DIVERGENT BOUNDARIES Divergent boundary of two continental plates

DIVERGENT BOUNDARIES

Divergent boundary of two continental plates. rift valley East African Rift Creates a _____. Example: _______

RIFT FORMATION

Length 70000 km. Width 3000 – 4000 km. Height 2 – 3 km in the axial rift zone. Characterized by shallow earthquakes (focus 2 - 8 km) in the axial rift, and small in magnitude. * First motion indicates that vertical faulting (Rifting) is the main mechanism. Ridge is not continuous, but offset by transform faults. OCEANIC RIDGE

Divergent boundaries also can rip apart ( ﺗﻤﺰﻕ rift) continents

Divergent boundaries: Chiefly at oceanic ridges (aka spreading centers)

SPREADING RATE AND TOPOGRAPHY OF OCEANIC RIDGE Slow 7 mm /year intermediate 7 -70 mm / year Mid Atlantic Ridge and SW Indian Ridges Carribbean Fast > 70 mm / year East Pacific Rice Rough topography Intermediate topography Flat topography Narrow magnetic Intermediate magnetic strips Wide magnetic strips

How magnetic reversals form at a spreading center. Width of strip depend on?

How rifting of a continent could lead to formation of oceanic lithosphere.

Doming (arching) or upwarping 3 arms: 2 successful while third fail e. g. , East Africa Rift (Birth) e. g. , Red Sea (Young) e. g. , Atlantic Ocean (Mature)

Pangea was ripped apart by such continental rifting & Drifted.