CONTINENTAL DRIFT THEORY
• ABRAHAM ORTELIUS1596 1 st Proposed the movement of continent
• ANTONIO PELLEGRINI – Drew a map showing Europe, America and
Africa together
• ALFRED WEGENER -1912 Proposed ‘Continental Drift theory.
PANGAEA
PANTHALASSA

DRIFTING OF CONTINENTS
LAURASIA
TETHYS SEA
GONDWANA

EVIDENCE IN SUPPORT OF THE CONTINENTAL DRIFT
• The Matching of Continents (Jig-Saw-Fit) Bullard in
1964.
• Rock of Same Age Across the Oceans- Radiometric dating.
• Tillite: Sedimentary rock formed out of deposits of glaciers.
• Placer Deposite: Deposits of gold in Ghana coast and veins in Brazil.
• Distribution of Fossils: Lemur occur in India, Madagascar and Africa. Mesosaurus a small reptile’s skeletons are found in southern cape province of south Africa and
Iraver formation of Brazil.

FORCES
Pole-felling
(Due to rotation of earth)
Tidal
(Due to attraction of Sun & Moon)

• Convectional Current Theory- Arthur
Holmes in 1930.
• Mapping of the Ocean Floor:

CONFIGURATION OF SEA FLOOR

CONFIGURATION OF SEA FLOOR
CONTINENTAL MARGINS
1. SHELF
ABYSSAL PLAIN
2. SLOPE
3. TRENCHES
MID-OCEANIC RIDGES
1
2
4
3

DISTRIBUTION OF EARTHQUAKES AND VOLCANOES
•Mid-Atlantic ridges
•It bifurcates a little south of Indian subcontinent with one branch moving into East Africa and other meeting
Myanmar to New Guiana.
•Alpine Himalaya system.
•Rim of Pacific called Ring of Fire.

• The theory proposed by Hess in 1961.
• Volcanic eruptions are common along Midoceanic ridges.
• Rocks equidistant on either sides of crest of midoceanic ridges shows remarkable similarities.
• The Ocean crust rocks are much younger then continental crust.
• Sediments on the ocean floor are unexpectedly very thin.
• The deep trenches have deep-sheeted earthquakes.

• Theory proposed by McKenzie and
Parker and Morgan in 1967.
• Tectonic Plate ore Lithosphere Plate is massive, irregularly-shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
• Thickness 5-100km in ocean and upto
200km in continental areas.

1. Antarctica plate
2. North American Plate
3. South American Plate
4. Pacific Plate
5. India-Australia-New Zealand Plate
6. Africa Plate
7. Eurasia Plate

1. Cocos Plate: Between Central America and
Pacific Plate
2. Nazca Plate: South America and Pacific
Plate.
3. Arabian Plate: South Arabian landmass.
4. Philippine Plate: Asiatic and Pacific Plate
5. Caroline Plate: Philippine and Indian Plate.
6. Fuji Plate: North-east of Australia.

• DIVERGENT BOUNDARIES: When two plates move away from each other.
• CONVERGENT BOUNDARIES: When two plate move towards each other.
• TRANSFORM BOUNDARIES: When two plates slide horizontally each other.

Artic ridge has the slowest rate
2.5cm/year
East Pacific Rise near Easter
Island in the South Pacific fastest rate of movement 15cm/ year.

• Arthur Homes and Herry Hess convectional current