Theory of Continental Drift
- The concept of drifting the continent was proposed by Antonio snider (French geographer) in 1858.
- The hypothesis of continental drift was prepared by Taylor in 1910.
- Alfred Wegener proposed the theory of continental drift in 1912.
- In the continental drift theory, Wegener proposed the first full-scale scientific theory which describes the breakup of a single supercontinent (Pangea) which was surrounded by the superocean named Panthalassa.
- The northern part of the Pangea includes North America, Europe, and Asia known as Angaraland or Laurasia.
- The southern block of Pangea includes Australia, peninsular India, Africa, South America, and Antarctica.
- The ocean named Tethys sea is situated between the northern and southern blocks of the Pangea.
- Sir, A. Wegener suggested that the existence of supercontinent Pangaea intact as early as about 300 million years ago, in the Carboniferous Period.
Breaking forces of Pangea described by the A. Wegner which caused the breakup of super continent.
- Basically, A. Wegner suggested that there are 2 major forces were responsible for breaking up the supercontinent: –
- The first one was the gravitational force which caused the movement of the continent at equator direction.
- The second force of cause was tidal forces generated by the gravitational pull by the sun and moon made the movement of continents in the direction of westward.
Evidences proposed by the A. Wegener which support the theory of Continental Drift
- A. Wegner presented that the coast structure of the Atlantic Ocean was in a shape of a jig saw fit. He focused on Africa and the S. American continent fig. 1 (Introduction Physical Geography by Alan Strahler).
- He presented several scientific evidences which proves the existence of Pangaea such as including the distribution patterns of fossils and present-day plant and animal species.
- The pieces of evidence from the time period of the Carboniferous Ice age showed the existence of the supercontinent of Pangea and the south pole was located near Durban at that time which was strong evidence of the A. Wegener’s Theory of continental drift.
- Wegener found many similarities in the geological history and structure of the coast of the Atlantic ocean.
Criticism of Wegener’s Continental Drift Theory.
- A. Wegener was failed for explaining that why the drift began only in Mesozoic era (Carboniferous Period) and not before.
Fig. 1: Alfred Wegener’s 1915 map fits together the continents that today border the Atlantic Ocean Basin.
- The theory of continental drift ignores the importance of the ocean.
- Within a few years, Wegener’s scenario was validated, but only by applying a mechanism for the process—seafloor spreading produced by mantle convection currents— that was never dreamed of in his time.
Significance of Continental Drift Theory
- Sir, Wegener was died in 1930 but his theory makes a platform for the development of different theories such as Arthur Holmes convection current, Harry Hess seafloor spreading theory and plate tectonic theory, etc.
- Data derived from different high-resolution geological earth observation satellite proves that rates of separation or of convergence between two plates are on the order of 5 to 10 cm (about 2 to 4 in.) per year, or 50 to 100 km (about 30 to 60 mi) per million years (Introduction physical geography by Alan Strahler).
:- Source, (Alan Strahler Introduction physical Geography)