Starter Questions

What type of seismic wave ….1. Is felt first?2. Wiggles from side to side?3. Causes the most damage?4. Is felt/heard by animals?5. Can go through the mantle but not the outer core?6. The theory of plate tectonics tied together the concepts

of; continental drift, seafloor spreading convection currents, but what evidence supported these concepts?

rock types, mountains, fossils, glacial erosionmagnetic field reversalsdistribution of earthquakes and volcanoes- aided by GPS and seismo-graphs

Explain these diagrams

Fossils & Glaciers

Mountains Ranges

The areas shown in blue show

mountain ranges that contain similar rock and formed at

the same time. When using

Wegner’s map of Pangaea, these

mountains line up into one major

range.

Rock Types

Wegener’s map also helps to

explain the similar matching rock

formations found oceans apart.

Topography: Sonar technology

Notice the high elevation under the oceans, as shown on this map in dark blue. They are underwater mountain ranges, some are volcanic.

Sea-Floor Spreading

Magnetic Evidence

Rocks are progressively older as they get further from the spreading center at the mid-oceanic ridge.

Map of Worldwide Earthquakes & Volcanoes (using Seismographs and GPS)

Plan your answer: exam question (10 marks)

Outline the evidence to support the theory of

continental drift.

Think about your structure.

10 minutes

Exam question: Outline the evidence to support the theory of continental

drift.

Remember: Point evidence explain

Intro: the theory of continental drift has been around for over 100 years however it was only fully accepted in 1965 when considerable scientific evidence accumulated from various sources.

Points:

- Rocks- type, mountains, glacial erosion (glacial landscapes, forms and striations) and fossils (e.g. Lystrosaurus in India, Africa and Antartica)

- Seafloor spreading: sonar technology to map the sea floor, palaeomagnetism to date

- Seismic waves discovery of liquid outer core and solid, liquid 'plastic' properties of mantle

Conclusion: These undeniable scientific findings assisted by advancements in technology all contributed to the now widely accepted and well known theories of plate tectonics and continental drift.

CSD

1915 Alfred Wegener

1919 Arthur Holmes (convection)

1946 sonar

1960 Harry Hess & Robert Dietz (Sea-floor spreading)

1963 palaeomagnetism

1965 J.Tuzo Wilson plate tectonics

Level 1 (1-4 marks) (Midpoint 3)

Simple statements stating evidence for continental drift.

No specific detail or elaboration provided; or two points discussed

well.

Level 2: (5-8 marks) (Midpoint 6)

Specific statements of a range of variations. Elaboration that

demonstrates good understanding of the interrelationships

between evidence and clear categorisation of evidence .

Level 3 (9-10 marks) (Midpoint 9)

A fully developed answer, with good elaboration of a range of

evidence. A rounded answer with good use of case studies and

clear structure to the work.

Key term Description Example

Benioff zone

Liquefaction

Andesitic lava

Basaltic lava

Rhyolitic lava

Jokulhaups

Lahars

Use the info sheets provided to complete this table:

Then use this table to answer this exam question: Explain the link between plate boundary type and the strength of earthquake (seismic) waves. (8 marks)Helpful hint – Think about which types of plate boundary create the most strain and release the greatest amount of seismic energy and why, and which release very little and why. Make reference to body and surface waves.

HWK: Exam question (10 marks)

Outline the evidence to support the theory of continental drift.Level 1 (1-4 marks) (Midpoint 3)

Simple statements stating evidence for continental drift.

No specific detail or elaboration provided; or two points discussed well.

Level 2: (5-8 marks) (Midpoint 6)

Specific statements of a range of variations. Elaboration that

demonstrates good understanding of the interrelationships between evidence and clear categorisation of

evidence .

Level 3 (9-10 marks) (Midpoint 9)

A fully developed answer, with good elaboration of a range of evidence. A rounded answer with good use of

case studies and clear structure to the work.