. Flashcards
(38 cards)
What happens at constructive margins?
Magma rises through the gap between two tectonic plates, resulting in volcanoes
This process often occurs below the ocean surface, forming mid-ocean ridges.
What is a plate margin or plate boundary?
The line where two adjacent tectonic plates meet.
What are the four types of plate margins?
- Destructive Margins
- Constructive Margins
- Collision Margins
- Conservative Margins
What occurs at destructive margins?
One tectonic plate made of oceanic crust dives beneath another plate, leading to pressure build-up and potential earthquakes.
What is subduction?
The process where a denser tectonic plate sinks beneath another plate.
What can happen when the sinking plate gets stuck at destructive margins?
A build-up of pressure occurs, which can lead to sudden slippage and powerful earthquakes.
True or False: Volcanoes can only be found at plate margins.
False
Volcanoes can also be found away from plate margins, such as the Hawaiian Islands.
What is the Pacific Ring of Fire?
A belt of volcanoes that encircles the Pacific Ocean.
Fill in the blank: Earthquakes and volcanoes are unevenly distributed around the Earth’s surface and are clustered in ________ that correspond to the positions of plate margins.
linear belts
What type of plate margins do earthquakes occur most frequently?
Destructive margins.
What are conservative margins characterized by?
Two plates moving past each other in opposite directions or in the same direction.
What is a notable example of a conservative margin?
The San Andreas Fault in California.
What is a hotspot?
A volcanic region that can occur away from plate margins.
What causes the friction and heat generation at destructive margins?
The interaction of the sinking plate with the overriding plate.
What is created when the continental crust buckles upwards at collision margins?
A range of mountains.
At which type of margin do no rising magma eruptions occur?
Collision margins.
What was the Earth like when it formed 4.56 billion years ago?
A sphere of molten rock, held together by gravity
What happens to denser substances during Earth’s formation?
They sink to the middle
What happens to lighter substances during Earth’s formation?
They rise to the top
What is the state of some substances towards the center of the Earth?
They remain molten due to heat from radioactive elements
What is the average thickness of continental crust?
30-50 km
What is the average thickness of oceanic crust?
7 km
What type of rock is primarily found in the continental crust?
Granite
What type of rock primarily makes up oceanic crust?
Basalt
