Topic 2: Materials, Process, Geometry

Question 1

What does the geomorphology equation mean?

Answer 1

landforms or landscapes are a function of materials, processes, and geometry and change over time.

Materials –> acted on by processes –> geometry

Question 2

what are clastic sediments?

Answer 2

• rock fragments/minerals that have been subject to erosional, transport and depositional processes
• they have been moved from their place of origins, where they accumulate to form sedimentary deposits

Question 3

What is the difference between soil and sediments?

Answer 3

• Soil is an IN-SITU process, that FORMS sediments
• sediments are physical minerals.

Question 4

Texture vs. sorting

Answer 4

texture: the size of grain present

Sorting: the distribution of grain sizes present in a deposit

Question 5

What does clast abundance mean? shape?

Answer 5

abundance: proportion of clasts larger than 4mm in diameter

shape: clast roundness is a measure of how the smooth the outline of a clast is

Question 6

What is sedimentary structure?

Answer 6

• how groups of grains sort themselves out within a unit
• visible arrangements of grains and clasts within a rock

Question 7

what is a ‘massive’ structure? “stratified”?

Answer 7

massive: has no visible structure. Mixed up or uniform

stratified: visible arrangements are present, but in layers (beds, laminae)

Question 8

What is a bed? lamina?

Answer 8

Bed: layer than is >1cm thick

Lamina: layer that is < 1 cm thick.

Question 9

what are bedforms?

Answer 9

• three dimensional features that form at the interface of a flowing medium and the bed.

Question 10

What is weathering?

Answer 10

• the breaking down of parent rock material into smaller and smaller components
• turns rocks into sediment
• physical or chemical

Question 11

what is stress?

Answer 11

• a force adjusted for the area over which it is distributed; comes in normal and shear forms

Question 12

what is strain?

Answer 12

• the physical change that results in response to stress

Question 13

What is shear strength?

Answer 13

• the magnitude of shear force the material can sustain before straining ex, moving)
• varied for different materials
• controlled by friction, sediment size, and cohesion.

Question 14

Normal stress vs shear stress?

Answer 14

normal: perpendicular to the sides of faces. like pushing something down. typically the force of gravity

shear: tends to skew to a parallelogram (if square). deforms in a different plane. applied by gravity, flowing mediums, moving objects

Question 15

Stress is initiated when shear stress exceeds….

Answer 15

shear strength!

Question 16

what is a threshhold?

Answer 16

the point at which something moves/changes (dependent on material)