PLATE TECTONICS THEORY

PLATE TECTONICS THEORY

WHAT IS PLATE TECTONICS THEORY?

• In 1967, McKenzie and Parker suggested this theory of plate tectonics.
• It was formulated from the Continental Drift Theory, Convection Current Theory, etc.
• According to this theory, the Earth’s lithosphere is broken into distinct plates which are floating on upper part of the mantle- Asthenosphere.
• Tectonic plates vary from minor plates to major plates.

WHICH ARE MAJOR TECTONIC PLATES?

1. Antarctica and the surrounding oceanic plate
2. North American plate
3. South American plate
4. Pacific plate
5. India-Australia-New Zealand plate
6. African plate

WHICH ARE MINOR TECTONIC PLATES?

1. Cocos plate: Between Central America and Pacific plate
2. Nazca plate: Between South America and Pacific plate
3. Arabian plate: Mostly the Saudi Arabian landmass
4. Philippine plate: Between the Asiatic and Pacific plate
5. Caroline plate: Between the Philippine and Indian plate
6. Fuji plate: North-east of Australia
7. Caribbean plate
8. Juan de Fuca plate Turkish plate

HOW DO VARIOUS PLATES INTERACT?

WHAT IS THE SIGNIFICANCE OF PLATE TECTONICS?

• Almost all major landforms are formed due to this theory.
• New minerals are thrown up from the core to crust.
• E.g. like copper and uranium are found near the plate boundaries.
• The shape of landmasses in the future can be predicted from the present knowledge of crustal plate movement.
•  For example, if the present trends continue, North and South America will separate.

WHAT IS THE EVIDENCE IN SUPPORT OF PLATE TECTONICS?

• OCEAN DEEP DRILLING
• HOT SPOTS
• PALEOMAGNETISM
• MAGNETIC REVERSAL AND SEAFLOOR SPREADING