Chapter 4

Question 1

What are the 3 main groups of sedimentary structures?

Answer 1

Stratification structure and Bedforms
Bedding plane Markings
Other Structures

Question 2

What are the 4 fundamental types of sedimentary rocks?

Answer 2

Deposition Structures
Erosional Structures
Deformation Structures
Biogenic structures

Question 3

What is a bed?

Answer 3

Tabular or lenticular layers of sedimentary rock that have lithological, textural, or structural unity that distinguishes it from the layers above and below it.

Question 4

What is a bedding plane?

Answer 4

The upper and lower surfaces of a bed

Question 5

What is a sedimentation unit?

Answer 5

A thickness of sediment deposited in near constant physical conditions

Question 6

What is Strata?

Answer 6

Beds thicker than 1 cm

Question 7

What is laminae?

Answer 7

Beds thinner than 1 cm

Question 8

What is a subdivision as it relates to bedding?

Answer 8

A division within a single bed marked by distinct associations with a sedimentary structure.

Question 9

What is an amalgamation surface?

Answer 9

A marked discontinuity between two beds of similar composition

Question 10

what is an amalgamation bed?

Answer 10

Beds separated by an amalgamation surface

Question 11

What is a bedset?

Answer 11

Groups of similar beds or crossbeds

Question 12

What are cross strata?

Answer 12

Layer/Laminae that are deposited at an angle to the bounding surface

Question 13

What is a single bedset?

Answer 13

2 or more superimposed beds characterized by similar composition, texture, and internal structures

Question 14

What are composite Bedsets?

Answer 14

A group of beds differing in composition, texture, and internal structure but deposited in a similar way

Question 15

What are the types of planar bedding?

Answer 15

Laminated, Graded, and Massive

Question 16

What is a planar bed?

Answer 16

Beds that do not contain internal dipping laminae

Question 17

How are laminated beds produced?

Answer 17

through less severe or short lived fluctuations in sedimentation

Question 18

How is a laminated bed formed?

Answer 18

Through the settling of fine particles from suspension and traction transport of sand in water

Question 19

What is Graded bedding?

Answer 19

Beds characterized by distinct gradations in size

Question 20

What is normal grading?

Answer 20

Going from coarse to fine in an upwards sequences

Question 21

What is reverse grading?

Answer 21

Going from fine to coarse in an upward sequence

Question 22

How does reverse grading happen?

Answer 22

Through dispersive pressures and kinetic sieving

Question 23

What is kinetic sieving?

Answer 23

Agitation of rock causing finer particles to move down.

Question 24

What is massive bedding?

Answer 24

A bed that lacks internal structure

Question 25

How is a massive bed formed?

Answer 25

Can be formed through liquefaction of sediments due to sudden shock.

Question 26

What are current ripples?

Answer 26

Asymmetrical ripples that develop in reaction to unidirectional flow and face downstream

Question 27

What are oscillation ripples?

Answer 27

Ripples that form by reaction

Question 28

How is cross bedding formed?

Answer 28

Through migration of ripples/dunes in water or air

Question 31

What is a trough cross bed?

Answer 31

A cross bedded unit in which 1 or more of the bounding surfaces are curved.

Question 32

What is a Flaser Bedding?

Answer 32

A type of ripple bedding in which thin streaks of mud occur between cross rippled laminated sediment.

Question 33

What is lenticular bedding?

Answer 33

inter-bedded mud and cross laminated sand in which the ripples are laterally and vertically discontinuous.

Question 34

What is a flame structure?

Answer 34

Wavy/flame shaped tounge of mud that projects upward into the overlying layer

Question 35

What are sole markings?

Answer 35

positive relief casts made at the base of a bed

Question 36

What is a groove cast?

Answer 36

elongated, nearly straight ridges resulting from infilling of erosional relief

Question 37

What is a flute cast?

Answer 37

elongated welts or ridges with a bulbous end and a flared end that merges with the bed plane