worcestershire.

Dick Bryant writes: this is a unique, easily accessible site which I have found has much to tell about the local environment during the last Ice Age affecting Britain.

Background

Beckford Gravel Pit is the sole well-kept survivor of the many large sand and gravel exposures that once existed in south-west Worcestershire, and because of its national geological and archaeological importance, it has been formally designated by Natural England as an SSSI (Site of Special Scientific Interest).  Other now defunct  sites lying in the immediate vicinity have also  contributed important evidence to the Beckford story. I suppose it’s a bit  like walking through the wardrobe in the ‘Lion, the Witch, and the Wardrobe’. Behind the ‘door’ of the Beckford Gravel Pit is a surprisingly rich field of scientific evidence about geology, archaeology, and environmental change in the local area.

The SSSI lies within the Beckford Nature Reserve on the northern edge of the picturesque village of Beckford, in the valley of the Currant Brook (fig.1) , which flows roughly from east to west and joins the River Avon at Tewkesbury, about 10 km away. The Nature Reserve has been created on the edge of one of the pits making up the complex of sand and gravel workings in the area. Although some extraction took place in the 1880s onwards, it wasn’t until the 1970s and 1980s that major commercial extraction was undertaken by Huntsman’s Quarries. When this activity ceased in 1989,  local volunteers demonstrated considerable foresight in raising  £60,000 to buy the old pit to protect the SSSI on behalf of Natural England and develop an interesting variety of lakeside biological habitats.

Fig. 1. An annotated Digimap image showing: the three pits described in the text;  sand and gravel deposits (Wasperton) member – buff colour;  former gravel workings – red diagonal stripes; head deposits – mauve colour; and  recent (Holocene) alluvium – yellow colour.

Much of what we know about the recent geological history of the Carrant valley was gleaned by investigations undertaken during the 20^th century period of intensive sand and gravel extraction. These revealed that the deposits related largely to the last Ice Age, which geologists call the ‘Devensian’, although the deposits also include reworked artefacts and other material derived from earlier times. The Devensian, which was the last of several cold stages characterising  the Quaternary period, lasted from 111,000 to 11,700 years ago. For much of this time, Britain had a fluctuating climate, colder on average than today. However, after about 25,000 years ago, the climate became extremely cold, sufficiently severe to generate a large ice sheet occupying much of the north and west of Britain, and reaching as far south as the Wolverhampton region.  The Carrant valley was not glaciated at this time.

Fig.2. Beckford Gravel Pit, summer 2020. This SSSI is maintained by volunteers from the Beckford Nature Reserve. Geo-maintenance presents an ongoing challenge, as the combined efforts of rabbits, Sand Martins, and mining bees, is causing the face to retreat fairly rapidly. Talus now masks the lower part of the face.

The Site

The site within the Nature Reserve is a vertical exposure of sand and gravel extending over a length of about 50 m, with a height of about 5 m. (Fig. 2). Nowadays, we are probably looking at only about half of the original face visible in the 1980s. The exposure is immediately on your right as you access the Reserve through the gate on the Ashton Road, locally also known as Rabbit Lane. As you stand facing the exposure,  on the left hand side the gravels are fairly chaotic and poorly bedded, but towards the right hand side it is fairly easy to make out multiple bands of alternating sands and gravels laid out in more or less continuous and gently sloping lines (Fig.3). The gravels layers here are about 20 cm thick, and contain lots of fragments of Cotswold limestone of a type (the Birdlip Formation) found in the higher parts of Bredon Hill, which lies to the north of the site. The gravels also contain occasional quartz and quartzite pebbles, and the odd flint. The larger stones (geologists call these ‘clasts’) are notably angular, indicating that they have not travelled very far. In contrast, much of the sand appears to be of a faraway origin, the nearest bedrock sandstones being found in north Worcestershire. If you have a hand lens, close examination might reveal that the individual sand grains are fairly rounded, indicating that they are probably wind-blown.

Fig. 3. Alternating layers of sand and fine gravel in the Beckford Gravel pit. These are typical of  quieter fluvial phases of deposition of the Wasperton sand and gravel member. Note the dark ‘nodules’ – no, these are not a result of random deposition but are in fact bee holes!

These sand and gravel layers are sometimes called ‘the Beckford sands and gravels’. The extent of these are displayed in figure 1. In geological parlance, they belong to the Wasperton sand and gravel member, which dates to the earlier part of the Devensian ice age, and they are generally correlated with the No. 2 terrace of the River Avon. The character of the sands and gravels suggest they were deposited under cold, dry conditions, with periodic torrents bringing the gravels down Bredon Hill in large fans and creating a wide swathe of deposits on both sides of the Carrant Valley (see figure 3). This swathe lies generally below about 48m O.D. In the nearby Avon valley, there is good evidence of sand wedges and fossil ice wedge polygons which resemble features of modern patterned ground in tundra areas. We can deduce that permafrost was a common characteristic of these cold conditions.  At Beckford, below the 48 m level, the sands and gravels merge downslope into the well-stratified (i.e. clearly differentiated layers) fluvial deposits of the Currant Brook, which was undoubtedly a much more powerful stream during the Devensian than it is now, although the interaction between material being washed down Bredon Hill, and that derived from the east by the Carrant stream, is probably complex.

Above the 48 m level, the sands and gravels become less well stratified and more chaotic, and are replaced upslope by much more variable slope deposits called ‘head’, resulting from mass movements, including solifluction (soil creep), which would have been a widespread process during the cold stages of the Quaternary period.  Towards the top of the exposure at the Beckford Gravels SSSI, you may be able to make out some larger clasts, indicating that the flowage of material may have been more vigorous in the final stages of deposition of the sands and gravels. This is likely to have occurred towards the end of the Devensian, when permafrost was melting and producing greater surface run-off under the influence of warmer summers.

In the photograph (fig.4) the now-buried part of the pit appears to be composed of  limestone gravel in which systematic bedding is hard to discern, although the vertical scars from the excavator bucket are clearly visible.

Fig. 4. The north face of Beckford Gravel Pit in the 1980s. Image kindly provided by Beckford Nature Reserve.

Adjacent sites

Beckford Priory Gravel Pits

A few hundred metres to the east of the Beckford Gravel Pit, behind the Beckford Silk craft workshop lies an area formerly known as Beckford Priory Gravel Pits (GR:98403615). These gravels are also part of the Wasperton member. The pits are now all filled with water and unfortunately there are now no visible exposures, the banks being comprehensively vegetated. in the period of active gravel extraction in the 1970s and 80s, they proved to be a rich source of archaeological material, including hand axes from the Lower Palaeolithic (over 300,000 years ago), Middle Palaeolithic scrapers, and  flint tools shaped by Neanderthals in the Upper Palaeolithic, as well as artefacts from the Mesolithic and the Neolithic. In addition, the sands and gravels proved to contain an impressive megafauna, representative of the different climates of the last half a million years or so, including woolly mammoth, woolly rhinoceros, bison, musk ox, giant ox, reindeer, and red deer. Many of these were discovered and catalogued by Paul Whitehead (see further information, below).

The Priory Gravel Pits also revealed strong evidence of ice wedges, and here there appears to have been two phases of formation. One was during the deposition of the gravels (so the wedges are termed ‘interformational’ ), and one after the deposition of the gravels. Within these deposits, an organic layer was discovered in the 1970s and radiocarbon dated to over 27,000 years ago, which is just before the coldest part of the Devensian ice age. This gives us an approximate date  after which the sands and gravels now seen in the upper part of the exposure in  Beckford Nature Reserve were deposited.

Court Farm Gravel Pit

Close by the SSSI and to the north-west, lies Beckford Court Farm (GR 97533655) which is part of the Overbury Estate. Two hundred metres or so north of the farm  are some more  gravel deposits, lying in an old pit at about 60 m O.D, that is, higher up the hill than the Beckford Gravel Pit.  In various limited exposures within this old pit, there are gravels which are very variable in size, poorly stratified, and  steeply dipping in a number of places (fig. 5).  The rough bedding appears to indicate a high energy flow broadly from the south-east to the northwest, and may represent an earlier course of a Carrant River which picked up frost-shattered material and dumped it within a short distance downstream. There are also some indications of vertical stone orientation within these gravels, likely to have been caused by frost heave during the Ice Age (fig. 5). However, there are currently no clearly defined relict frost wedges here, nor at the SSSI.

Fig.5. The east face of Court Farm Gravel Pit, Beckford. The trowel marks the location of figure 6 (below).

Overall the gravels at Court Farm Pit presents an interesting contrast to Beckford Gravel Pit, and as they lie above and outside the area mapped geologically as Wasperton gravels, they may be older in age than those at the SSSI. Note that the Court Farm pit lies on private ground within the Overbury Estate, and groups should contact the Estate Office at Overbury before making a visit.

Fig.6. Indications of frost heave in the Devensian, in the form of vertically orientated gravels, at Court Farm Gravel Pit.

Further Information:

For more geological details about the Beckford Gravel Pit click here

For information about the archaeology and the megafauna:

(1) Russell, O, and Daffern N., Beckford Priory Gravel Pit in: Putting the Palaeolithic into Worcestershire’s HER. Worcestershire County Council.

(2) Whitehead, P.F. 2014.The historical ecology of Beckford, Worcestershire, England. (Written for the Beckford Nature Reserve).

For essential information about the Nature Reserve: www.beckfordnature.org.uk.

To visit site – please see this link.