1.
Comprehensively analyse how one selected feature in your
geographic environment has been formed by interacting processes.
One feature that occurs in my geographic environment is a
stack. This has been formed by the interaction between the
processes of volcanism, tectonic action and wave erosion.
The region was affected by volcanism long ago when the plate
boundaries were much closer to the region. Molten magma was
extruded into the environment at this time that later cooled to
create a hard, resistant volcanic rock. This is significant as if the
rock had been softer the feature could not exist.
Another important stage in development was tectonic uplift.
Due to this process the headland was lifted above sea level to
then make it vulnerable to wave action. As a result both of these
processes help to create the necessary conditions in which the
major process to shape the feature – wave action could then
occur.
As waves approach the headland they slow down due to friction
between the water and the sea floor. While the velocity near the
end of the headland slows the waves further away continue at
their previous speed. This causes the waves to appear to bend or
refract. This bending then concentrates wave energy onto the
headland where erosion takes place. Sub processes such as
hydraulic action (water compressed into cracks) and attrition
(waves use sediment to batter the rock) slowly break down the
rock in weak areas to create a notch and then a cave. Since the
waves approach the headland from 3 sides caves finally merge
to form an arch. The weight of rock makes the roof of the arch
vulnerable to further erosion and as a result of gravity it finally
falls down to leave an isolated column of rock called a stack.
This explains how the processes of volcanism, tectonic action and
wave erosion all work together to create this feature.
Good interactions and analysis but lacks any reference to specific environment
so cannot score.
2.
Comprehensively analyse how one selected feature in your
geographic environment has been formed by interacting processes.
My geographic environment is South Muriwai which is located
40 km NW of Auckland Central and extends from Okiritoto
stream in the north to Maori Bay in the south, a distance of
approximately 5km. One feature that occurs in this
environment is a stack called Mototara Island. This feature is
about 50m high and is located approximately 20 metres SW of
the Otakamiro headland to which it was once attached. It is
formed of a conglomerate rock called a breccia which is
sandstone with volcanic intrusions.
It was mainly formed by different wave processes. Waves at
Muriwai are very high averaging 1.5m all year but reaching
over 5m in the winter.
The waves hit the Otakamiro headland where they form a hole.
This widens into a cave such as the large one found on the north
side of the headland accessed from the wave cut platform called
fisherman’s Rock. Similar caves form on the south side of the
headland which then merge to form an arch. The roof of the
arch then collapses to leave behind a column of rock or the stack.
Eventually this will get eroded even more by the waves to
finally cause a stump. You can tell that these processes are
happening today since there is evidence of a stump close by.
The stack is presently the site of over 5,000 pairs of gannets that
nest here from October until March and which attract
numerous visitors to the region. These birds further erode the
stack through bird poo or guano.
As a result both the waves and the gannets have formed the
shape of the stack today.
While this has some good specific information the answer lacks any analysis as is
descriptive only. Need to say HOW the processes work to score.
3.
Comprehensively analyse how one selected feature in your
geographic environment has been formed by interacting processes.
The Morotara stack is a significant feature that occurs in the
south Muriwai coastal environment (SMCE) located 40km NW
of Auckland and which extends for Okiritoto stream in the
north to Maori bay in the south.
17 million years ago volcanic activity occurred in this
environment with the production of large underwater
volcanoes. This is because of the Pacific plate subducting below
the Indo-Australian plate close by and allowing magma to
escape in weak spots below the Muriwai region. They created
the hard rock that forms the stack.
Muriwai experiences high energy waves due to the large
2,000km fetch across the Tasman sea and the prevailing SW
winds that blow over 11 knots 75% of the time. As these waves
approach the beach they slow down and bend to concentrate
their energy on the Otakamiro headland.
Wave erosion happens when the waves attack the hard rock. The
water gets compressed into cracks splitting them apart.
Sediment held in the waves is hurled at the rock and further
breaks it down. This results in a notch and then a cave. Caves
either side of the Otakamiro headland then merge to form an
arch. The roof of the arch is susceptible to erosion so gravity
causes this to collapse leaving behind a column of rock or the
Mototara stack as seen today.
This explains how the stack has been formed by volcanism and
wave action.
Good specific information and analysis but there is no interaction between the
processes provided so cannot score.
4.
Comprehensively analyse how one selected feature in your
geographic environment has been formed by interacting processes.
A big feature that exists at Muriwai is a stack that was once
part of the headland nearby.
Huge big waves come into the environment across the ocean. As
they get closer to the headland they slow down as they hit
shallow water and bend and crash into it causing erosion. Bits of
sand inside the waves are used like sandpaper and rub against
the rock to break it down. At the same time water is pushed into
small cracks and make them bigger. This will then turn into a
cave. Several caves will meet allowing even more water to rush
in and erode them. Eventually the roof above becomes unsteady
as the rock is so heavy so it falls down. This leaves the stack on
its own separate from the headland like an island. It is called the
Mototara Island.
Waves keep attacking the part of the island below sea level. At
the same time another process is also happening which is called
wave splash. The waves splash up the rock and wet it. When it
dries out salt is left behind and the salt eats the rock and
weakens it. The top of the stack is home to thousands of gannets.
When these gannets poo the chemicals in it also break the rock
down more.
As a result the processes of wave erosion, wave splash and bird
poo action together help to make the stack the shape it is today.
This answer while not good has enough specific information and analysis
(reasons for the processes and how they work) and implies interaction to allow
achievement. It lacks any technical knowhow or terminology to allow any higher.
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