Landscape variations in the SIHC
5 06 2008Now that you have completed a short answer quiz about the natural processes in the South Island High Country, it is time to have a go at a long answer that requires qualitative information.
Go to the following NZQA page with past Level 2 exam questions: Choose your own Natural Landscape question and develop an answer over the next two lessons.
Your answer needs to be about the SIHC, but you can use questions from the New Zealand Setting or the Continental Setting.
Remember to use Mr Cranston’s Handy Geo Writing Guide. and What essay ‘command words’ mean.
Please submit your selected question and answer as a comment. 
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Natural Feature 1: Landforms
The landform differs depending on the location in the South Island High Country and what side of the Southern Alps which is kind of like the backbone of the South Island. There are 3 main types of Rock found in the South Island High Country. Sedimentary, Igneous, Metamorphic. These main types of rocks have their own properties and features. Other rocks are grouped into these main rock groups.
Sedimentary:
Gravel, Sand, Ash, Mud
Limestone, Siltstone, Sandstone
Greywacke
Igneous:
Rhybolite, Ignimbrite, Pumice, Ash
Andesite, Basault
Metamorphic:
Schist
Greiss
Granite
I do hope this is right?!?
(i) The South Island High Country vast area in the South island which covers approximately 70% of the island has been shaped for millions of years and this still continues today with the erosion of glaciers. The South Island High Country was shaped in three main stages: submergence, uplift and denudation.
After periods of uplift and denudation New Zealand land was relatively flat and was submerged under the Pacific ocean, the land consistedprimarily of greywacke and deposits from the ocean floor. Twenty million years ago the land was uplifted again known as the Kaikoura orogeny the Southern Alps started to form and the alpine fault was developed as the pacific plate over rid the Indo-Australian plate, the plates colliding forced the land to move vertically along the newly created fault line. The high altitude of the Southern Alps means they have been subjected to glacial, fluvial erosion and the still relatively weak greywacke was easily eroded. The Canterbury plains were developed by step High Country rivers depositing alluvium in low lands.
(ii) Glacial erosion has had a large effect on the South Island High Country the glaciers are retreating and as the glaciers melt the water mixes with ground up rock creating a milky white colour. This has the largest effect on the landscape as the glacier retreats more finger lakes and valleys are created which are the most obvious changes. The climate will be effected when the glaciers eventually melt away because the sun will be able to evaporate more water due to a larger surface area (water can cover a more vast surface are than ice) and then more rain will fall. So therefore glaciers retreating will eventually have a rather large effect on the climate as it will become a wetland. Erosion also has an effect on the Southern Alps and even though they are still growing they are also being eroded.
LANDFORMS - MOUNTAINS: the South Island High Country is formed from the great Alpine fault running down the south island. The Alpine fault, where the indo-Australian plate and the Pacific plate meet is a reverse transform fault in is responsible for creating the huge mountain ranges where they meet. The Mountains are large and either have a smooth or jagged top; this is due to there heights and the types of erosion that effect them e.g the taller mountains have sharp rocky tops because no soil in able to exist on the vertical cliffs and also because of ice and wind erosion.
LANDFORMS - ROCKS: because of the location of the south island high country over the Alpine fault there is also a variation in rock types. On the west side of the fault Granite is present which comes from the Indo-Australian plate. On the east side there is a rock known as Haast schist. These rocks are also sorted into different types due to their process of creation; the rocks such as schist and Greywacke are sedimentary rock wear Granite is Metamorphic.
VEGETATION: vegetation such as beech trees vary as you travel up the mountain in the south island high country due to the change in altitude. At the base of the mountains the forest generally contains mainly Red and Silver Beech trees where as the trees toward the top of the mountains are normally mountain beech. Mountain beech has adapted to the higher altitude and thrives in the cold climate. The larger trees then slowly become smaller and stunted after they pass their preferred climate conditions. Tussocks and ground shrubs populations increase as you get higher up the mountains and the trees disappear. These small hardy plants can survive were forests no longer dominate and were they can get a sustainable supply of sunlight. Because of their low level to the ground wind has a lesser effect on their growth.
But even tussocks disappear on the higher mountain due to the increasingly harsh conditions. The mountains are left with a bare rocky surface.
Hmmm some of this is guess work
Within the South Island High Country, New Zealand, there are different types of landscape and vegetation. These change due to their location.
There are three main types of vegetation in the South Island High
Country. These are Beech forests –tall, native, evergreen trees with only a small amount of undergrowth; tussock –a thick, brown grass; and Alpine herbs and mosses. Beech forests are found mainly on the western side of the Southern Alps, up to approximately 1500 metres. Tussock dominates up to this height on the Eastern side. Above the tussock and Beech forest grow the Alpine herbs and mosses, up to about 1800 metres above which there is no vegetation.
Beech trees need lots of rain and prefer moderate temperatures. They cannot survive extreme weather changes. Because of this, Beech forests grow on the West Coast. The West Coast has a high rainfall – moist air from above the Tasman Sea is blown over to the South Island. When it reaches the mountains the air is forced upwards, condenses and precipitates. There are no extreme temperature changes on the West Coast -again because of its location close to the sea. The sea traps more warmth than the land meaning the air near it is warmer.
Tussock prefers a drier climate. It is a very hardy grass so is able to survive the extreme weather changes of the eastern side of the Southern Alps. This area is quite dry as rain falls mainly on the west side. Temperature can change a lot here as it is in the centre of the South Island - and the further inland you go, the more extreme the weather is. Alpine herbs and mosses like the cold climate above 1800 metres, but cannot survive any higher this land usually covered in snow.
The landscape also changes in different areas of the South Island High Country. The relief on the West Coast is very steep compared to the eastern side of the Southern Alps which is quite flat. Glaciers also affect the landscape of the SIHC by forming U-Shaped Valleys.
The Alpine fault stretches down the west side of the Southern Alps. It is where the Pacific Plate overrides the Indo-Australian Plate. Forces between these plates formed the Southern Alps in the Kaikoura Orogeny, 20 million years ago. The land was vertically uplifted, making a horst. It created the steep land on the West coast. The continuous forces along the Alpine fault line mean the Southern Alps keep growing. It is the high altitude of the mountains that subject them to fluvial, aeolian and glacial erosion, preventing them from rising much more than their 3754 metres. Greywache sediment from this erosion is transported down rivers to create alluvial lowlands like the Canterbury Plains.
Glaciers are valleys which have been filled by snow and compressed into a hard ice. Gravity causes the glacier to move down, carving out a steep sided valley. When the climate is warmer the ice melts and the glacier retreats, leaving a valley shaped as a U.
These are some reasons for the vegetation and landscape differences we see in the South Island High Country today. Landscape differences are due to the movement of the tectonic plates and their effect on the landscape either side of the Southern Alps, and because of glacial processes in the mountains. Vegetation differences are also because of the location and the preferred climate.
SECTION B: NATURAL LANDSCAPES – NEW ZEALAND SETTING
In the box below, name the New Zealand landscape you have studied this year.
New Zealand landscape:
South Island High Country!
Use this landscape to answer Question Three.
QUESTION THREE
The location of natural features in the environment often shows spatial variation.
Select TWO natural features of your New Zealand landscape from:
• Landforms
• Soils
• Vegetation.
Explain how and why each varies in their location within the landscape.
Use specific information from your New Zealand landscape to support your answers.
You may answer this question with a written explanation or with labelled sketches?/?maps?/?diagrams or a combination of a written explanation and labelled sketches?/?maps?/?diagrams.
Natural Feature 1: Vegetation
In the South Island High Country (SIHC), there are three different types of vegetation that vary throughout the landscape in Altitudinal Zonation. These are:
~Beech Forest
~Tussock
~Alpine Herbs and Grasses.
In the SIHC, Beech forest grows from ground level up to 1500m. From ground level to 1100m Silver Beech grows and from 1100m to 1500m Mountain Beech grows, but Beech Forest only grows on the West Coast of the SIHC. This is because Beech requires a lot of rain and cold temperatures that occur in the west e.g. Hokitika, Haast.
Tussock also requires the same temperature but differs where it lies on the East Coast of the SIHC. This is because Tussock prefers dryer weather and can survive the harsh winters and extreme summers where it can go without rain for months. Tussock lies from ground level (0m) to 1500m and is in places such as Alexandra and Central Otago.
From 1500m to 1800m, Alpine Herbs and Grasses grow. This is because they prefer the extremely cold temperatures and can grow without large amounts of soil which are needed for Beech and Tussock. Because they are small, the herbs and grasses are not affected by the wind.
From 1800m up, no vegetation exists. This is due to the fact that Aeolian erosion has been taking place, which has stripped the highest altitude of the SIHC of any vegetation and soil so there is only bare rock from 1800m up, although throughout the year this part of the SIHC is generally covered in snow.
Natural Feature 2: Landforms
In the SIHC, the type rock that exists varies in different locations. The types of rocks would include the Sedimentary rock Torlesse Greywacke and Metamorphic rocks Haast Schist and granite.
Hundreds of years ago, before the Kaikoura Orogeny 20 million years ago, New Zealand was mainly Greywacke but also there were traces of Schist because of the compression of sediments from the ocean. During the Kaikoura Orogeny, The Torlesse Greywacke was uplifted as were the Southern Alps, because of the collision between the Indo-Australian plate and the Pacific plate which is marked by the Alpine Fault. The SIHC does not consist of a lot of Greywacke anymore because the brittle rock was subjected to erosion, such as Aeolian, peri-glacial and fluvial, the Greywacke sediments were transported via rivers e.g. Rangitata and created alluvial lowlands on both the East and West Coast of the SIHC e.g. Canterbury Plains.
Haast Schist rock however is not as brittle and weak like Greywacke. Like Greywacke, Schist was also uplifted during the Kaikoura Orogeny and also sedimentary Greywacke was further compressed to form Haast Schist during the Orogeny, but however, the Haast Schist lay underneath the Greywacke and was only exposed to erosion along the eastern side of the Alpine Fault, so was only exposed to erosion once the Greywacke had eroded away. This is why Haast Schist exists in areas such as Haast, Queenstown and Arrowtown, places which lie on the East oast of the SIHC and lie amidst it.
Granite was a remnant of the Gondwana land that existed on the Indo-Australian plate. Once this plate collided with the Pacific plate, the Granite rock has been unable to travel, so is still lying on the West Coast of the SIHC underneath the alluvium that has been transported by steep high country rivers.
MR CRANSTON!!!!! it wont let me put my diagrmas on which i proudly designs-*cough*
i’ll print my essay out and give it to you at school okay?!? should there be more than two comments anyway on here?
The formation of the Southern Alps
The process that has the most effect on the evolution of the Southern Alps is Tectonic because it involves a major process of Uplift, which affects the evolution of the Southern Alps by the Pacific Plate ramming up over the Australian Plate caused by the Alpine Fault forming the Southern Alps mountain range.
Tectonic is the most significant process because it has the greatest affect on the evolution on the Southern Alps The Tectonic process of the Kaikoura Orogeny effects the climate for example it is rainy on the west of the Southern Alps and sunny on the east of the Southern Alps.
Many types of Erosion would not occur if there wasn’t a mountain range for example glacial erosion.The southern Alps are very high and it would take a long time before it is eroded away. A tectonic process would more likely occur before the Southern Alps is eroded away.
Wow im doing geo y2 12 and this has been amazingly helpful for me, i’d just like to thank everybody who toke the time to write answers =)