2016

TG2404 : Tractor working at the quarry bottom

taken 8 years ago, near to Caistor st Edmund, Norfolk, England

Tractor working at the quarry bottom
Tractor working at the quarry bottom
The surface of the chalk layer is broken up with a disc harrow, preparing it for quarrying.
Caistor Chalk Pit

Chalk is a white or grey limestone formed from the microscopic shells of planktonic organisms. In Norfolk, the chalk is over 460 metres thick in places, and the county has the greatest range of chalk strata of anywhere in Britain. It principally presents as a low, rolling plateau in West Norfolk and along the north Norfolk coast as well as near Norwich, where the rivers Yare and Wensum have exposed overlying beds by cutting through them.

The Caistor chalk pit > Link near the South Norfolk village of Caistor St Edmund, about four kilometres south of Norwich, is the last remaining well-exposed inland section of part of the Beeston Chalk formation of the Upper Campanian 'Norwich Chalk' and it is also the last remaining inland section of any size in the Upper Campanian succession of the Transitional Province. It is rich in macrofossils and well-preserved microfaunas, and hence of great interest to paleontologists and geologists alike. For instance, belemnites > Link collected here were important in establishing the scheme of local belemnite zones an sub-zones. Fossil hunters know the quarry as a particularly good source for fish remains which can be found in the lower beds. Echinoids > Link and brachiopods as well as bivalves are also common, along with sponges from the flint spoil heaps. The pit is also well documented for its hollow flints > Link which have been used in developing a model for the formation of flint.

The pit has been in commercial use for more than 70 years and still is a working quarry > Link - Link - Link - Link and currently owned by Needham Chalks (HAM) Ltd. Formerly exploited mainly for its thick layer of chalk > Link - Link which in the old days was dug by hand and transported by horse and cart and is used primarily as an agricultural fertiliser > Link. The operations have since moved towards an area where the overlying sands and gravel beds are being quarried > Link at the expense of the chalk. Chalk is however still extracted here, using disc harrows > Link for the production of agricultural lime. Norwich Crag sands > Link cover the Cretaceous chalk, where fossil mammal bones can often be found, forming a protective layer.

The chalk layer also contains flints > Link of all sizes including very large round nodules referred to as paramoudras > Link and also known as potstones, because they can be used as natural planters. Paramoudras are believed to have formed by precipitation of silica around vertical tubes or burrows in the chalk sediment. One of the best places to see paramoudras in abundance is West Runton beach at low tide > Link - Link - Link. Flints were valued in prehistoric times for tool making and more recently for making gunflints and are to this day widely used in Norfolk as a building stone. Needham Chalks is the UK’s largest producer of whole and knapped flints for the building trade.


My grateful thanks go to Russel Yeomans for his kind invitation to join members of the Yorkshire Geological Society > LinkExternal link on a guided tour of the Caistor quarry, which is not open to the public. It can however be seen from an elevated position by taking the footpath > Link leading along its eastern edge.

For more detailed information read: LinkExternal link


Creative Commons Licence [Some Rights Reserved]   © Copyright Evelyn Simak and licensed for reuse under this Creative Commons Licence.
Geographical Context: Quarrying, Mining
This photo is linked from: Automatic Clusters: · Chalk Layer [12] ·
1:50,000 Modern Day Landranger(TM) Map © Crown Copyright
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TG2404, 207 images   (more nearby 🔍)
Photographer
Evelyn Simak   (more nearby)
Date Taken
Saturday, 7 May, 2016   (more nearby)
Submitted
Saturday, 7 May, 2016
Subject Location
OSGB36: geotagged! TG 2427 0482 [10m precision]
WGS84: 52:35.6922N 1:18.5911E
Camera Location
OSGB36: geotagged! TG 2420 0482
View Direction
EAST (about 90 degrees)
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Image classification(about): Geograph
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