Himalayas

Origin and Formation of Himalayas

CONTINENTAL DRIFT THEORY• PROPOSED BY ALFRED WEGNER IN 1912• A SINGLE CONTINENT PANGAEA SORROUNDED BY A SINGLE OCEAN

PANTHALASA• 200 MILLION YEARS AGO PANGAEA BROKE INTO TWO MAJOR LANDMASSES-

ANKARA LAND AND GONDWANA LAND• INDIA WAS A PART OF THE GONDWANA LAND LOCATED IN THE SOUTHERN

HEMISPHERE

MOVEMENT OF CONTINENTS• CONTINENTS STARTED MOVING IN DIFFERENT DIRECTIONS• FORCE-TIDAL FORCE POLAR FLEEING FORCE

PLATE TECTONIC THEORY

• PROPOSED BY MCKENZIE,PARKER AND MORGAN IN 1969• EARTH CRUST IS MADE UP OF TECTONIC PLATES AND COMPRISES

OCEANS AND CONTINENTS.• FORCE-CONVECTIONAL CURRENT INSIDE THE EARTH

TYPES OF PLATE BOUNDARIES

• CONVERGENCE• DIVERGENCE• TRANSFORM FAULT

CONVERGENCE• In plate tectonics, a convergent boundary, also

known as a destructive plate boundary • An actively deforming region where two (or more)

tectonic plates of lithosphere move toward one another and collide.

• As a result of pressure, friction, and plate material melting in the mantle, earthquakes and volcanoes are common near convergent boundaries.

• When two plates move towards one another, they form either a subduction zone or a continental collision.

• During collisions between two continental plates, large mountain ranges, such as the Himalayas are formed.

•

DIVERGENCE• In plate tectonics, a divergent boundary or

divergent plate boundary is also known as a constructive boundary or an extensional boundary

• It is a linear feature that exists between two tectonic plates that are moving away from each other.

• Divergent boundaries within continents initially produce rifts which produce rift valleys.

• Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges.

• Divergent boundaries also form volcanic islands which occur when the plates move apart to produce gaps which molten lava rises to fill.

TRANSFORM FAULT• A transform fault or transform boundary, also

known as conservative plate boundary• since these faults neither create nor destroy

lithosphere, is a type of fault whose relative motion is predominantly horizontal,

• most transform faults are hidden in the deep oceans where they form a series of short zigzags accommodating seafloor spreading

FOLDING• WHEN THE FORCE IS HORIZONTAL IT LEADS TO FOLDING

FAULTING

• WHEN THE FORCE IS VERTICAL IT LEADS TO FAULTING

Rift Valley

• A rift valley is when two normal faults occur parallel to each other and the land sinks between the faults.

• There are two major examples of this. One being the Great Rift Valley in North Africa and the other, the San Andreas Fault in California.

• The top right picture is San Andreas Fault and on the bottom right is a diagram of what a rift valley looks like.

FORMATION OF HIMALAYAS• HIMALAYAS HAVE BEEN FORMED DUE TO THE COLLISION OF TWO CONTINENTAL PLATES-

INDO AUSTRALIAN PLATE AND EURASIAN PLATE

RISING OF HIMALAYAS

EVIDENCES• ARTEFACTS USED BY STONE AGE PEOPLE• FOSSILS OF SEA ANIMALS IN HIGH HIMALAYAS• SEDIMENTARY ROCK MATERIALS