Transcript Plate Boundaries PPT - Coventry Local Schools

Plate Boundaries
Plate Boundaries
Plate Tectonics
▪ Plate Tectonics – the theory that the
Earth’s lithosphere is divided into
tectonic plates that move around on
top of the asthenosphere
▪ The lithosphere is made of two types of
crust
▪ Continental – Less dense, Thicker on average
▪ Oceanic – More dense, Thinner on average
What Directions Do Plates Move?
▪ 3 types of plate boundaries
1. Convergent – Plates are moving towards each other
2. Divergent – Plates are moving away from each other
3. Transform – Plates are moving past each other
Convergent Plate Boundary
▪ Convergent – Plates are moving towards each other
▪ Subduction – subduction occurs when one
tectonic plate is pushed underneath another
▪ DENSITY!!
▪ More dense plates will sink below less dense plates
Oceanic-Oceanic
▪ Arrows –
▪ Picture –
▪ Land Features – Trenches, Island Arc, Underwater
Volcanoes
Ocean-Continent
▪ Arrows –
▪ Picture –
▪ Land Features – Very active volcanoes, Trench from
subduction zone
Continent-Continent
▪ Arrows
▪ Picture
▪ Land Features – Mountain Ranges
Divergent Plate Boundary
▪ Divergent – Plates are moving away from each other
▪ Sea-floor Spreading – at divergent boundaries
magma rises and cools, slowly pushing the plates
apart
▪ Where the magma comes up is called an Oceanic Ridge
Transform Plate Boundary
▪ Transform – Plates are moving past each other
▪ Strike-Slip-Fault – Plates are moving past each
other causing friction and earthquakes
▪ Famous Example – San Andreas Fault