Pennines and adjoining areas - Geology - Revision history

Dbk at 15:57, 18 April 2016

2016-04-18T15:57:55Z

← Older revision		Revision as of 16:57, 18 April 2016
Line 18:		Line 18:
	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:Pennines and adjoining areas - summary \| 01]]

Dbk at 14:49, 7 October 2014

2014-10-07T14:49:30Z

← Older revision		Revision as of 15:49, 7 October 2014
Line 3:		Line 3:

	==Geology at depth==		==Geology at depth==
	[[Image:~~P902242~~.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in Figure ~~P902241~~. ~~P902242~~.]]		[[Image:P902266.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in Figure P902265. P902266.]]
	[[Image:~~P902243~~.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in Figure ~~P902241~~. ~~P902243~~.]]		[[Image:P902267.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in Figure P902265. P902267.]]
	Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:		Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:

Line 10:		Line 10:
	* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.		* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.

	The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. '''Figures ~~P902242~~''' and '''~~P902243~~''' are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.		The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. '''Figures P902266''' and '''P902267''' are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.

	The Pennine Hills run north—south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline ('''Figure ~~P902242~~'''). Because of erosion the oldest layers are preserved north—south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north—south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline ('''Figure P902266'''). Because of erosion the oldest layers are preserved north—south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (see '''Figure ~~P902241~~'''), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface (see '''Figure P902265'''), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]

Jeth1 at 14:33, 6 October 2014

2014-10-06T14:33:34Z

← Older revision		Revision as of 15:33, 6 October 2014
Line 14:		Line 14:
	The Pennine Hills run north—south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline ('''Figure P902242'''). Because of erosion the oldest layers are preserved north—south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north—south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline ('''Figure P902242'''). Because of erosion the oldest layers are preserved north—south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface (see '''Figure P902241'''), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]

Jeth1 at 14:31, 6 October 2014

2014-10-06T14:31:30Z

← Older revision		Revision as of 15:31, 6 October 2014
Line 3:		Line 3:

	==Geology at depth==		==Geology at depth==
	[[Image:P902242.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in P902241. P902242.]]		[[Image:P902242.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in Figure P902241. P902242.]]
	[[Image:P902243.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in P902241. P902243.]]		[[Image:P902243.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in Figure P902241. P902243.]]
	Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:		Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:

Line 10:		Line 10:
	* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.		* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.

	The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. P902242 and P902243 are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.		The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. '''Figures P902242''' and '''P902243''' are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.

	The Pennine Hills run ~~north - south~~ and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (P902242). Because of erosion the oldest layers are preserved ~~north – south~~ along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north—south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline ('''Figure P902242'''). Because of erosion the oldest layers are preserved north—south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

Dbk at 16:27, 2 October 2014

2014-10-02T16:27:57Z

← Older revision		Revision as of 17:27, 2 October 2014
Line 3:		Line 3:

	==Geology at depth==		==Geology at depth==
	[[Image:P902242.jpg\|thumb\|~~300px~~\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in P902241. P902242.]]		[[Image:P902242.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in P902241. P902242.]]
	[[Image:P902243.jpg\|thumb\|~~300px~~\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in P902241. P902243.]]		[[Image:P902243.jpg\|thumb\|400px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in P902241. P902243.]]
	Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:		Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:

Dbk at 16:27, 2 October 2014

2014-10-02T16:27:41Z

← Older revision		Revision as of 17:27, 2 October 2014
Line 3:		Line 3:

	==Geology at depth==		==Geology at depth==
			[[Image:P902242.jpg\|thumb\|300px\|Schematic cross-section of the geology of The Pennines and adjacent areas from The Fylde to North Yorkshire. The alignment of the section and key are shown in P902241. P902242.]]
			[[Image:P902243.jpg\|thumb\|300px\|Schematic cross-section of the geology of The Pennines and adjacent areas from the Wirral to Nottinghamshire. The alignment of the section and key are shown in P902241. P902243.]]
	Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:		Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:

Line 8:		Line 10:
	* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.		* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.

	The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. ~~Figures 2~~ and 3 are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.		The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. P902242 and P902243 are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.

	The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (~~Figure 2~~). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (P902242). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

Dbk at 16:25, 2 October 2014

2014-10-02T16:25:04Z

← Older revision		Revision as of 17:25, 2 October 2014
Line 12:		Line 12:
	The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (~~[[file:P902241.jpg \|~~ see P902241]]), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface (see P902241), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]

Dbk at 16:24, 2 October 2014

2014-10-02T16:24:38Z

← Older revision		Revision as of 17:24, 2 October 2014
Line 12:		Line 12:
	The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface ([[~~see P902241 \|~~file:P902241.jpg]]), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface ([[file:P902241.jpg \| see P902241]]), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]

Dbk at 16:24, 2 October 2014

2014-10-02T16:24:10Z

← Older revision		Revision as of 17:24, 2 October 2014
Line 12:		Line 12:
	The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.		The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

	The basement rocks are very rarely encountered at the surface (~~Figure 1~~), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.		The basement rocks are very rarely encountered at the surface ([[see P902241 \|file:P902241.jpg]]), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

	A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.		A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]

Dbk at 10:34, 2 October 2014

2014-10-02T10:34:17Z

← Older revision		Revision as of 11:34, 2 October 2014
Line 1:		Line 1:
			==Recent surface deposits==
			The region has widespread geological deposits of relatively recent origin, formed over the past 2 to 3 million years and spanning the Ice Ages and Interglacial periods. These are known as superficial deposits and include clays, sands, gravels and peat deposits laid down by former ice-sheets, rivers and coastal processes. Although absent in some areas, these deposits are present at depths of up to 70 m beneath parts of Greater Manchester. They include stiff boulder clays, sand and gravel, and soft clay that are particularly common in lowland parts of North Yorkshire, north Cheshire and west Lancashire. Layers of peat also form lowland mires to the south and west of Manchester whilst a blanket of thin peat covers much of the moorland areas in the Pennines and Peak District. Most of the superficial deposits are soft and easily eroded, as they have not been deeply buried and consolidated to form strong rocks. The superficial deposits are not considered further in this account.

			==Geology at depth==
			Below the geologically recent surface deposits, or with just a cover of soil where such deposits are absent, are older rocks which geologists broadly split into two distinct types:

			* The sedimentary bedrock geology is composed of quite hard rocks which were deposited between about 360 to 200 million years ago as layers of sediments in shallow seas, deserts and swamps (in similar environments to the present-day Mississippi delta and Arabian Gulf) in times when Britain lay closer to the Equator and the climate and landscape were very different from those of today.
			* The basement geology, which underlies the bedrock, is over 420 million years old and mainly comprises harder, denser rocks which have been strongly compacted and folded. They include both rocks originally deposited as sediments and others that are products of volcanic activity or formed from the solidification of molten rock below ancient volcanoes.

			The Pennine region has been affected by several phases of earth movements that caused local uplift of the sedimentary rocks, resulting in removal by erosion (in some parts of Lancashire up to several thousand metres of rocks are thought to have been removed). These processes have allowed older rocks that were once deeply buried to be brought close to the surface. Figures 2 and 3 are vertical sections through the geology, referred to as geological cross-sections, which illustrate the variations in geology across the region.

			The Pennine Hills run north - south and are composed of sedimentary bedrock with the overall structure of a dome or arch that geologists refer to as an anticline (Figure 2). Because of erosion the oldest layers are preserved north – south along the centre of the hills with the overlying sedimentary layers becoming younger to the east and west down the flanks.

			The basement rocks are very rarely encountered at the surface (Figure 1), but are known to be present at depths of at least 1500 m beneath the remainder of the region. The basement geology has only been drilled by a few deep exploration boreholes for oil and gas. Much of the structure at this depth is interpreted from other techniques including seismic surveys and other geophysical surveys, carried out on land or by low flying aircraft, which reveal patterns of the Earth’s gravity and magnetic field.

			A major potential hydrocarbon resource has recently been identified within some of the shale rocks (the Craven Group) present under parts of the region. Although commercial production is probably some years away, exploration is now underway in parts of Lancashire. Any production of gas from the shale layers by the process known as fracking is likely to take place over 1500 m below the surface.

	[[Category:8. Pennines and adjoining areas \| 01]]		[[Category:8. Pennines and adjoining areas \| 01]]