A Brief Guide to the Last Glaciation of Britain
A Brief Guide to the Last Glaciation of Britain
This is a brief account of the last glaciation period which was responsible for the creation of much of our landscape.
Some of it is, no doubt, completely wrong and there are things I would , and will, change.
The general drift of the sequence of events that i have generated here has been gathered in close scrutiny of BGS North Sea Memoirs, and some other sources.
The ice age then, started 120,000 years ago and before it began the temperature of the planet was very high, and remained so for 20,000 years. Sea levels were high, so the chart below is a guess for the outline of the coast of Britain at the start of the ice age.
At 120,000 years ago snow began to fall, and continued to fall until around 70,000 years ago. It was thickest on high ground, and at high altitudes. The places that it accumulated most deeply were Britain, Norway, and the Alps of southern Europe.
After 70,000 years ago there was a slight rise in temperatures, enough to bring warm waters from the equator and to cause a significant melting of the ice sheet edges. There was also a great melt from alpine southern Europe which sent a huge river of sludge north to the North Sea where it collided with debris crashing from the mountains of northern England and Scotland. These debris Formations remain as the Coal Pit Formation from the north, and the Dogger Bank from the south.
The Capeshore Formation was created in the complete destruction of the Shetland ice cap.
This warm period lasted from 70,000 years ago to 40,000 years ago, and was warmest at 43 000 years ago. This was a time when thick ice sheets remained on the high mountains of Britain, the Norwegian Channel flowed with meltwater, and the Dogger Bank, Coal Pit, and Capeshore Formations were dry land as sea level had not yet risen to overtop them.
As meltwater and drainage continued to run off England and Scotland hills they carved into the Capeshore, Coal Pit, and Dogger Bank Formations creating Lagoons along the east coast of Scotland and England.
These are the Swatchway, Marr Bank, Wee Bankie, and Bolders Bank Formations.
Drainage from the Marr Bank Lagoon was released by overtopping around the south coast of the Dogger Bank.
At this time humans and animals, like mammoth, were present in the foothills of the mountains of England. The humans were tool makers working in the Upper Paleolithic techniques of flint working.
From 40,000 years ago the snow returned adding more ice sheets over the whole landscape, from the Atlantic coast to the Norwegian Channel, and down to the English Channel. Only southwestern England and southern Ireland was free of significantly thick ice sheets.
The Marr Bank Lagoon seems not to have been frozen or covered over by the ice sheet.
The ice sheets did not move at this time, nor did they move significantly at any time.
At 15,000 years ago the ice sheets had been removed from all lowland areas, leaving gullies in the North Sea, including the Outer Silver Pit at the southern end of Dogger Bank, the Devil's Hole, further north, and the Witch Ground close to Orkney. These, and the valleys on the mainland, were formed by the fast collapse of the ice sheets.
In the dying years of the glaciation the ice sheets on the mountains of Britain collapsed, forming huge piles of ice blocks, and broken stones, in a soup of muddy slurry. Over time these piles were drawn away from the broken edge of the ice sheet, and they slid down any available slope until they reached seawater or lake water. On the way to their destination the rocks in the slurry scraped the surfaces they ran over causing linear scratch lines as they passed. When the mass of slurry reached water the ice melted, leaving a moraine of sand silt and rocks, a linear feature, spread along the water's edge.
By 11,000 years ago most ice sheets were gone from northern Europe, and Mesolithic people were roaming much of Britain and the North Sea/ Doggerland.
At 8,200 years ago a tsunami, the Storegga Submarine Landslide, sent a tidal wave onto Shetland with such force that a 30 metre run up was forced onto the island. Such a powerful wave is likely to have been instrumental to the erosion of much of the land here in the North Sea, but the land did not prevent runup from the same wave of 3 to 6 metres running up on Scottish coasts.
It is not clear that there was land above the water surface at this time, only that there had been more seabed material present in the North Sea during the immediate post-glacial period than there is now. The Orkney vole is likely to have been able to cross from Belgium to Orkney by way of Doggerland at any time in the Mesolithic period, but perhaps not after the advent of the Storegga Submarine Landslide.
In the 4th millennium BC, the time of the first nomadic migrants , those who came to leave a mark on the land, sea levels rose and began breaking through the corridors of land that linked the islands of the British archipelago together. The Minches was broken through (?) between Outer Hebrides and Scotland. The North Channel of the Irish Sea broke through separating Ireland from Scotland. The English Channel was cleared isolating England from Europe, and the northern North Sea swallowed up the North of Doggerland completely separating Shetland and Orkney from each other and from Scotland.
The date for this separation , specifically between Orkney and Scotland, but possibly elsewhere also is suggested to be 3000BC based on the evidence of tidal wave activity affecting the Norwegian Coast of the Norwegian Channel at that date.
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Index
The rich history of archaeology on Orkney provides source material for the following observations.
"Neolithic Migrants to Orkney" The story of the First, Founding Immigrants to Orkney
"A Bizarre Idea" What's the Story, then?
"Walkable land in the North Sea" describes evidence that walkable land was present between Norfolk and Holland at a time when prehistoric people were occupying northern Europe.
"Archaeology in the North Sea" looks at the elusive evidence that people could have walked from Caithness to South Ronaldsay.
"3000BC" gives detailed evidence of tsunami events on the Norwegian Coast.
"A Brief Guide to the Last Glaciation" How did the North Sea develop?
"Mainland Settlements" discusses and dates the early settlements across mainland Orkney.
"Barnhouse" describes this "Neolithic Village" a substantial group of Neolithic structures on the shore of Harray Loch.
"Barnhouse Sweat Lodge" describes Structure 8, the Sweat Lodge at Barnhouse.
"Modern Sweat Lodge Practices" describes present day Sweat Lodge ceremonies.
"The Stones of Stenness" describes anomalies in the settings of the stones that formed the stone circle.
"The Ring of Brodgar" discusses just how many stones are there, or are not there, at the Ring of Brodgar.
"A Custom Among the Lower Class of People" , about 18th century Orkney people and the Stones at Brodgar.
"Maeshowe, a Wonder of the Neolithic World" is the personal account of the excavation of the Maeshowe Cairn by the man who excavated it. I include it because it is so personal, not because it adds anything to our understanding.
"Cairns of Orkney" is the commentary of several antiquarian archaeologists writing in previous centuries as they excavated Cairns in England, Scotland, and Orkney. Although these cairns may not have been excavated to a high standard, the commentary provided in these reports is, in my view, very personal, and highly approachable.
"Cairns and the People in them" examines the bones of the people who were laid in cairns, and tells their stories.
"The Westrays" describes the Knap of Howar settlement, and the desolation of the islands that were found by the people of the Links of Noltland when they settled there at the end of the 3rd millennium BC.
"Skara Brae, RCAHMS" is the official description of the Neolithic "Village"
"Skara Brae, Excavation", is an account of the excavation of Hut 7 in 1927. This is an interesting personal account of the Gordon Childe's Excavation by J Wilson Paterson.
"Dating Skara Brae" gives detailed dating evidence for Skara Brae
"The Ness of Brodgar Excavation" and account of the excavation , before 2020, by Nick Card.
"Dating the Ness of Brodgar" gives Dating evidence for the Ness of Brodgar
"The Ferriby Boats" The first seafaring vessels?
"The Orkney Vole" discusses the evidence that the Orkney Vole migrated from Europe to Orkney without setting foot on mainland Britain.
Bere Barley, a Neolithic grain derivations of Bere Barley.
"Concluding" , some simple remarks in conclusion.
"Finally" closing remarks.
All views and opinions expressed are my own, but it remains a work-in-progress for which positive criticism and comment is welcomed.
Jeffery Nicholls
South Ronaldsay
Orkney
Jiffynorm@yahoo.co.uk
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