Eastern England from the Tees to the Wash areas - Yorkshire and Linconshire Wolds: Difference between revisions

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[[Image:P595813.jpg|thumb|400px|Typical landscape of the Yorkshire Wolds with rolling hills and deep valleys underlain by the Chalk. P595813.]]
[[Image:P595813.jpg|thumb|400px|Typical landscape of the Yorkshire Wolds with rolling hills and deep valleys underlain by the Chalk. P595813.]]
This area includes the upland areas of Lincolnshire and Humberside, plus parts of North Yorkshire (Plate P595813); the area extends east to the coast. Important settlements include Grimsby, Kingston upon Hull and Bridlington.
This area includes the upland areas of Lincolnshire and Humberside, plus parts of North Yorkshire '''(Plate P595813)'''; the area extends east to the coast. Important settlements include Grimsby, Kingston upon Hull and Bridlington.


===Sedimentary Bedrock===
===Sedimentary bedrock===
Boreholes spread throughout this area enable the overall shape and thickness of the sedimentary bedrock layers to be generally well-understood to a depth of at least 1000 m. These layers are thinnest in the south of this area, at around 1250 m, and increase rapidly to over 6000 m in the north. The uppermost sedimentary layers are of Cretaceous age and are mostly comprised of chalk. Chalk is a special type of fine-grained white and grey rock composed of minute grains and fossils made up of calcium carbonate, so is a special type of limestone. The Chalk in this area is relatively hard with abundant flint nodules (a fine-grained crystalline type of silica) in the upper parts. The Chalk layers are generally tilted to the northeast and their thickness increases towards the coast to about 500 m. The Chalk is a major aquifer in which water generally flows along the fractures within and between the layers. Water taken from the Chalk is typically rich in calcium carbonate.
Boreholes spread throughout this area enable the overall shape and thickness of the sedimentary bedrock layers to be generally well understood to a depth of at least 1000 m. These layers are thinnest in the south of this area, at around 1250 m, and increase rapidly to over 6000 m in the north. The uppermost sedimentary layers are of Cretaceous age and are mostly composed of chalk. Chalk is a special type of fine-grained white and grey rock composed of minute grains and fossils made up of calcium carbonate, so is a special type of limestone. The Chalk in this area is relatively hard with abundant flint nodules (a fine-grained crystalline type of silica) in the upper parts. The Chalk layers are generally tilted to the north-east and their thickness increases towards the coast to about 500 m. The Chalk is a major aquifer in which water generally flows along the fractures within and between the layers. Water taken from the Chalk is typically rich in calcium carbonate.


In the north and south of the area, the Chalk sits on a slightly younger sequence of relatively thin (Lower Cretaceous) mudstone and sandstone layers that die out across the centre of the area.
In the north and south of the area, the Chalk sits on a slightly younger sequence of relatively thin (Lower Cretaceous) mudstone and sandstone layers that die out across the centre of the area.


The 200 to 145 million year old (Jurassic) bedrock layers and thickness changes described in adjacent areas continue beneath this area. This sequence of layers reaches a minimum thickness of about 40 m in the Market Weighton area and thickens considerably to over 600 m in the north and south of the area. Beneath these layers is the package of (Permian and Triassic) rocks that includes the Mercia Mudstone, Sherwood Sandstone, Magnesian limestone and mineral salts, they thin towards the south. These layers include important deposits of natural gas in the southeast of the area and reach depths of 1000 m across most of the area where they sit on the older sedimentary bedrock layers including the Coal Measures described from the adjacent areas.
The 200 to 145 million year old (Jurassic) bedrock layers and thickness changes described in adjacent areas continue beneath this area. This sequence of layers reaches a minimum thickness of about 40 m in the Market Weighton area and thickens considerably to over 600 m in the north and south of the area. Beneath these layers is the package of (Permian and Triassic) rocks that includes the Mercia Mudstone, Sherwood Sandstone, Magnesian limestone and mineral salts, they thin towards the south. These layers include important deposits of natural gas in the south-east of the area and reach depths of 1000 m across most of the area where they sit on the older sedimentary bedrock layers including the Coal Measures described from the adjacent areas.


Basement rocks underlie the bedrock layers at around 1250 m depth in the south of the area. These rocks have not been reached by any boreholes in this area, but are likely to be similar to those described for the area to the south.
Basement rocks underlie the bedrock layers at around 1250 m depth in the south of the area. These rocks have not been reached by any boreholes in this area, but are likely to be similar to those described for the area to the south.


[[Category:9. Eastern England from the Tees to The Wash areas | 05]]
[[Category:9. Eastern England from the Tees to The Wash areas | 05]]

Revision as of 14:49, 16 October 2014

Typical landscape of the Yorkshire Wolds with rolling hills and deep valleys underlain by the Chalk. P595813.

This area includes the upland areas of Lincolnshire and Humberside, plus parts of North Yorkshire (Plate P595813); the area extends east to the coast. Important settlements include Grimsby, Kingston upon Hull and Bridlington.

Sedimentary bedrock

Boreholes spread throughout this area enable the overall shape and thickness of the sedimentary bedrock layers to be generally well understood to a depth of at least 1000 m. These layers are thinnest in the south of this area, at around 1250 m, and increase rapidly to over 6000 m in the north. The uppermost sedimentary layers are of Cretaceous age and are mostly composed of chalk. Chalk is a special type of fine-grained white and grey rock composed of minute grains and fossils made up of calcium carbonate, so is a special type of limestone. The Chalk in this area is relatively hard with abundant flint nodules (a fine-grained crystalline type of silica) in the upper parts. The Chalk layers are generally tilted to the north-east and their thickness increases towards the coast to about 500 m. The Chalk is a major aquifer in which water generally flows along the fractures within and between the layers. Water taken from the Chalk is typically rich in calcium carbonate.

In the north and south of the area, the Chalk sits on a slightly younger sequence of relatively thin (Lower Cretaceous) mudstone and sandstone layers that die out across the centre of the area.

The 200 to 145 million year old (Jurassic) bedrock layers and thickness changes described in adjacent areas continue beneath this area. This sequence of layers reaches a minimum thickness of about 40 m in the Market Weighton area and thickens considerably to over 600 m in the north and south of the area. Beneath these layers is the package of (Permian and Triassic) rocks that includes the Mercia Mudstone, Sherwood Sandstone, Magnesian limestone and mineral salts, they thin towards the south. These layers include important deposits of natural gas in the south-east of the area and reach depths of 1000 m across most of the area where they sit on the older sedimentary bedrock layers including the Coal Measures described from the adjacent areas.

Basement rocks underlie the bedrock layers at around 1250 m depth in the south of the area. These rocks have not been reached by any boreholes in this area, but are likely to be similar to those described for the area to the south.