Geology and Plate Tectonics

Flashcards covering key concepts in geology and plate tectonics based on lecture notes.

Continental Drift

The idea proposed by Alfred Wegner in 1915 that continents are moving across the Earth's surface.

Seafloor Spreading

The process proposed by Harry Hess in 1960 that not only continents but the entire Earth's crust is moving, with new material appearing at mid-ocean ridges.

Paleomagnetism

The study of the record of the Earth’s magnetic field in rocks, where the Earth's magnetic polarity is locked in upon solidification of igneous rocks.

Plate Tectonics

The theory stating that Earth's surface is divided into plates that move and interact with one another.

Divergent Boundaries

Areas where tectonic plates are moving away from each other, often associated with mid-ocean ridges.

Convergent Boundaries

Areas where tectonic plates are coming together, which can lead to the formation of mountains or volcanic activity.

Transform Boundaries

Areas where one tectonic plate slides past another, often leading to earthquakes without volcanic activity.

Igneous Rocks

Rocks formed from molten rock, categorized by their silica content and grain size.

Sedimentary Rocks

Rocks formed from sediments or chemical precipitation, categorized into clastic, chemical, and biochemical rocks.

Metamorphic Rocks

Rocks formed by applying heat and pressure to pre-existing rocks, classified as foliated or non-foliated.

Epicenter

The point on the Earth's surface located directly above the focus of an earthquake.

Focus

The point inside the Earth where an earthquake originates.

Mercalli Scale

A qualitative scale that measures the intensity of an earthquake based on observed damage and human perception.

Richter Scale

A quantitative scale measuring the energy released by an earthquake, calculated from the amplitude of seismic waves.

Viscosity

A measure of a liquid's resistance to flowing; in volcanoes, it affects the explosiveness of eruptions.

Hotspot

An isolated area of volcanic activity, resulting in a chain of volcanoes as tectonic plates move over it.

Convection in the Mantle

The process driving plate tectonics, where hot mantle material rises, cools, and sinks, creating a cycle that moves tectonic plates.

Half-life

The time required for half of a sample of a radioactive isotope to decay, used in radiometric dating.