Evolution of Continental Drift Theory - Vocabulary

Vocabulary flashcards covering key terms related to the Continental Drift Theory, evidence, and plate tectonics from the notes.

Continental Drift Hypothesis

Proposed by Alfred Wegener; continents were once joined in a single supercontinent (Pangaea) and have since moved apart.

Alfred Wegener

Scientist who proposed the Continental Drift Hypothesis and supported it with coastlines, fossils, and rock similarities.

Pangaea

The supercontinent that existed before breaking up into Laurasia and Gondwanaland.

Laurasia

Northern supercontinent comprising what are now North America, Europe, and Asia before breakup.

Gondwanaland (Gondwana)

Southern supercontinent consisting of what are now South America, Africa, India, Antarctica, and Australia before breakup.

Tethys Sea

Ancient ocean that lay between the continents during the time of Pangaea; evidence of past connections.

Continental Fit

Observation that the shapes of continents appear to fit together like puzzle pieces.

Fossil Evidence

Similar fossils found on continents now separated, suggesting they were once connected.

Mountain Similarities

Similar rock formations and mountain ranges across continents indicating a shared geologic history.

Glacial Evidence

Evidence of past glaciation and similar glacial deposits across continents, indicating a connected past.

Paleoclimatic Evidence

Ancient climate indicators in rocks showing past conditions different from today.

Plate Tectonics Theory

Lithosphere is divided into rigid plates that move relative to one another.

Lithosphere

Rigid outer shell of Earth that includes the crust and upper mantle.

Seafloor Spreading

New oceanic crust forms at mid-ocean ridges and moves outward, separating plates.

Mantle Convection

Heat-driven circulation in the mantle that powers plate motions.

Hotspots

Fixed mantle plumes that create volcanic chains; their age patterns track plate movement (e.g., Hawaii).

Paleomagnetism

Study of ancient magnetic fields recorded in rocks; used to infer plate movements.

Apparent Polar Wandering

Apparent movement of the magnetic poles over time, explained by plate motion rather than a moving pole.

Mid-Ocean Ridge

Undersea mountain chain where seafloor spreading occurs and new crust forms.

Breakup of Pangaea

Event in which Pangaea split into the modern continents (Laurasia and Gondwanaland).

Permian Period

Geologic period preceding the Triassic (roughly 299–251 million years ago).

Triassic Period

Geologic period following the Permian; part of the timeline when Pangaea began to split.

Jurassic Period

Geologic period between Triassic and Cretaceous; continued continental breakup.

Cretaceous Period

Geologic period after Jurassic; ongoing plate movements and end with a major extinction event.