Convection currents in the mantle drive the movement of tectonic plates.
The mantle is made of solid rock.
The three main types of plate boundaries are convergent boundaries, divergent boundaries, and transform boundaries.
The features of a divergent plate boundary include mid-ocean ridges, rift valleys, and volcanic activity.
The features of a convergent plate boundary include subduction zones, volcanic arcs, and mountain ranges.
Transform plate boundaries are characterized by the horizontal sliding of two lithospheric plates past each other, resulting in earthquakes and the absence of volcanic activity.
Characteristics of a convergent plate boundary include the collision or subduction of tectonic plates, the formation of mountains or trenches, and the potential for volcanic activity and earthquakes.
At a transform plate boundary, two tectonic plates slide past each other horizontally, causing earthquakes.
At a convergent plate boundary, two tectonic plates collide and can either form mountains or cause one plate to be subducted beneath the other.
At a divergent plate boundary, two tectonic plates move away from each other, creating a gap where magma rises to form new crust.
Subduction in plate tectonics is the process where one lithospheric plate sinks beneath another into the Earth's mantle.
The two types of crust on Earth are continental and oceanic.
The three main layers of the Earth are the crust, mantle, and core.
Some evidence for continental drift are:
continental fit
similarity of rocks and mountain ranges
fossil evidence
Alfred Wegener proposed the Continental Drift hypothesis in 1912.
The pangea consists of:
Laurasia (Northern land mass)
Gondwana (Southern land mass)
Features of the seafloor includes:
Continental margin
Abyssal plain
mid-oceanic ridges
Ocean trenches
Convection: the hot fluid goes up, cold fluid goes down.
Paleomagnetism is the remnant magnetism in ancient rocks.
Seafloor spreading was proposed by Harry Hess in 1962.
Seafloor spreading theory suggested that seafloor separates at oceanic ridges and provided the “how” to Wegener’s hypothesis.
Oceanic crust at the spreading ridges are younger than oceanic crusts farther from ridges.
Unifying Theory
Patterns of the continents
Patterns of seafloor ages
Patterns of seafloor depth
Patterns of magnetism
Patterns of volcanoes
Patterns of earthquakes
Examples of convergent (oceanic-oceanic) boundaries can be seen in Japan and the Philippines.
An example of oceanic-continental convergent is the Andes.
An example of continental-continental is the Eurasia-India plate/Himalayan mountains.
What moves the plates?
Convective heat system and gravity-driven plate motion
What are some sources of heat?
Radioactive decay, accretion, and differentation
What is ”slab-pull”?
Pulling the platebehind a subduction cold slab of lithosphere
What is “ridge-push”?
Gravity pushes oceanic lithosphere away from higher spreading sites and towards subduction.