Earth Science Exam 2: Rock Cycle and Rock Deformation

What is a rock?

A naturally occurring solid composed of one or more minerals - major component of the Earth’s crust

What are the three types of rocks?

Igneous, sedimentary, and metamorphic

What happens during lithification of sediment to sedimentary rock?

Turns loose sediments (sand, clay, or silt) into solid sedimentary rock

What are the three types of sedimentary rocks and how do they form?

• Clastic - Formed from fragments of previous rocks (sandstone, shale, etc.) Chemical - Formed from minerals crystalized from water (rock salt, limestone, etc.)

• Organic - Formed from materials that were parts of organisms (coal, shelly limestone, chalk, etc.)

What is foliation in metamorphic rocks and why does it develop? 

Develops if minerals re-crystalize in a single orientation

• due to different stress

• minerals can separate into bands

What is a joint, where do they form, and how do they differ from faults?

• A crack or fracture in a rock where it has broken but there is no significant movement that has occurred along the fracture plane (It is a crack WITHOUT movement)

• Cooling and contraction, unloading or expansion, and tectonic stresses - enlarged by weathering and erosion

• It is NOT a fracture with movement along it

What are the four types of faults and can you identify them on a diagram?

• Reverse - hanging wall moved up (indicates compression)

• Normal - hanging wall moved down (indicates extension)

• Thrust - law-angle reverse fault (shows compression & substantial horizontal motion)

• Strike-slip - horizontal motion (steep or detail fault, indicates shear)

What are anticlines and synclines and where are the oldest rocks in each?

• Unfolded in the middle (oldest rock in the center)

• Downloaded in middle (youngest rocks in center)