The document summarizes four types of plate boundaries: 1) Destructive boundaries occur where oceanic crust sinks under continental crust, forming trenches and volcanoes. Examples are the Nazca and South American plate. 2) Constructive boundaries form where plates move apart and new crust is created, like at the Mid-Atlantic Ridge in Iceland. 3) Collision boundaries happen when continental plates crash into each other, pushing the crust upward to form mountain ranges like the Himalayas. 4) Conservative boundaries experience little change as plates slide past each other, such as the Pacific and North American plate along the San Andreas Fault in California.

1. Plate Margin Destructive Constructive Collision Conservative
Type of crust Oceanic and Continental Continental Continental
continental
Direction of plate Oceanic crust Two plates move Two continental Two plates move
movement moves towards away from each crusts collide sideways past each
continental crust other. New and as neither other – land is
but being heavier oceanic crust can sink, are neither formed nor
sinks and is appears, forming forced up into destroyed.
destroyed, mid-ocean ridges fold mountains.
forming deep sea with volcanoes.
trenches and
island arcs with
volcanoes.
Example of location Nazca and South Mid-Atlantic Indo-Australian Pacific and North
American plate, Ridge, e.g. and Eurasian American Plate, e.g.
Juan de Fuca and Iceland Plates, e.g. San Andreas,
the North Himalayas California
American plate
EARTHQUAKE Violent * * *
Less *
violent
Rare
VOLCANO Violent * None None
Less *
violent
Rare
Destructive plate boundary

2. Constructive plate boundary
Collision zone
Conservative plate boundary