Geologic Time Flashcards

Flashcards covering key vocabulary and concepts from the Geologic Time lecture notes.

Mass Extinctions

Sudden catastrophic events that abruptly decimated life on Earth, followed by the emergence of new life-forms.

Permian Extinction

The most dramatic extinction event, occurring 248 million years ago, wiping out 90% of marine species and significant portions of terrestrial life.

Meteorite Impact

Extraterrestrial object suggested to have caused the terminal Cretaceous extinction.

Cretaceous Extinction

The extinction event that occurred 65 million years ago, wiping out one-fourth of all species, including the dinosaurs.

Iridium

Element found in high concentrations in the clay layer between rock layers with and without dinosaur fossils, suggesting a meteorite impact.

Meteorite Impact Hypothesis

Hypothesis supported by evidence of a large crater in the Caribbean Sea, explaining the Cretaceous extinction.

Volcanic Eruptions

Aerosols and gases from these can cause atmospheric cooling and warming, and have been linked to mass extinction events.

Flood Basalts

Large-scale outpourings of lava, such as those in Siberia 248 million years ago, possibly linked to the Permian extinction.

Supercontinent

The single landmass that formed when all continents joined together, affecting ocean currents and carbon dioxide levels.

Carbon Dioxide Removal

Process by which surface marine organisms remove carbon dioxide from the atmosphere and transport it to the sea floor.

Earth Systems Feedback Mechanisms

The feedback process involves tectonic plate movement altering ocean basins, which in turn affects currents and atmospheric composition, leading to a rapid extinction event.