Tectonic Plates Theory

What is tectonics in relation to the Earth?

Movement of the Earth’s lithosphere (crust + upper mantle) which is made up of the lithosphere.

What are plate tectonics?

Movement of discrete segments of Earth’s lithosphere in relation to one another, divided into more than a dozen plates.

What geological activities result from tectonic activity?

Earthquakes, volcanism, and mountain building.

What is mantle convection?

The process where convection of the Earth’s mantle raises hot rocks beneath mid-ocean ridges, which spread laterally, dragging the lithosphere above, cool, and sink back into the mantle.

How do volcanoes form in relation to tectonic plates?

As lava comes up from the ground, the moving plate forms volcanoes that can erupt multiple times over thousands or millions of years.

What happens to the age of the seafloor as it moves away from the ridge crest?

The crust gets older as it moves away from the ridge crest.

What are deep sea trenches formed by?

They are formed when one plate moves downwards.

Differentiate between active and passive boundaries.

Active Boundary: Intersection of boundaries with activity. Passive Boundary: No intersection or activity.

What are the three types of boundaries in plate tectonics?

Divergent, Convergent, and Transverse/Transform boundaries.

What occurs at divergent boundaries?

Plates move apart, hot material wells up causing tension that leads to faulting and cracking.

Describe convergent boundaries.

Plates move together, collide, causing stress, mountain building, or volcanism; subduction occurs here.

What characterizes transverse/transform boundaries?

Plates slide past each other, which can lead to earthquakes.

What evidence reemerged the continental drift theory in the 1950s?

Ruggedness of the ocean floor, confirmation of magnetic field reversals, seafloor-spreading hypothesis, and concentration of earthquake and volcanic activity along oceanic trenches.

How do glaciers relate to tectonics?

Glaciers flow from the ocean and are influenced by land movements and tectonic shifts.