Plate Motions and Earth's Geological History

This set of vocabulary flashcards covers key concepts of plate tectonics, the geologic record, and the evidence for Earth's surface changes over time.

Lithosphere

The rigid outer layer of Earth, which is divided into major and minor tectonic plates that drift relative to each other.

Tectonic Plates

Large sections of the Earth's lithosphere that move slowly, reshaping continents and ocean basins over time.

GPS and Seafloor Mapping

Technological methods used to confirm that tectonic plates move at rates of a few centimeters per year.

Mid-ocean Ridges

Geological features produced at the boundaries where tectonic plates diverge from one another.

Trenches

Geological features formed in zones where tectonic plates converge.

Transform Faults

Geological features created in areas where tectonic plates slide past each other.

Geologic Record

The evidence preserved in rock layers and fossils that documents Earth's dynamic history, including ancient seas and volcanic eruptions.

Unconformities

Discontinuities in rock layers that preserve sequences of events and mark gaps in the geologic record.

Fossil Assemblages

Matching sets of fossils found across separated continents, such as South America and Africa, indicating they were once part of the same landmass.

Sedimentary Layers

Sequences of rock, including fossil-rich limestone and volcanic ash, that help geologists reconstruct Earth's past environment.

Cross-cutting Relationships

A geological principle used to study sequences of events by observing how features intersect within rock layers.