Mount Clarence
Along the southern coast of Western Australia is a band of rock that is the remnant of an ancient mountain range. The mountains formed during a collision between a west Australian continent and eastern Antarctica. Albany is situated in this ancient mountain range and the granites on which the town is built crystallised some 10 - 20km below the Earths surface.
The purpose of this Earthcache is to introduce only the basics about granite. The main lessons to be learned will be about the formation of granite. Granite is one of the hardest types of rock and is crystalline in nature. Granite is made up mostly of quartz and feldspar which are the lighter colors, the whites and the pinks, that you see when you look at a piece of granite. Granite is an Igneous rock as it is formed through the cooling and solidification of magma or lava. The large mineral crystals in granite are evidence that it cooled slowly from molten rock. That slow cooling occurred beneath the earth's surface and required a long period of time. For this reason Granite is generally classed as an Intrusive as opposed to Extrusive. An Intrusive igneous rock cools slowly on the surface and is created by lava. Since the cooling process is slow, intrusive igneous rocks have larger crystals and course grain.
Granite is a coarse-grained light colored igneous rock composed mainly of feldspars and quartz which together make up 90% of the rock. Quartz ranges from 20-45% and feldspar up to 60% of the granite. It is the interlaced crystals of feldspar and quartz, two very hard minerals, that gives granite it strength and makes it such a good building material. Granite also has a varying amount of other minor minerals, such as the black mica biotite, and the black amphibole hornblende, both of which gives granite its classic salt and pepper appearance.
Granite is classified as igneous, arising from magma many miles below the surface.
Please email me the answers to the following questions:-
1. What kind of rock form is Granite? (Igneous/Sedimentary/Metamorphic)
2. Examine the granite at the listed coordinates. Would you classify the grain as large or small?
3. Based on the grain size, has this granite cooled quickly or slowly?
4. Is this granite therefore Intrusive or Extrusive?
5. Take a picture of yourself in the vacinity and upload it with your found log.
In accordance with the guidelines, the procedure for logging an Earthcache is:
- Send me the answers.
- Log your visit. "People do not need to wait for permission to log your EarthCache."
Please note : If answers have not been received within 10 days, you will risk having your found log removed.