Transcript PLATE MOVEMENT AND CONTINENTAL GROWTH

According to Convection Theory, rocks in the mantle soften
expand and rise. When they reach the base of the crust
they move horizontally and cool. The cool material sinks.
All of this rising and sinking make the crust bulge, buckle
and crack.
Unscramble the letters in parentheses, and
write in the space provided what else you
think the molten material might cause the
crust to do.
(tshecrt)
(rpemcul)
(nilerwk
(arpw)
PLATE MOVEMENT AND
CONTINENTAL
GROWTH
8.4
RECONSTRUCTING THE PAST
 SCIENTISTS
USE
– ROCKS IN MOUNTAINS LIKE
APPALACHAIN AND URAL MTNS.
– AGE OF ROCKS IN OCEAN BASINS
– FOSSILS
– LAND AREAS – TROPICAL AND POLAR
REVERSES
Plate movements have caused the positions of Earth’s
landmasses to shift over time. Scientists think that all
continents were once part of a single landmass they
call Pangaea.
Pathalassa
Ocean
Tethys
Sea
200 million years ago
Laurasia
180 million years ago
North America
Asia
Africa
South America
India
Australia
Antarctica
65 million years ago
North
America
Europe
Asia
Africa
South
America
Australia
Antarctica
Modern Day
Continental Growth
The shapes of the landmasses have also changed. At the
core of each continent is a craton, the oldest rock on the
continent.
The North
American craton
Sources of Continental Growth




DEEP SEA SEDIMENTS – SCRAPED OFF
IGNEOUS ROCK – PLUTONS, VOLCANOES AT
SUBDUCTION BOUNDARIES
RIVER SEDIMENTS – MISSISSIPPI RIVER DELTA
TERRANES – LARGE BLOCK OF LITHOSPHERIC
PLATE THAT HAS BEEN MOVED, OFTEN
THOUSANDS OF KM, AND ATTACHED TO THE
EDGE OF THE CONTINENT
REVIEW

Plate Boundary Overview