Bell Rapids Validation Flashcards
What does the exposed tree tell us about past river levels ?
The exposed tree tells us that past river levels were higher and past climates were wetter.
How has are state land use made the river salty ?
The river is usually salty because of the weatbelt saline soil being washed into the river. Deep root native plants like trees keep the water level down, but then we replaced them with shallow rooted plants. This increase the river level and then the water evaporates and leaves a salt layer.
How does gneiss form ?
Gneiss forms from heat and direct pressure from regional metamorphism.
Formation of amphibilite and why it has weathered to form a channel ?
Amphibilite forms from the metamorphose of dolerite. The channel forms from the resistance to weathering of granite and weathering of amphibilite. The amphibilite weathers because it contains amphiboles and pyroxene which are mafic minerals and aren’t resistant to weathering. The surrounding granite contains Quartz which is a felsic mineral and is resistant to weathering.
What is a Boudin ?
A boudin is a resistant or hard piece of rock that has not fully melted and is squeezed off the rest of the rock by heat and pressure
Why has the bend at Bells Rapid occurred ?
Granite is resistant to weathering because of its felsic minerals like Quartz and orthoclase feldspar. The water takes the path of least resistance and creates a bend.
