plate techtonics Flashcards
test revise
how old is earth
The Earth is estimated to be around 4.6 billion years old,
3 features of Precambrian Era
land masses began to form
intense volcanic activity that released toxic gases into the atmosphere.
emergence of early life in the form of bacteria,
when was the Palaeozoic Era
540 million – 250 million years ago
4 features of Palaeozoic Era
formation of Pangea
Cambrian explosion
emergence of land plants, insects, and reptiles.
Permian extinction
when was the Mesozoic Era
250 million – 65 million years ago
3 features of Mesozoic Era
dominance of reptiles
Pangaea broke apart
mass extinction caused by an asteroid
when was the Cenozoic Era
65 million years ago – Present
4 features of Cenozoic Era
the rise of mammals, birds, and flowering plants.
The Earth’s climate cooled and dried,
shaping the continents into their present forms.
The first humans appeared
what are the 4 Era’s in chronology order
Precambrian Era
Palaeozoic Era
Mesozoic Era
Cenozoic Era
what is the earths 4 layers called from outer to inner
Crust to Mantle to outer core to inner core
what are the properties of the crust
(location)
(basic properties)
This is the outer skin of the Earth and it is very thin and brittle. It is broken into pieces.
what are the properties of the Mantle
(location)
(length)
(material)
This layer is between the crust and the inner core. This is the thickest layer (2900-3000km). It is made up of hot molten rock.
what are the properties of the outer core
(material)
(product)
This layer is made of liquid iron nickel and creates Earth’s magnetic field as it spins.
what are the properties of the inner core
(location)
(material)
(temperature)
This is the central layer of Earth’s structure and is made up of solid iron nickel. It is the hottest layer at 5500 degrees C.
name the 3 main people that observed the plate tectonics theory in order
Alexander von Humboldt
Alfred Wegener
Harry Hess
what was Alexander von Humboldt’s contribution to the plate tectonics theory
Noticed how the coastlines of South America and Africa seemed to fit together like puzzle pieces.
Suggested that Earth’s continents might have once been connected.
what was Alfred Wegener’s contribution to the plate tectonics theory (what evidence did he provide)
stated the theory of continental drift, and that all continents were once joined in a supercontinent called Pangaea
(evidence)
Fossils: Similar fossils found on continents separated by oceans.
Geological Features: Mountain ranges on different continents lining up.
Climate Evidence: Fossils of tropical plants found in Antarctica.
what was Harry Hess’s contribution to the plate tectonics theory
proposed the hypothesis of seafloor spreading.
what were the past 4 super continents in chronological order
1 Nuna
2 Rodinia
3 Gondwana
4 Pangea
formation of Nuna
Formation: 1.8 billion years ago
formation of Rodina
Formation: 1.1 billion to 750 million years ago
formation and time period of Gondwana
Formation: 550 million years ago
Time Period: Late Precambrian Era
formation and time period of Pangea
Formation: 335 million years ago
Time Period: Late Paleozoic & Mesozoic Era
name a possible future super continent
Pangea Ultima
Aurica
Novopangea
Amasia
what are the 4 types of plate boundary
Conservative Boundary
Collision Boundary
Destructive Boundary
Constructive Boundary
what happens at Conservative Boundary
The two plates are sliding in the same direction/opposite directions.
As the plates slide past each other they get stuck.
Pressure and tension builds up as the plates lock together.
Eventually, the plates snap causing a sudden surge of energy.
What happens at Collision Boundary
Two continental plates crash into each other.
As they collide, they trigger earthquakes.
The rocks between the plates get pushed up and folded - because they are the same density.
What happens at Destructive Boundary
Two plates are pushed together, and the heavier oceanic crust gets subducted beneath
the lighter continental crust.
Heat from friction and the mantle starts to melt the subducted plate into magma.
This magma builds pressure, eventually breaking through the crust as a volcano.
What happens at Constructive Boundary
Two plates move apart from each other.
A gap appears, and molten magma rises to fill the gap.
This solidifies to create new rocks on the sea bed.
Over time, the layers of new rock build up and break through the surface of the ocean.
what do Conservative Boundaries cause
Earthquakes
what do collision boundaries cause
Fold mountains & Earthquakes
what do destructive plate boundaries cause (3 things)
Volcanoes, Earthquakes, Deep Ocean Trenches
what do constructive plate boundaries cause (4 points)
Mid-Ocean Ridges, Volcanic Islands, Rift Valleys, Volcanoes
how does a Hotspot work
Earth’s core’s Heat rises through the mantle forming magma. and then through the crust’s cracks erupting as lava. then it solidifies. creating lands and as the plates move its like a conveyor belt constantly forming new islands.
where are the oldest and newest lands made by Hotspots
the oldest lands would be the furthest from the Hotspot while the recent ones would be closer due to the movement of the plate
All Volcanoes fall under 3 categories what are they and describe them
Extinct
Unlikely to erupt again. Volcanic activity finished.
Dormant
Erupted in the past 2000 years but not recently (sleeping).
Active
Erupted recently and likely to erupt again.
what are the 2 types of volcanoes
Shield Volcano
Composite Volcano
what are composite volcanoes:
shape (why)
what are they made of
feel of lava
The lava running down the volcano is thick like honey!
The volcano is made up of layers of ash and lava.
Composite volcanoes have a narrow base due to the slow-moving lava. It cools and sets before it travels far. This means there are steep sides.
what are composite volcanoes:
what plate boundaries are they found on
what are there eruptions like
what natural disaster happen when they erupt
found at destructive plate boundaries.
They have very violent eruptions, which forces volcanic bombs out of the vent. The lava also escapes through a number of vents.
Lahars (mudflows) can happen when rainwater mixes with ash.
What are shield volcanoes:
what plate boundaries are they found on
what are there eruptions like
They have very gentle eruptions and no volcanic bombs. Its lava runs downhill quickly and spreads over a long distance before it cools. and The lava escapes through one large crater, which means lots of lava reaches the surface.
Are found at constructive plate boundaries.
What are shield volcanoes:
shape (why)
what are they made of
feel of lava
Shield volcanoes are only made of lava.
Because the lava travels far before it sets, the base of the volcano is very wide and the slopes very gentle.
Shield volcanoes have thin runny lava which moves quickly.
what is a crater
Opening at the top of a volcano
what is a Magma Chamber
Store of hot molten rock beneath the volcano
What is Layers of ash and Lava
Build up overtime to form the sides of the volcano
What is a main vent
The tunnel in which magma rises to the top of the volcano
what is a secondary vent and cone
Allows magma to escape from the side of the volcano
what is a Lava flow
Molten rock flowing down the side of the volcano
what is a volcanic cloud
Gas, steam and ash escaping from the volcano
what is a volcanic bomb
Large pieces of rock ejected from the volcano
why do plates move
plates move because of convection currents in the mantle
what are convection currents
Convection currents are the circular movements of fluid caused by heat transfer, where hot, less dense material rises and cools down so then this cooler, denser material sinks, creating a continuous flow. In Earth’s mantle, these currents drive the movement of tectonic plates.
what is plate tectonics
movement of plate and the activity inside earth is called plate tectonics
give an example of a Hotspot and the island it created
the Hawaiian Hotspot Created the Hawaiian Islands such as Hawai’i
give me an example of Conservative Boundaries
San Andreas Fault
give me an example of Collision Boundaries
Himalayas
give me an example of constructive boundaries
Mid-Atlantic Ridge
give me an example of Destructive plate boundaries
Andes Mountains
give me a example of Composite Volcanoes
Mount Fuji.
give me a example of a shield volcano
Mauna Loa in Hawaii.
when was the Precambrian Era
4.6 billion to 540 million years ago
