Ooze
Pillowed Basalt
Sheeted Dyke Dolerite
Gabbro
Layered Peridotite

Crust- 5km
Upper mantle- 0-80km

pillow lava- lava erupts underwater, cools instantly into pillow like lumps

earthquakes- shallow focus earthquakes triggered by 1) upward movement of magma which empties the magma chamber and causes the roof to collapse 2) movement of oceanic plate stretches the crust and causes cracks and faults to open up and large crustal blocks sink down

black smokers- chimney like structures of mineral deposits, deposited from hot volcanic fluids flowing out of cracks

transform faults- large faults that cut across the mid oceanic ridge at right angles to the ridge axis.

7000km so is one of the largest mountain ranges in the world

subduction zone- descent of the heavier plate at an angle of between 30-50 degrees

trenches- areas of very deep ocean water (5000-11000m)

accretionary prism- massive zones of upthrusted oceanic sediments scraped off the surface of the subducting plate

fold mountains- uplift occurs along low angle thrust faults or by folding

volcanoes- melting of the descending plate triggers volcanism directly above the subduction zone. Andesitic volcanoes

earthquakes- jerky movement triggers earthquakes at various depths

oceanic-oceanic - create island arc volcanoes e.g Aleutian Islands in the Northern Pacific

continental-oceanic- occur along continental margin where they converge e.g along the wear margin of South America

MANTLE CONVECTION- magma that is hotter and less dense rises at the mid-ocean ridge and cooler, denser magma sinks

RIDGE PUSH- molten magma rises and heats the rock around it which expands and becomes elevated which produces a slope down away. Colder, denser rocks further away slide away due to gravity