Continental Drift Theory
Alfred Wegener (1912) · Pangaea & Panthalassa · Laurasia & Gondwanaland (28 Micro-Realms)
The Mobilist Revolution (1596 – 1912)
First noted by Abraham Ortelius (1596) and mapped by Antonio Pellegrini (1858), the Continental Drift Theory was formally propounded by German meteorologist Alfred Wegener in 1912—proposing that all continents once formed a single supercontinent, Pangaea ("All Earth"), surrounded by a mega-ocean, Panthalassa ("All Water"), which began splitting 200 million years ago into Laurasia and Gondwanaland.
I. Early Precursors & Alfred Wegener's 1912 Hypothesis
Abraham Ortelius (1596)
- Dutch mapmaker (1596)
- First proposed symmetrical fit
- Americas, Europe & Africa
Antonio Pellegrini (1858)
- First joined 3-continent map
- Matched plant fossils
- Atlantic opening illustration
F.B. Taylor (1910)
- American geologist (1910)
- "Creeping" polar continents
- Equatorward mountain building
Alfred Wegener (1912)
- German meteorologist & geophysicist
- Comprehensive Drift Theory (1912)
- Book published in 1915
Palaeoclimatic Paradox
- Climatic zone shifts in past
- Either climate zones shifted
- Or landmasses drifted!
SIAL Rafting on SIMA
- Lighter granitic SIAL continents
- Float on denser basaltic SIMA
- Assumed frictionless ploughing
Fixism vs Mobilism
- Old view: Sunken land bridges
- Violates isostatic buoyancy
- Mobilism: Continents split apart
II. Pangaea, Panthalassa & The 200-Ma Split
Supercontinent Pangaea
- Greek "Pan + Gaia" = All Earth
- Single united landmass
- Assembled in Late Palaeozoic
Mega-Ocean Panthalassa
- Meaning "All Water"
- Colossal surrounding ocean
- Ancestral Pacific Ocean
Carboniferous Intact State
- Intact during Carboniferous
- South Pole near Natal (SA)
- Equatorial coal belt in N.A./EU
The Tethys Sea
- Shallow East-West geosyncline
- Wedged into eastern Pangaea
- Divided North & South blocks
200 Ma Initial Split (NCERT)
- Began ~200 million yrs ago
- Early Mesozoic (Triassic/Jurassic)
- Rifted into 2 giant blocks
Laurasia (Angaraland)
- Northern supercontinent half
- North America + Greenland
- Europe + Asia (minus India)
Gondwanaland (Southern)
- Eduard Suess (Gond region, India)
- S. America, Africa, Madagascar
- Peninsular India, Australia, Antarctica
III. Mesozoic–Cenozoic Breakup of Laurasia & Gondwanaland
Central Atlantic Rift (180 Ma)
- Jurassic initial opening
- N. America splits from NW Africa
- Birth of North Atlantic
South Atlantic Unzip (130 Ma)
- Early Cretaceous rifting
- S. America separates from Africa
- Unzips from south to north
India & Madagascar Break
- Rifts from East Africa (160 Ma)
- Splits from Madagascar (88 Ma)
- Rapid northward sprint
Birth of Indian Ocean
- Opens behind drifting India
- Replaces shrinking Tethys Sea
- Réunion hotspot Deccan flood
Australia–Antarctica Split
- Eocene–Oligocene separation
- Australia drifts northward
- Isolates icy Antarctica
North Atlantic Final Split
- Laurasia rifts in Cenozoic (~60 Ma)
- Greenland separates from Europe
- Completes S-shaped Atlantic
Closure of Tethys Sea
- Africa & India collide north
- Crushes Tethys marine sediments
- Uplifts Alps & Himalayas
IV. Wegener's Drift Directions, Mountain Building & Legacy
Two Drift Vectors
- 1. Equatorward (North/South)
- 2. Westward (East to West)
- Wegener's dual movement scheme
Equatorward Drift
- "Flight from the Poles"
- Gravity + centrifugal bulge
- Drove Africa & India north
Westward Drift
- Sun & Moon tidal attraction
- Brakes against West-to-East spin
- Pushed N. & S. America west
Rockies & Andes Folding
- Leading western prow resistance
- SIAL crumples against SIMA
- Wegener's Cordillera explanation
Island Arc Festoons
- Trailing eastern margin lag
- Detached slivers left behind
- Kuril, Japan, Philippines arcs
Apparent Polar Wandering
- Magnetic poles stayed near axis
- Continents drifted over time
- 1950s palaeomagnetic vindication
Supercontinent Wilson Cycle
- Columbia $\to$ Rodinia $\to$ Pangaea
- 300–500 Myr assembly cycle
- Future Amasia / Pangaea Ultima
Core Distinctions
Laurasia (Northern): North America, Greenland, Europe, and Asia (north of the Himalayas). Gondwanaland (Southern): South America, Africa, Madagascar, Peninsular India, Arabian Peninsula, Australia, and Antarctica.
2. Why Peninsular India is Part of Gondwanaland, Not LaurasiaAlthough India lies in the Northern Hemisphere today, it was attached to East Africa, Madagascar, Antarctica, and Australia in the Southern Hemisphere until the Mesozoic breakup—sharing identical Gondwana coal seams and Glossopteris fossils.
3. Continental Drift (1912) vs. Plate Tectonics (1967)Wegener thought only the SIAL continents drifted like icebergs ploughing through stationary SIMA ocean floors. Modern Plate Tectonics proved that both continents and ocean floors move together as rigid Lithospheric Plates atop the ductile Asthenosphere.
Continental Drift Chronology
NCERT Chapter 4 Key Milestones