Plate Tectonics Flashcards
The differences between the asthenosphere and the lithosphere
Is how these layers can flow.
Rocks in the lithosphere are rigid (meaning they can bend but cannot flow)
Rocks in the asthenosphere are plastic, meaning they can flow in response to deformation. Even though it can flow, the asthenosphere is still made of solid (not liquid) rock; you can think of it kind of like silly putty
What types of volcanism occur at divergent plate boundaries:
Mid-ocean ridge:
Fissures and vents:
Shield volcanoes:
Why?
Mid-ocean ridge:
Is an underwater mountain range formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath oceanic crust and create magma where two tectonic plates meet at a divergent boundary
Fissures and vents:
The fissures are deep cracks in the ground. Fissures can form in the areas surrounding large volcanic eruptions these events disrupt the earth’s surface, resulting in many fissures forming away from the central volcano. These fissures, just like the fissures under the ocean floor, allow magma to escape.
Shield volcanoes:
Are the result of high magma supply rates. They can be found along subduction related volcanic arcs or all by themselves
Convergent plate boundary
A tectonic plate ever two plates are moving towards each other, if the two plates are of equal density, they usually push up against each other, forming a mountain chain. If they are of unequal density, one plate usually sinks beneath the other kuna subduction zone
Divergent plate boundary
A tectonic boundary where tow plates are moving away from each other and new crust is forming from magma that rises from the earth’s surface between two plates.
The middle of the Red Sea, and the mid ocean ridge (running the length of the Atlantic Ocean( are divergent plate boundaries.
Transform plate boundaries
Are locations where two plates slide plates one another the fracture zone that forms a transform plate boundary is known as a transform fault.
Most transform faults are found in the ocean basin and connect offsets in the mid ocean ridges
Subduction
Subduction is a geological process that takes place at the convergent boundaries of tectonic plates where in plate moves under another and is forced the sink due to gravity in the mantle. Regions where this process occurs are known as subduction zones.
Trench
Ocean trenches.
Trench: very deep, elongated cavity bordering a continent or an island arc: it forms when one tectonic plate slides beneath another.
Volcanic arc:
a volcanic arc is a chain of volcanoes formed above a subduction plate, positioned in an arc shape.
Sea floor spreading
Sea floor spreading is a process that occurs at mid-ocean occurs at mid ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge
Mid-ocean ridge:
Is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary
Transform fault
A transform fault or transform boundary is a plate boundary where motion is predominantly horizontal. It ends abruptly and is connected to to another transform, a spreading ridge, or a subduction zone
The super continent cycle
Is a quasi-periodic aggregation and dispersal is the earth’s continental crust. There are varying opinions as to wether the amount of continental crust is increasing, decreasing, or staying about the same, but it is agreed that the earth’s crust is constantly being reconfigured.
Wilson cycles
The cyclical opening and closing of ocean basins caused by movement of the earth’s plates. The Wilson cycle begins with a rising plume of magma and the thinning of the overlying crust.
Fracture zone
A fracture zone is a linear oceanic feature-often hundreds, even thousands of kilometers long- resulting from the action of offset mid-ocean edge axis segments. They are a consequence of plate tectonics.
Hit zone/hot spot track
Are volcanic regions thought to be fed by the underlying mantle that is anomalously hot compared with the surrounding mantle
