This earthcache will take you to 95 Buchanan Street. You need to examine the panels under the windows and answer the questions.
The purpose of this earthcache is to learn about serpentine and how it is formed.
The panels below the windows of this building are made of dark green serpentine. This is a green metamorphic rock formed by the alteration of ultrabasic (very low in silica and rich in minerals such as peridotite and dunite) igneous rocks. Serpentine is usually greyish, white or green: the green colour is a result of iron replacing magnesium. The name is derived from the fact that the rock resembles snake skin.
Metamorphic rocks are those which have been altered from their original state, either by heat, pressure, or very often, both. The altered state often results in new crystals, textures and foliation forming within the rock. Metamorphic rocks were originally igneous or sedimentary, before being subjected to high temperatures and pressures: when limestone is metamorphosed, it results in marble, a rock often used for cladding buildings. Many of the original limestones contain impurities and these give rise to new minerals when metamorphosed. The resulting marbles show many colour variations.
Q1. What are the most obvious properties of the serpentine you can see?
- colour
- how it feels
- general appearance.
Q2. Using the information above, where does the colour come from?
Q3. Please provide a photo of yourself or a personal item near GZ (without giving away the answers).
Answers to questions 1-3 should be sent by the message centre or email. Please DO NOT include the answers in your log.
Please send your answers BEFORE logging the cache. You do not need to wait for a reply, but if there is a problem, we will let you know.
ANY LOGS ENTERED WITHOUT ANSWERS BEING SENT WITHIN TWO WEEKS WILL BE DELETED.
