INTRODUCTION

As this is an EarthCache, a type of Virtual Cache, there is no physical container here. 

This EarthCache adheres to the principles and ethics of geocaching and leaves No Trace.

Welcome to another amazing place, not visited before Geocaching brought me here.

ACTIVITY

Go inside the cairn,

and on the left hand side, you will see this .... (this picture is in greyscale)

1. Please describe the two main colours in #1 'slice' What do you think has caused one colour to be stronger than the other?

2. Please describe the colour #2 'slice' why do you think that it is this colour?

3. Please describe the colour of #3 'slice' why do you think that it is this colour?

4.  Please describe the colour #4 'slice' why do you think that it is this colour?

5. Please describe the colour #5 'slice' why do you think that it is this colour?

6.  As this is an EarthCache, you need to send me the answers to the questions or your log will be quietly deleted. Under the 2010 guidelines, a photograph can be requested. 

Please log the EC and include your photograph of you at the opening of the cairn.

Please send me a message and you get one confirming your answers as soon as I am able.

As long as you have done your best, and proved that you were there, it should be fine.

THE CLAVA CAIRNS - A SACRED SITE

The Clava Cairns comprise part of one, if not two, Bronze Age cemeteries. This landscape was an important place for ritual and burial activities in the Bronze Age. Later burials at the site suggest continued significance for over a millennia.

The three well-preserved cairns at Balnuaran each have a central chamber. But while the two outer cairns have entrance passages, the chamber of the central one is enclosed. Each cairn is surrounded by a ring of standing stones. Many of the stones used to construct the cairns have cup marks on them – these may have been reused from another place, perhaps an earlier sacred site.

The cairns’ burial chambers were cleared out long ago, but we can tell from similar monuments that only one or two people would have been buried in each cairn. It would have taken a large number of people to build the Clava Cairns, indicating that these were perhaps resting places for important individuals.

Reference: https://www.historicenvironment.scot/visit-a-place/places/clava-cairns/history/

Parking is free. Why not do the Lab Set there too :)

A WEE GEOLOGICAL LESSON

How sandstone is made

As the name suggests, sandstone is stone formed from sand due to high pressure and heat as the sand subsides into the earth’s crust. It is composed of varying amounts of feldspar, quartz, and even silt and clay. As the earth’s crust moves, the sandstone may be pushed back up to the surface, where wind and water begins wearing it back down into sand before it’s pushed once more back into the crust to become sandstone again (this cycle takes around 200 million years

How does it get its colouring and bands?

The answer is iron oxidisation and slow sand depositing. Sandstone is made primarily from quartz surrounded by iron oxides. The more iron oxides are present, the more colour in the sand – as it quite literally rusts. White sandstone has little or no iron oxides present.

For the bands to form, vast amounts of sand are deposited in fine layers over millennia. These layers receive their colouring and width depending on the minerals they are comprised of. As the layers are pushed into the earth’s crust, these bands can become folded, creating even more intricate patterns. Sandstone then, is a physical record of the wearing down of stone millions of years ago.

Colours of Sandstone

Sandstone gets its colour from the minerals and materials present in its composition. The colour of sandstone can vary widely depending on the types and amounts of minerals present in the rock. Some common minerals that can give sandstone its colour include:

1. Iron oxide: Iron oxide minerals, such as hematite (red) and limonite (yellow), can impart red, pink, yellow, or brown hues to sandstone.
2. Clay minerals: Clay minerals like illite, kaolinite, and smectite can contribute to a variety of colours, including white, gray, and green.
3. Organic matter: Decomposed plant material or other organic matter can sometimes give sandstone a dark colour, such as black or dark brown.
4. Other minerals: Trace amounts of other minerals, such as feldspar, mica, and quartz, can also influence the colour of sandstone.

The combination of these minerals and materials in different proportions can result in a wide range of colours and patterns seen in sandstone formations. The colour of sandstone can also be affected by factors such as weathering, the presence of impurities, and the environment in which the rock formed.

EarthCache placed with the kind permission of Historic Scotland