The Ice Age Hereford geocache trail is a series of 9 traditional caches and 4 EarthCaches that explores the ice age landscape of Hereford.
The EarthCache is on a footpath at Kenchester, there is some space for parking outside the chapel further up the road.
The EarthCache is also point 11A on the Ice Age Landscape Tour, from which the Geology notes are taken.
This EarthCache is point 3 of the Ice Age Hereford Geocache trail.
Visiting
This EarthCache is situated along a public footpath on private farmland. This farm is the site of a number of Ice Age ponds but most cannot be viewed from the footpath. All tasks can be completed from the footpath. Please note that the level of the pond can vary and at certain times it may lie across the footpath.
The Tasks
Before beginning the tasks let us orientate ourselves in the landscape, look directly south across the pond, the ice of the Wye valley glacier would have been advancing from your right.
Please respond to these tasks via the message centre, or email me.
- Look around you at the pond’s location in the landscape, describe where the pond sits in relation to the hummocks (mounds) around it?
- What does the shape of the landscape suggest about the water catchment of the pond?
- If possible (if the water level is low enough) continue along the footpath until you are stood in line with the middle of the pond. Now look to your west across the pond and consider the detail of the pond's profile, describe the pond’s profile
- Does this profile indicate a natural or man-made origin for the pond?
If the water level is too high and the main track in underwater, walk around the perimeter of the pond as far as is safe, making an assessment of its profile.
Background
The pond is one of the largest of a cluster that lie in depressions in the terrain around Kenchester. One of the key features of Ice Age ponds is that they often form in clusters.
Ice Age Ponds formed in distinct hollows and the next section describes how they formed. They are not generally connected to a river or stream, unless they have been modified, and so the water that fills them is from rain or runoff from the fields. However the water of level of this pond rises and falls in ways that do not correspond with the amount of rainfall the area has experienced. This is because there is a small spring to the west of the path (on the northern shore of the pond) which alters the ponds water level.
The Geology
You are now in hummocky moraine territory and there are many Ice Age ponds. The Kenchester ponds are regarded as classic kettle holes formed by infill of deep hollows created by ablation (melting and burying) of ice. This pond is one of the largest on this site, but its size varies greatly. There is little emergent vegetation, but it remains attractive to waders and wildfowl. Many Ice Age ponds have a base composed partly or mostly of peat. Each pond lies in a closed depression between hummocks of glacial sediment.
Kettle hole ponds normally originate in hummocky moraine terrain by the melting of ice. If a pond shows the following characteristics, we identify it as a kettle hole:
- Forms a closed depression in the landscape (elongate forms are likely to be channels not kettle holes)
- Surrounded by glacial sediments
- Where evidence is available from geophysics or coring, the pond is underlain by sediments different from the surroundings.
Cartoons to show the formation of a kettle hole pond and its filling by peat or other deposits are included below. There comes a point when the glacier stagnates and the ice stops moving forward. Then this “dead” ice gradually melts away and locations where there is little sediment end up as depressions, this process can take thousands of years to be completed. Although peat is shown as their infill, there is often just as much washed-in sediment too. The oldest infill in Herefordshire kettle holes found by carbon- dating formed around 13,500 to 15,000 years ago.
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