Lecture 9

Question 1

What are sedimentary environments?

Answer 1

Distinct places where sediment can accumulate under specific environmental conditions.

Question 2

What are facies?

Answer 2

Set of characteristics, determined by sedimentary structures, lithological features, and fossils that define a particular sedimentary environment.

Question 3

What is the difference between facies and sedimentary environments?

Answer 3

Facies are small scale, where sedimentary environments are concerned with large scale patterns

Question 4

What are facies represented by?

Answer 4

Walther’s Law

Question 5

What is Walther’s Law?

Answer 5

As depositional environments migrate laterally, the sediments of one environment come to lie on top of sediments of the adjacent environment.

Question 6

What are the three main categories sedimentary environments can be grouped into?

Answer 6

1. Terrestrial
2. Marginal Marine
3. Marine

Question 7

What is paleosol?

Answer 7

Fossil soil formed from erosion and weathering of host rock, and have an organic component due to plant growth

Question 8

What is paleosol commonly associated with?

Answer 8

coal

Question 9

What is an important indicator of paleosol?

Answer 9

root traces and animal burrows

Question 10

What are alluvial fans? Where do they develop?

Answer 10

• low, cone-shaped structures

- develop where mountain slope meets valley floor

Question 11

What does a change in slope reduce with alluvial fans?

Answer 11

reduces stream velocity

Question 12

What often forms breccia?

Answer 12

alluvial fans

Question 13

Describe the transport of sediment by streams.

Answer 13

Water and sediment move from mountains to sea through a variety of depositional systems.

Question 14

What is total load?

Answer 14

All stream transported material

Question 15

What is dissolved load?

Answer 15

ion rich water from groundwater

Question 16

What is suspended load?

Answer 16

controlled by water velocity and grain size

Question 17

What is bed load?

Answer 17

particles move by rolling, sliding, saltation (bounding on bottom)

Question 18

What are 3 types of stream systems?

Answer 18

1) braided streams
2) meandering streams
3) anastomosed streams

Question 19

What are braided streams?

Answer 19

complex network of flow paths dominated by coarse sediment

Question 20

What are meandering streams?

Answer 20

channel on low gradient floodplain in shape of sweeping bends, stream erodes at cut banks, deposits at point bars

Question 21

What are anastomosed streams?

Answer 21

true, deep interwoven channels dominated by fine sediment

Question 22

What are generally straight channels in areas of high relief with coarse-grained materials, like sand and gravel?

Answer 22

braided systems

Question 23

Describe the channels of braided systems.

Answer 23

channels tend to be wide and relatively shallow

Question 24

What are meandering systems?

Answer 24

winding, bending channels in plain areas

Question 25

What do meandering systems carry?

Answer 25

fine grained material (silt and sand) carried ins yspension

Question 26

What has a high channel stability, and tends to be deep and narrow?

Answer 26

meandering systems

Question 27

What are channels, point bars, levees, and floodplains examples of?

Answer 27

meandering systems

Question 28

Describe anastomosing systems? What type of channels and what type of materials? Where are they found?

Answer 28

• winding, with multiple interconnected channels in low gradient areas
• very stable, deep channels
• fine grained materials (silt and mud)

Question 29

What type of environment is a lake?

Answer 29

terrestrial environment

Question 30

What is lacustrine (lakes)?

Answer 30

An area filled with water in a localized basin that is surrounded by land.

Question 31

When are lake to have more likely preservation?

Answer 31

at a lower elevation

Question 32

Describe sediments in lakes?

Answer 32

• courses around lake margin
• finest at centre
  (often layered)

Question 33

What types of fossils are found in lakes?

Answer 33

freshwater fossils

Question 34

What are the two types of lakes based on hydrology?

Answer 34

1) open lakes

2) closed lakes

Question 35

What is an open lake?

Answer 35

• have an outlet
• stable shorelines
• freshwater

Question 36

What is a closed lake?

Answer 36

• without an outlet
• fluctuating shorelines
• often hypersaline