What lies beneath
The post last week about Old Hunstanton and its cliffs got me interested again in the landscape around Sedgeford itself.
So after a little bit of online research, let me walk you through the local geology and superficial geography of the Sedgeford area, thanks to the good people at the British Geological Survey. You can find their interactive Geology of Britain map here if you live in the UK and want to check out your own bit.
A disclaimer before we proceed: your author is no geologist! Feel free to leave comments on Facebook to set me straight if and where required.
Here is a BGS screen capture without any overlay. You'll see Sedgeford in the lower centre of the image; Heacham is to the left (west) and Docking to the right (east). Old Hunstanton, where we were visiting last week, is at the top of the image (north) and you'll see Cliff Parade marking out the location of the Hunstanton Cliffs that carry on towards Old Hunstanton.
And here we are again with the bedrock overlay and its key. You'll see that the two shades of green covering Sedgeford parish indicate that it's chalk bedrock all the way, baby.
This will not surprise any of us who have spent time huddled in the Chalk Pit, that den of (rather innocuous) iniquity to which SHARPies who don't want to go to bed at curfew-time banish themselves.
Chalk bedrock implies that this area was once under an ancient sea, with the shells of gazillions of tiny sea creatures settling to the sea floor and building up a thick layer of calcium carbonate. The area below Sedgeford seems to have been laid down over the Late Cretaceous period, between 100 and 66 million years ago.
Fast forward a few dozen million years, and we come to the superficial geology. This is what has been left behind after the action of the last glacial period ending about 12,000 years ago.
Imagine glaciers covering the land, walls of ice carving and scouring the landscape and leaving odd deposits in various places.
You'll see that the area around Sedgeford doesn't have any particular identified deposits. However when we zoom in a little more, some familiar features start to reveal themselves.
There's the line of the Heacham River making its way from Fring north-westwards to the Wash at Heacham. There are the spring heads, like fingers extending at right angles to the river, one of which goes right under SHARP's Trench 23 and soaks the woodlands next to our track to the river.
And here is where we can start to relate these images to the geography that is so well-known to SHARPies.
The furrow of the Heacham valley is the defining feature of Sedgeford, slicing across the parish from east to west and creating the conundrum that has been at the centre of the Project almost from the beginning: why did the village start here, on the south side of the valley? And why did it move over there to the north side, and when?