In this presentation,it is taking about plate tectonics and sea floor spreading with suitable diagrams respectively. During and just after World War II, the technological improvement to submarines led to an improvement in underwater navigation and surveying that revealed many intriguing underwater features. The most important of these were immense, continuous chains of volcanic mountains running along the ocean basins. These features are now termed mid-ocean ridges or more accurately, oceanic ridge systems.
2. Plate Tectonics
• The science of plate tectonics has revealed the
nature of Earth’s crustal structure and internal
strata
• Contrary to what has been described ,
1.Earth’s crust is neither a jig – saw puzzle nor a set
of geometrically identical segments.
2.Continents are neither separate from nor
structurally independent of oceans , seas and each
other.
3.Also land massses do not sit atop oceans and seas
(i.e. SIAL does not float over SIMA).
3. According to the principle of plate tectonics :
• Earth’s crust (lithosphere) is a fluid mosaic of
many irregular rigid segments or plates.
• These plates drift about slowly, yet steadily in
different directions atop much hotter and softer
layer of Earth’s mantle, the asthenosphere.
• These enormous blocks of Earth’s crust vary in
size and shape, and have definite borders that
cut through continents and oceans alike.
4.
5. • Where plates converge , mountains and volcanoes
are often found.
• Oceans are born and grow wider where plates
pull apart
• Earthquakes are the result of plates grinding and
slipping past each other.
• The energy responsible for these tectonic plate
shifts, drifts , collisions, and interactions
originate deep in Earth’s inner core and
interactions originate deep in Earth’s inner core
and is manifest in the outer core/ mantle
dynamics.
6. Plate tectonics is the theory that Earth’s outer
shell is divided into several plates that glide
over the mantle , the rocky inner layer above
the core. The plates act like a rigid shell
compared to Earth’s shell compared to Earth’s
mantle. This strong outer layer is called the
lithosphere
7.
8.
9. Harry Hammond Hess (May 24, 1906-August 25,
1969) was a geologist and U.S. navy officer in
WW II. Considered one of the “founding
fathers” of the unifying theory of plate
tectonics.
13. Vine –Matthews-Morley hypothesis
Geophysicist Frederick John Vine and the
Canadian geologist Lawrence W. Morley
independently realized that if Harry Hess’s sea
floor spreading theory was correct, then the
rocks surrounding the mid-oceanic ridges
should show symmetric patterns of
magnetization reversals.
