Read pages 545 - 550 of Hamblin for details on the tectonic movements along Transform Boundaries. Other Continental Transform Fault boundaries: Dead Sea, New Zealand: the Southern Alps.

Far from Plate boundaries, the movement of plates and earth’s internal heat together produce a new set of landforms. These are produced at the Hot Spots above the mantle plumes.

Latest addition to the theory: in 1963 from observations in Hawaii. Volcanoes are progressively older along the direction of plate movement.

mantle plume

Hot spots do not drift with the plates. They are rooted deep in the mantle.

The lava erupted here are different from the ones produced at divergent plate boundaries: derived from deep in the mantle

Plumes rise from 400 -- 700 km below

Plumes carry materials of significantly higher temperatures (200ºc) than the mantle; ther rise from the base of the mantle; they are driven by internal heat;they lose heat with time (about 100 million years): temporary features.(Read pages 586 - 598 of Hamblin, but you may reduce the contents)

Iceland lies at the intersection of Mid-Atlantic Ridge but also sits on a mantle plume which makes the volcanic material different from the usual basaltic rocks of the mid-oceanic ridges.

60 million years ago

Today

30 million years ago

(Read pages 41 - 42 of Hamblin)

Plates and Plate Motion

Earth’s major features, rocks, structures can be understood from the interactions of the plates in the tectonic system1. Divergent margins: being pulled apart: marked by oceanic ridges2. North and South American plates are moving westward: interacting with Pacific, Juan de Fuca, Cocos, and Nazca plates3. Pacific plate is moving NW: deep sea trenches in western Pacific basin4. Australian plate, includes Australia, India and NE Indian Ocean: moving Northward: produced Himalayan Ranges, Volcanic Arcs of Indonesia5. African Plate, including Africa, SE Atlantic and W. Indian ocean: moving Northward: colliding with Eurasian plate6. Eurasian plate moving eastward7. Antarctic plate: includes Antarctica and floor of Antarctic Ocean: surrounded by oceanic ridges