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WorksheetsGeology of Peppermint Grove and Cottesloe Beach
Total questions: 28
Worksheet time: 24mins
Sedimentary sequences formed while sea level rises.
Transgressive
Regressive
Postgressive
Pregressive
Sedimentary sequences like this can be formed as sea levels fall.
Postgressive
Transgressive
Regressive
Pregressive
Describe the features of fossiliferous limestone
Layered
Friable (breaks easily)
Fossiliferous (contains fossils) and contains shells
Sandy or clastic
There are four distinct sequences of deposition in Perth cliff faces. They range from deep marine, to shallow marine, to beach zones, to land. What features are present in 1: Deep Ocean?
Clearly rippled
Larger layers, curves, and trought
Cross-bedding
Rhizoliths
There are four distinct sequences of deposition in Perth cliff faces. They range from deep marine, to shallow marine, to beach zones, to land. What features are present in 2: Shallow Marine?
Larger layers, curves, and troughs.
Planar-bedding
Clearly rippled
Cross-bedded
There are four distinct sequences of deposition in Perth cliff faces. They range from deep marine, to shallow marine, to beach zones, to land. What features are present in 3: Beach Zone?
Lightly rippled
Planar-bedded
Flat layers
Phizoliths
There are four distinct sequences of deposition in Perth cliff faces. They range from deep marine, to shallow marine, to beach zones, to land. What features are present in 4: Land?
Little layering or structure
Clearly rippled
Aeolian
Rhizoliths
Point of deposition for 4: Land?
Underwater (near shore) - rippling due to waves near shore
Open air - large scale cross beds relate to sand dunes
Transition to marine - flat deposition in swash zone
Underwater - troughs suggest flow channel and accumulation of marine fossils indicates river or sea floor
Point of deposition for 3: Beach Zone?
Underwater - troughs suggest channel flow
Open air - large scale cross beds relate to sand dune
Transition to marine - flat deposition on swash zone
Underwater (near shore) - rippling due to waves near shore
Point of deposition of 2: Shallow Marine?
Open air - large scale cross beds relate to sand dunes
Transition to marine - flat deposition in swash zone
Underwater - troughs suggest channel flow and accumulation of marine fossils indicates river or sea floor
Underwater (near shore) - rippling due to waves near shore
Point of deposition of 1: Deep Marine?
Underwater (near shore) - rippling due to waves near shore
Transition to marine - flat deposition in swash zone
Underwater - trough suggests channel flow and accumulation of marine fossils indicates river or sea floor
Open air - large scale cross beds relate to sand dunes
Which type of rock could be found in this area at the base of a cliff?
(a)
How could the breccia in the area of the cliffs have formed, and been moved to the base of the outcrop.
OR formed from the cementation of calcium carbonate
OR formed from broken beach rock and cemented at the cliff face
OR formed from a small landslide which caused the rock to break while still being subsequently cemented
OR long since formed and transported by the elements
Select the correct order of rhizolith development:
1. Calcification of tap root
2. Cementation surrounding tap root
3. Living tap root
4. Extensive cementation
1. Living tap root
2. Cementation surrounding tap root
3. Calcification of tap root
4. Extensive cementation
1. Living tap root
2. Cementation surrounding tap root
3. Extensive cementation
4. Calcification of tap root
1. Living tap root
2. Calcification of tap root
3. Cementation surrounding tap root
4. Extensive cementation
Explain why tap roots look different along coastal cliffs than on inland cliffs. Talks about types of plants, geographical location, etc.
What is the predominant wind direction in Perth?
North East to South West
South East to North West
South West to North East
North West to South East
What is the breeze that blows in from the coast in summer evenings, and help us determine the predominant wind direction?
(a)
How do cross beds help to tell us the predominant weather conditions from the past, and how they compare to today?
Cross beds show the predominant wind direction, deposited on the lee side of the dunes.
Cross beds contain fossils that can tell us the weather in their biological composition
Today, we have the Freo Doctor, which blows in the direction of the cross beds, which gives evidence that weather conditions are similar now and in the past.
It doesn't.
Does Peppermint Grove represent a transgressive or regressive sequence? Talk about definitions, superposition, fossilisation, transitioning between marine and terrestrial, and evidence for terrestrial vegetation (rhizoliths) in latest sediments.
The law of superposition states that:
Units layer from younger to older interspersedly
Older units are at the bottom, and younger units are at the top.
Younger units are at the bottom, and older units are at the top.
Units are intermingled.
How is limestone formed?
Salt water caused sediments to clump together and form a rock.
Calcium carbonate from shells and skeletons of marine organisms dissolved.
Precipitation caused cementation and the lithification of limestone.
Calcium carbonate expands and engulfs nearby sediments.
How did features such as the fossilised coral in tree stump form?
Rhizoliths
Wave action and scour stones led to creation of potholes.
Precipitation of calcrete around the roots, which eventually fossilised them.
It can be assumed that water was once much lower for the tree to grow, then much higher for the coral with a higher temperature, and then trangressing again so we can see it.
What can form from the transgression and regression of the ocean and where waves break?
Strikes
Wave-cut platforms
Notches
Dips
When building the Cottesloe Groyne, why was local limestone not used?
Local limestone is friable and soft
Therefore easily weathered and eroded
Therefore the groyne would need replacing more frequently
Therefore local limestone was not used as it would be damaging to the coral.
Why are dark sands present on Cottesloe Beach?
They were weathered from igneous rocks on the land, in which the erosion landed them in the sea.
They are from oil spills in the bay that has washed through the sand and turned it a dark colour.
They were carried with ocean currents and deposited on the lee side of the groyne because the movement is slower.
Because the energy in the area is not high enough for the heavier black sand, it stays put whilst the other sand is washed around by the waves.
What makes up the dark sands at Cottesloe Beach?
(a)
Why is the black sand at Cottesloe Beach important?
Source of titanium and other minerals such as gold and even diamonds
Can be used is planes, artificial joints, pigments, paints, pharmaceuticals
It has a large variety of uses
It can make tinted glass.
Rocks that have been formed from air, and not water are...
(a)
