Divergent Plate Boundaries Flashcards

Study Notes

Divergent Plate Boundaries

Divergent plate boundaries occur when two tectonic plates separate, leading to the formation of new land, primarily in oceanic regions.
The Mid Atlantic Ridge is a prominent example of a divergent plate boundary located in the ocean.
The Great Rift Valley in Africa represents a land-based divergent boundary that is anticipated to eventually fill with water and create a new sea.

Mid Ocean Ridges

Mid ocean ridges are where tectonic plates pull apart, resulting in the formation of a rift valley between the separating plates.

Evidence of Plate Movement

One form of evidence for tectonic plates moving apart is the symmetrical age of the sea floor on either side of mid-ocean ridges.
Another form of evidence involves magnetic pole reversal, indicating changes in Earth's magnetic field over time.

Crust Age Comparison

Continental crust is significantly older than oceanic crust, illustrating the different geological histories of these landforms.

Rift Valley

A rift valley is specifically the area within a mid-ocean ridge where tectonic plates are actively separating and new crust is forming.

Rock Age Distribution

The youngest rocks are located in the rift valley of mid-ocean ridges, while the oldest rocks are found furthest from the ridges, on the Atlantic coasts of North America and Africa.

Continental Drift Evidence

The age similarity of rocks on the Atlantic coast of North America and the west coast of Africa supports Wegener's theory of continental drift, indicating that these landmasses were once joined.

Hot Spots

Hot spots are locations of superheated magma plumes rising from the mantle and are not associated with plate boundaries; they are stationary while tectonic plates move over them.
Hot spots provide indicators of the speed and direction at which tectonic plates are shifting.

Examples of Hot Spots

Notable hot spots include the Galapagos Islands, Hawaiian Islands, Yellowstone National Park, and Iceland.

Iceland's Formation

Iceland is currently being shaped by two main forces: the Mid Ocean Ridge and the presence of hot spots.

Key Definitions

A plume refers to an upwelling column of magma from the Earth's mantle.
Convection currents are cycles of heating, rising, cooling, and sinking that drive plate movement.
Convection describes the process where heated fluid rises while cooler fluid sinks, facilitating energy transfer within molten rock.
Density is defined as mass per unit volume, which influences the behavior of materials within the Earth's layers.
Tectonic plates are sections of the Earth's lithosphere that shift due to underlying convection currents.

Magnetic Reversal

Magnetic reversal occurs when the outer core's flow changes, which alters Earth's magnetic field direction, providing evidence of tectonic plate movement through the differing orientations of magnetized rocks found symmetrically along ocean floors.

Description

Test your knowledge of divergent plate boundaries with these flashcards. Learn about the locations, formation, and examples, such as the Mid Atlantic Ridge and the Great Rift Valley. Perfect for geology students seeking to understand tectonic processes.