Jimperding Gneiss
The geology of southern Western Australia is dominated by the Yilgarn Craton, an ancient and relatively stable area of granites and gneiss (a metamorphic banded granite-like rock). The Jimperding metamorphic belt is a band of very mixed and often mafic rocks that runs NNW to SSE through Northam along the Avon valley. The rest of the Northam district consists of narrow bands of mafic soil formed on dolerite dykes.
The Jimperding metamorphic belt is an area of ancient rock that is most evident in the Avon Valley. This belt is synonymous with the Jelcobine system. The Jelcobine system is very hilly and dissected with mainly fertile loamy and clay soils formed from the surrounding Metamorphic rocks. It extends roughly from Beverley to Bolgart with the Avon River being the major feature of the area. This Jimperding belt has a lot of mafic gneisses and other metamorphic rocks. Gneiss is generally quite dark grey in colour, but the mafic forms of Gneiss are more redy/brown. It is this type of Gneiss that forms red loam and clay soils
Once at the site you will be able to look across the road toward the reference point. There you will see the road cutting. The cutting provides a good view of the underlying regolith.
Definitions
Craton : An old and stable part of the continental plate
Laterites : Soil and rock type rich in iron and aluminium. Laterites are usually porous and clay-like.
Mafic : Igneous rock that is rich in magnesium and iron
Regolith : The layer of soils covering the rocks below
Please email me the answers to the following questions:-
1. What kind of rock is Gneiss? (Igneous/Sedimentary/Metamorphic)
2. Study the surrounding rocks and soils, and describe the colours you can see in them?
3. Based on your observations for question 3, is the Gneiss here Mafic or not?
4. In the cutting you'll notice the bands of rock are on a certain angle. What is the angle of the incline? (angle between rocks and horizontal)
Optional
Feel free to take a picture of yourself nearby.
Please note : You are welcome to log this Earthcache after sending your answers to me. If no answers are received, your log will be deleted. Please be mindful of your logs to ensure there are no spoiler images/answers for the questions above, spoilers will also be removed.
Reference: https://researchlibrary.agric.wa.gov.au/cgi/viewcontent.cgi?article=1016&context=bulletins