Transcript 91240 Demonstrate geographic understanding of a large

91240 Demonstrate geographic understanding of a
large natural landscape- The Amazon Basin
Aspects are selected from:
– the characteristics of a large natural environment eg
landforms and vegetation (and the patterns created by them)
– how the elements and processes of the large natural
environment interact
– how a large natural environment is formed and changes over
time (Natural landscapes evolve as elements (characteristics)
and processes interact. This interaction varies in time and
space. You need to be able to explain how characteristics and
interaction varies from place to place.)
– how people interact with a large natural environment
– how people's perceptions of a large natural environment
change over time(Perception of groups/individuals at 2
different points in time, and why their viewpoints have
changed)
Fact Sheet AMAZON
Area of 7m sq km. Located close to equator, 5-10’S.
On junction of Pacific Plate and S. American Plate
Flood plain = Varzea/ Soil Terra Rosa(red earth)
Amazon River largest in the Amazon Basin. Flows from Andes, which are
fold mts in the W, created by 2 plates converging, where the river
erodes, to the Atlantic Ocean in E, where the river deposits 3m tons
of sediment.
In the N is the Guyana Plateau and in the S the Brazilian Plateau.
Experiences 2-3000mm rain p.a./ 26-29’C/ ITCZ brings a lot of the rain.
6,400km from source in Andes to sea, mouth 300km wide, contains
25% of earths fresh water, 33% of worlds tropical forests. The
gradient is so small, it drops only 100m in height from Iquitos to the
sea.
Plants have medicinal purposes eg Catclaw-potential for curing cancer
and aids.
Trans Amazon highway-5,500km Recife to Peruvian border. completed
1975.
.
Practice drawing sketch maps locating and labelling
characteristics like landform features and vegetation
To N and S of
Amazon Basin=
remnants of
Gondwanaland
To West of Amazon
Basin-fold mts formed
At plate boundary
Sedimentary rocks
Drained by Amazon
R and tributaries
Remember you can draw a cross section
How the LANDFORMS in your large natural environment are
formed and change over time as elements (characteristics)
and processes interact. You need to be able to explain how
characteristics and interaction varies from place to place
and from past to present.)
1.Amazon Basin is a low-lying basin in the centre of the area. Manaus
is only 44m above sea-level. Iquitos on the edge of the Andes is
only 100m above sea level. It was created 10m years ago when the
uplift of the Andes caused the Amazon to flow east into the
Atlantic. Before this , it flowed west.
2. Varzea or flood plain is on either side of Amazon River. Flat area, 10100m wide. Newest sediments replaced every year when river
floods..
3. Guyana shield mts to North 3000m at highest point. Brazilian Shield
mts to South. Remnants of ancient Gondwanaland (500m years ago
split up)that have been worn down (eroded) over time. Oldest
features, ancient rocks.
4. Andes mts to West average 6000m high. As the Andes have been
pushed upwards, the amazon river flowed toward the Atlantic fed
by snow melt. 2m years ago, glaciation weathered and eroded the
Andes, depositing the sediment in the Amazon Basin.
5. Coastal Plain is a flat area where the river meets the Atlantic, at the
Evolution and Change
500m yrs ago
Gondawanaland split and convection currents began moving the
plates.
90m yrs ago
As S America moved W it collided with the Nazca plate moving E,
pushing up the Andes fold mts.
10m yrs ago
Amazon changed direction and flowed towards the Atlantic
2m yrs ago
During the Ice age weathering (freeze-thaw) and glacial erosion
broke up the sedimentary rocks of the Andes.
Present
Amazon transports sediment produced downstream and
deposited it to form Amazon Basin
Processes that produce the landforms.
1 Tectonic processes. 500m – 200m years ago.
Subduction of Nazca Plate under South American
Plate pushes up Andes fold mts. The rivers then
flow eastwards as tributaries to the amazon and
the sea.
2 River erosion and deposition. 1m years ago.
Amazon has over 1,000 tributaries eg Tambopata
River, eroding rocks of the Andes and depositing
the recent sediments on the flood plain.
3 Climatic processes. Rainfall 2,500mm max, av temp
27*C. These wash sediment into the rivers and
encourage weathering of rocks.
4 Vegetation processes eg roots that break up rocks.
Land Modifying Processes
Spatial patterns of vegetation
3 Savanna to N and S on higher,
cooler plateax
2 Evergreen
Rainforest to
The west
In rain shadow
of Andes
1 Selva-Seasonal rainforest
In Central area with av 27’C an
2700mm rain pa average but
Seasonal due to ITCZ.
4 Thorn forest
Coast due to
salty winds
How the VEGETATION/SOILS in your large natural environment is
formed and changes over time as elements (characteristics) and
processes interact. You need to be able to explain how
characteristics and interaction varies from place to place and from
past to present.)
Vegetation
1. Selva –seasonal tropical rainforest in centre of Amazon Basin.
Because of the high average rainfall 2,500mm but seasonal due to
movement of ITCZ during the year. The ITCZ is only overhead for
part of the year from March-Sept. High temps 27*C all year due to
sun being nearly overhead all year and this causes convectional
rainfall.
2.Evergreen rainforest caused by rain shadow close to the Andes
mountains.
3. Savanna grassland 1m high to north and south of rainforest.
Long dry season March-Sept as ITCZ has moved north and rain
only 1700mm pa.
4. Coastal thorn forest has developed along the coast to resist
salty winds.
Soils
1. Alluvial deposits (Terra Rosa) after flooding of Amazon
2. Latosols on varzea rich in humus at top layer but leached below
by heavy rains.
As air rises at the equator air around the region is sucked
towards the equator – the air that moves is called Trade
Winds
1 How people interact with a large
natural environment
2How people's perceptions of a large
natural environment change over
time(Perception of groups/individuals at
2 different points in time, and why their
viewpoints have changed)
Who are the People and groups whose activities impact on
the Amazon?
How people interact with their environment in a sustainable
way.
1.Shifting Cultivation/Slash and Burn-Yanomaminomads/leave land to regenerate when they move on.
Enawene Nawe grow crops and fish in Juruena River. Only
take what need to eat (kaitiakitanga) and fish reproduce.
2. Floodplain cultivation-cattle on rafts. Fertility of soil
replaced each year by sediment deposited by flood.
3. Rubber tappers/Brazil Nutters-slash trees and collect sap
and collect Brazil nuts. Trees are not damaged and
continue to produce.
4. Eco-Tourism-sustainable eg Tambopata National Reserve,
1.3m hectare conservation area. -MedicinesQuinine/Cinchona Tree
The Yanomami (pop 9,000)live in ‘yanos’ which are large, communal
dwellings made of tree trunks and thatches of palm leaves. There are between ten
to twenty families that live in a yano. Each family has its own section and fire.
These dwellings are only temporary and over a period of time they will become
infested by cockroaches and bats.
The Yanomami are semi nomadic. They build their yanos near suitable land for
cultivation. The forest provides firewood, nuts, berries and animals to hunt. The
Yanomami hunt, gather, fish and farm the land for 5 to 10 years and then move
onto another area. This is called shifting cultivation.
How people interact with their environment in a
non-sustainable way.
1. Cattle ranchers-remove trees for grass which results in soil
erosion and leaching (loses 45% of nutrients in 3 Yrs). 38%
of deforestation is caused by ranchers grazing cattle for
beef patties for McDonalds.
2. Loggers eg Yari Project-destroyed native trees
3. Settlers. Colonisation Programme began 1985-over 2m
settlers from poorer parts in the NE. Given 250 acres by
government. Cut down trees and damage environment.
4. Modern development projects- mining iron ore at Carajas
pollutes the environment, visual pollution of open-caste
mine. 5 HEP dams to provide electricity flood native
Indians land (Enawene Nawe) and prevent fish migration.
5 Trans-Amazon Highway encourages development along the
road.
6 Iron-ore mining-Carajas results in visual pollution.
Iron ore Mining in the Amazon: Carajas
Carajas is an integrated minerail-port system processing
deep
Belem
45 million tonnes of iron ore
water
annually (plus manganese,
port
gold). It is the backbone
Sao Luis
of development in the north
of Brazil(680km SW of Belem).
Tucurui
rail link
The mine contains 18 billion
tonnes, taking 400 years to extract.
It is one of the largest open cast
mines in the world. Historically geologists found the
iron ore in 1967, but it wasn’t until
1978 that the Carajas project
began with the laying of 900km ofCarajas
railway. Costing more than NZ$6 Billion this mining project
TransAmazonian
is the largest project in Brazil. A township
Highway
was built to house employees, over 6000 – it is fully equipped
0 and
100km
with schools, farms, hospitals
recreation facilities.
Only 1.6% of the 13,000 km² of this project are assigned to mining activities
and townships. However, the impact on the environment is significant.
Impact of Mining on the Amazon
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Burning of trees for charcoal-now replaced by HEP.
Forest cleared = increased erosion and silting up of rivers
near open cast mine
Chemicals used to purify the metals dumped into rivers –
pollution and discolouring them
Increased dust in the atmosphere – dust haze.
Tailing dams built to hold waste materials (sludge from
washing the ore).
However, the official mines have made some efforts to
repair some of the environmental damage they have
caused. For example, at a large bauxite mine on the
Trombetas River in the state of Para, the mining company
has stopped dumping their tailings (sludge from washing the
ore) into the river and they have started a reforestation
project.
Sketch map/diagram to show human
activities Amazon
Amazon Indians
Shifting cultivators
Forest re-grows
Located deep in
Rain forest
Carajas mineOpen cast
Visual pollution
Located by mineral deposits
Ranchers destroy
Forest for pasture S of
Amazon. Soil loses fertility
How people's perceptions of a large natural environment change
over time(Perception of groups/individuals at
2 different points in time, and why their viepoints have changed)
1 Native Indians-Enawene Nawe have become more
militant. Live in Mato grosso state. In the past saw the land
as theirs as indigenous people, now something to fight for.
11 dams planned on Juruena R.
16/8/2012 federal judge suspended work on massive Belo
Monte Dam, costingUS $11billion as a result of activists
who say it will devastate wildlife and livelihoods of 40,000
people who live in the area to be flooded. Interfere with
Yakwa rituals.
2 Soya Bean King, mayor of Mato Grosso, Blair Maggio,
now defending the forests. Past economic perspectivemake money by cutting down forest and growing soya
beans. 2003 destruction of the Amazon rose by 2/5ths. Aim
to triple agricultural production in 10yrs. Now political
viewpoint- needs votes and public opinion is defending the
forests.