Editing Geology and landscape of Holy Island and Bamburgh - an excursion

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Continue to the gth century settlement site at Green Shiel, turn south past deteriorating kilns of the Kennedy Limeworks (c. 1850) and join the western waggonway which leads back towards the village and the carpark.
 
Continue to the gth century settlement site at Green Shiel, turn south past deteriorating kilns of the Kennedy Limeworks (c. 1850) and join the western waggonway which leads back towards the village and the carpark.
  
==== Locality 10, The Snook [NU 100 437] ====
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==== Locality10, The Snook [NU 100 437] ====
  
 
Should time and tides permit, park off the road at the Lindisfarne Causeway and Jack Mathison's Bank junction [NU 107 434] and walk northwest towards Snook House. On the coast to the north the dolomitized and flexured Eelwell Limestone is exposed, containing the compound coral ''Actinocyathus florybrmis ''and brachiopods. This limestone was worked for lime burning in the 1790s and calcined in a one pot kiln on site (no longer visible) using local coals for fuel.
 
Should time and tides permit, park off the road at the Lindisfarne Causeway and Jack Mathison's Bank junction [NU 107 434] and walk northwest towards Snook House. On the coast to the north the dolomitized and flexured Eelwell Limestone is exposed, containing the compound coral ''Actinocyathus florybrmis ''and brachiopods. This limestone was worked for lime burning in the 1790s and calcined in a one pot kiln on site (no longer visible) using local coals for fuel.
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In the crag below the castle the Whin Sill is transgressive across the cross-bedded, red Carboniferous sandstone, rising from northeast to southwest.
 
In the crag below the castle the Whin Sill is transgressive across the cross-bedded, red Carboniferous sandstone, rising from northeast to southwest.
  
==== Locality 12, Harkess Rocks [NU 177 356] ====
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=== Locality 12, Harkess Rocks [NU 177 356] ===
  
 
Here the upper chilled margin of the Whin Sill is well exposed on the foreshore close to the base of the small cliff. Just below the chilled contact are numerous elongated amygdales (of a similar nature to those seen in the Holy Island Dyke), indicating that this upper contact was horizontal during sill emplacement. The amygdales can often be measured in metres, are often filled with quartz and calcite with a little chlorite, and frequently have ropy-flow structures, the latter indicating an east–west flow direction. A few inclusions of limestone and shale are visible close to the contact.
 
Here the upper chilled margin of the Whin Sill is well exposed on the foreshore close to the base of the small cliff. Just below the chilled contact are numerous elongated amygdales (of a similar nature to those seen in the Holy Island Dyke), indicating that this upper contact was horizontal during sill emplacement. The amygdales can often be measured in metres, are often filled with quartz and calcite with a little chlorite, and frequently have ropy-flow structures, the latter indicating an east–west flow direction. A few inclusions of limestone and shale are visible close to the contact.
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To the northwest the sill is covered by sand, but reappears at a higher level as a 1.50 m fault scarp, perpendicular to the coastline, in which inclusions of shale can be seen. Towards the sea, the sill transgresses up through shale along a north–south line; this exposure is terminated by a fracture zone with several splay faults trending east-northeast. A second complex fracture zone occurs some 20–30 m further northwest, with the dips of coarse sandstones changing from 35° east to 20° northwest across the fault zone.
 
To the northwest the sill is covered by sand, but reappears at a higher level as a 1.50 m fault scarp, perpendicular to the coastline, in which inclusions of shale can be seen. Towards the sea, the sill transgresses up through shale along a north–south line; this exposure is terminated by a fracture zone with several splay faults trending east-northeast. A second complex fracture zone occurs some 20–30 m further northwest, with the dips of coarse sandstones changing from 35° east to 20° northwest across the fault zone.
  
==== Locality 13, Stag Rock [NU 175 358] ====
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=== Locality 13, Stag Rock [NU 175 358] ===
  
 
This almost vertical exposure, trending almost due east, is ornamented by the painted figure of a stag. Adjacent to the lighthouse the Whin Sill has been injected into shale above the Budle Limestone, but halfway to Stag Rock the sill has transgressed into shales underlying the limestone, which is now on the dip slope above the sill. Further out towards the sea the Budle Limestone is again found below the sill. Northwest of the lighthouse the limestone, in an anticline, again rests on the sill.
 
This almost vertical exposure, trending almost due east, is ornamented by the painted figure of a stag. Adjacent to the lighthouse the Whin Sill has been injected into shale above the Budle Limestone, but halfway to Stag Rock the sill has transgressed into shales underlying the limestone, which is now on the dip slope above the sill. Further out towards the sea the Budle Limestone is again found below the sill. Northwest of the lighthouse the limestone, in an anticline, again rests on the sill.
  
==== Locality 14, [NU 172 360] ====
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=== Locality 14, [NU 172 360] ===
  
 
Here the sill contains a large basin-shaped limestone inclusion some 1.5 thick and 20 m in diameter, whilst 300 m further west [NU 171 360], the Whin Sill and the overlying limestone have been polished and etched by wind-blown sand.
 
Here the sill contains a large basin-shaped limestone inclusion some 1.5 thick and 20 m in diameter, whilst 300 m further west [NU 171 360], the Whin Sill and the overlying limestone have been polished and etched by wind-blown sand.
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== [[Northumbrian rocks and landscape: a field guide#Bibliography|Bibliography]] ==
 
== [[Northumbrian rocks and landscape: a field guide#Bibliography|Bibliography]] ==
  
{{EWwalks}}
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{{EGwalks}}
  
 
[[Category:7. Northern England]]
 
[[Category:7. Northern England]]

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