TECTONIC PLATES & CONTINENTAL DRIFT

Where did we use the term tectonic plates in the previous lecture?

What is the age of the earth?

TWO THINGS TO REMEMBER

What is tectonic plates?What are the different tectonic plates?What is the history of tectonic plates?Do the tectonic plates move?Briefly explain the movement of plates?What is continental drift?What is the evidence of continental drift?

SYNOPSIS

IAL - ?

THE KEYWORD, PLEASE

CANZA, (Clue : The 4th theatre in Coimbatore is still kicking, Akka)

AABRAIN (Clue : Dubaia, Bahraina, Sharjahava?)

RICARBEAN (Clue : West Indies)

THE NAMES, PLEASE

THE BEST ACTOR, PLEASE

The lithosphere is divided into several slabs or blocks or plates. These plates are supported from below by Asthenosphere. These plates are called Lithosphere plates or Tectonic Plates.

Some of these plates encompass continents, some of these plates encompass oceans and some of the plates encompass both oceans and continents.

1. TECTONIC PLATES

The plates are divided into three categoriesPrimary PlatesSecondary PlatesTertiary Plates

The primary plates and secondary plates are together called major plates.

The tertiary plates are sub divisions of Primary and Secondary Plates

2. DIFFERENT TECTONIC PLATES

PrimaryAfrican PlateAntarctic PlateEurasian PlateIndo-Australian Plate (sometimes Indian and Australian)North American PlatePacific PlateSouth American PlateSecondaryArabian PlateCaribbean PlateCocos PlateJuan de Fuca PlateNazca PlatePhilippine Sea PlateScotia Plate

DIFFERENT TECTONIC PLATES

225 million years ago (Permian) PANGAEA200 million years ago (Triassic)LAURASIA, GONDWANA125 million years ago (Jurassic)NENA,COLUMBIA,ZEALANDIA65 million years ago (Cretaceous)LEMURIACURRENT150 million years laterAMASIA

3. HISTORY OF TECTONIC PLATES

4. DO THE TECTONIC PLATES MOVE?

MOVEMENT OF TECTONIC PLATES

The movement of tectonic plates is believed to be induced by the asthenosphere which induces heat and convection currents.

The plates are capable of drifting with respect to each other along their plate boundaries.

Based on the plate movement, there are 3 principal type of boundaries namelyDiverging BoundariesConverging BoundariesTransform Boundaries

Divergent Boundary – moving _____Convergent Boundary – moving ________Transform Fault Boundary – moving

_____________

Divergent Boundaries North American Plate & Eurasian Plate

Convergent Boundaries South American Plate & Nazca Plate

Transform Boundaries North American Plate & Pacific Plate near the JDF Plate

EXAMPLES

When two continental plates diverge, a rift is created. Eg. East African Rift

When two oceanic plates diverge, a ridge is created. Sea Floor Spreading is said to occur.Eg. Mid Atlantic Ridge

When two oceanic plates converge, an island arc and trench are created.

When an oceanic and convergent plate converge, a volcano and trench are created.

When two continental plates converge, a mountain range is formed.

PLEASE NOTE

When two continental plates or oceanic plates or continental/oceanic plates transform, ______

PLATE MARGIN, ANY GUESSES?

PLEASE NOTE