Transcript power point notes

Plate Tectonics
The Earth’s crust consists of a number of
plates which are in motion (quite slow)
The Layers of the Earth
The movement of crustal plates results from
convection currents in the Mantle. Heat from
the formation of the Earth and radioactive
decay escapes at the Earth’s surface.
Some plates contain
mainly oceanic crust and
some contain both
continental and oceanic
crust.
Shortcut to Bullard Fit of
Continents
The Glomar Challenger was the first research vessel
specifically designed in the late 1960s for the purpose of
drilling into and taking core samples from the deep ocean
floor.
Remote Sensing- uses
energy signals from
Earth to determine
many different kinds
of information
Earthquake Zones
Earthquake and Volcano
Activity closely matches
the plate boundaries!
Mid-Ocean Ridges
Computer-generated detailed topographic map of a segment of
the Mid-Oceanic Ridge
Shortcut to Sea Floor
Spreading Shortcut to
Formation of Ocean Crust
There is
evidence of
“Sea floor
spreading”
on either
side of the
MidAtlantic
Ridge
Divergent boundaries occur along
spreading centers where plates
are moving apart and new crust is
created by magma pushing up
from the mantle.
Iceland is
right on an
oceanic-oceanic
Divergent
Plate
Boundary
Plate Boundaries
Convergent boundaries are
where plates are moving toward
each other, and sometimes one
plate sinks (is subducted) under
another. The location where
sinking of a plate occurs is
called a subduction zone.
subduction
Heat from friction melts rock and the
magma forms volcanoes
Mount Baker (Washington)
Mount Rainier (Tacoma in foreground)
Deep trenches are formed in the
ocean floor where subduction begins
Oceanic-oceanic convergent boundaries
produce volcanic Island Arc’s
An oceanic-oceanic convergent
boundary.
They also produce a trench
Where might we
find trenches?
The
Mariana
Trench is
the deepest
known
trench.
The bottom of the trench (Challenger Deep) is further below
sea level than Mount Everest is above it. The trench has a
maximum depth of 10,911 m (35,798 feet) below sea level.
Continental-continental
Convergent plate boundaries can
produce mountain ranges.
Transform Boundaries
The zone between two plates
sliding horizontally past one
another is called a transformfault boundary, or simply a
transform boundary.
transform faulting
Some
Transform
Boundaries
The San
Andreas Fault
Measuring displacement in a small
transform fault
Remote sensing from satellites
can detect small movements on
either side of a fault.
In Transform Boundaries, no new
crust is formed and no crust is
destroyed. Earthquakes often
occur along transform boundaries.
Hot Spot Volcanoes
Hot Spot
Volcanoes are
not at plate
boundaries
Oceanic Crust moves over fixed hot
spot.
hot spot volcanoes
The oldest volcanic island is
farthest from the hot spot in the
direction of the plate movement.
Eroded volcanic islands which are below
the surface are called Seamounts
The trail of underwater mountains created as
the the tectonic plate moved across the
Hawaii hotspot over millions of years, known
as the Hawaiian-Emperor seamount chain, or
the Emperor Seamounts (Which direction do you think
the Pacific Plate is moving?)
Mauna Loa, comprising over half of the Big
Island, is the largest shield volcano on the
planet. The measurement from the base
locally depressing the sea floor in the
Hawaiian Trough to its peak is about 17 km
Sea Level to peak of Everest is 8,848
(56,000 feet)
meters (29,028 feet)