Geology and Paleontology: Key Concepts and Plate Tectonics

Organic

Living or once living and made of carbon

Fossil

The preserved evidence in rocks or soils of organisms that were once alive

Palaeontology

The study of prehistoric life

Sedimentary Rock

Formed from deposits of pre-existing rocks, minerals, or organic matter that are compacted and cemented together on or near the Earth's surface

Geological Time Scale

A time scale showing the history of the life and geology of Earth

Relative dating

A method of dating in which the age of one fossil or rock is compared with that of another

Absolute dating

A method of determining the actual age of rocks and fossils

Radioactive isotope

An atom with an unstable nucleus that spontaneously emits energy and particles (radiation) to become more stable

Half-life

The time it takes for half of a radioactive sample to decay

Law (or Principle) of Superposition

States that in an undisturbed sequence of rock layers, the oldest layers are at the bottom and the youngest at the top

Continental Drift

The separating of continents by drifting across Earth's surface

Pangaea

A supercontinent that existed 300 million years ago and was made up of all the continents of today

Gondwana

A supercontinent made up of modern day South America, Africa, Australia, India, Madagascar and New Zealand

Tectonic plates

Section of Earth's crust that moves about on Earth's surface

Magnetic Striping

Patterns of magnetism trapped in rocks on each side of plate boundaries

Convergent boundary

Where plates are colliding with each other

Transform boundary

Where plates are sliding parallel to each other but in opposite directions

Divergent boundary

Where plates are moving apart from each other in opposite directions

Subduction

When one plate sinks below another plate during a collision

Convection current

Churning circulation of the Earth's semi-solid mantle, driven by heat of the Earth's core

Faulting

Process where rocks break and move along a fracture, causes a displacement of rock masses (caused by transform boundaries