Chapter 16 Flashcards Preview

Geology > Chapter 16 > Flashcards

Flashcards in Chapter 16 Deck (45):
1

A general term for sediment deposited by streams

Alluvium

2

A stream down cuts its bed at a pace equal to the rate of uplift

Antecedent stream

3

Small scale channel deposits where streams continually pick up sediment in one part of their channel and deposit it down stream

Bar

4

The lowest elevation to which a stream can erode its channel; level at which the mouth of a stream enters the ocean, a lake, or a trunk stream

Base level

5

Coarse material, including coarse sands, gravels, and even boulders typically move along the bed of a channel

Bed load

6

Form at the end of glaciers, where there is a large seasonal variation in discharge

Braided stream

7

The maximum load of solid particles a stream can transform per unit time

Capacity

8

The measure of a streams ability to transport particles based on size rather than quantity

Competence

9

the outside of a meander is a zone of active erosion; debris acquired by the stream at the ________ moves downstream where the coaster material is generally deposited as point bars

Cut bank

10

Form where sediment-charged streams enter the relatively still waters of a lake, an inland sea, or the ocean

Delta

11

Characterized by irregular branching of tributary streams that resemble the branching pattern of a deciduous tree

Dendritic pattern

12

The quantity of water in a stream that passes a given point in a period of time

Discharge

13

The portion of a streams load that is carried in solution

Dissolved load

14

A section of stream that leaves the main flow

Distributary

15

An imaginary line that separates the drainage of two streams, often found along a ridge

Divide

16

The land area that contributes water to a stream

Drainage basin

17

The overflow of a stream channel that occurs when discharge exceeds the channels capacity. The most common and destructive geologic hazard

Flood

18

The flat, low lying portion of a stream valley subject to periodic inundation

Floodplain

19

A stream that has the correct channel
Characteristics to maintain exactly the velocity required to transport the material supplied to it

Graded stream

20

The slope of a stream, generally expressed as the vertical drop over a fixed distance

Gradient

21

The extension upslope of the head of a valley due to erosion

Headward erosion

22

The unending circulation of Earths water supply. The cycle is powered by energy from the sun and is characterized by continuous exchanged of water among the oceans, atmosphere, and the continents

Hydrologic cycle

23

A meandering channel that flows in a steep, narrow valley. It forms when an area is uplifted or when the base level drops

Incised meander

24

They movement of surface water into rock or soil through cracks and pore spaces

Infiltration

25

The movement of water particles in straight line paths that are parallel to the channel. The water particles move downstream without mixing

Laminar flow

26

The level of a lake, resistant rock layer, or any other base level that stands above sea level

Local base level

27

A loophole bend in the course of a stream

Meander

28

The point downstream where a river empties into another stream or water body

Mouth

29

An elevated landform composed of alluvium that parallels some streams and acts to confine their waters, except during flood stage

Natural levee

30

A curved lake that is created when a stream cuts off a meander

Oxbow lake

31

A crescent shaped accumulation of sand and gravel deposited on the inside of a meander

Point bar

32

A system of streams running in all directions, away from central elevated structure, such as a volcano

Radial pattern

33

A drainage pattern characterized by numerous right angle bends that develop on jointed or fractured bedrock

Rectangular pattern

34

Tiny channels that develop as unconfined flow begins producing threads of current

Rills

35

Water that flows over land rather than infiltrating into the ground

Runoff

36

Transportation of sediment through a series of leaps or bounces

Saltation

37

Runoff moving in unconfined thin sheets

Sheet flow

38

Diversion of the drainage of one stream that results from the headscarf erosion of another stream

Stream piracy

39

A stream that cuts through a ridge lying across its path. The stream established its course on uniform layers at a higher level without regard to underlying structures and subsequently downcut

Superposed stream

40

A flat, bench like structure produced by a stream, which was left elevated as the stream cut downward

Terrace

41

A system of streams in which nearly parallel tributaries occupy valleys cut in folded strata

Trellis pattern

42

Erratic movement of water often characterized by swirling, whirlpool like eddies. Most streamflow is of this type.

Turbulent flow

43

Sea level; the lowest level to which stream erosion could lower the land

Ultimate base level

44

A pass through a ridge or mountain in which a stream flows

Water gap

45

Consists of coarse sediments that are deposited when mountain streams reach flat lowlands; where rapid streams emerge from a mountainous area onto a flatter surface, a distinctive cone-shaped accumulation of sediment forms

Alluvial fan