Deformation of Crust

By Spenser Bryant, Paige Johnson, Dakota Brown, Lauren Johnston

S.1 2011

DefinitionsSection One

• Deformation: Bending, tilting, breaking of crust

• Isostasy: equilibrium between lithosphere/athenosphere

• Stress: amount of force on an area

• Strain: Change rocks by shape/volume

• Fold: Ductile strain; rock layers bend

• Fault: Break in body of rock

What is…?

• Compression: Squeezes and shortens• Tension: Stretches and pulls• Shear Stress: Distorts in opposite

directions• Fracture: Break along rock that doesn’t

move• Fault Plane: Surface along which motion

occurs• Hanging Wall: Rock above fault plane

What is…? Cont.

• Foot Wall: Rock below fault plane

• Normal Fault: Hanging wall moves down

• Reverse Fault: hanging wall moves up

• Thrust Fault: Reverse, but low angled

• Strike-Slip: Rock slides horizontally

Anatomy/Types of Folds

• Limbs: Sloping sides of the fold

• Hinge: Where the limbs meet

• Overturned: Lying on side

• Anticline: Oldest layer in center

• Syncline: Youngest in center

• Monocline: Limbs are horizontal

Questions• 1.) Difference between fold/fault?

A.) Fault: Break; Fold: BendB.) Fault: Bend; Fold: Break C.) Fault: Rat; Fold: Hippopotamus

2.) Definition of strain:A.) Pulled muscleB.) Bending, tilting, breaking of crustC.) Change rocks by shape/volume

• 3.) Definition of DeformationA. When two tectonic plates shiftB. Bending, tilting, breaking of crustC. Magma turns to lava

4.) What is Isotasy?A. A balance between the Sun and MoonB. equilibrium between

lithosphere/athenosphere C. An Elephant balancing on a ball

Questions cont.5.) How many faults are there?

A.) 3B.) 4C.) 5

6.) Difference between anticline/syncline?A.) Anticline: Old center; Syncline: YoungB.) Anticline: Young center; Syncline: Old center

7.) Difference between Normal/Reverse faults?A.) Normal: H-wall up; Reverse: H-wall downB.) Opposite A.)

8.) What are Strike-Slip faults?A.) Rock slides then pushes upB.) Rock slides then slips downC.) Rock slides horizontally

Answers

• 1.) A• 2.) C• 3.) B• 4.) B• 5.) B• 6.) A• 7.) B• 8.) C

Section 2: Definitions

• Mountain Range: Grouping of adjacent mountains

• Folded: Tectonic movements push together; Accordion

• Fault-Block: Faults break Earths crust; some drop

• Dome: Circular structure that slope

What is…?

• Mountain System: Groups of adjacent mountains

• Mountain Belts: Two large systems; Eurasian-Melanesian/Circum-Pacific

• Collisions:

Continental-Oceanic- Oceanic subducts

Oceanic-Oceanic- Denser subducts

Continental-Continental- Denser subducts

What is…? Cont.

• Plateau: Large flat areas above sea-level

• Grabens: Long and narrow valleys

• Volcanic Mountains: Formed when magma reaches surface

• Hot Spots: Volcanic areas far from tectonic activity

Questions1.) Definition of Mountain Range?

A.) Grouping of adjacent mountainsB.) Mountains surrounding a plainC.) A range on a mountain

2.) Difference between Folded/Fault-Block?A.) Fold: pull apart; Fault-Block: slideB.) Fold: slide; Fault-Block: pull apartC.) Fold: pushed; Fault-Block: sides drop

3.) What is a dome mountain? A.) A mountain in the shape of a dome.B.) A plate shiftC.) The Palomar Observatory

4.) When Oceanic/Continental plates collide…?A.) Oceanic subductsB.) Continental subducts

Questions… Cont.

5.) What is a plateau?

A.) A rocky domed area

B.) Sandy mountain

C.) Flat topped figure above sea level

Answers

• 1.) A

• 2.) C

• 3.) A

• 4.) A

• 5.) C