The Heart of Neolithic Orkney – Geological and human history entwined

A 5000-year-old village with furnished houses still intact; a monumental tomb pre-dating the great pyramid of Giza; a recently-discovered settlement with ceremonial architecture that is rewriting the story of Neolithic Britain; not to mention awe-inspiring and enigmatic stone circles

1. Standing stones of Stenness utilising the local thinly bedded flagstones. Image: John Gordon.

The structures that make up the Heart of Neolithic Orkney UNESCO World Heritage Site, spanning the central and western part of Mainland Orkney, include Skara Brae, Maeshowe, the Ness of Brodgar, the Ring of Brodgar and the Stones of Stenness.

Skara Brae, a close-knit community of eight houses that were occupied before Stone Henge was built, is found at the Bay of Skaill on the west coast. The other sites cluster around the Lochs of Harray and Stenness further east. The Ness of Brodgar, a natural land bridge between the two lochs provides a dramatic setting for what is proving to be a large-scale settlement, flanked by the Stones of Stenness to the south east and the Ring of Brodgar to the north west. Excavations at the Ness of Brodgar have revealed large, well-built structures with evidence of painted decoration, enclosed by a wall that is six metres thick. Modern visitors cannot fail to be astounded at what is still coming to light through the excavation. Consider the social organization and ingenuity that was required to quarry, transport and erect the huge standing stones at Brodgar and Stenness, or to lay precisely dressed rocks, many several square metres in size, at the chambered tomb of Maeshowe east of the Loch of Harray.

This remarkable group of archaeological treasures seems an unlikely collection of human achievements to find on a small group of windswept islands north of the Scottish mainland. So why are they here?

As with all prehistoric archaeology we can only theorise, but it is reasonable to assume that one contributing factor is geological. Orkney has sandstone of great building quality, with the attractive habit of splitting on a slant, thanks to cracks formed by joints that run through the rocks in parallel sets, which intersect to form rough parallelograms. The clue is there when you look at the wedge-shaped standing stones at Brodgar and Stenness. The same classic outline is repeated in the stall divisions of Neolithic chambered tombs such as Mine Howe on the Orkney island of Rousay. It’s as if the people were inspired to build these structures by the very nature of the bedrock.

The origins of the Orkney sandstone are found many degrees to the south, when, far from being an island group, ‘Orkney’ was landlocked within a huge desert supercontinent and lying close to the Equator. The collision of three continents formed a single landmass over 400 million years ago, and this thrust up a massive mountain chain – the Caledonian Mountains – that then eroded rapidly. Subsequent stretching of the continental crust created depressions, or basins, of which the Orcadian basin was one. Erosion products from the mountains collected in the basin, carried and deposited by meandering braided rivers and sometimes settling in temporary lakes. These sediments formed what we know today as the Old Red Sandstone. This rock occurs across much of north-eastern Scotland and makes up the entirety of Orkney. The temporary lakes contained the most basic of life forms – cyanobacteria and planktonic algae whose fossilized remains can be found as stromatolites at Yesnaby to the south of Skara Brae – and primitive fish, the fossilized remains of which are found at Sandwick close to the ancient settlement.

Orkney’s geological story continues today with coastal erosion a major issue as the land is being submerged due to rising sea levels. Efforts continue to glean information about Neolithic Orkney from sites like Swandro in Rousay that are rapidly being lost to the sea.

Text contributed by Robina Barton

Find out more
Orkney and Shetland: a landscape fashioned by geology – Alan McKirdy , 2011 Download from https://www.scottishgeology.com/find-out-more/publications/#orkney
The Ness of Brodgar Digging Deeper – The Ness of Brodgar Trust 2017
Ness of Brodgar excavations website http://www.nessofbrodgar.co.uk
Maeshowe and the Heat of Neolithic Orkney – Historic Environment Scotland 2017
UNESCO website http://whc.unesco.org/en/list/514

Skara Brae, built with local stone. Image: Angus Miller.

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