Lesson 12 Mountain Building

Orogenesis

Is the name given to the geological processes that collectively produce a mountain belt.

Orogen: is the physical manifestation of orogenesis.

(or where a plate is breaking up)

Mountains form at plate margins

Mountains at divergent plate boundaries

Locations of Divergent Margins

Active processes: Normal Faulting (shallow earthquakes) Magmatism-mostly lava flows

East African Rift System

Rift Valley

Basin and Range Province

Mountains at convergent plate boundaries

Convergent Margins:

• Continent-Continent collision • Ocean-Continent subduction • Intra-Oceanic subduction

Locations of Convergent Margins

Active processes: Reverse Faulting (shallow and deep earthquakes) Magmatism-Large volcanoes

Intra-Oceanic Subduction

Volcanic island arcs form

Volcanic Island Arc

Mt. Fuji, Japan

Volcanic Island Arc

Jan 4, 2007

Soufrière Hills Montserrat

Ocean-Continent Subduction

Continental Volcanic Arc

• Volcanic arc • Accretionary wedge

Andean-type Orogen

Sierra Nevada Coastal Ranges

Collisional Mountain Ranges

Himalayan Orogen

Cenozoic Orogenic Belts

What about the Appalachians?

Supercontinent Cycle