4. 1. The zone of motion between two plates is called plate
boundary.
2. Marginal part of a single plate is called plate margin.
Two plate margin meet at a common plate boundary.
3. All seismicity, volcanicity & tectonic activity is
localized amount plate margins.
4. Hence Boundaries between different plates are of
particular interest.
5. Depending on the relative motions of adjacent plates,
the plate boundaries are classified into three groups..
Divergent Boundary Convergent Boundary
Transform Fault Boundary
6. 1. Divergent boundaries are also called the constructive
zones. Because in these zones the new crust is
continuously created.
2. Divergent boundary form due to the two adjoining
plates are pulling move away from each other.
3. In the process of plate separation, the magma rises up
from the asthenosphere and fills the gap thus created.
In this way new crust is created along the trailing
edges of the divergent plates.
7. example:- Mid-Atlantic Ridge, which splits nearly the entire
Atlantic ocean north to south, is probably the best known &
most studied e.g. of divergent pate boundary.
8. 1. These boundary are also called destructive boundaries or
subduction zone.
2. Convergent boundary are boundaries along which two plates
during on each other.
3. The convergent boundaries are characterized by basaltic &
andesitic fold mountain ranges.
Types of Convergent Boundary :
Ocean to
continent
Ocean to Ocean Continent to
continent
10. Transform fault boundaries are boundaries along which
plates slides past one another & there is no production or
destruction of lithosphere.
Example : Most of the
transform fault occur in
the oceanic crust, a few
found within continuous ,
such as the San Andreas
fault (Southwestern
U.S.A.)
11. 1. The earth is of a constant surface area. It demands
that if the area of some plates increases that of other
must decreases.
2. Hence in theory it is parible that a plate may be
completely destroyed & mid oceanic ridges & deep
ocean trenches may migrate freely with respect to each
other.
3. Plates change both in size & shape. This means that
new plates can form by the breaking up or welding
together of other plates. This result in the birth &
death of ocean.
