Download Plate Movement Notes key - Glenwood Primary School

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NOTES for Plate Boundaries, Stresses and Faults
The Lithosphere is made of the CRUST and the UPPER rigid MANTLE. Plates may be called
by different names, like CRUSTAL Plates, Lithospheric Plates and TECTONIC Plates.
( Remember! Plates around Earth move in different directions & cause different geologic
events, which are things that happen on Earth).
Remember! What makes the plates move? >>>Answer: CONVECTION Currents in the mantle
move the plates as the core heats the slowly-flowing asthenosphere (the elastic/plastic-like
part of the mantle).
PLATE BOUNDARIES: There are 3 types of Plate Boundaries. Each one has a type of
STRESS on the rock & a way that it breaks, called a FAULT. The three types of
BOUNDARIES are divergent boundaries, CONVERGENT boundaries and transform
boundaries.
What is
this kind
of
boundary
?
(define it)
What
does this
kind of
boundary
look like?
(draw it)
Divergent Boundary
Place where 2 plates pull
away from each other
(like dissecting or dividing)
Convergent Boundary Transform Boundary
Place where plates
Place where two plates
crash together, causing slide past each other
one plate to subduct
(sink under)
DIVERGENT BOUNDARIES – plates Divide
Question: How is the rock pulled at Divergent Boundaries? Answer: Rock gets THIN in the middle as it is
PULLED apart. This stress is called TENSION.
Question: What happens when the rock SNAPS from the Stress of Tension? Answer: A Normal FAULT
(fault is a break in Earth’s crust). Rock DROPS down as it breaks.
Question: What happens next @ Divergent Boundaries? Answer: A GEOLOGICAL FEATURE may form on
continents & THROUGH SEA FLOOR SPREADING in the ocean .
NORMAL FAULT
STRIKE-SLIP FAULT
REVERSE FAULT
CONVERGENT BOUNDARIES – plates crash together
Question: How is the rock pushed at convergent boundaries? Answer: Rock is PRESSED or squeezed
together.
Question: What happens when the rock is squeezed from the Stress of Compression? Answer: A REVERSE
FAULT. Rock is forced UPWARD as it is squeezed.
Question: What happens next @ Convergent Boundaries? Answer: They may form MOUNTAIN ranges like
the Himalayas or the Rockies. Volcanoes may form @ subduction zones as more dense oceanic plates sink
under less dense continental plates.
TRANSFORM BOUNDARIES - Rocks are PUSHED AWAY in opposite directions.
Question: What happens when the rock is sheared (or “cut”) from the Stress of Shearing? Answer: A
STRIKE-SLIP FAULT, which is when rocks on each side of the fault slip past each other as they break.
Question: What happens next at Transform Boundaries? Answer: This may cause EARTHQUAKE when the
rock snaps from the pressure. (A famous fault at a Transform Boundary is the San Andreas Fault in California.)
•
HELPFUL HINTS: Shearing means cutting (“Shears” are like scissors)
•
Transform boundaries run like trains going past each other in different directions & they shake the
ground!