Introduction to Natural Introduction to Natural LandscapesLandscapes

AS90331AS90331

Explain a Natural LandscapeExplain a Natural Landscape

Assessment Specifications Assessment Specifications

• Variations within a natural landscape– This refers to how and why features of the

environment have spatial variation within the landscape area

• How a landscape evolves and changes, which refers to:– Climatic processes– Tectonic and other internal processes– Erosion, transportation, deposition and other surface

processes.

• The effect of cultural perspectives and human activities on a natural landscape– This refers to particular ways in which groups

of people interpret and explain landscapes through their knowledge, practices and beliefs

SettingsSettings

• Continental Scale Setting– The Amazon Basin

• New Zealand Setting– Tongariro Volcanic Centre

What is a Natural Landscape?What is a Natural Landscape?

• View the following images and state whether you consider them to be natural landscapes

Defining Natural LandscapesDefining Natural Landscapes

• What do we mean by natural?– Parts of the environment that are present

within it without the influence of people

• What do we mean by landscape?– All the features of the environment that can be

seen or observed

Describing a LandscapeDescribing a Landscape

• Concentrating on a couple of the images we have already looked at, how can we describe the landscape in more detail?

Elements of a LandscapeElements of a Landscape

• Relief: The height and shape of the land, and the processes that have formed it over geological time

• Climate: the average weather conditions over a long period of time, and the processes causing these conditions. This includes rainfall, temperature, sunshine hours, wind and humidity

• Soils: weathered or eroded material produced from rocks. Of interest are type, fertility, and drainage

• Biotic System: the plants and animals in a particular landscape and their effect on it.

Interaction Model Interaction Model

RELIEF

SOILS

CLIMATE

BIOTIC SYSTEM

Relief Patterns and ProcessesRelief Patterns and Processes

• Match the words from the list below with their correct definitionMOUNTAINS PLATEAUS ROLLING HILL COUNTRYROUGH HILL COUNTRY PLAINS

• Areas of flat, low, land (under 200m in elevation); mostly found in coastal areas.

• Area of flat upland; the most prominent one of these in NZ is in the central North Island

• Gently undulating hill country, found mostly in the North Island• Steep land that rises much higher than the surrounding

landscape, either as a single feature or in a chain or range over 1000m or over 340m from summit to base. Makes up 70% of the South Island so is the dominant landform type in NZ

• Areas lower than 1000m with rugged relief and often steep land, common in the North Island

AnswersAnswers

• PLAINS: Areas of flat, low, land (under 200m in elevation); mostly found in coastal areas.

• PLATEAUS: Area of flat upland; the most prominent one of these in NZ is in the central North Island

• ROLLING HILL COUNTRY: Gently undulating hill country, found mostly in the North Island

• MOUNTAINS: Steep land that rise much higher than the surrounding landscape, either as a single feature or in a chain or range over 1000m or over 340m from summit to base. Makes up 70% of the South Island so is the dominant landform type in NZ

• ROUGH HILL COUNTRY: Areas lower than 1000m with rugged relief and often steep land, common in the North Island

New Zealand’s Landform PatternsNew Zealand’s Landform Patterns

• Use an appropriate graphing technique to display the information on the next slide regarding the pattern of New Zealand’s landforms

• Make sure you use all of the correct graphing conventions for the type of graph you have chosen

New Zealand’s Landform PatternsNew Zealand’s Landform Patterns

% Mountain

s

% Rough Hill

Country

% Rolling Hill

Country

% Plateau % Plains

New Zealand 49 25 15 3 8

North Island 18 45 26 6 5

South Island 70 12 9 0 9

Cycle of LandformingCycle of Landforming

Land Building Processes

Folding FaultingVolcanism

Land Modifying Processes

ErosionWeathering Transportation

Deposition

Causes of erosionGlaciers RiversWind WavesFreezing and Thawing

• In places where the surface is fractured or broken these convection current move large sections of the Earth’s crust known as tectonic plates. This process is known as plate tectonics.

• Volcanism occurs when descending oceanic rock escapes through the surface through a weakness.

• Typical features of volcanic landscapes include: mud pools, geysers, hot springs, etc.

Land Building Processes - Land Building Processes - VolcanismVolcanism

• The core of the earth is extremely hot, estimated to be about 7000°C. As you move towards the surface of the earth, this temperature cools. This temperature differential forms a convection current, where molten rock heats up away from the core and as it nears the surface cools and sinks, with this sequence being repeated over and over again.

Land Building Processes – Land Building Processes – Folding and Faulting Folding and Faulting

• Faulting is the movement of the earth’s plates along zones of weakness. It is the result of pressure building up and causing old brittle rocks to shatter and move in blocks. The land shifts upwards, downwards, or sideways. In NZ they tend to run in a NE to SW direction; the largest example of which is known as the Alpine Fault

• Folding is the process by which sedimentary rock is pushed and squeezed as hard surrounding rock is moved by plate tectonics. The soft rock twists and bends into folds rather than fracture like hard rock would. This creates a more rolling landscape than what faulting does.

Erosion, Transportation, and Erosion, Transportation, and Deposition Deposition

• Erosion is the general term that is used to describe the wearing down and subsequent transportation of the earth’s surface

• The Three stages are:

Erosion Transportation Deposition

Different types of erosionFluvial

– Caused by the action of rivers

Glacial – Caused by the action glaciers

Freeze-Thaw– Caused by the freezing and melting of water in rocks. As water

freezes and can cause rocks to shatter

Aeolian– Caused by the movement of wind

Waves– Caused by the action of waves

Climate Processes Climate Processes The Water Cycle

• Interception• Infiltration • Runoff• Precipitation• Groundwater flow• Stream and river

flow• Movement of

atmospheric moisture

• Evaporation • Ocean• Evaporation from

land, vegetation, rivers, and lakes

• Storage areas (lake, wetland)

17

6

5

43

211

10

9

8

Copy the diagram above and use the list from the column to label correctly each of the different processes involved in the Water Cycle

Answers1. Interception2. Infiltration3. Groundwater flow4. Stream and river flow5. Ocean6. Evaporation7. Movement of atmospheric moisture8. Storage areas (lake, wetland)9. Evaporation from land, vegetation, rivers, and lakes10. Precipitation11. Runoff

Types of RainfallTypes of Rainfall

Orographic

Moist air forced to rise

Rain shadow on leeward side

Air warms as it descends

Air cools as it rises

Rain Dry

Convectional

Warm Surface

Warm moist air rising

Altitude

Convectional Rainfall

Frontal – Warm Front

Drizzle

Warmer air nimbostratus

Frontal surface

Wide band of heavy rain

Cooler air (denser)

Frontal – Cold Front

Narrow bank of heavy rain

Cumulus

Cumulonimbus

Squalls

Cold air (denser)

Warm air (less dense)

Frontal surface

Climate Controls Climate Controls

• Latitude: Generally the closer to the Equator the warmer the temperature. This is because light at the Equator hits at less of an angle than at the poles. Northland at 36°S has an average temp of 14°C, whereas Southland at 46°S has an average temp of 10°C.

• Altitude: Saturated air cools at the rate of 0.6°C per 100 vertical metres.

• Relief: This can cause orographic rain (e.g. West Coast South Island) and cause wind funnelling (e.g. Cook Strait).

• Size of landform: Small landmasses have climates moderated by the sea whereas large landmasses have extremes of climate.

• Proximity to oceans: Sea breezes moderate the climate• Ocean current: Air masses passing over warm ocean

create warm breezes and vice versa.• Wind and Pressure systems: The world is divided into

different zones of pressure. The Equator has low pressure, and the Poles have high pressure. In general, the direction of wind movement is from high to low pressure air masses.

Soil Patterns and Processes Soil Patterns and Processes

Soil is material on the earth’s surface produced by rocks (parent material) which has been altered by physical, chemical and biological weathering.

There are 4 factors that contribute to soil development. They are:

• Climate: particularly temperature and precipitation• Relief: in particular slope angle. Steep slopes will have

poor shallow soils as erosion easily takes place. On flatter slopes alluvium (material deposited by rivers during flood periods) can build up to produce good quality soils

• Parent Material: includes the structure and mineral composition of the original rock weathered to form the soil

• Time: the length of time elapsed while the soil is being formed is important in characterising soils. Young soils will reflect the characteristics of the parent material, whereas older rocks will develop their own characteristics under other influences.

Soil LayersO: Organic material at the surface A Horizon: the topsoil; contains

some weathered material and organic elements, is rich in humus

B Horizon: contains weathered parent and animal material and some organic elements; material leached from the A Horizon maybe deposited

C Horizon: the subsoil (weathered parent material)

D Horizon – the parent material