Sedimentary structures- Fluvial facies

Question 1

What are the 2 types of fluvial systems?

Answer 1

1. Low sinuosity (alluvial fans and braided rivers)

2. High-Sinuosity (Meandering river)

Question 2

What is sinuosity?

Answer 2

the deviation of a river channel from a straight path

Question 3

What is the most important geologic agent bringing about a change to Earth’s land surface?

Answer 3

Running water

Question 4

Running water transports and deposits sediment in or adjacent to?

Answer 4

alluvial fans
braided rivers
meandering streams

Question 5

Where to alluvial fans occur?

Answer 5

The base of mountains, where a stream flows out onto a level plain

Question 6

How do braided streams normally transport sediment?

Answer 6

bed load

Question 7

Rivers and streams are what kind of systems?

Answer 7

DYNAMIC

Question 8

What is the depositional process of an alluvial fan?

Answer 8

gravity flow and fluid flow

Question 9

sediments in an alluvial fan are typically ________ sorted and include ________ gravel.

Answer 9

poorly, abundent

Question 10

does grain size in an alluvial fan increase or decrease down-slope towards the margin of the fan?

Answer 10

DECREASE

Question 11

What is a Bajadas?

Answer 11

Two or more coalescing alluvial fans

Question 12

Fluvial depositional systems are the dominant conduit from what regions to what region?

Answer 12

mountains to oceans/basins

Question 13

How are fluvial depositional systems characterized?

Answer 13

sinuosity(low sinuosity or high sinuosity)
AND
sediment load
(bed load, suspended load or mixed load)

Question 14

What does aggradation mean?

Answer 14

the process if building up a surface by deposition (eg. alluvial fan)

Question 15

What are the 3 fluvial systems?

Answer 15

1. Alluvial fans
2. Low sinuosity braided rivers
3. High sinuosity meandering rivers

Question 16

Define alluvial fan deposits

Answer 16

Coarse grained

poorly sorted

Question 17

Alluvial fan full fan sequences coarsen upward or downward?

Answer 17

UPWARD (prograde)

Question 18

What a formation formed by a braided stream complex?

Answer 18

Lower Mcmurray formation

Question 19

A braided channel has what kind of log response?

Answer 19

Even block with sharp top and base

Question 20

What kind of log response does a fluvial point bar have?

Answer 20

fining upward and sharp base (retrograding)

Question 21

What kind of log response does a crevasse splay have?

Answer 21

Coarsening upward and sharp top (prograding)

Question 22

Give an example of a point bar deposit formation?

Answer 22

Cardium

Question 23

What is a crevasse splay?

Answer 23

forms when a stream breaks its natural or artificial levees and deposits sediment on a floodplain

Question 24

what is a levee?

Answer 24

an embankment built to prevent the overflow of a river.

Question 25

What is an Oxbow lake?

Answer 25

a curved lake formed at a former oxbow where the main stream of the river has cut across the narrow end and no longer flows around the loop of the bend

Question 26

What are sheet flows?

Answer 26

Sheet flows are turbulent flows with significantly more water and less mud than debris flows.

Question 27

What is a slow canyon?

Answer 27

A slot canyon is a narrow canyon, formed by the wear of water rushing through rock. A slot canyon is significantly deeper than it is wide