PLATE TECTONIC EVIDENCE

Praag Dogra

Timeline

■ 1620■ 1820■ 1913■ 1945-1960■ 1963 (x3)■ 1964■ 1970■ 1990+

1620 – Francis Bacon

■ Francis Bacon came up with the idea of a ‘Jig-saw’ fit of the continents.

■ He noted that the South American Continent fitted in with the African Continent.

1820

■ Palaeontology geology was founded and suggested fossil similarities across continents over the earth

■ Glossopteris, Lystrosaurs and Mesosaurus are among the most noted fossils found over earths continents

1913 – Alfred Wegener■ Alfred Wegener suggested the theory of continental drift■ He spotted rock similarities across oceans basins and mountain chains

over the world■ He found Paleoclimatic evidence of glacial metamorphic ground

moraine (rock deposits) like Tillite in Namibia and chalk in the UK■ This evidence suggests that Namibia and the UK must have both been

over the equator over the last 200 million years

1945-1960

■ The Worlds scientists mapped the sea floors

1963 (1) – Harry Hess

■ Harry Hess suggested that convection currents are responsible for the spreading of the sea floor

1963 (2) – Vine and Matthews

■ Fred Vine and Drummond Matthews found that there are Paleomagnetic stripes either side of the Indian ocean ridge

■ It shows how Earths magnetic field reverses its polarities over time. As this occurs, there are extrusions of magma (called hematite) which solidify pointing the magnetic pole at their time of solidification. This causes a series of alternation north and south facing parallel polarity stripes of rock wither side of the Indian mid ocean ridge.

1963 – USA and USSR

■ During the cold war, the US and USSR placed over 100 seismometers across the oceans to find out the impact of bomb testing and their sizes.

■ What was actually found was high proportions of earthquakes across destructive plate boundaries.

1964

■ This is the date of the Great Alaskan earthquake.■ This was the reason for finding subduction at destructive plate

boundaries.

Early 1970’s

■ There was the invention of seismic tomography■ This measured the P and S waves through the lithosphere

1990’s +

■ This was when there was an increase in the use of GPS measurements for more accurate readings.