Tectonic Tectonic PlatesPlates

Tectonic Tectonic PlatesPlates

Pangea- A super continent that held all our modern continents.

Pangea- A super continent that held all our modern continents.

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This super continent broke apart and formed modern continents. This super continent broke apart and formed modern continents.

Similar fossils have been found on Different continents. Similar fossils have been found on Different continents.

Remains of warm-weather plants in _______________ areas and glacial deposits in__________________ areas suggest that continents have moved.

Remains of warm-weather plants in _______________ areas and glacial deposits in__________________ areas suggest that continents have moved.

At first, continental drift was not accepted because no one could explain ____________ or __________continents had moved.At first, continental drift was not accepted because no one could explain ____________ or __________continents had moved.

Alfred Wegener proposed the

hypothesis of continental drift in

1911

Wegener's Idea

Alfred Wegener proposed the

hypothesis of continental drift in

1911

Wegener's Idea

Using ______________ waves, scientists discovered a system of underwater mountain ranges called the mid-ocean ridges in many oceans.

Using ______________ waves, scientists discovered a system of underwater mountain ranges called the mid-ocean ridges in many oceans.

Ocean RidgesOcean Ridges

Courtesy of www.ngdc.noaa.govCourtesy of www.ngdc.noaa.gov

In the 1960s, Harry Hess suggested the theory of ______ __________ to explain the ridges.In the 1960s, Harry Hess suggested the theory of ______ __________ to explain the ridges.

Hot, less dense material below Earth’s ______________ rises upward to the surface at the mid-ocean ridges.

Then, it flows sideways, carrying the _______________ away from the ridge.

As the seafloor spreads apart, ______________ moves up and flows from the cracks, cools, and forms new seafloor.

Hot, less dense material below Earth’s ______________ rises upward to the surface at the mid-ocean ridges.

Then, it flows sideways, carrying the _______________ away from the ridge.

As the seafloor spreads apart, ______________ moves up and flows from the cracks, cools, and forms new seafloor.

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Evidence for seafloor spreading

Evidence for seafloor spreading

_________________ rocks are located at mid-ocean ridges.

_________________ rocks are located at mid-ocean ridges.

Youngest at ridge

Progressively older away from ridge

Mirror image across the ridge

Youngest at ridge

Progressively older away from ridge

Mirror image across the ridge

Courtesy of www.ngdc.noaa.govCourtesy of www.ngdc.noaa.gov

Reversals of Earth’s _________________ field are recorded by rocks in strips parallel to ridges.Reversals of Earth’s _________________ field are recorded by rocks in strips parallel to ridges.

Plate movementsPlate movements

1.Earth’s ______________ and upper mantle are broken into sections.

2.The sections, called _______________, move on a plasticlike layer of the mantle.

3.The plates and upper mantle form the ____________________.

4.The plasticlike layer below the lithosphere is called the ______________________.

1.Earth’s ______________ and upper mantle are broken into sections.

2.The sections, called _______________, move on a plasticlike layer of the mantle.

3.The plates and upper mantle form the ____________________.

4.The plasticlike layer below the lithosphere is called the ______________________.

Plate movementsPlate movements

Plates moving ______________—divergent boundariesPlates moving ______________—divergent boundaries

IcelandIcelandIceland has a divergent plate boundary running through its middleIceland has a divergent plate boundary running through its middle

Plates moving _________________ —convergent boundaries

Plates moving _________________ —convergent boundaries

a.Denser plates sink under less ______________ plates.

a.Denser plates sink under less ______________ plates.

b.Newly formed hot ______________ forced upward forms volcanic mountains.

b.Newly formed hot ______________ forced upward forms volcanic mountains.

Plates collidePlates collide

a.Plates crumple up to form _________________ ranges.

b.____________________ are common.

a.Plates crumple up to form _________________ ranges.

b.____________________ are common.

Plates slide past—called __________________ boundaries; sudden movement can cause earthquakes

Plates slide past—called __________________ boundaries; sudden movement can cause earthquakes

Convection inside Earth—the cycle of heating, rising, cooling, and sinking of material insideEarth is thought to be the ______________ behind plate tectonics.

Convection inside Earth—the cycle of heating, rising, cooling, and sinking of material insideEarth is thought to be the ______________ behind plate tectonics.

Features caused by plate tectonicsFeatures caused by plate tectonics

1.Faults and _____________ valleys

2.Mountains and ___________________

3.Strike-slip faults—cause of ____________________

1.Faults and _____________ valleys

2.Mountains and ___________________

3.Strike-slip faults—cause of ____________________

Testing for plate tectonics—scientists can measure __________________ as little as 1 cm per year.

Testing for plate tectonics—scientists can measure __________________ as little as 1 cm per year.