The Normans built a new castle on the site, which forms the core of the present one. William II unsuccessfully besieged it in 1095 during a revolt supported by its owner, Robert de Mowbray, Earl of Northumbria. After Robert was captured, his wife continued the defence until coerced to surrender by the king's threat to blind her husband.
Bamburgh then became the property of the reigning English monarch. Henry II probably built the keep. As an important English outpost, the castle was the target of occasional raids from Scotland. In 1464 during the Wars of the Roses, it became the first castle in England to be defeated by artillery, at the end of a nine-month siege by Richard Neville, 16th Earl of Warwick.
The Forster family of Northumberland provided the Crown with twelve successive governors of the castle for some 400 years until the Crown granted ownership to Sir John Forster. The family retained ownership until Sir William Forster (d. 1700) was posthumously declared bankrupt, and his estates, including the castle, were sold to Lord Crewe, Bishop of Durham under an Act of Parliament to settle the debts.
The castle deteriorated but was restored by various owners during the 18th and 19th centuries. It was finally bought by the Victorian industrialist William Armstrong, who completed the restoration.
But enough of the history lesson and on to the real reason we are here ...
Bamburgh Castle is built on top of the Great Whin Sill, a tabular layer of dolerite rock which lies partly in the North Pennines Area of Outstanding Natural Beauty and partly in Northumberland National Park and stretches from Teesdale northwards towards Berwick.
The Great Whin Sill is one of the key natural features of the area - Bamburgh Castle, Dunstanburgh Castle, Lindisfarne Castle and stretches of Hadrian's Wall all strategically take advantage of high, rocky cliff lines formed by the sill. The Whin Sill complex is usually divided into three components: Holy Island Sill, Alnwick Sill and the Hadrian's Wall-Pennines Sill, which were created by separate magma flows but about the same time.
Dolerite is formed when molten magma is pushed up into the crust and it cools and solidifies. In this case, the magma was pushed between layers of carboniferous limestones, sandstones and shales to form a thin sheet of rock called a sill. As the intrusive magma cooled, it contracted, forming the characteristic joints in the rock. The intrusion is complex, cutting across layers of sediments to form sheets at multiple levels. It appears to have been fed by more than one chamber. Whin Sill is therefore not a single sill but a collection of cross-cutting sills and flat, lens-shaped intrusions. Since the intrusion, the carboniferous rocks and the dolerite have been gently tilted.
Please make your way to Waypoint 1
Question 1a - Describe the rock you see in front of you in terms of colour, texture and appearance.
Question 1b - Estimate the height of the outcrop at this point.
Question 1c - Tell me the name of this rock, the rock type to which it belongs and how it was formed.
Please make your way to Waypoint 2
Question 2a - Describe the rock you see in front of you in terms of colour, texture and appearance.
Question 2b - Estimate the height of the layers at this point.
Question 2c - Tell me the name of this rock, the rock type to which it belongs and how it was formed.
Please make your way to Waypoint 3
Question 3a - Tell me the type of stone used for the repair and renovation of the castle in the late 1800's and where it was quarried.
Question 3b - You have learned about two types of rock in the locality - tell me which rock is better for foundation stone and which is better for walling stone and explain your answer.
Question 3c - Optional - post a photo of you or your GPS with the Castle in the background.
Please email your answers to the questions to me through my geocaching.com profile. You do not need to wait for confirmation to log the Earthcache, but any logs which are not followed up with the correct answers within 24 hours will be deleted, to deter armchair cachers.
I hope you have enjoyed this tour of Bamburgh Castle and have learned something about the geology of the area.
THANK YOU FOR VISITING