Plate Tectonics and Geologic Time Flashcards

Flashcards covering key vocabulary and concepts related to plate tectonics.

Continental Drift

The hypothesis that continents were once joined together and have drifted apart over time.

Evidence for Continental Drift

Continental jigsaw puzzle fit, matching fossils on different continents, similar rock types and geologic features across continents, and evidence of ancient climates.

Pangaea

A supercontinent that existed millions of years ago, comprising most or all of Earth's landmasses.

Wegener's Continental Drift Hypothesis

Proposed that continents were once joined but lacked a plausible mechanism for how they moved.

Theory of Plate Tectonics

The scientific theory explaining the structure and movement of Earth's lithospheric plates.

Lithosphere

The rigid outer layer of Earth, consisting of the crust and uppermost part of the mantle.

Asthenosphere

The weak, ductile layer in the upper mantle beneath the lithosphere that allows for plate movement.

Ridge Push

A gravity-driven force that results from the elevated position of mid-ocean ridges pushing plates.

Slab Pull

The force resulting from the sinking of a cold, dense slab of oceanic lithosphere at a subduction zone, major driving force of plate motion.

Divergent Plate Boundaries

Constructive margins where plates move apart, resulting in the upwelling of magma and the creation of new crust.

Convergent Plate Boundaries

Destructive margins where plates collide, resulting in subduction or mountain building.

Transform Plate Boundaries

Conservative margins where plates slide past one another horizontally, without creating or destroying lithosphere.

Evidence for Plate Tectonics

Ocean drilling results, mantle plumes and hot spots, paleomagnetism.

Paleomagnetism

The study of the record of Earth's magnetic field in rocks, used to determine past locations of the magnetic poles and plate movement.

Plate Motion Measurement

Ocean drilling and GPS measurements.