Earth Science, Tarbuck Chap 7

Question 1

force applied equally in
all directions is called

Answer 1

Confining Pressure

Question 2

What does Confining pressure do to rocks

Answer 2

compacts mineral grains to reduce the volume of rock bodies. Note that Confining Pressure does not cause Deformation

Question 3

Deformation is caused by

Answer 3

Differential Stress

Question 4

3 types of differential Stress

Answer 4

Compressional, Tensional, Shear

Question 5

What is compressional Stress

Answer 5

squeezes a rock mass. Associated with convergent boundaries

Question 6

What is Tensional Stress

Answer 6

pulls apart rock bodies. Associated with Divergent boundaries

Question 7

What is Shear Stress

Answer 7

movement of one part of a
rock body past another. Associated with transform boundaries

Question 8

What is Strain?

Answer 8

When differential stress changes a rock’s shape, the resulting deformation is called strain.

Question 9

What is another way other than strain Mineral Grains change responding to Differential Stress

Answer 9

Recrystallization of the Crystals caused by movement of atoms from high to low stress

Question 10

What are the types of deformation that lead to strain

Answer 10

elastic, brittle, and ductile

Question 11

What is elastic deformation

Answer 11

A temporary shape change that is self-reversing after the force is removed, so that the object returns to its original shape

Question 12

What is Brittle Deformation

Answer 12

When a rock is deformed beyond its ability to respond elastically, rocks that break into smaller pieces undergo Brittle deformation

Question 13

What is Ductile Deformation

Answer 13

slippage along surfaces of weakness within the rock and the gradual reshaping of mineral
grains. This can cause some rocks to flow very slowly

Question 14

What happens to rocks when temperature is higher

Answer 14

Rocks can undergo Ductile deformation more easily

Question 15

Order from smallest to largest temperature gradients and why: Mid-ocean Ridge, Hot spots, Subduction zones

Answer 15

Subduction zones(Cool oceanic crust goes deeper into the mantle, leading to small temperature gradients), Hot Spots(Both Mid-ocean ridges and Hot spots have large temperature gradients but mid-ocean ridges typically have the most elevated geotherms because their unusually thin crust allows hot mantle to push up near the surface), Mid-ocean Ridges

Question 16

When temperatures are lower, what commonly occurs to a rock

Answer 16

Brittle Deformation is common

Question 17

As confining pressure increases, what happens to rocks

Answer 17

Rocks are harder to break

Question 18

What are Folds

Answer 18

Along convergent plate boundaries, rock strata are often
bent into a series of wavelike undulations

Question 19

What is an anticline fold

Answer 19

arching of sedimentary layers

Question 20

What is a Syncline Fold

Answer 20

Downfolds or troughs

Question 21

Basic Folds are described as _______ or _________ folds

Answer 21

Symmetrical or Asymmetrical

Question 22

A fold is said to be Overturned when

Answer 22

both limbs dip in the same direction

Question 23

What is a recumbent fold

Answer 23

axial plane is horizontal

Question 24

What is a plunging fold

Answer 24

when hinge lines penetrate Earth’s surface

Question 25

What is a dome

Answer 25

broad, upward bulge in rock layers, forming a roughly circular or oval shape

Question 26

What is a Basin

Answer 26

inverse of a dome, a downwarped structure

Question 27

What are Monocline Folds

Answer 27

large, steplike folds

Question 28

What is a fault

Answer 28

fracture along which motion has occurred, so that the rocks on either side are offset from each other. Caused by Brittle Deformation

Question 29

What are dip-slip faults

Answer 29

movement is primarily parallel to the slope of the fault surface

Question 30

What is Dip?

Answer 30

angle at which the fault surface is inclined relative to the horizontal.

Question 31

What is Hanging wall block in a fault

Answer 31

Hanging wall block is the wall block that is "hanging" on the footwall

Question 32

What are fault scarps

Answer 32

long, low cliffs due to vertical displacement along dip-slip faults

Question 33

What is a normal fault

Answer 33

hanging wall block moves down relative to the footwall block. Caused by Tensional Stresses

Question 34

What are fault-block mountains

Answer 34

large normal faults that can form to create mountains

Question 35

What are horsts and grabens

Answer 35

Horsts are uplifted fault blocks, while Grabens are down-dropped block

Question 36

What are Reverse and Thrust Faults

Answer 36

hanging wall block moves up relative to the footwall

Question 37

What causes reverse and thrust faults to from

Answer 37

Compressional Stresses

Question 38

Difference between reverse and thrust faults

Answer 38

Thrust faults are reverse fault in which the fault’s angle is less than 45 degrees.

Question 39

What are Strike-Slip Faults

Answer 39

Fault's dominant displacement is horizontal. Caused by Shear stress

Question 40

What are Joints

Answer 40

brittle-fracture surface in rocks along which little or no displacement has occurred.

Question 41

Most joints are formed from ______ stresses

Answer 41

tensional

Question 42

Processes that produce a mountain belt are collectively termed

Answer 42

Orogenesis

Question 43

What is an orogeny

Answer 43

episode of mountain building

Question 44

What is an accretionary wedge

Answer 44

accumulation of deformed and thrust faulted sediments and scraps of ocean crust scraped onto the edge of the overriding plate in subduction zones

Question 45

What is a forearc basin

Answer 45

region between Accretionary wedge and volcanic arc formed when the accretionary wedge builds up enough sediment to protrude through the ocean and form a basin.

Question 46

What is a terrane

Answer 46

crustal fragment that consists of a distinct and recognizable series of rock formations and has been transported and accreted by plate tectonic processes.

Question 47

What is a suture

Answer 47

zone where two continents collide and are “welded” together

Question 48

What is Isostatic Adjustment

Answer 48

process of establishing a new gravitational balance in response to loading or unloading in the crust

Question 49

What is Isostasy concept

Answer 49

crust floats in gravitational balance in the mantle

Question 50

What is Gravitational Collapse in a mountain

Answer 50

rocks deep within the developing mountain, which are relatively warm and weak, begin to flow laterally as gravity pulls the mountain downwards