Grade 12 Geography unit 1: Major geological processes associated with plate tectonics

When the supercontinent Pangaea broke apart during the Mesozoic era, its northern part became known as Laurasia, while the southern part was called Gondwanaland.

Erta Ale is an active volcano because it has erupted within the last 500 years. Mount Zuqualla is classified as extinct, and Mount Kilimanjaro is dormant.

Along a transform boundary (conservative boundary), plates slide past each other horizontally along faults, so crust is neither created nor destroyed.

When rock layers are compressed and bend upward, they form an upfold called an anticline. A downward arch is called a syncline.

Fossils of Mesosaurus, a small reptile that lived about 250 million years ago, were discovered in both South America and Africa, supporting Wegener's theory.

The eastward-moving Nazca Plate is denser oceanic crust that is subducted beneath the westward-moving South American continental plate, producing the Andes Mountains.

More than 75 percent of annual seismic energy is released by shallow focus earthquakes, which originate at depths of less than about 60 kilometers.

Deposits that build upward from the cave floor are called stalagmites. Columns that hang down from the cave ceiling are called stalactites.

A dike forms when magma rises through a near-vertical crack and cools into a vertical sheet of rock. A sill is a horizontal sheet between layers, and a batholith is a massive dome-shaped intrusion.

The Ural Mountains (along with the Appalachians and Scandinavian Mountains) are old fold mountains dating back 250 to 300 million years. The Himalayas, Alps, and Atlas Mountains were formed during the recent Alpine orogeny.