An Earth cache- Another very good reason to stop and explore Mitchell's Cottage between Alexandra (13Kms South) and Roxbugh.< It is about 1 km off the state highway and is well sign posted at the turn off in to Symes Road, with DOC signage. It is accessible during the day only ( most days) between 10.00am-4.00pm /p>
Mitchell's Cottage is made from the local material--schist rock! and so are its outbuildings etc. etc
What is schist rock?
Schist is a foliated metamorphic rock made up of plate-shaped mineral grains that are large enough to see with the naked eye. These mineral grains vary in colour from very pale to dark layers and are often alternated.
The deep burial and tectonic forces that formed hard greywacke rocks from sediments were applied to greater extremes with the basement rocks of Otago which are usually mudstone or shales . This resulted in the development of schist where the original minerals in the sediment have been forced to change (metamorphose) into denser new minerals under the pressure and much higher temperatures.
Platy minerals such as the micas biotite and muscovite have grown in response to the pressure forming foliated (flaky) schist layering. The distinctively flat-lying foliation through much of central Otago is the result of aligned minerals and mineral layers.
This schist rock is not of great commercial construction material due it the layering of this rock which tends to split along these layer- a process called 'schistosity". but it is used as a more decorative rock in walls, gardens and even decorative cladding of some houses. etc.
At this site you will see how the builder...-Andrew Mitchell, using stone masonary techniques that he learnt from his father in the Shetland Islands.- used this local stone in a variety of ways. Wander around and Check out how this rock has been utilised here. There are probably about 8 ways in a broad sense.
To log this as a find you need to-
1 Describe how this schist rock was formed- in your own words,
2 Describe its uses in our world today and why it is not used as a major construction material?
3 Look at it, feel it even lift some. what are the properties that you discover- name 3?
4 Identify 5 ways this rock is used at this site.
IF YOU ARE HOPING TO DO THE NEARBY MULTI GCP3VC THE MISSING NUMBER FROM INSIDE THE COTTAGE IS 01625