Alfred Wegener• He was an astronomer of 20st century.• He noticed that some places were separating from each other while in other parts of the globe were places bringing closer.• He proposed that the continents we know today were once all attached in a single landmass called…
Pangaea• In the past, all the continents formed a single one: Pangaea.• Because of some force* they separate from each other and nowadays have their actual position.• To test his hypothesis he gave some kinds of evidences
Evidences• Shape of continents: South America and Africa.• Fossil evidence on the shape of continents:• Matching rock types.• Geologic structures.• Ancient climate partners.
But…• He did not answer what induce it: the force what induces the displacement of continents.• So, his theory did not came up.
How was the theory accepted?• Arthur Holmes published his idea that thermal convection in earth’s mantle bankrupts the mantle and makes moving landmasses, continents.
How was the theory accepted?• Holmes suggested that the continents didnt move but were ‘carried’.
And in World War II• Discoveries of the Mid-Ocean Ridge and the work of Harry Hess and others led to the development of plate tectonics.• After that the theory of Continental Drift was engaged wide acceptance.