Zusammenfassung der Ressource
Plate Tectonics-AQA
- Earth Structure
- The earths structure
is made from the
CRUST, MANTLE,
LIQUID OUTER CORE,
SOLID INNER CORE
- MANTLE is the widest section,
thickness aprox. 2900KM, made
up of semi molten rock of
silicate, iron and nickel
- CRUST is the outer layer, aprox.
5-70KM thick, the rocks are less
dense, rocks rich in silica, oxygen,
aluminium, potassium and sodium
- CONTINENTAL
- Age: over 1500mil
thickness:
30-70km, less
dense,
composition:
granite rich in
silicon, aluminium (sial)
- OCEANIC
- Age: less than
200mil, thickness:
6-10KM, more
dense,
composition:
basalt rocks rich in
silicon,
magnesium,
oxygen (sima)
- LIQUID OUTER CORE is a liquid
due to changes in pressure, aprox.
2000KM thick, made out of iron and
nickel, extremely hot
- SOLID INNER CORE is the hottest,
with temperatures of 5500-6000,
made out of iron and nickel, 1300KM
thick
- DESTRUCTIVE PLATE
MARGIN
- O-O TWO PLATES
CONVERGE, DENSER
OF THE TWO WILL BE
SUBDUCTED
- PACIFIC AND
PHILIPPINE PLATE
- MOVING TOWARDS
EACHOTHER, THE
DENSER OF THE TWO
WILL BE SUBDUCTED,
CREATES: DEEP SEA
TRENCHES AND ISLAND
ARCS
- EARTHQUAKES; YES
VOLCANOES:YES
- C-C two continental plates,
much lower density, not much
subduction, produce FOLD
MOUNTAINS, NO VOLCANIC
ACTIVITY, TRIGGER SHALLOW
FOCUS EARTHQUAKES,
INDO-AUSTRALIAN PLATE 5.8
COM YEAR
- MOVING TOWARDS EACHOTHER,
FOLD MOUNTAINS
- INDO-AUSTRALIAN AND
EURASION PLATE
- EARTHQUAKES:YES
VOLCANOES:NO
- O-C PLATES CONVERGE,
MORE DENSER OCEANIC
CRUST IS SUBDUCTED
UNDER THE LESS DENSE
CONTINENTAL
- NASCA AND
SOUTH AMERICAN
PLATE
- EARTHQUAKES:YES
VOLCANOES: YES
- MORE DENSER OCEANIC CRUST IS
FORCED UNDER THE LESS DENSE
CONTINENTAL (SUBDUCTED)
CREATES: DEEP SEA TRENCHES AND
YOUNG FOLD MOUNTAINS
- DEEP SEA TRENCH- PERU CHILE TRENCH IN THE PACIFIC OCEAN
- CONSERVATIVE PLATE MARGIN
- TWO PLATES SLIDE PASS EACHOTHER EITHER IN THE
SAME DIRECTION AT A FAST SPEED OR IN OPPISITE
DIRECTIONS
- EARTHQUAKES: YES
VOLCANOES:NO
- CREATES LOW RIDGES
- NORTH AMERICAN
AND PACIFIC PLATE
SAN ANDREAS FAULT
- Theory
- Wegener
- Wegener suggested that all the
continents once fitted all together in
one super continent, PANGEA, 300 mil
years ago. Which later split into
North:Laurasia and
South:Gondwanaland. Published in
1912
- Why was he not believed?
- he was a METEOROLOGIST which studies the
weather, couldn't explain SEA FLOOR SPREADING,
GERMAN didn't help due to the cold war, already
EXPLANATIONS approved (land bridges)
- Evidence
- CLIMATOLOGICAL,
ANTARCTICA, NORTH
AMERICA, SVALBARD AND UK
CONTAIN COAL DEPOSITS OF
SIMILAR AGE- COAL IS ONLY
FORMED IN TROPICAL
CONDITIONS, THEY ARE NO
LONGER IN TROPICAL
CONDITIONS, MUST HAVE
MOVED FURTHER FROM THE
EQUATOR
- BIOLOGICAL, SIMILAR FOSSIL
FORMATIONS FOUND ON
EITHER SIDE OF
ATLANTIC-MESOSAURUS,
PLANT GLOSSOPTERIS IS A
FERN THAT HAS BEEN FOUND
IN AFRICAAUSTRALIA, SOUTH
AMERICA
- GEOLOGICAL,
SIMILAR GLACIAL
DEPOSITS- AMERICA
INDIA ANTARCTICA,
ROCKS OF SAME AGE
AND TYPE AND
DISPLAYING SAME
FORMATION- SE
BRAZIL AND SOUTH
AFRICA
- JIGSAW FIT OF CONTINENTS,
THE WESTERN SEABOARD OF
AFRICA AND EASTERN
SEABOARD OF SOUTH
AMERICA
- Further evidence to prove
- Mid-Atlantic ridge was
discovered in 1948, it ran
from the north to the south
of the Atlantic Ocean
(1000KM WIDTH 2.5KM
HEIGHT)
- HARRY HESS 1962, found the
youngest in the middle and the
oldest nearest to the USA and
the CARRIBEAN, with the
newest near ICELAND (rate of
spreading 5cm)
- Palaeomagnetism
confirmed sea floor
spreading, it studies
the earth magnetic
field. Changes every
400,000 years,
magnetite align
themselves with it
- CONSTRUCTIVE PLATE MARGIN
- DIVERGING PLATES, THE MANTLE BENEATH IS
UNDER PRESSURE THEN RELEASED AT THE
MARGIN
- CREATES MID-OCEAN RIDGE
AND RIFT VALLEYS, EAST
AFRICAN RIFT VALLEY
- EURASIAN AND
NORTH AMERICAN
PLATE