Lecture 5 Flashcards

A series of flashcards covering key terms and concepts related to continental drift and plate tectonics for review.

Continental Drift

Theory proposed by Alfred Wegener suggesting that all continents were once part of a supercontinent called Pangea.

Plate Tectonics

The unifying theory in Earth sciences explaining the movement of Earth's lithospheric plates.

Convection Currents

Movements in the mantle that drive the process of plate tectonics.

Isostasy

The principle of buoyancy that allows continents to maintain their elevation without collapsing under weight.

Divergent Boundaries

Plate boundaries where plates move apart, creating rift valleys and new ocean basins.

Convergent Boundaries

Plate boundaries where plates collide, forming mountains or causing subduction.

Transform Fault Boundaries

Plate boundaries where plates slide past each other, often resulting in earthquakes.

Evidence from Fossils

Fossils like Glossopteris found in different continents, supporting evidence for continental drift.

American vs. European Scientists

Differences in acceptance of Wegener's theories, influenced by empirical vs. theoretical approaches.

Geological Evidence

Discovery of matching mountain ranges and identical rock types across continents.

Alfred Wegener's Proposal

In 1912, he proposed that continents were once part of a supercontinent, backed by geological and fossil evidence.

GPS Technology

Used to measure plate movements, illustrating that plates move approximately 2 cm/year.

Historical Context of Continental Drift

Continental drift ideas persisted beyond Wegener's death in 1930, leading to further research.

Scott's Antarctic Expedition

Expedition by Robert Scott that carried fossils supporting biodiversity connection across continents.

Geographical Transformations

Changes in Earth's surface due to cumulative plate movements over millennia.

Early Cartography and Observations

Early maps, such as the von Symoner map (1507), illustrate continent shapes. Sir Francis Bacon later observed that continent coastlines, like those of Africa and South America, appear to fit together like puzzle pieces, predating detailed geological theories.

Evidence of Mesosaurus Distribution

The discovery of Mesosaurus fossils exclusively in specific freshwater deposits in both South America and Africa provides compelling evidence that these continents were once joined, as the reptile could not have traversed the vast Atlantic Ocean.