A PALACE BUILT OF SAND
Here you are standing in front of Dalkeith Palace, the former seat of the Dukes of Buccleuch. The building stones, varying in colour from tawny white to pinkish red, started off as sediments in giant rivers in this area over 300 million years ago. Then they were compacted over time into hard rock before being quarried over the last 600 years for the building of Dalkeith Palace, and some of the most famous streets and squares in Edinburgh.
The first recorded building on this site dates from the 15th century, and subsequent generations have added on and improved to create the palace you see today. But they have always used sandstone.
These sandstones started off in a river environment. How do we know, because sandstone can also be found in a marine or desert environment? The grains are the key, those which have been carried by wind in the desert or flowed in rivers or settled in the sea have different characteristics. In addition, different animals inhabited each environment so their remains , as fossils, are also important clues.
Walk round the palace, admire – wonder at - the diversity of the basic stones. Have a look at the pot diagram above. Imagine pouring sediment of different colours and amounts into this pot, to create bands of different colours and widths. The same process creates sandstone. But in a river or shallow water environment rather than in a pot, the sediments arrive at different speeds and directions, or there are other factors. These have an impact on what would otherwise be the well-ordered bedding planes of our pot.
Each stone, apart from the tell-tale clues of a river environment, has its own story to tell.
For instance
Contorted Bedding or soft stone deformation occurs when the newly bedded saturated sand is “de-watered” when buried by more sediment, and the original layers of twisted. Imagine standing on wet sand, the water expelled between your toes, and the sand reshaped by your weight. That’s contorted bedding. Gone go the neat layers of our pot!
Ripple laminations. Imagine some flat sand, then along comes a flow of water which agitates the surface. These ripple laminations, little disturbances and lines of discoloured sediment, are recorded in the sandstone.
Iron stone nodules. These are quite simply iron compounds which have got buried with the other sediments, coming together to form small nodules, which impart a brown colour to their surroundings.
Recycled Stone where the builders have used stone from another building rather than introduce newly quarried stone.
The sandstone of Dalkeith Palace varies in colour from pinkish red to almost white. Variations in the colour of sandstone is determined by the metal-based compounds present, An example of this is red oxide which imparts a “reddishness” to sandstone and vivid orange in higher concentrations.
The sandstones of the Palace were probably first quarried from the nearby valleys of the North and South Esk rivers and then, from further afield, top quality ‘Craigleith Sandstone’ from the Granton district of Edinburgh and quarries owned by the Duke of Buccleuch. .
Q1. Locate the stones above in picture 2 labelled A-D. And indicate
a. Which stones show good examples of the following:-
- Contorted Bedding
- Ripple Laminations
- Iron stone nodules
-Recycled stone
b. Which direction are the stones facing? i.e north, south etc ?
Q2. What are the tell-tale clues in the grains that tell us the stones are from a river environment rather than a desert? Ok, it helps if you have a microscope.
Q3. What fossils would you expect to find in a sandstone from a marine environment?
Q4. From a builder’s point of view what is unusual about the stone in Picture C? The clue is geological and lies in the bedding plane.
Q5. What links are there between Dalkeith and Granton that support the evidence that much of stone for Dalkeith Palace came from Granton?
Please now go ahead and log this cache, and a photo is always welcome.
We hope you have enjoyed this cache.
This earthcache has been provided by the Lothian and Borders GeoConservation in cooperation with the ranger service of Dalkeith Country Park
http://www.dalkeithcountrypark.co.uk/